Mutual coupling characteristics of patch array antenna with choke for repeater systems

In this paper, we examine the structure of a patch array antenna suitable for repeater systems. An FB (Front to Back) ratio is determined with a choke structure set up at the edge of the ground plane. An FB ratio of 45 dB is realized when the choke parameters are optimized by electromagnetic analysis. The mutual couplings are about 100 dB when the distance between the elements is 4λ. We also discuss the antenna structure of a 4 port feed type and the coupling of a beam tilted antenna, and confirm that the mutual coupling is changed by the FS (Front to Side) ratio of the element. Experimental and calculated results are also compared.