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doc. Ing. Přemysl Hudec, CSc.

Všechny publikace

Broadband Target Simulator for FMCW Radar Sensors With Mirror Target Suppression

  • DOI: 10.1109/COMITE52242.2021.9419874
  • Odkaz: https://doi.org/10.1109/COMITE52242.2021.9419874
  • Pracoviště: Katedra elektromagnetického pole
  • Anotace:
    This article describes a target simulator for FMCW radar sensors which, working on the frequency shift principle, deals with the presence of an unwanted (mirror) target. A simple method is proposed to suppress the mirror target by utilizing an IQ mixer in simulator circuitry which enables single-sideband modulation. Achievable combinations of speed and distance of simulated targets are also presented. In addition, the generation of targets closer than the physical distance of the simulator, a radar parameter estimation and a simulator calibration are included. All presented principles were verified by a laboratory experiment with a 24 GHz FMCW radar module and other commercially available components.

On the Testing of Advanced Automotive Radar Sensors by Means of Target Simulators

  • DOI: 10.3390/s20092714
  • Odkaz: https://doi.org/10.3390/s20092714
  • Pracoviště: Katedra elektromagnetického pole
  • Anotace:
    The rapid development and wide commercial implementation of automotive radar sensors are strengthening the already considerable interest in matching radar target simulators. Such simulators boast promising results when used for both essential functional inspections of active sensors and the high-speed testing of numerous traffic scenarios while examining complex reactions of automobile electronic systems. For these purposes, advanced versions of target simulators enabling a generation of multiple targets moving at different velocities and ranges are required. The design, practical implementation and system programming of advanced sensor simulator setups require a detailed analytical description concerning all important technical aspects. An abundance of detailed information on the behavior and parameters of automotive radar sensors can be found in the references, but similar knowledge on sensor simulator setups is lacking. This article presents detailed analyses of the all-important RF parameters, where special attention is paid to phase noise, and its analytical description takes into account an even greater number of simulated targets. The derived analytical formulas enable both an optimal setup implementation and system programming of a wide range of practical testing procedures.

A Microwave Interferometric Sensor for Measuring Fast Mechanical Processes in Demanding Environments

  • Autoři: Ouředník, P., doc. Ing. Přemysl Hudec, CSc., Pánek, P.
  • Publikace: Proceedings of European Microwave Conference in Central Europe (EuMCE 2019). Louvain-la-Neuve: European Microwave Association (EuMA), 2019. p. 146-149. ISBN 978-2-87487-066-8.
  • Rok: 2019
  • Pracoviště: Katedra elektromagnetického pole
  • Anotace:
    Research, development and operation of modern devices is dependent on the use of a number of different sensors. This includes sensors used for contactless measurement of mechanical motions. For these purposes, devices ranging from inductive to ultrasound to optics are commonly employed. If the mechanical motions are fast and are going on in a demanding environment, e.g. in heavy dust, using the above-mentioned sensors is challenging. In this work, a relatively simple contactless sensor based on a CW radar structure was developed and its function verified by practical tests. The sensor can be used for a variety of measurements. This particular work was motivated by the measurement of mechanical transient responses of military vehicles hit by land mines.

Doppler Frequency-Shift Unit for Digital-Analog Automobile Radar Target Simulator

  • Autoři: Ouředník, P., Židkov, A., doc. Ing. Přemysl Hudec, CSc.,
  • Publikace: Proceedings of European Microwave Conference in Central Europe (EuMCE 2019). Louvain-la-Neuve: European Microwave Association (EuMA), 2019. p. 285-288. ISBN 978-2-87487-066-8.
  • Rok: 2019
  • Pracoviště: Katedra elektromagnetického pole
  • Anotace:
    Importance of radar target simulators moves up with ongoing fast development of radar sensors. Especially, this concerns the FMCW sensors used widely in automotive industry. The simulators are necessary for both radar calibration, and simulation of different traffic scenarios. The digital target simulators based on digital signal processing belong to the most advanced devices. But their practical deployment can be limited by relatively high latency of used digital circuits, and related high minimum detection range. That is why relatively simple analog simulators can also find their use. One problem connected with design of analog units relates to generation of Doppler frequency shifts corresponding to simulated target radial velocities. Usually, an IQ mixer equipped with two DACs, two anti-aliasing filters and one μ-controller is employed. The presented paper shows that substantially simpler and more efficient structure can be used. It is based on directly digitally-controlled phase shifter, and offers low insertion loss, wide frequency bandwidth, wide range of settable Doppler frequencies, high suppression of non-linear products and very good stability.

Vývoj radarových senzorů pro aktivní ochranu bojových vozidel

  • Autoři: doc. Ing. Přemysl Hudec, CSc.,
  • Publikace: XXIX. konference Radiokomunikace 2019 - Sborník přednášek. Pardubice: Unit s.r.o., 2019. p. 247-255. ISBN 978-80-87942-57-4.
  • Rok: 2019
  • Pracoviště: Katedra elektromagnetického pole
  • Anotace:
    Základním principem aktivní ochrany bojových vozidel je detekce přibližujících se ohrožujících střel a aktivace vhodné protistřely, která ohrožující střelu zneškodní nebo alespoň výrazně sníží její účinky. První vyvíjené a testované senzory používaly CW strukturu a pro lokalizaci ohrožujících střel speciální konfigurace antén. Pro určení bodů dopadu byly také testovány interferometrické senzory typu MISO. Bylo také navrženo a realizováno inovativní řešení založené na využití směrových antén typu „leaky-wave“. Poslední verze senzorů pracují s technikou PN-CW, tedy s digitální modulací CW signálu pomocí pseudonáhodných posloupností. Celý systém pracuje jako multisenzorový s tím, že bod a čas dopadu jsou vyhodnocovány v centrální jednotce pomocí Kalmánovy filtrace z měření radiálních rychlostí a vzdáleností prováděných současně několika senzory. Stávající přesnost určení bodu dopadu je cca ±15 cm, stávající přesnost určení času dopadu je cca ±0,7 ms, na vyhodnocení celý systém potřebuje čas i menší než 100 ms. To jsou parametry dostatečné na to, aby bylo možné detekovat i střely odpálené ze vzdálenosti nižší než 30 m od chráněného vozidla. Praktické testy vyvíjeného systému aktivní ochrany vykazují velmi dobrý stupeň funkčnosti.

Extended Noise Analysis Model of CW-type Radar Sensors with IQ Down-Conversion

  • DOI: 10.13164/re.2018.0620
  • Odkaz: https://doi.org/10.13164/re.2018.0620
  • Pracoviště: Katedra elektromagnetického pole
  • Anotace:
    CW-type structures belong to the most frequently employed radars, especially in a form of small sensors used, for example, in security applications or automotive industry. Range and reliability of operation of these sensors strongly depend upon their noise parameters. This paper extends previously published works by considering all potential inner noise sources and creating complex noise model of the concerned radar family including often used IQ signal processing. The noise sources cover local oscillator amplitude-noise and phase-noise, noise of a RF signal path and noise of a low-frequency signal path. The resulting noise model was verified by practical measurements which included different local oscillator types, different low-frequency bandwidths and different time-delays of the cross-talked signals. In all cases, the agreement between theory and measurement was within estimated limits. The developed model is applicable for noise analysis and design of all common CW-type radars.

