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The paper presents recent developments in designing quasi-optical multipliers in the sub-THz frequency domain. An extensive measurement campaign is described in detail in which issues are addressed concerning the non-trivial nature of the problems met. In particular, attention is paid to impedance measurements of the core element, the integrated antenna-multiplier (dubbed the ‘multenna’), together...
A nonlinear synthesis problem according to given amplitude radiation pattern for plane aperture is considered in two ways. An analytical formula for the optimal current is obtained in the first approach. This current generates the amplitude radiation pattern which is close to the given one with the prescribed accuracy. The second approach consists of variational statement of synthesis problem. The...
This paper offers a review of the most valuable results of antenna array research and development at NTUU “KPI” within the last ten years for ultrawideband radar applications. First, paper describes a novel way to optimize the unilateral tapered slot antenna (TSA) being an element of a wideband scanning array. Second, theoretical and practical results of proposed volume horn array antenna with slant...
A sub-Terahertz circular dichroism spectrometer is developed and built based on a vector network analyzer driven quasi-optical system at 220–325 GHz sub-THz frequency domain (VNA-CD). The main goal is to explore the potentially significant absorption features in THz signatures of aqueous protein samples.
Recent advances in problem-oriented and general-purpose microwave-oriented software and applications developed in the department of computational electromagnetics are considered. Numerical-analytical automatic mode-matching based models are extended on the objects given in cylindrical coordinate system. The geometry has to be specified as the set of piece-wise coordinate fragments in Cartesian (MWD1...
This paper describes some aspects of wideband (or ultrawideband) measurements of characteristics of antennas which does not require expensive anechoic chambers. The idea of the method is based on exciting the antenna under test by very short impulse which spectrum covers the band of interest and on analysis of spectra of the radiated signals. Reliability of the method is proved by comparison of simulated...
The paper presents generalization of micromechanical control principle for number of microwave devices, such as tunable phase shifters and resonator based filters. Starting with one dimensional dielectric discontinuity model, control principle is propagated to microstrip line devices and dielectric resonators. Maximum possible tuning range is discussed along with accompanying insertion loss.
Short description of new ground radiometric complex, working on 40 GHz and 94 GHz frequencies and providing remote continuous measurements of full vertical atmosphere attenuation, effective temperature values and liquid-water content of clouds, integral content of vaporous moisture in atmosphere. The feature of the complex is the availability of digital signal processing of detected signals mode.
The solution of a scientific problem of determination the informational reliability of the digital channel of troposphere communication with the help of adaptive methods of signal control is currently of great interest. Adaptive methods of signal identification at the output of an adaptive antenna and receiver using signal control and inter-comparison are considered. At the same time the conditions...
This work presents results of research and development of antennas, antenna arrays, polarizers, devices based on plasmon-polariton structures. Mathematical models and computer simulations are developed and tested by researchers of Institute of Telecommunications, Radio Electronics and Electronic Engineering in Lviv Polytechnic National University. Obtained results can be applied for solving various...
The development of slotted waveguide antennas with an integrated radome is discussed. The integrated radome is intended to improve the resistance of slotted-waveguide antennas against complex environmental conditions and to extend application areas of the antennas. Efficient approaches to the design, simulation, and fabrication of such antennas are considered. The development of a single plane monopulse...
This paper considers the problem of formation and optimization of the electromagnetic fields in dielectrics, filling a metal cylinder. The results of mathematical modeling of dielectric heating of liquid in the stream are presented.
Examination of nonlinear periodic composite media based on opal matrices and metal-carbon nanostructures is conducted. This can constitute a new element base opening possibilities for the modern radioelectronics. The considered nanostructures have the substantial potential for their application in perspective nanotechnologies directed on creation of radioelectronic devices for SHF, EHF and HHF bands...
Numerical method for solving the nonlinear two-parameter spectral problems arising in nonlinear synthesis theory of antennas with a flat radiating aperture is considered. The numerical algorithms to find the connected components of the spectrum of linear homogeneous two-dimensional integral equations which describe the branching lines of solutions of synthesis problems of the flat apertures and antenna...
Radiation field calculation method is considered for reflector antenna in its near-field region. The method is based on using field integral representations for reflector antenna obtained with Lorenz reciprocity theorem. The mirror edges contribution to antenna full field is considered using solving simulative problem of plane monochromatic wave diffraction at perfectly conducting wedge. The near-field...
Radiation fields of a radially oriented dipole located on a metal sphere coated with a thin layer of absorbing metamaterial are investigated. Numerical simulations were performed by using the electric Green's function for the space outside of an impedance sphere. An impedance of the metamaterial layer required to minimize the influence of the spherical scatterer with resonant dimensions upon the directivity...
The problem of determining the electromagnetic fields, created by slotted coaxial line, is solved in the present work. To determine the coaxial-slot antenna near-fields the Kirchhoffs method has been applied. Electromagnetic field distributions in the near-zone of coaxial-slot radiator have been explored for different values of feeder parameters on a large range of wavelengths. Field diffraction patterns...
Using the vectorized Kirchhoff integral, the external problem of electrodynamics is solved for emission of continuous aperture antennas with a circular shape radiating opening. The mathematical support was developed and calculations of amplitude and phase characteristics of electric and magnetic fields in the direction of the normal to the radiating opening and on plane surfaces parallel to the opening...
The method for calculating directional characteristics of thin antennas with large dimensions: directional patterns, directivity, pattern factor is proposed. The analytical expressions are determined, and characteristics of metal dipoles, V-dipoles and analogous in-phase radiators are calculated. The importance of accounting the pattern factor for the estimate of a communication range is shown. The...
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