Summary
International Symposium on Antennas and Propagation
2010
Session Number:3TA4
Session:
Number:3TA4-4
A Cross Polarization Suppressed Sequential Array for a Primary Radiator of a Parabolic Antenna
Kazuki Ikeda, Keigo Sato, Ken-ichi Kagoshima, Shigeki Obote, Atsushi Tomiki, Tomoaki Yoda,
pp.-
Publication Date:2010/11/23
Online ISSN:2188-5079
Summary:
A typical parabolic antenna on a satellite adopts a horn antenna as a primary radiator, which has wide bandwidth, high gain, and circular polarized radiation. However, it has structural disadvantage such as large dimension and weight. It is desired for a primary radiator of a satelliteborne high gain antenna to be compact and light with maintaining radiation properties as that of the horn antenna. A sequential rotated array consisting of microstrip antennas (MSA) has an advantage in low-profile geometry and light weight, and has wideband circular polarized characteristics [1]. However, a cross polarization level in the φ=45 degree plane is high which degrade radiation efficiency when a conventional sequential array with linear polarized MSA elements [2] is employed. To our knowledge, researches and reports are very few to overcome this problem. In addition, radiation patterns of the sequential array are affected by input impedances of element antennas whose bandwidths are narrow [3]. One of the conventional techniques to broaden the bandwidth of the MSA is an electromagnetically coupled feed. It has been reported that the MSA fed by electromagnetically coupling with an inverted-L shaped probe (L-probe fed MSA) [4][5] has the bandwidth of 36% where a VSWR is less than two [4]. In this paper, we present a sequentially rotated array antenna with a rectangular patch MSA fed by L-probe. Since it is important to decrease couplings between patch elements in order to suppress the cross-polarization level, rectangular patches with aspect ratio of k are adopted. We investigate the cross-polarization level of the sequential array and discuss the relationship between the cross-polarization level and the amount of mutual coupling.