TRL-based Measurement of Embedded Circuits in Microwave Printed Circuit Boards Including Frequency Conversion

  • DOI: 10.13164/re.2018.1077
  • Odkaz: https://doi.org/10.13164/re.2018.1077
  • Pracoviště: Katedra elektromagnetického pole
  • Anotace:
    The paper deals with the measurement of individual components or circuits embedded in more complex radio frequency (RF) or microwave printed circuit boards (PCBs). Since no standard RF measurement enables the direct parallel connection of an analyzer to the boards being tested, individual components are often measured by destructively cutting manufactured boards and by attaching the RF connectors to the concemed parts. This article shows that this problem, thanks to suitable calibration standards that have been designed and manufactured, can be solved by vector measurements and a TRL calibration proces. The measurements also work when the boards to be measured include frequency conversion. The epplicability of the developer method has been verified by practical measurements and its accuracy influenced ot the parameters of the sumounding circuits has been investigated by an uncertaity analysis

Adaptive Kalman Filter for Tracking of Fast Accelerating Targets

  • Autoři: doc. Ing. Přemysl Hudec, CSc., Pánek, P.
  • Publikace: European Microwave Week 2017 - Conference Proceedings - EuRAD 2017. Louvain-la-Neuve: European Microwave Association (EuMA), 2017. p. 267-270. ISBN 978-2-87487-049-1.
  • Rok: 2017
  • Pracoviště: Katedra elektromagnetického pole
  • Anotace:
    Active defense (AD) is a new method for protecting military vehicles. Instead of using thick and extremely heavy armors, the actively protected vehicles monitor approaching threatening missiles and de-active them by a suitable active counter-measures. The majority of AD systems is based on radar sensors capable of detecting the concerned missiles and measuring their parameters important for the protective functions. Often, these radar sensors are required to operate in a near-zone (from zero to tens of meters) and find and track relatively small and fast-flying targets. Beside that, it is necessary to take into account the fact that the velocity of the monitored targets can instantaneously vary. This problem especially refers to ignition of rocket engines which can abruptly introduce extremely high accelerations. If the concerned radar sensors employ signal-processing methods based on Kalman filtration, these high-order time-derivatives can cause substantial convergence problems. The main purpose of this article is to present the newly developed adaptable filtering which can reduce these effects. The designed procedures were verified using practically recorded data from flight of RPG-7 missiles.

Advanced Evaluation of Minimum Insertion Loss of Power-Line EMI/RFI Filters in RF and Microwave Frequency Bands

  • DOI: 10.1109/TEMC.2017.2689926
  • Odkaz: https://doi.org/10.1109/TEMC.2017.2689926
  • Pracoviště: Katedra elektromagnetického pole
  • Anotace:
    This article concerns a new approach for the characterization of power-line EMI/RFI filters in a general impedance environment and continues to broaden the scope of one of previously published works. Specifically, the paper focuses on analyzing the lowest possible insertion loss of threewire, single-phase EMI/RFI power-line filters in their stop-band at high megahertz or gigahertz frequencies.

Multimode Adaptable Microwave Radar Sensor Based on Leaky-Wave Antennas

  • Autoři: doc. Ing. Přemysl Hudec, CSc., Pánek, P., Jeník, V.
  • Publikace: IEEE Transactions on Microwave Theory and Techniques. 2017, PP(99), 1-9. ISSN 0018-9480.
  • Rok: 2017
  • DOI: 10.1109/TMTT.2017.2653104
  • Odkaz: https://doi.org/10.1109/TMTT.2017.2653104
  • Pracoviště: Katedra elektromagnetického pole
  • Anotace:
    New research and recent developments in active defense systems represent a promising way to protect military vehicles by detecting and subsequently eliminating threatening missiles with appropriate active counter-measures. Operating these defense systems requires a number of sensors, usually microwave, which must, above all, identify and track the target while generating signals to determine the correct counter-measure reaction. This paper shows that such multifunction and multimode sensors can be designed and implemented using leaky-wave antennas (LWAs). Connected radar circuits often employ a wideband modulation, so an analysis of the influence of the LWAs used on such a modulation is also included. A multimode adaptable pseudonoise radar equipped with LWAs was tested using bullets and live, armed cumulative missiles. The results confirm the functionality of the solutions presented.

Suppression of False Targets from Active Defense Radar Sensors

  • Autoři: doc. Ing. Přemysl Hudec, CSc., Pánek, P., Ouředník, P.
  • Publikace: European Microwave Week 2017 - Conference Proceedings - EuRAD 2017. Louvain-la-Neuve: European Microwave Association (EuMA), 2017. p. 77-80. ISBN 978-2-87487-049-1.
  • Rok: 2017
  • Pracoviště: Katedra elektromagnetického pole
  • Anotace:
    Military active defense systems are based on the detection of threatening missiles and their de-activation by suitable counter-measures. Often, these defense systems are based on microwave radar sensors. Practical tests indicate that when detecting threatening missiles, the process can be complicated by frequent false targets. In this work, we show that these false targets can disrupt the convergence of a Kalman filtration process for effective counter-measure actuation. More detailed analyses led to conclusions that generation of false targets is caused by two different physical phenomena. Their description and proposals how to suppress their negative influences represent the main topics of this paper.

TRL-based measurement of active antennas and other more complex microwave structures

  • DOI: 10.1109/ARFTG.2017.8000834
  • Odkaz: https://doi.org/10.1109/ARFTG.2017.8000834
  • Pracoviště: Katedra elektromagnetického pole
  • Anotace:
    A common approach to active antenna design consists of a passive radiator (intrinsic antenna) and an output or input amplifier; all situated on a single microwave board. Such designs show higher radiated power or lower noise floor resulting from low interconnecting line losses. However, since more microwave circuits are connected directly together on a single board, their testing is more difficult. In the given case, this concerns measurement of reflection coefficient of the passive radiator. Methods developed in frames of this work employ the VNA measurement and TRL cahbration, and enable one to evaluate radiator input reflection coefficient in a complete structure without need of any disconnecting or switching. Performed practical measurements show that results can be satisfactorily precise. Generally, the method can be applied for measurement of individual microwave circuits embedded in more complex system PCBs.

General Method for Characterization of Power-Line EMI/RFI Filters Based on S-Parameter Evaluation

  • DOI: 10.1109/TEMC.2016.2583221
  • Odkaz: https://doi.org/10.1109/TEMC.2016.2583221
  • Pracoviště: Katedra elektromagnetického pole
  • Anotace:
    This paper deals with a general working approach for determining the lowest possible insertion loss of power-line interference filters in their stop bands at high megahertz or gigahertz frequencies. It is shown that at these frequencies, the measurement methods recommended for testing of interference filters in available standards for frequencies up to 1 GHz fail in determining their lowest possible insertion loss. This problem is solved by the newly developed method which also enables the characterization of concerned filters in a completely impedance unknown environment. It is based on two-port vector network analyzer measurement and postmeasurement data processing applying an impedance matching technique. Experimental verification of the new method using two Maury Microwave automated tuners and a cascade of low-pass coaxial filters was performed in the frequency band from 6 to 12 GHz. The results show that measurement-evaluation procedures performed according to the newly developed method provide more reliable and precise results when compared to measurement procedures corresponding to methods described in common standards. The new method was also applied to the characterization of a professional EMI/RFI filter from 1 to 10 GHz.

