Calculation of external aperture admittance and radiation pattern of a narrow slot cut across an edge of a sectoral cylinder in terms of a spectrum of two-dimensional solutions

Abstract

A slotted triangular cylinder is a candidate for a base station antenna in mobile communications. This paper presents an analysis of the external aperture admittance and the radiation pattern of a transverse narrow slot cut across one of the wedges of a sectoral cylinder, the cross section of which approximates the actual triangular shape. Thereby, the external region can be described in terms of two canonical shapes, for which the dyadic Green's functions are obtained analytically. The aperture admittance of the slot is expressed in terms of the integrals of magnetic current over the slot aperture and the infinitely extended interface of the canonical regions. These integrals are evaluated in the spatial and spectral domains, respectively. This hybrid analysis provides good convergence of the results. The dependence of the 3-dB beamwidth and the front to back ratio of the transverse radiation pattern from the slot upon the size and the sector angle of the cylinder are also presented.

Analysis of a Rectangular Waveguide, Edge Slot Array With Finite Wall Thickness

“…The forward Fourier transform is defined as (8) and a indicates a spectral-domain quantity. So, the reaction in (6) becomes (9) where the spectral integrand in (9) is (10) Because the integral equation kernel has a branch point at and the solution fails at the poles of the Green's function, which are related to the scatterer cross-section, the integration path is deformed to the path shown in Fig. 5.…”

“…An excellent overview of the S2DS method applied to scattering problems is given in [7], and a detailed discussion of the use of the electric field integral equation in the S2DS method is found in [8]. The S2DS method is used to treat several types of transverse edge slot antennas in [9]- [11] Another hybrid method that combines a spectral domain method, moment method, and the finite difference method to analyze a single edge slot is presented by Prakash et al in [12], and then extended to full array analysis in [13]. It is noted that the spectral-domain method used to rigorously incorporate the external waveguide structure in [12] and [13] is based on a finite difference method, whereas the spectral-domain method used in the present paper is based on an integral equation method.…”

Analysis of a Slotted Waveguide Array with Baffles in terms of a Spectrum of Two-Dimensional Solutions

“…When a single layer slotted waveguide array is used for plasma excitation, conducting baffles [3] parallel to the waveguide axis are placed in the exterior region as a vacuum window as is shown in Fig.1. A Spectrum of Two-Dimensional Solutions (S2DS) is used to effectively analyze an infinitely-long structure uniform along the waveguide axis [4]. In the present paper, the mutual coupling of multiple slots for co-phase feed model and alternating phase feed model in the external region including the baffles is evaluated by using the S2DS approach which is based on the assumption that the excitation is uniform in the direction transverse to the waveguide axis.…”

“… 4. Frequency characteristics of (a) the reflection coefficient S 11 and (b) the transmission coefficient S 21 for single slot and six-slot array.…”