Vol 62, No 1 (2017)

A spectral problem in a bi-isotropic waveguide filled nonuniformly in the cross section is considered. A generalized formulation of the problem is considered, making possible, while using Lagrange finite elements, a substantial reduction in the number of spurious modes in the spectral region of interest and shifting them to the higher frequency region. An algorithm for calculating the propagation constants and fields in the given waveguide is implemented. A series of calculations of dispersion curves and fields in a waveguide with different cross-section structures are performed.

An opportunity of determining the lunar soil characteristics via bistatic radar involving high-power ground-based transmitters operating in meter and decameter wave ranges and receivers located aboard Moon satellite is analyzed. Direct and inverse problems concerning stratified soil sounding to a large depth, as well as algorithms for determining the regolith layer thickness, permittivity, radio wave absorption, and regolith and bedrock densities, are examined.

The method of effective dielectric constants for rapid analysis of parameters of nanoplasmon optical waveguides with metal layers is proposed. A rigorous technique of volume integral equations is used to verify the efficiency of the proposed method.

The problem of the matrix synthesis of an antenna array with complex control with the use of a generalized energy functional is solved. It is shown that the proposed solution of the synthesis problem is more general than well-known solutions and enables formation of a specified array complex pattern with required shape of the main lobe with consideration for local requirements on the phase pattern of the antenna array. Results of a numerical experiment performed by the example of a multielement antenna array with complex control, which confirm potentialities of the synthesis method, are presented.

A numerical–analytical method for solution of equations and calculation of the input impedance of thin dipole antennas of arbitrary shape has been developed. High efficiency of the method has been demonstrated by examples.

Spoofing is a deliberate attack that can coerce Global Positioning System (GPS) receivers into providing false position/navigation solutions. Spoofing is more dangerous than jamming since the target receiver is not aware of this menace. In this paper, a novel signal processing scheme is proposed for rejecting the repeat spoofing, which is based on the strong self-coherence property of the C/A code. Firstly, the number and Direction-of-arrivals (DOAs) of spoofing attacks are estimated by the MUSIC-Like DOA estimation method based on the Framework of Beamforming (MLFB). Then, the constrained version of cross spectral self-coherence restoral (cross-SCORE) algorithm is applied to mitigate the spoofing. The proposed scheme can simultaneously mitigate spoofing and adaptively provide high beamforming gain for authentic signal without the prior information of DOAs of the authentic signal. Moreover, the scheme can be used as an independent spoofing mitigation module that can be embedded in the GPS receiver. Simulation experiments demonstrate the effectiveness of the proposed scheme.

Design problems of resonator systems for klystrons of millimeter and submillimeter wave bands are considered. It has been shown that, for efficient interaction of the resonator’s field and the electron beam in such devices, it is necessary to use resonators with high wave impedance. A quality factor, which allows one to compare resonators having different shapes, has been introduced. Different means of increasing the resonator’s wave impedance and circuits coupling resonators to input and output transmission lines have been investigated.

An original design of a compensation magnetic system is suggested and implemented: it enables one to measure the difference signal by placing in the measuring device a film on a paramagnetic device and the original paramagnetic substrate, thereby providing the full compensation of the paramagnetic substrate.

Characteristics of the logical states of TTL ICs are numerically simulated under repetitively pulsed high-power broadband irradiation. It is demonstrated that the repetitively pulsed irradiation leads to accumulation of thermal energy and internal heating of the transistor structure, which cause the drift of logical levels that may result in static and dynamic errors in the IC. Durations of the leading edges are quantitatively estimated for the switching of the logical states of ICs.

An 8-bit parallel DAC with a segmented architecture that employs a 4-bit binary and an unary segments is presented. A switched current source and a thermometric decoder are discussed. A test chip is fabricated using a 180-nm CMOS technology. Measured results show higher conversion rate and smaller chip area in comparison with other papers.