Measurement of Point-of-Impact Based on Microwave PNCW Radar and Kalman Filtration

  • Autoři: doc. Ing. Přemysl Hudec, CSc., Kozák, F., Pánek, P.
  • Publikace: European Microwave Week 2015 Conference Proceedings. London: Horizon House Publications, 2015. pp. 1606-1609. ISBN 978-1-4673-9572-4.
  • Rok: 2015
  • DOI: 10.1109/EuMC.2015.7346086
  • Odkaz: https://doi.org/10.1109/EuMC.2015.7346086
  • Pracoviště: Katedra elektromagnetického pole
  • Anotace:
    Radars based on digital modulation of the transmitted continuous wave by pseudo-noise sequence belong to a wider xCW radar family. Simpler members of this family enable measurement of target speed, while more complex structures are capable of measuring also the target range. Although the FMCW radars are best known and widely used, for definite applications, the pseudo-noise CW (PNCW) radars can be beneficial. This concerns, for example, military applications, where this structure shows a high immunity against interferences and jamming, and enables relatively easy operation of more sensors in a close area. That is why the PNCW radars are good candidates for sensors employed in the active defense systems. These modern defense methods are especially developed for protection of military vehicles (MVs) and are based on detection of threat missiles, and their elimination by suitable active counter-measures. The presented sensor is formed by the microwave low-range PNCW radar and two couples of small antennas, fixed on the protected MV. In spite of its simplicity, the setup is capable of detecting threat missiles shot even from close vicinity of the MV, and evaluating the point of impact and time of impact of the missile with respect to the MV. The performed practical tests proved satisfactory functionality of the developed solution.

Microwave Radar Sensor Based on CRLH SIW Leaky-Wave Antennas

  • DOI: 10.1109/EuRAD.2014.6991205
  • Odkaz: https://doi.org/10.1109/EuRAD.2014.6991205
  • Pracoviště: Katedra elektromagnetického pole
  • Anotace:
    Modern methods of active defense of military vehicles are based on detection of threat missiles and their elimination by suitable active counter-measures. For these purposes, special radar detection systems are often used. The presented solution employs the SIW based leaky wave antennas which enable detection of the threat missiles in an immediate vicinity of the protected vehicle. The missiles are detected by two tilted detection planes: one main detection plane (as described in [1]), and the other, operating ahead of the main plane. Since the missiles fly through two different planes set under two different angles, system triggering can be improved and more missile parameters can be measured. The sensor structure is relatively simple and occupies merely little space on the surface of the protected vehicle. The performed tests prove functionality of the developed solution.

Radio Sensor for Monitoring of UMTS Mobile Terminals

  • Pracoviště: Katedra elektromagnetického pole
  • Anotace:
    Relatively simple and low-cost radio sensor for monitoring of 3rd generation (3G) UMTS mobile terminals (i.e. phones) has been designed and practically tested. The main purpose of this sensor is to serve as an extending module that can be installed into systems used for monitoring of standard 2nd generation (2G) GSM and DCS mobile phones in highly guarded buildings and areas. Since the transmitted powers of UMTS mobile terminals can be very low in relation to GSM and DCS specifications, the new UMTS sensor is based on a highly sensitive receiver and additional signal processing. The radio sensor was practically tested in several scenarios representing worst-case mobile terminal-base station relations. The measured detection ranges attain values from approx. 11 m inside of rooms to more than 30 m in corridors, which seems to be sufficient for the expected application. Results of all performed tests correspond fairly well with the presented theoretical descriptions. An extended version of the radio sensor can be used for monitoring of mobile terminals of all existing voice or data formats.

Digitally-Controlled Calibrator for Measurement and Testing of CW Doppler Radars

  • Autoři: Jeník, V., Plhák, Z., doc. Ing. Přemysl Hudec, CSc., Černý, P.
  • Publikace: 43rd European Microwave Conference - European Microwave Week 2013 Conference Proceedings. Louvain-la-Neuve: European Microwave Association (EuMA), 2013. pp. 1283-1286. ISSN 2325-0305. ISBN 978-2-87487-031-6.
  • Rok: 2013
  • Pracoviště: Katedra elektromagnetického pole
  • Anotace:
    CW Doppler radars are often used for short-range detection of moving targets and measurement of their velocities. Beside the basic analog structure, the CW radar family also includes more complex FMCW or digitally modulated types of radars. The dynamic range of these sensors can be substantially enhanced by means of the HW elimination of static reflections and cross-talks, which complicates calibration and testing procedures. Consequently, the radars can be tested only by using moving targets, yet this can be costly and time-consuming. That is why a stationary calibrator able to simulate moving targets with a well defined RCS and velocity can be very useful. The presented paper describes the design, realization and testing of such device capable of simulating moving targets within the 8-12 GHz frequency band. As the calibrator is digitally controlled, well defined and precise parameters are reached.

Digitally-controlled calibrator for measurement and testing of CW doppler radars

  • Autoři: Jeník, V., Plhák, Z., doc. Ing. Přemysl Hudec, CSc., Černý, P.
  • Publikace: 43rd European Microwave Conference - European Microwave Week 2013 Conference Proceedings. Louvain-la-Neuve: European Microwave Association (EuMA), 2013. p. 1283-1286. ISSN 2325-0305. ISBN 978-2-87487-031-6.
  • Rok: 2013
  • Pracoviště: Katedra elektromagnetického pole
  • Anotace:
    CW Doppler radars are often used for short-range detection of moving targets and measurement of their velocities. Beside the basic analog structure, the CW radar family also includes more complex FMCW or digitally modulated types of radars. The dynamic range of these sensors can be substantially enhanced by means of the HW elimination of static reflections and cross-talks, which complicates calibration and testing procedures. Consequently, the radars can be tested only by using moving targets, yet this can be costly and time-consuming. That is why a stationary calibrator able to simulate moving targets with a well defined RCS and velocity can be very useful. The presented paper describes the design, realization and testing of such device capable of simulating moving targets within the 8-12 GHz frequency band. As the calibrator is digitally controlled, well defined and precise parameters are reached.

