Microwave measurements

Who are we?

We are a research group engaged in the microwave measurement, design and construct of high-frequency circuits and systems. Our work covers a wide spectrum of the microwave domain from the theory of the calibration-correction methods to complex designs and large microwave measurement systems.

Karel Hoffmann

• He is leader of the “Microwave measurements” group.
• On the department of electromagnetic field he is coordinating work related with microwave measurement and with design of planar microwave devices. His main research is focused on design of active and passive microwave integrated circuits, precise microwave measurement and modelling of electromagnetic components.

Přemysl Hudec

• Among his main interests belongs design of systems for active radar defense of vehicles and buildings, precise microwave measurements and design of integrated circuits and systems.
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Zbyněk Škvor

• His main activities include the design of active and passive microwave integrated circuits, precision microwave measurement and modeling of microwave components.

Viktor Adler

• He is a graduate student at the department of electromagnetic field.
• Among his main interests belongs microwave interferometic measurements, evaluation of uncertainties and design of microwave circuits and systems.

Aleksandra Baskakova

• She is a graduate student at the department of electromagnetic field.
• Her PhD is focused on development of new circuit structures using interferometric approach applicable in scanning microwave microscopy or microwave imaging.

Petr Ouředník

• He is a graduate student at the department of electromagnetic field.
• Among his main interests belongs RADAR sensors, in-system microwave measurement and design of microwave circuits and systems.

Martin Haase

• He is a graduate student at the department of electromagnetic field.
• His main research is focused on the measurement of extreme impedances, which covers simulations of complex structures in electromagnetic simulators like CST and HFSS. Among his further activities belongs the design of active and passive microwave circuits. He is also interested in precise microwave measurement, numerical methods for electromagnetic field (e.g. FEM) and evaluation of uncertainties.

Vojtěch Jeník

• He is a graduate student at the department of electromagnetic field.
• Among his main interests belongs design of systems for active radar defense of vehicles and buildings, precise microwave measurements and design of integrated circuits and systems.

 

Past memebers

Filip Kozák

• His main interest is the simulation of the electromagnetic field. Other interest include design and construct active radar system for protection of vehicles.

Ondřej Morávek

• His main research focus is modelling complex planar structures in CST and HFSS. Among his interests are design of active and passive microwave components and precise microwave measurements.

Milan Příhoda

• His main interest is the microwave interferometry and interferometric measurements. Other interests include design of active and passive microwave components.

Research directions

We are interested into research and application in the microwave frequencies. We are also developing microwave systems for wide range of purposes. Our goal is competitive research in the high frequency area and development of modern measurement techniques. We are also focused into the computer simulations of microwave structures and circuits in advanced 3D electromagnetic field simulators (CST Microwave Studio and ANSOFT HFSS) and application of the obtained results in the development of microwave circuits or another precise components for measurement. We are also interested into active radar defence of buildings and vehicles.

Pictures of some practical realizations

Design of active and passive microwave circuits and components

   

            

The results of cooperation with external workplaces

  

    

Equipment of measuring workplaces

     

Simulation of microwave structures in advanced 3D electromagnetics field simulators.

  

What is it good for?

Results of our work impact design of novel or improved measurement methods, integrated circuits or whole measurement systems in the microwave frequency range. Research in the area of measurement technique finds application in characterization of modern transistors, devices and materials in the high frequencies range. Together with development and improvement of measurement methods we also aim to design novel types of active and passive high-frequency circuits. Our work is applicable in industry and not only in the high frequency components but also for precise measurement of distances or thicknesses. Our cooperation with industry includes development of active protection of vehicles and buildings against ballistic missiles.

What are we working on?

• Measurement of extreme impedances (In microwave range using VNA)
• Precise measurement of thickness and distance
• Precise vector measurement in open (planar) structures
• Microwave interferometric measurements
• System for active radar defense of buildings and vehicles
• Modeling and electromagnetic simulations of transistor packages
• Multimode planar structures
• Calibration and corrections methods for microwave measurement

Sponsors of our research

• 2018 – 2020 – MPO ČR – Pokročilé testování automobilových radarů.
• 2016 – 2020 – MARIE SKLODOWSKA-CURIE INNOVATIVE TRAINING NETWORKS – Convergence of Electronics and Photonics Technologies for Enabling Terahertz Applications.
• 2015 – 2017 – TAČR TH – Program na podporu aplikovaného výzkumu a experimentálního vývoje EPSILON “Mikrovlnný měřič tloušťky kovového pásu pro dělicí linky”.
• 2014 – 2015 – NBÚ Praha – Výzkum a vývoj metod a postupů měření vložného útlumu filtrů v kmitočtovém pásmu do 10GHz.
• 2013 – 2016 – EMRP RESEARCHER GRANT CONTRACT NO. SIB62-REG1 Researcher Excellence Grant (REG) in reference to JRP: SIB62 HFCircuits.
• 2013 – 2015 – Vojenský výzkumný ústav – Pokročilá aktivní ochana – Pokročilá balistická aktivní ochrana vozidel proti útokům RPG a PTŘS.
• 2005 – 2011 – MSM6840770015 – Výzkum metod a systémů pro měření fyzikálních veličin a zpracování naměřených dat.

