Title :
A Novel Matched Feed Structure for Achieving Wide Cross-polar Bandwidth for an Offset Parabolic Reflector Antenna System
Author :
Jana, Rajib ; Bhattacharjee, Ratnajit
Author_Institution :
Dept. of EEE, IIT Guwahati, Guwahati, India
Abstract :
This letter presents the details of a novel matched feed structure which promises improved cross-polar performance for an offset parabolic reflector antenna. Feed aperture formed by an intersection of circular and rectangular waveguides provides wide cross-polar bandwidth due to the cutoff wave numbers being close for the two modes used in conjugate matching. The mode coefficients and relative phase difference are estimated using particle swarm optimization (PSO) technique for the specified antenna system. Physical optics (PO) is used to evaluate the reflector pattern; feed radiation pattern is obtained using mode field patterns and cutoff wave numbers, which are computed using 2-D finite element method (FEM). The higher order mode which is combined with the main operating mode of the waveguide for conjugate matching is generated using two posts placed behind the aperture. The antenna system performance is evaluated using HFSS and CST Microwave Studio.
Keywords :
antenna radiation patterns; aperture antennas; circular waveguides; finite element analysis; offset reflector antennas; particle swarm optimisation; rectangular waveguides; reflectarray antennas; reflector antenna feeds; waveguide components; 2D FEM; 2D finite element method; PO; PSO technique; circular waveguide; conjugate matching; feed aperture radiation pattern; matched feed structure; offset parabolic reflector antenna system; particle swarm optimization technique; physical optics; rectangular waveguide; wide cross-polar bandwidth performance; Antenna radiation patterns; Apertures; Bandwidth; Feeds; Impedance; Optical waveguides; 2-D finite element method (FEM); cross-polar bandwidth; matched feed; offset parabolic reflector; particle swarm optimization (PSO); physical optics (PO);
Journal_Title :
Antennas and Wireless Propagation Letters, IEEE
DOI :
10.1109/LAWP.2015.2413837