Mutli-Sensor Surveillance Radar Based on MISO Sensors and Kalman Filtration

  • Autoři: Jeník, V., Kozák, F., doc. Ing. Přemysl Hudec, CSc.,
  • Publikace: 43rd European Microwave Conference - European Microwave Week 2013 Conference Proceedings. Louvain-la-Neuve: European Microwave Association (EuMA), 2013. ISSN 2325-0305. ISBN 978-2-87487-031-6.
  • Rok: 2013
  • Pracoviště: Katedra elektromagnetického pole
  • Anotace:
    of approaching threat missiles and activation of various kinds of active countermeasures. The presented surveillance radar was developed for detection and tracking of missiles in question in the close vicinity of military vehicles. Apart from the determination of the missile trajectory, the device is capable of calculating the expected point-of-impact. It consists of a set of MISO radar sensors and applies the ESPRIT method for determination of DOA and extended Kalman filtration. The realized 2-sensor sample was tested by using real military missiles and proved to be able to detect and track them efficiently.

Mutli-Sensor Surveillance Radar Based on MISO sensors and Kalman Filtration

  • Autoři: Jeník, V., Kozák, F., doc. Ing. Přemysl Hudec, CSc.,
  • Publikace: 43rd European Microwave Conference - European Microwave Week 2013 Conference Proceedings. Louvain-la-Neuve: European Microwave Association (EuMA), 2013. p. 1835-1838. ISSN 2325-0305. ISBN 978-2-87487-031-6.
  • Rok: 2013
  • Pracoviště: Katedra elektromagnetického pole
  • Anotace:
    Specific modern military defense systems are based on detection of approaching threat missiles and activation of various kinds of active countermeasures. The presented surveillance radar was developed for detection and tracking of missiles in question in the close vicinity of military vehicles. Apart from the determination of the missile trajectory, the device is capable of calculating the expected point-of-impact. It consists of a set of MISO radar sensors and applies the ESPRIT method for determination of DOA and extended Kalman filtration. The realized 2-sensor sample was tested by using real military missiles and proved to be able to detect and track them efficiently.

Novel Low-Profile Foam Dielectric Over the Shoulder Antenna Based On Coupled Patches Technique

  • DOI: 10.1002/mop.27389
  • Odkaz: https://doi.org/10.1002/mop.27389
  • Pracoviště: Katedra elektromagnetického pole
  • Anotace:
    The paper presents a novel wearable antenna composed of two coupled patches excited by an overlapping folded dipole. In spite of being operated in a relatively low frequency band 380 ÷ 390 MHz, the antenna shows a very low profile and other dimensions are acceptable as well. Besides a very low absorption of the radiated RF power by any nearby human body, it also ensures a very good immunity against influence on antenna parameters. In comparison to commonly used simple conformal monopole antennas, the presented solution provides a double-side radiation pattern and a substantially higher gain. The antenna can be manufactured using very light and twistable foam dielectric and conductive fabric, and can be worn as a strap placed over the shoulder. It is intended to be used together with personal radio communication transceivers operated in the given frequency band.

Parametric Study of the Low-Profile Foam Dielectric Over-the-Shoulder Antenna Based on Coupled Patches Technique

  • Pracoviště: Katedra elektromagnetického pole
  • Anotace:
    The paper presents a parametric study of the over-the-shoulder foam dielectric antenna based on coupled patches technique for 380 ÷ 390 MHz frequency band. Despite having a very low profile (0.0072 λ0), it shows the satisfactory radiation efficiency and very good immunity from the negative influences of the human body. Influence of the antenna elements to the radiation efficiency, gain, frequency bandwith and impedance matching is evaluated by means of the parametric study.

Simulation of Electromagnetic Field of a Fast Moving Target Close to Antennas

  • Pracoviště: Katedra elektromagnetického pole
  • Anotace:
    Experiments have shown that Doppler signatures of a missile moving in a close vicinity of the antenna is quite complex. Experimentally obtained spectrograms exhibit clusters of Doppler frequencies instead of a single one. This is due to the fact that radial velocities differ significantly for different parts of the missile. Partial numerical simulations of this complex problem have been carried out for thin long fast-moving targets (wires). Simulation results compare well with measured Doppler signatures and enable better understanding of the problem and therefore improve the ability to distinguish dangerous targets from ordinary ones.

Microwave Multi-Sensor System for Estimation of Positions of Fast-Flying Objects

  • Autoři: Jeník, V., doc. Ing. Přemysl Hudec, CSc.,
  • Publikace: Proceedings of the 6th European Conference on Antennas and Propagation (EUCAP 2012). Piscataway: IEEE, 2012. pp. 1917-1919. ISBN 978-1-4577-0918-0.
  • Rok: 2012
  • Pracoviště: Katedra elektromagnetického pole
  • Anotace:
    The described multi-sensor system was developed for application in active defense (AD) systems. These systems represent a new method of protecting military vehicles against anti-armor threat missiles. The multi-sensor system is able to detect approaching missile, determine its the most probable position with respect to the protected vehicle, and generate impulses for activating suitable counter-measure. Since detection and localization must be performed in a close vicinity of the vehicle, CW radar sensors with zero blind-zone and frequencies of output signals equal to Doppler frequency shifts are employed. For determining the horizontal position, the system measures and processes signals from a set of radar sensors and compares their Doppler frequencies. The entire setup was practically tested at an army shooting range, the achieved results are promising.

MISO Radar for Detection and Tracking of Fast-Flying Objects

  • Autoři: Jeník, V., Kozák, F., doc. Ing. Přemysl Hudec, CSc.,
  • Publikace: Proceedings of the 9th European Radar Conference. London: Horizon House Publications, 2012. pp. 99-102. ISBN 978-2-87487-029-3.
  • Rok: 2012
  • Pracoviště: Katedra elektromagnetického pole
  • Anotace:
    The presented MISO radar was developed for detection and tracking of threat missiles as one of sensors used in an active defense system. This way of protection of military vehicles is based on detection of approaching missiles and activation of suitable counter-measures. The objective MISO radar is supposed to be the first sensor, which detects the missile in a medium distance from the protected vehicle. Its main purpose is to find the missile, measure its velocity, monitor its trajectory and estimate the most probable point of impact. The realized test sample operates at 11 GHz and transmits 20 dBm of a CW power. It employs one transmitting channel and 4 receiving channels with a direct coherent conversion to a baseband. The applied signal-processing method is focused on calculating the direction-of-arrival (DOA), which is important for the required tracking capabilities. The presented measured results show that the designed radar meets the above stated requirements.

Noise Parameters of CW Radar Sensors Used in Active Defence Systems

  • Pracoviště: Katedra elektromagnetického pole
  • Anotace:
    Active defense represents an innovative way of protecting military vehicles. It is based on the employment of a set of radar sensors which detect an approaching threat missile and activate a suitable counter-measure. Since the radar sensors are supposed to detect flying missiles very fast and, at the same time, distinguish them from stationary or slow-moving objects, CW Doppler radar sensors can be employed with a benefit. The submitted article deals with a complex noise analysis of this type of sensors. The analysis considers the noise of linear and quasi-linear RF components, phase-noise of the local oscillator as well as the noise of low-frequency circuits. Since the incidence of the phase-noise depends strongly upon the time delay between the reference and the cross-talked signals, a new method of measuring noise parameters utilizing a reflecting wall has been developed and verified. The achieved results confirm potentially high influence of the phase-noise on the noise parameters of the mentioned type of radar sensors. Obtained results can be used for the analysis of noise parameters of the similar but even more complex sensors.