Our partners

• Vojenský výzkumný ústav, s. p. – Veslařská 230, 637 00 Brno
• ALCOMA spol. s.r.o. – Vinšova 11, 106 00 Praha 10
• Ingersoll-Rand Equipment Manufacturing Czech Republic s.r.o., Centrum výzkumu a vývoje – Floriánova 2460, 253 01 Praha Hostivice, Czech Republic
• Český metrologický institut – Okružní 772/31, 638 00 Brno
• ZAT a.s. – K  Podlesí 541, 261 80 Příbram, Česká republika
• NBU ČR – Na Popelce 2/16, Praha 5, 150 06
• ERA, a.s. – Průmyslová 387, 530 03  Pardubice-Pardubičky
• ROHDE & SCHWARZ – Praha, s.r.o. – Hadovka Office Park, Evropská 2590/33c, 160 00 Praha 6
• T-CERAM, s.r.o. – 503 44 Libřice 60

Selected publications

• [1] Hoffmann,K., Sokol,V.; Škvor,Z.; “Arbitrary Q-Factor Dielectric Resonator”, Radioengineering, December 2001, vol. 10, no. 4, pp. 21-23. (pdf)
• [2] Hoffmann,K., Vajtr,J.; “Solenoid above Ground Plane – Equivalent Circuit”, Radioengineering, December 2001, vol. 10, no. 4, pp. 17-20. (pdf)
• [3] Sokol,V., Hoffmann,K., Vajtr,J.; “Noise Figure Measurement of Highly Mismatched DUT”, Radioengineering, September 2003, vol. 12, no. 3, pp. 13-15. (pdf)
• [4] Sokol,V., Černý,P., Hoffmann,K., Škvor,Z.; “Assembly Influence on the Small-Signal Parameters of a Packaged Transistor”, Radioengineering, December 2005, vol. 14, no. 4, pp. 75-80. (pdf)
• [5] Závodný,V., Hoffmann,K., Škvor,Z.; “Seven State PTP for Vector Network Analyzer”, Radioengineering, December 2005, vol. 14, no. 4, pp. 87-90. (pdf)
• [6] Hudec,P., Polívka,M., Pechač,P.; “Microwave System for the Detection and Localization of Mobile Phones in Large Buildings”, Microwave Theory and Techniques, IEEE Transactions on, vol.53, no.6, pp. 2235- 2239, June 2005. (IEEEXplore)
• [7] Zela,J., Hoffmann,K., Hudec,P.; “Errors in Measurement of Microwave Interferograms Using Antenna Matrix”, Radioengineering, Semptember 2008, vol. 17, no. 3, pp. 25-32. (pdf)
• [8] Polívka,M., Švanda,M., Hudec,P., Zvánovec,S.; “UHF RF Identification of People in Indoor and Open Areas”, Microwave Theory and Techniques, IEEE Transactions on, vol.57, no.5, pp. 1341-1347, May 2009. (IEEEXplore)
• [9] Randus,M., Hoffmann,K.; “A Method for Direct Impedance Measurement in Microwave and Millimeter-Wave Bands”, Microwave Theory and Techniques, IEEE Transactions on, vol.59, no.8, pp. 2123-2130, Aug. 2011. (IEEEXplore)
• [10] Randus,M., Hoffmann,K.; “Microwave Impedance Measurement for Nanoelectronics”, Radioengineering, March 2011, vol. 20, no. 1, pp. 276-283. (pdf)
• [11] Morávek,O., Hoffmann,K.; “Improvement to Load-pull Technique for Design of Large-signal Amplifier in K Band”, Radioengineering, December 2011, vol. 20, no. 4, pp. 828-831. (pdf)
• [12] Morávek,O.; Hoffmann,K.; “Measurement and Simulation of Coaxial to Microstrip Tansitions’ Radiation Properties and Sbstrate Influence”, Radioengineering, June 2012, vol. 21, no. 2, p. 568-572. (pdf)
• [13] Morávek,O.; Hoffmann,K., “Radiation properties of Coaxial-to-coplanar transitions in K band”, In: Electronics Letters. 2012, vol. 48, no. 16, p. 1003-1004. (IEEEXplore)
• [14] Příhoda, M.; Hoffmann, K., “Novel Multimode Planar Absorbing Structure,” IEEE Microwave and Wireless Components Letters. 2013, vol. 23, no. 1, p. 7-9. ISSN 1531-1309. (IEEEXplore)
• [15] Příhoda, M.; Hoffmann, K., “Self-calibrating evaluation method for microwave interferometry measurements,” Electronics Letters. 2013, vol. 49, no. 49(5), p. 356-358. ISSN 0013-5194. (IEEEXplore)
• [16] Moravek, O.; Hoffmann, K.; Polivka, M.; Jelinek, L., “Precise Measurement Using Coaxial-to-Microstrip Transition Through Radiation Suppression,” Microwave Theory and Techniques, IEEE Transactions on , vol. 61, no. 8, pp. 2956 – 2965. (IEEEXplore)
• [17] Adler, V.; Hoffmann, K., “Six-Port Spatial Electromagnetic Wave Measurement,” Microwave Theory and Techniques, IEEE Transactions on, December 2014, vol. 62, no. 12, pp 3161 – 3171. (IEEEXplore)
• [18] Haase, M.; Hoffmann, K.; Hudec, P., “General Method for Characterization of Power-Line EMI/RFI Filters Based on S-Parameter Evaluation,” October 2016, IEEE Transactions on Electromagnetic Compatibility, vol. 58, no. 5, pp. 1465 – 1474. (IEEEXplore)
• [19] Haase, M.; Hoffmann, K.; Hudec, P., “Advanced Evaluation of Minimum Insertion Loss of Power-Line EMI/RFI Filters in RF and Microwave Frequency Bands,” December 2017, IEEE Transactions on Electromagnetic Compatibility, vol. 59, no. 6, pp. 1887-1896. (IEEEXplore)
• [20] Hudec, P.; Panek, P.; Jenik, V.; “Multimode Adaptable Microwave Radar Sensor Based on Leaky-Wave Antennas,” September 2017, IEEE Transactions on Microwave Theory and Techniques, vol. 65, no. 9, pp. 3464-3473. (IEEExplore)