Mutual Coupling Reduction between Closely-Placed MSAs for Bi-Static Radar Using Wave Absorber

Takenori YASUZUMI  Koudai TAKAHASHI  Naoki SANO  Ryosuke SUGA  Osamu HASHIMOTO  

IEICE TRANSACTIONS on Electronics   Vol.E96-C   No.1   pp.77-83
Publication Date: 2013/01/01
Online ISSN: 1745-1353
DOI: 10.1587/transele.E96.C.77
Print ISSN: 0916-8516
Type of Manuscript: PAPER
Category: Microwaves, Millimeter-Waves
microstrip antenna (MSA),  mutual coupling,  radiation pattern,  wave absorber,  

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This paper presents a new simple method for reducing mutual coupling between dual-element microstrip antennas (MSAs) for bistatic radar using a wave absorber. The two elements are closely placed on a substrate by the distance of λ0/4 through the wall-shaped absorber. The height and width of the absorber were optimized for minimum mutual coupling with the electromagnetic simulator. It was found that less than -60 dB minimum mutual coupling can be achieved by the impedance matching of the absorber in a near field. The influence for the reflection characteristics from the absorber is small enough, and the reduction of the antenna gain is only 1.1 dB. The rate of the lost power characteristics showed that the absorption improves the mutual couplings. Then the proposed structure for a practical configuration was investigated. The measurement results of the optimized structure tallied well with the simulation results.