Design and Testing of Multi-Sensor Radar Microwave Curtain

  • Autoři: Jeník, V., doc. Ing. Přemysl Hudec, CSc.,
  • Publikace: European Microwave Week 2011 "Wave to the Future" - Conference Proceedings. London: Horizon House Publications, 2011. pp. 293-296. ISBN 978-2-87487-021-7.
  • Rok: 2011
  • Pracoviště: Katedra elektromagnetického pole
  • Anotace:
    A microwave curtain can be formed by a set of radar sensors equipped with antennas showing narrow radiation diagrams in the vertical plane and wide radiation patterns in the horizontal plane. One of the possible applications concerns active defense (AD) systems, which should protect military vehicles against the most dangerous types of missiles. The AD systems detect approaching missiles and activate suitable countermeasures. The microwave curtain can be "uncurled" around the protected vehicle and is able to detect flight of any thread missile through the defined planes. Signals generated by the microwave curtain can be used for identification of the thread missiles. Furthermore, it is possible to develop impulses that are able to activate efficient counter-measures.

Measurement of Noise Parameters of CW Radar Sensors

  • Autoři: Jeník, V., doc. Ing. Přemysl Hudec, CSc.,
  • Publikace: 78th ARFTG Microwave Measurement Conference Proceedings. Piscataway: IEEE Microwave Theory and Techniques Society, US, 2011. pp. 65-68. ISBN 978-1-4673-0281-4.
  • Rok: 2011
  • Pracoviště: Katedra elektromagnetického pole
  • Anotace:
    The CW radar sensors show no dead-zone and their output signal frequency is equal to the Doppler frequency. Owing to that, they can be used for many different purposes. Noise parameters of any radar sensor are decisive for its detection range, so their measurement is of the prime interest. The presented paper indicates all important sources of noise within the CW radar sensor and describes the method of measurement of its noise parameters. The noise sources include noise of linear and quasi-linear RF circuits, noise of LF circuits and noise contribution caused by the phase-noise of local oscillator. Since the latter noise source represents a strong function of the time-delay of signal cross-talked from the transmitter to the receiver, the developed measurement method is based on employment of the reflecting wall placed in front of sensor antennas or variable time-delay circuit connected within the receiver. Using the latter method enables the automatic measurement of noise parameters a

Missile Measurement and Identification

  • Autoři: Jeník, V., doc. Ing. Přemysl Hudec, CSc.,
  • Publikace: Proceedings of 21st International Conference Radioelektronika 2011. Brno: VUT v Brně, FEKT, Ústav radioelektroniky, 2011. pp. 341-344. ISBN 978-1-61284-322-3.
  • Rok: 2011
  • DOI: 10.1109/RADIOELEK.2011.5936399
  • Odkaz: https://doi.org/10.1109/RADIOELEK.2011.5936399
  • Pracoviště: Katedra elektromagnetického pole
  • Anotace:
    The paper presents results of the missile measurement and shows a possibility how to estimate a horizontal position of the missile. The missile is detected by a set of microwave curtains installed side by side on the top of a steal gate. For missile recognition, required for proper function of active defense system, the missile imprint seems to be important. The imprint of three different missiles is shown and discussed. As the 9 mm bullet's imprint is very simple, the one of the RPG-7 missile is much more complex due to more complicated structure. The measured imprints could be also useful for dynamic electromagnetic phenomena explanation and for missile identification.

Active UHF Antennas for Demanding RFID Applications

  • Pracoviště: Katedra elektromagnetického pole
  • Anotace:
    One of possible applications of RFID systems concerns identification of goods equipped with TAGs, densely and randomly accommodated in a larger space. This refers e.g. to the identification of many TAGs fixed on clothes in large cartoon boxes. The TAGs can be located very close to each other, mutually coupled, screened, randomly oriented and placed in an environment with a wide range of wave propagation parameters. The presented paper describes one of the possible solutions. The designed identification system is equipped with active reader antennas that enable the illumination and the read-out of the TAGs from many different locations as well as angles, and with a wide range of illuminating power. According to preliminary measurements, such conditions conduce to 100% correct and reliable identification. The designed RFID system is very likely to be able to work well even in more demanding identification tasks.

Digital Signal Processing Applied to Radar Sensors Operated in Active Defense Systems

  • Autoři: doc. Ing. Přemysl Hudec, CSc., Plašil, J., Dohnal, P.
  • Publikace: European Microwave Week 2010 "Connecting the World" Conference Proceedings. London: Horizon House Publications, 2010. pp. 483-486. ISBN 978-2-87487-019-4.
  • Rok: 2010
  • Pracoviště: Katedra elektromagnetického pole
  • Anotace:
    The active defense (AD) is deemed a very promising way how to protect military vehicles, especially in contemporary fight against terrorism in the Third world countries. Cheap and easily accessible hand-held cumulative missiles (e.g. RPG-7) are able to penetrate up to 300 mm of the hard-hardness armour (HHA). Thus light transport military vehicles equipped typically with less than 10 mm thick armours, used frequently e.g. in Afganistan are very vulnerable. The AD systems are based on radar sensors that detect approaching missiles and activate a suitable counter-measure able to destroy the threatening missile. The article describes the microwave curtain, which is one of the radar sensors applicable in AD systems, and signal-processing methods used for generation of ignition signals from its output signals. Practical results obtained at army shooting range are also presented.

Microwave Doppler Radar Sensor with Enhanced Immunity against Interferences

  • Autoři: Jeník, V., doc. Ing. Přemysl Hudec, CSc.,
  • Publikace: Proceedings of 15th Conference on Microwave Techniques COMITE 2010. Brno: VUT v Brně, FEKT, Ústav radioelektroniky, 2010. pp. 117-120. ISBN 978-1-4244-6351-0.
  • Rok: 2010
  • DOI: 10.1109/COMITE.2010.5481560
  • Odkaz: https://doi.org/10.1109/COMITE.2010.5481560
  • Pracoviště: Katedra elektromagnetického pole
  • Anotace:
    Modern anti-armor missiles represent enormous threat for any military vehicle. Simple hand-held missiles are able to penetrate 300 mm, more sophisticated missiles up to 1000 mm of the best steel armors. Active defense methods seem to be promising ways how to face this problem. These systems are based on sensors able to detect and measure approaching threat missile and generate signals that activate a suitable counter-measure. The paper describes Doppler radar sensors designed for active defense configurations. The designed version solves one of potential problems connected with employment of these radars at military vehicles. This concerns sufficiently high immunity against both unintentional and intentional interfering signals.

Microwave Radar Sensors for Active Defense Systems

  • Pracoviště: Katedra elektromagnetického pole
  • Anotace:
    Modern anti-armor missiles represent enormous threat for any military vehicle. Simple hand-held missiles are able to penetrate 300 mm, more sophisticated missiles up to 1000 mm of the best steel armors. Active defense methods seem to be promising ways how to face this problem. Systems of active defense are based on sensors able to detect and measure approaching threat missile and generate signals that activate a suitable counter-measure. The paper describes several different designed radar sensors tested in active defense configurations. This concerns narrowband sector sensor, "microwave curtain" and a new wideband sensor with a distance measurement capability. All practical tests were performed using real missiles at army shooting ranges.

