Vadim Pazynin

An FFT-Accelerated FDTD Scheme with Exact Absorbing Conditions for Characterizing Axially Symmetric Resonant Structures

An accurate and e-cient flnite-difierence time-domain (FDTD) method for characterizing transient waves interactions on axially symmetric structures is presented. The method achieves its accuracy and e-ciency by employing localized and/or fast Fourier transform (FFT) accelerated exact absorbing conditions (EACs). The paper details the derivation of the EACs, discusses their implementation and discretization in an FDTD method, and proposes utilization of a blocked-FFT based algorithm for accelerating the computation of temporal convolutions present in nonlocal EACs. The proposed method allows transient analyses to be carried for long time intervals without any loss of accuracy and provides reliable numerical data pertinent to physical processes under resonant conditions. This renders the method highly useful in characterization of high-Q microwave radiators and energy compressors. Numerical results that demonstrate the accuracy and e-ciency of the method are presented.

COMPRESSION AND RADIATION OF HIGH-POWER SHORT RF PULSES. II. A NOVEL ANTENNA ARRAY DESIGN WITH COMBINED COMPRESSOR/RADIATOR ELEMENTS

The paper discusses the radiation of compressed high power short RF pulses using two difierent types of antennas: (i) A simple monopole antenna and (ii) a novel array design, where each of the elements is constructed by combining a compressor and a radiator. The studies on the monopole antenna demonstrate the possibility of a high power short RF pulses e-cient radiation even using simple antennas. The studies on the novel array design demonstrate that a reduced size array with lower pulse distortion and power decay can be constructed by assembling the array from elements each of which integrates a compressor and a radiator. This design idea can be used with any type of antenna array; in this work it is applied to a phased array.

COMPRESSION AND RADIATION OF HIGH-POWER SHORT RF PULSES. I. ENERGY ACCUMULATION IN DIRECT-FLOW WAVEGUIDE COMPRESSORS

Proper design of e-cient microwave energy compressors requires precise understanding of the physics pertinent to energy accumulation and exhaust processes in resonant waveguide cavities. In this paper, practically for the flrst time these highly non-monotonic transient processes are studied in detail using a rigorous time-domain approach. Additionally, in∞uence of the geometrical design and excitation parameters on the compressors performance is quantifled in detail.

Imaging Properties of Finite Maxwell Fish Eye Medium

The imaging properties of the Maxwell medium filling a spherical finite-radius domain have been analyzed. An analytical expression has been obtained for the field of the radial electric dipole inside the sphere. It is shown that the finite Maxwell medium of arbitrarily large size cannot overcome classical Abbes diffraction limit in optical systems. Perfect imaging in the infinite Maxwell medium is the consequence of its electrodynamic closure, i.e., the absence of waves outgoing to infinity.

Passive compression of optical pulses in uniform isotropic and dispersive medium

The compression process of a pulse plane electromagnetic wave in an infinite, homogeneous and dispersive medium is studied. This pulse can be compressed into the pulse of required shape on the segments of a wave path of finite length. The possibility of strict definition of frequency and amplitude modulation laws of the compressed pulse is demonstrated on the example of polystyrene medium.

Radial electric dipole inside finite Maxwell medium

An analytical expression for the field of the radial electric dipole inside the finite Maxwell Fish Eye (MFE) medium is obtained. It is found that arbitrarily large size medium cannot outperform classical Abbes diffraction limit.

Analysis and model synthesis of resonant units for radiators of high-power short radio pulses

This paper deals with the theoretical problems associated with synthesis of resonant units for microwave power compressors compressed in a section of supplying waveguide.

The package of programs for solving model initial boundary-value problems in the theory of nonsinusoidal electromagnetic waves

The package of programs for solving a wide range of two-dimensional problems in the theory of transient electromagnetic fields is presented. This pattern contains all the styles that should be used in the paper. The detailed instructions are presented in This work.

Exact 'absorbing' conditions in initial boundary-value problems of the theory of pulse wave radiation

The outcomes of a search for efficient and correct ways of the truncation of computational domain in finite-difference methods are presented. The relevant mathematical problem is resolved rigorously both for two-dimensional scalar model problems and for three-dimensional vector problems. In the framework of this abstract, we describe briefly only two typical two-dimensional situations. The peculiarities associated with a change to the analysis of three-dimensional vector problems are to be covered in the report.