Surface and leaky waves of a planar dielectric waveguide with a diffraction grating

Abstract

The eigenwave propagation problem is solved for a periodic waveguide composed of a planar dielectric waveguide and a reflecting diffraction grating. The technique the authors used is the spectral theory of open waveguide structures. The numerical data for the dependences of the propagation constants of surface and complex (leaky) eigenwaves are presented versus frequency and geometrical parameters of the periodic waveguide. In the frequency range of leaky eigenwaves, the angular‐frequency characteristics of the radiation directivity are experimentally studied. The experimental results demonstrate the feasibility of the proposed approach.

General Approaches to Solving Problems of Analysis and Synthesis of Directional Properties of Antenna Arrays

“…The chosen option for constructing a power divider makes it possible to perform simulation without taking into account the final level of radiator matching [39] since the main part of the power reflected from the radiators is dissipated in the balanced loads of the directional coupler. The simulation was performed taking into account the following initial data: operating frequency range of the antenna: from 2,7 GHz to 2,85 GHz (5,4%); number of power divider outputs: N = 54; analyzed frequency range: fl = 2,68 GHz, fh = 2,87 GHz, M = 1901; normal frequency: fn = 2,77 GHz; type of delay line waveguide: rectangular (section a×b=62,4×17 mm); linear losses in delay lines: α = 0,07 dB/m; the number of wavelengths at the frequency of the normal forming the period of the delay line: nλ = 2,5; coefficients that determine the shape of the antenna array: p = 0,19, g = 1,65; efficiency of the power divider: η = 79%; standing wave coefficient for the voltage of the bends of the delay line (Rbn): distributed according to a random uniform law in the range from 1,02 to 1,04; standing wave ratio for the voltage of the directional coupler (Rcn): distributed according to a random uniform law in the range from 1,05 to 1,07; the initial phase of the reflection coefficient : distributed according to a random uniform law in the range from 170° to 190°.…”

Numerical simulation of characteristics of propagation of symmetric waves in microwave circular shielded waveguide with a radially inhomogeneous dielectric filling

“…Note that the matrix T does not depend on β, therefore, when solving the dispersion equation (7), it is calculated only once, which significantly reduces the search time for the roots of the dispersion equation. Note that, when deriving equations ( 6) and (7), no restrictions were imposed on the form of dependence ε(r), i.e.…”

“…Note that the matrix T does not depend on β, therefore, when solving the dispersion equation (7), it is calculated only once, which significantly reduces the search time for the roots of the dispersion equation. Note that, when deriving equations ( 6) and (7), no restrictions were imposed on the form of dependence ε(r), i.e. this method allows one to calculate symmetric H-waves with a completely arbitrary nature of the change in the dielectric constant along the transverse coordinate, while ε can also be a complex quantity, which allows, for example, calculating waveguides with a complex absorption distribution in the crosssection, that is, to solve non-self-adjoint boundary value problems, in which the identity of the differential operators of the direct and adjoint boundary value problems is satisfied.…”

“…7) with the number of steps equal to 20. The results of the calculation of the field distribution obtained by solving the dispersion equation (7) are shown in Fig. 8.…”

“…Circular non-uniformly filled waveguides, possessing a number of unique features (anomalous dispersion, complex waves, complex resonance [1][2][3][4][5][6][7]), are widely used [8][9][10][11][12] in the construction of microwave devices such as attenuators, delay lines, bandpass filters, resonators for radio spectroscopes, etc. Calculation and optimization of the parameters of such devices require the development of numerical and analytical methods for studying waveguides with arbitrary dielectric filling.…”