UHF RF Identification of People in Indoor and Open Areas

  • DOI: 10.1109/TMTT.2009.2017305
  • Odkaz: https://doi.org/10.1109/TMTT.2009.2017305
  • Pracoviště: Katedra elektromagnetického pole
  • Anotace:
    UHF RFID read range tests have been performed with a novel electrically small low-profile TAG antenna equipped with artificial-like surfaces providing very good immunity against the influence of a near human body. The RFID system equipped with this antenna has been tested for the detection of a person in indoor and outdoor areas within 869 MHz band and reached read range up to 9 and 16 m, respectively.

UHF RFID of People

  • Pracoviště: Katedra elektromagnetického pole
  • Anotace:
    The book chapter is focused on radiofrequency identification of people: review, design and measurement of low profile antenna types suitable for RFID of persons; modeling and measurement of received signal level both in indoor and open environments, shadowing and corresponding signal fading; optimization of identification task geometry; read range identification tests and reliability identification tests both in indoor and open spaces including one person and a group of persons moving from slow to fast.

An Experimental Study of the Lowest Troposphere Layers at 10 GHz - First Results

  • DOI: 10.1109/COMITE.2008.4569896
  • Odkaz: https://doi.org/10.1109/COMITE.2008.4569896
  • Pracoviště: Katedra elektromagnetického pole
  • Anotace:
    This paper introduces an extensive innovative experiment for both local and remote combined sensing of the troposphere. The experiment is based on a unique set of mutually linked, time-space dependent, synchronized radio-electrical and radio-meteorological measurements. The results for the first two months of operation are also presented and discussed.

Efficiency Treatment of Composite Right/Left-Handed TL Zeroth-Order Resonator Antenna

  • Pracoviště: Katedra elektromagnetického pole
  • Anotace:
    Antenna efficiency of zeroth-order resonator (ZOR) antenna implemented in composite right/left-handed transmission line (CRLH TL) microstrip structure is treated by method of moment simulator IE3D. Radiation is investigated from individual portions of the antenna structure according to calculated amplitude of surface current density. Dominantly radiating regions are identified, geometrically emphasized, nad efficiency improved version of CRLH ZOR antenna is designed, realized, measured and compared with initial design. Improvement of simulation antenna efficiency from 10 to 75 % and 4x increased measured gain at design ZOR frequency has been found.

Errors in Measurement of Microwave Interferograms Using Antenna Matrix

  • Pracoviště: Katedra elektromagnetického pole
  • Anotace:
    New antenna matrices for both scalar and vector measurement of microwave interferograms for the frequency 2.45 GHz were developed and used for an analysis of sources of measurement errors. Influence of mutual coupling between individual antennas in an antenna matrix on a measurement of microwave interferograms, particularly on a measurement of interferogram minimum values, was studied. Simulations and measurements of interferograms, proposal of a new calibration procedure and correction method are presented. Influence of differences in radiation patterns of individual antennas of an antenna matrix on a measurement of microwave interferograms was studied as well.

Hidden Problems in Precise Calibration on Microstrip

  • Pracoviště: Katedra elektromagnetického pole
  • Anotace:
    A study of calibration problems on microstrip with respect to interaction of electromagnetic fields around SMA to microstrip launcher and microstrip short was carried out in frequency band up to 26 GHz. Omni Spectra SMA to microstrip launcher, 50 Ω microstrip line on Arlon CuClad 223 0.508 mm thick substrate and microstrip shorts with reflective wall above the upper side of substrate as a calibration elements were used for simulations in CST Microwave Studio. Strong influence of dimensions of shorts and distance between the shorts and the launcher on simulated calibration data was observed. Reasonable dimensions of the short and the distance between the short and the launcher making possible correct precise calibration were determined.

Highly Selective Power Meter for Measurement of Free Space Attenuation in Microwave Frequency Region

  • Autoři: doc. Ing. Přemysl Hudec, CSc., Slezák, O., Zela, J.
  • Publikace: Proceedings of the 14th Conference on Microwave Techniques COMITE 2008. Praha: Československá sekce IEEE, 2008. p. 283-286. ISBN 978-1-4244-2137-4.
  • Rok: 2008
  • DOI: 10.1109/COMITE.2008.4569944
  • Odkaz: https://doi.org/10.1109/COMITE.2008.4569944
  • Pracoviště: Katedra elektromagnetického pole
  • Anotace:
    The paper describes design and construction of a power-meter used in a system measuring free-space attenuation on microwave frequencies. The power-meter has a high dynamic range, employs two levels of filtration and provides very high immunity against influence of signals propagating on nearby frequencies in the same area.

Radar Sensor for Detection and Measurement of Anti-Armour Missiles

  • Pracoviště: Katedra elektromagnetického pole
  • Anotace:
    Přednáška je zaměřena na popis problematiky měření dvou základních typů protipancéřových střel v mikrovlnném frekvenčním pásmu. Popsány jsou vlastnosti a konstrukce úzkopásmového a širokopásmového senzoru, uvedeny jsou příklady měření provedených na armádních střelnicích s použitím reálných střel.

Radar Sensor for Detection of Anti-Armour Missiles

  • Pracoviště: Katedra elektromagnetického pole
  • Anotace:
    The anti-armour missiles represent one of the biggest threads for any military vehicle, both in a standard combat or e.g. during UN humanitarian as well as peacekeeping operations. Millions of extremely dangerous missiles, able to break-through even tank armour-plates, are widely spread even in the world's most dangerous hot spots and geostrategic areas. Standard lighter vehicles and helicopters alike do not have, by themselves, any chance against them. As a result, the possibly more efficient methods of defense against them are under scrutiny and are subject to a continuous development. Active defense methods are based on a detection of the thread missiles and activation of an efficient counter-measure. The presented paper describes parameters of two most dangerous missiles and calculates parameters decisive for their detection in microwave frequency range. The practical measurements verify and confirm the calculated detection parameters.

A Scalar Microwave Interferometric Measurement System for Nondestructive Testing

  • Pracoviště: Katedra elektromagnetického pole
  • Anotace:
    In this contribution is presented design and realization of a new scalar microwave interferometric measurement system and results obtained with this measurement system.

Application of the UHF RFID System for the Identification of Sportsmen in Mass Races

  • Pracoviště: Katedra elektromagnetického pole
  • Anotace:
    A modification of a standard UHF RFID system for identification of sportsmen during mass races was proposed, realized and verified. The performed mathematical simulations and measurements indicated the system components that are decisive for correct identification, i.e. primarily, both the reader and the transponder (TAG) antennas, their radiation patterns, tilt and efficiency. The optimized RFID system was tested in a standard outdoor operation with several configurations of sportsmen moving with different speeds from approx. 4 km/h up to 15 km/h. The obtained final results show 100 % identification reliability.

