B.A. Galwas

Warsaw University of Technology, Warszawa, Masovian Voivodeship, Poland

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Publications (32)5.37 Total impact

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    ABSTRACT: Here we present an investigation of the electric field distributions in the cross-sections of the cylindrical metamaterial hollow-core and rod waveguides. The radius of the cylindrical waveguides is r=3 mm and the azimuthal index m=1. We have calculated the electric field distributions for the main and three higher modes, propagating in the metamaterial hollow-core waveguide. We have also calculated the electric field distribution of the main mode propagating in the metamaterial rod waveguide. Our calculations were made at the frequencies f=100 and 112.5 GHz. The calculation results show that the electric field distributions in the waveguide cross section for the different frequencies and modes as well as for different waveguide geometries are strong dissimilar to each other. The electric field distribution of the waveguide main mode is unlike for double and single negative metamaterial. We are aware of the fact that the electric field penetrates into metamaterial of all investigated waveguides.
    Microwaves, Radar and Wireless Communications, 2008. MIKON 2008. 17th International Conference on; 06/2008
  • P. Wojtyra, B. Galwas
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    ABSTRACT: Novel photonic microwave filters based on time delay introduced by a dispersive media are presented. This is followed by description and analysis of issues concerning microwave filters theory, architecture, tuning, reconfiguration and processes of obtaining negative taps.
    Microwaves, Radar & Wireless Communications, 2006. MIKON 2006. International Conference on; 06/2006
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    ABSTRACT: In this paper the system for 3<sup>rd</sup> order intercept point measurements of RF amplifiers and mixers is presented. "The fragmentary method" which bases on narrow band measurements of fundamentals and 3<sup>rd</sup> order products is described. The decreasing of the measurement time and the spectrum analyzer dynamic range improvement method was presented.
    Microwaves, Radar & Wireless Communications, 2006. MIKON 2006. International Conference on; 06/2006
  • R. Rajkowski, B. Galwas
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    ABSTRACT: The analysis of harmonic design amplifier for different type FET's transistors and their models.
    01/2006;
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    ABSTRACT: A planar InGaAsP/InGaAs/InGaAsP p-i-n photodiode has been fabricated and used for frequency conversion of two optical signals. Nonlinear properties of the photodiode have been investigated. It is shown that photodiode responsivity R(V) dependence on bias voltage can be characterized by a parameter of the nonlinearity A, which is equal to R(V)middotR'(V) and the maximal conversion efficiency is achieved at the bias voltage where the parameter A has the maximal value
    IEEE Transactions on Microwave Theory and Techniques 03/2005; · 2.23 Impact Factor
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    ABSTRACT: The aim of the article is to present a groundwork for a Web-based course on microwave transistor power amplifiers for postgraduate students from Poland and Italy. Among lecturers are professors of the Universita degli Studi di Roma Tor Vergata in Italy. What follow is a course description and its aims.
    Microwaves, Radar and Wireless Communications, 2004. MIKON-2004. 15th International Conference on; 06/2004
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    ABSTRACT: In our paper, we calculated the distribution of an electric field modulus at several parallel cross-sections of a model heart (with a catheter inside of its right atrium). The catheter was created out of dielectric or metal material. The frequency of the microwave signal was f = 10 GHz. The distribution of the electric field modulus has resonance peaks. The electric field could be concentrated in different places of the heart depending on weather the material of the catheter was dielectric or metal.
    Microwaves, Radar and Wireless Communications, 2004. MIKON-2004. 15th International Conference on; 06/2004
  • B.A. Galwas, F. Giannini
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    ABSTRACT: In the paper there have been discussed the main purposes of the authors of International Travelling Summer Schools, the fourteenth edition of which has been organized this year. The inspiring role, which the TEMPUS programme had in organizing the first summer schools, has been described. The evolution of subject matters and their links with the tendencies in the development of electronics and optoelectronics has been discussed. The plans and intentions for the future have been outlined, putting into evidence the new opportunities coming from a European Network of Excellence.
    Microwaves, Radar and Wireless Communications, 2004. MIKON-2004. 15th International Conference on; 06/2004
  • B. Galwas
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    ABSTRACT: The paper offers a description of a new model of academic book on "Fundamentals of Microwaves" based on modern multimedia tools. The new model was specially designed for the distance studies via the Internet offered by the Warsaw University of Technology. A detailed description of a universal structure of a textbook (e-book) is followed by the description of the tree-model of a lecture both from the technical and functional perspective.
    Microwaves, Radar and Wireless Communications, 2004. MIKON-2004. 15th International Conference on; 06/2004
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    ABSTRACT: Three planar InGaAsP/InGaAs/InP p-i-n photodiodes have been fabricated and used in a frequency conversion process of two optically transmitted signals. Nonlinear properties of the photodiodes have been measured. The differences between photodiode characteristics and obtained frequency conversion product level are discussed.
    Microwaves, Radar and Wireless Communications, 2004. MIKON-2004. 15th International Conference on; 06/2004