Generalized Approach for Phase Interferometric Measurements of Electromagnetic Field

  • DOI: 10.2529/PIERS070520090330
  • Odkaz: https://doi.org/10.2529/PIERS070520090330
  • Pracoviště: Katedra elektromagnetického pole
  • Anotace:
    A new generalized approach for microwave phase interferometric measurement of electromagnetic field using an antenna matrix (AM) was developed. The approach allows correction of most significant measurement errors caused by mutual couplings of closely spaced antenna elements. It is based on vector measurements of the AM designed for the frequency 2.60 GHz and Matlab simulations.

Generalized Approach for Phase Interferometric Measurements of Electromagnetic Field

  • DOI: 10.2529/PIERS070520090330
  • Odkaz: https://doi.org/10.2529/PIERS070520090330
  • Pracoviště: Katedra elektromagnetického pole
  • Anotace:
    A new generalized approach for microwave phase interferometric measurement of electromagnetic field using an antenna matrix (AM) was developed. The approach allows correction of most significant measurement errors caused by mutual couplings of closely spaced antenna elements. It is based on vector measurements of the AM designed for the frequency 2.60 GHz and Matlab simulations.

Generalized Approach for Phase Interferometric Measurements of Electromagnetic Field

  • Pracoviště: Katedra elektromagnetického pole
  • Anotace:
    A new generalized approach for microwave phase interferometric measurement of electromagnetic feld using an antenna matrix (AM) was developed. The approach allows correction of most signifcant measurement errors caused by mutual couplings of closely spaced antenna elements. It is based on vector measurements of the AM designed for the frequency 2.60 GHz and Matlab simulations.

Short-Range Detection and Measurment of Small High-Speed Objects in Microwave Frequency Region

  • Pracoviště: Katedra elektromagnetického pole
  • Anotace:
    Systems of active defense of vehicles or buildings are based on detection and measurement of potentially dangerous anti-armor missiles. Radar measurement of these missiles is complicated by their usually very low radar cross-section (RCS) values. Knowledge of RCS values plays crucial role in design of reliable detection system. The purpose of this paper is to present first results of 3D electromagnetic field simulations of accurate models of two common types of anti-armor missiles. The results are discussed with respect to the impact on detection and measurement range of active-defense systems.

The Optimization of the RFID System for the Identification of Sportsmen in Mass Races

  • DOI: 10.1109/EUMC.2007.4405296
  • Odkaz: https://doi.org/10.1109/EUMC.2007.4405296
  • Pracoviště: Katedra elektromagnetického pole
  • Anotace:
    Paper deal with the optimization of a standard UHF RFID system for usage in an identification of mass race sportsmen. Proposed improvements has been realized and the optimized RFID system has been tested in a standard outdoor operation, the results proved 100% identification reliability.

Vector Measurement of Microwave Interferograms with Antenna Matrix

  • Pracoviště: Katedra elektromagnetického pole
  • Anotace:
    A new antenna matrix for vector measurements of microwave interferograms at frequency 2.4 GHz was developed. Influence of mutual couplings between antennas in the antenna matrix on measurement of microwave interferograms, particularly on measurement of their minimum values was studied. A simulation of corresponding measurement errors based on measurement of a real antenna matrix, proposal and experimental verification of a new calibration and correction method are presented as well.

A New Scalar Microwave Interferometric Measurement System

  • Pracoviště: Katedra elektromagnetického pole
  • Anotace:
    A new scalar network analyzer system with an antenna matrix for microwave interferometric measurement was realized on frequency 2.45 GHz. Experimental results are compared with interferometric measurement using vector network analyzer (VNA) and an antenna x-y positioning system. The new system is supposed to be used in non-contact deformation and non-homogeneity measurements in civil engineering and other similar areas.

A Novel Vector Microwave Phase Interferometer

  • Pracoviště: Katedra elektromagnetického pole
  • Anotace:
    The paper describes a concept of a novel vector microwave phase interferometer based on a vector network analyzer system. The instrument is designed for fast vector measurements of a space distribution of an interference electromagnetic field using a matrix of antennas. It is supposed to be used in non-contact deformation and non-homogenity measurements in civil engineering and other areas. Results of first measurements performed in the 2.45 GHz frequency band are presented.

Analysis and Measurement of the RFID System Adapted for Identification of Moving Objects

  • Pracoviště: Katedra elektromagnetického pole
  • Anotace:
    A system study of ability of using a commercially available 869 MHz RFID system for identification of moving objects has been performed. The study has been focused on a power budget of received signal levels and on identification of main signal fadings and their quantification. Two types of TAG antennas have been used. Comparisons of their radiation properties when operated in the close vicinity of the a human body (or a simple phantom of a human body) have been performed. Suitability of their use is discussed. Results of this study provide deeper insight in the given problem and information in which way the system should be improved in order to comply with the intended purposes.

Measurement Trials in the 3G and Millimetre Frequency Bands using a Low Altitude Airship

  • Pracoviště: Katedra elektromagnetického pole
  • Anotace:
    The aim of this paper is to introduce options for measurements conducted at the CTU Prague using a low altitude airship. Experiments were proposed in the 3G and millimetre frequency bands. An example of measured data at the 2 GHz frequency is presented. An overview of planned experimental work is given. The goal is to obtain experimental data that can be used to plan communication systems delivered via High Altitude Platforms (HAPs).

Vector Network Analyzer for Microwave Interferometry Measurement

  • Pracoviště: Katedra elektromagnetického pole
  • Anotace:
    The paper describes a concept of a novel vector microwave phase interferometer based on a simple vector network analyzer. It is supposed to be used in non-contact deformation and non-homogeneity measurements in civil engineerign and other areas.

10 GHz Broadside Radiated Linearly Polarized Microstrip Patch with Enhanced Gain

  • Pracoviště: Katedra elektromagnetického pole
  • Anotace:
    Broadside radiated microstrip patch with enhanced gain has been designed with center frequency of 10 GHz. In order to achieve gain enhancement together with broadside linearly polarized radiation novel technique that uses radiation of surface modified rectangular microstrip patch operating with TM21 mode has been used. Designed radiator has been realized and measured. Gain of 11.5 dBi of single fed patch radiator has been reached. Comparision with properties of a simple rectangular patch operating with basic TM01 mode is also presented.

A Selective I/Q Demodulator with High Dynamic Range for Microwave Interferometer

  • Pracoviště: Katedra elektromagnetického pole
  • Anotace:
    The paper describes a basic concept of a novel microwave phase interferometer based on a multi-port vector network analyzer (VNA). A block diagram of the designed system is presented. The main goal of this paper is to describe the crucial part of the microwave interferometer - the selective I/Q demodulator - with high dynamic range. An experimental verification of the designed I/Q demodulator is presented.

High Dynamic Range Multiplier for Detection and Localization of BPSK WCDMA Signals

  • DOI: 10.1109/EUMC.2005.1608866
  • Odkaz: https://doi.org/10.1109/EUMC.2005.1608866
  • Pracoviště: Katedra elektromagnetického pole
  • Anotace:
    A special signal multiplier has been designed and measured. Its main purpose is to remove spreading from BPSK WCDMA signals and to improve their detection and measurement. Extending units based on this multiplier will be tested in existing systems that detect an illegal usage of standard TDMA/FDMA mobile phones in prison buildings and areas.

Microwave System for the Detection and Localization of Mobile Phones in Guarded Buildins

  • Pracoviště: Katedra elektromagnetického pole
  • Anotace:
    Novel monitoring system for the detection and localization of mobile phones in large buildings based on a matrix of microwave sensors has been designed and practically employed. Each sensor consists of three RD channels for a separate detection of differenct mobile services. Both time-domain and frequency domain analyses are applied on the RF receiver output signals in order to differentiate individual mobile services. Up to now, microwave systems with approximately 2000 sensors have been installed and successfully operated in 13 prisons in the Czech Republic. The system has been found as one of effient tools for improving security in large highly guarded buildings.

Microwave System for the Detection and Localization of Mobile Phones in Large Buildings

  • DOI: 10.1109/TMTT.2005.848750
  • Odkaz: https://doi.org/10.1109/TMTT.2005.848750
  • Pracoviště: Katedra elektromagnetického pole
  • Anotace:
    A novel monitoring system for the detection and localization of mobile (cellular) phones in large buildings based on a matrix of microwave sensors has been designed and practically employed. The system enables detection of all active mobile services and ensures very high immunity against all other radio signals. The designed antennas, system structure and signal processing provide high probability of correct localization of the transmitting mobile phone.

Microwave System for the Detection and Localization of Mobile Phones in Large Highly Guarded Buildings

  • Pracoviště: Katedra elektromagnetického pole
  • Anotace:
    Novel monitoring system for the detection and localization of mobile phones in large buildings based on a matrix of microwave sensors has been designed and practically employed. Each sensor consists of three RF channels for a separate detection of different mobile services. Both time-domain and frequency domain analyses are applied on the RF receiver output signals in order to differentiate individual mobile services. Up to now, microwave systems with approximately 2000 sensors have been installed and successfully operated in 13 prisons in the Czech Republic. The system has been designed as one of efficient tools for improving security in large highly guarded buildings.

On the Perpendicular Coax-Microstrip Transition

  • Pracoviště: Katedra elektromagnetického pole
  • Anotace:
    The perpendicular coax-microstrip transition was studied using two kind of standard SMA connectors. A A generalized equivalent circuit along with parameter for Arlon 25a substrate is proposed. The low-pass nature, parasitic resonance and unwanted radiation of a perpendicular transition are demonstrated. Simulated data were verified by measurement in the frequency range 0.045-15 GHz.

Daulband Quarter Wavelength Plannar Antenna for Signal Detection in GSM 900/DCS 1800 Bands

  • Pracoviště: Katedra elektromagnetického pole
  • Anotace:
    Properties of dual band quarter wavelength planar antenna for signal detection in GSM900/DCS1800 band are presented. The antenna consist of two quarter wavelength planar antennas with air dielectric with one point feed. Reflection coefficient in uplink subbands (from mobile station MS to base station BS) of both bands at presented antennas versions is not as good as is required for transmitting antennas but in case of antennas for signal detectionpurposes is quite goog enough. Directional characteristics has been measured too.

Microwave Sensor for the Detection of Mobile Phones

  • Pracoviště: Katedra elektromagnetického pole
  • Anotace:
    Microwave sensor for the detection of mobile services has been proposed based on the spectrum analyzer concept with advantages of RF wideband detectors. The sensor applies two or more RF channels for the separate detection of mobile services. Time-domain analysis is applied on the RF detector output voltage to further differentiate indvividual mobile services. Prototype of the sensor has been designed, realized and successfully tested.

Upgrade hybridních opticko-koaxiálních sítí CATV pro širokopásmový datový provoz

  • Pracoviště: Katedra elektromagnetického pole
  • Anotace:
    Příspěvek popisuje základní pravidla pro úpravu stávajících sítí CATV pro obousměrné datové komunikace.

Study of Trial Band Quarter Wavelenght Plannar Antenna for Signal Detection in NMT 450/GSM 900/DCS 1800 Bands

Measurement Transmitter and Receiver for the 1900 MHz Frequency Band

  • Autoři: doc. Ing. Přemysl Hudec, CSc., Nisznanský, M., Mádle, E.
  • Publikace: Radioelektronika 2001 - Conference Proceedings. Brno: VUT v Brně, FEI, Ústav radioelektroniky, 2001. pp. 123-126. ISBN 80-214-1861-3.
  • Rok: 2001

Radio System for Measurement of Wave Propagation in the 900 MHz GSM Band

  • Autoři: doc. Ing. Přemysl Hudec, CSc., Daniel, D., Hájek, P.
  • Publikace: COMITE 2001. Praha: IEEE Czechoslovakia Section, 2001. pp. 123-125. ISBN 80-902417-9-4.
  • Rok: 2001

System for 1900 MHz Mobile Measurements Controlled by PDA Computer

TOPNET 4.2 - optimalizace nastavení zpětných signálových cest v TKR

  • Autoři: doc. Ing. Přemysl Hudec, CSc.,
  • Publikace: Workshop CAD&CAE 2000. Prague: Czechoslovakia Section IEEE, 2000. pp. 8-11. ISBN 80-902417-6-3.
  • Rok: 2000

Komponenty pro digitální radiové přenosy v pásmech 2,45 a 5,8 GHz

Microwave Directional Bridge for Reflection Measurements

Scalar Analyzer System with a High Dynamic Range

  • Autoři: doc. Ing. Přemysl Hudec, CSc.,
  • Publikace: The 10th Conference on Microwave Techniques COMITE 1999. Prague: Czechoslovakia Section IEEE, 1999. pp. 203-206. ISBN 80-902417-3-5.
  • Rok: 1999

900 MHz Signal Attenuation Measurement for Mobile Wireless Communications in Urban AREA

Computer Models of the CATV Optical Transmitters and Receivers

Parabolic Antenna Patch Feeder for 2,45 GHz Band

Noise in CATV Networks

Optimum Setting of Microwave Radio Links Using Spread-Spectrum Modulation

Počítačový návrh hybridních sítí TKR

  • Autoři: doc. Ing. Přemysl Hudec, CSc.,
  • Publikace: Workshop CAD and CAE 97. Praha: ČVUT FEL, Katedra elektromagnetického pole, 1997. pp. 28-30. ISBN 80-902417-1-9.
  • Rok: 1997

Automatizovaný systém pro měření směrových charakteristik antén

Determination of Temperature Dependencies of GaAs MESFE Tranzistor S- and Noise Parameters Using Modelling Techniques

Distribuce signálu pro mobilní komunikace

Návrh dálkového napájení zasilovačů v sítích TKR

Návrh VF radioreléových tras do 100GMz

Odrazy v sítích TKR

Šumový návrh sítí TKR

The Antenna Characteristics Measurement System

TOPNET 2.2 - The CAD Program for a CATV Network Design

Procedures for Exact Noise Analysis of Microwave Circuits

Za stránku zodpovídá: Ing. Mgr. Radovan Suk