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    ABSTRACT: A photovaractor for the remote optical control of microwave circuits was studied. The photovaractor was fabricated as a p-i-n photodiode placed in a pigtailed fiber optical module. The study of the impedance in the frequency range up to 3 GHz in darkness and under illumination has shown that the photovaractor capacitance strongly depends on the incident optical power. The capacitance variation of the photovaractor diode under illumination is discussed.
    IEEE Microwave and Wireless Components Letters 07/2002; · 1.78 Impact Factor
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    ABSTRACT: Investigations were carried out on microstrip lines with a substrate having two layers of semiconductor GaAs and dielectric SiO<sub>2</sub> using a quasi-static approximation. The dependence of the microstrip line wave impedance, wavelength, effective permittivity, attenuation coefficient, and capacity per unit length on the upper substrate layer thickness, the strip conductor width, and its distance from the substrate edges has been studied. In addition, the quasi-TEM wave electric field distribution in the microstrip line has been determined.
    Microwaves, Radar and Wireless Communications, 2002. MIKON-2002. 14th International Conference on; 02/2002
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    ABSTRACT: In this paper we report on computations of the scattered plane electromagnetic (EM) field by a model human heart at selected incidence polar θ and azimuthal φ angles of the microwaves. The heart model is composed of the myocardium as well as the right and left atria with ventricles. The 3D surface model of the heart has been created in 3D StudioMAX. The method of singular integral equations (SIE) was applied. For verification of the SIE algorithm we compared our computational results with experimental data for a metal disk.
    Microwaves, Radar and Wireless Communications, 2002. MIKON-2002. 14th International Conference on; 02/2002
  • Z.R. Szczepaniak, B.A. Galwas
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    ABSTRACT: The use of injection-locking to obtain the phase shifting for an array antenna transmitter is considered The general idea, described earlier by York and Itoh (see IEEE Trans. MTT, vol.46, no.11, p.1920-29, 1998) and by Qian and Itoh (see IEEE Trans. MTT, vol.46, no.11, p.1891-1900, 1998), consist in applying the tuning of the oscillator while it is injection-locked. In such a way it is possible to obtain the phase shift between the locking and output signals of the oscillator. It was shown that this solution could be improved with photonics with the use of the optical injection-locking and the optical tuning of the oscillator. Especially, the oscillator with a photovaractor can be useful, because optical locking and tuning can be applied with the use of the same laser diode and the optical fibre link.
    Microwaves, Radar and Wireless Communications, 2002. MIKON-2002. 14th International Conference on; 02/2002
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    ABSTRACT: A new type of semiconductor optoelectronic device, which is called as photovaractor, was used in a self-bias mode of operation to obtain an optically-variable impedance. This approach allowed designing an optically-switched microwave band-pass filter. The use of the photovaractor in the microwave structure was investigated. The measurements of the photovaractor, the idea of the self-bias mode, and the simulations of the filter have been presented.
    Microwave Conference, 2001. 31st European; 10/2001
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    Jolanta Chęć, Mariusz Pajer, Bogdan A Galwas
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    ABSTRACT: New tools of modern education, connected mainly with Internet, are described in the paper. Their charac-teristics, principles of application were discussed in succes-sion. Evaluation trail of their usefulness was done. Possi-bilities of carrying on laboratory experiments and distance designing were described. Probe to foresee directions of fur-ther development of Internet tools in the educational process was done.
    01/2001;
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    Bogdan A Galwas, Mariusz Pajer, Jolanta Chęć
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    ABSTRACT: Structure of electronic book, prepared as auxil-iary materials of courses for specialists in the field of telecom-munications and informatics, will be described. Assumptions undertaken and their grounds will be presented. Model of a single lecture, way of a control of student progress and technique of movement through the course content will be described.
    01/2001;
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    ABSTRACT: The photovaractors for microwave photonic application were studied. The photovaractors were fabricated as a planar p-i-n or metal-semiconductor-metal (MSM) photodiodes placed in a pigtailed fiber optical module. The study of S11 parameters in the frequency range up to 3 GHz under illumination has shown that capacitances of p-i-n and MSM photodiodes strongly depend on the optical power. The capacitance variation of the photo-varactor diode under illumination is discussed.
    Microwave Conference, 2000. 30th European; 11/2000
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    ABSTRACT: We describe a short-distance three-channel optical-microwave link with subcarrier multiplexing for transmission of digital and/or analog data between different points of industrial measurement systems. The optical fiber link operates with a Fabry-Perot laser at 1300 nm, multimode fiber and PIN photodiode receiver. From a microwave point of view three carriers with frequencies 600 MHz, 800 MHz and 1000 MHz were chosen. The structure and main parameters of the link are reported and discussed
    Microwaves, Radar and Wireless Communications. 2000. MIKON-2000. 13th International Conference on; 02/2000
  • Z.R. Szczepaniak, B.A. Galwas
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    ABSTRACT: In our transmission system there was a need to use a binary PSK modulator. However there was a condition assuming a microwave signal phase control by means of an optical fibre link. To accomplish these requirements optically controlled microwave phase shifters and a 3 dB-quadrature (90°) microwave coupler were used. The simulations and the measurements of the optically controlled PSK modulator were investigated and presented
    Microwaves, Radar and Wireless Communications. 2000. MIKON-2000. 13th International Conference on; 02/2000