Design of Novel Compact Directional Branch Line Coupler (BLC) Using Microstrip coupled line for GSM Application

We present here a novel model with compact size of directional branch-line coupler for personal communication. The branch-line coupler (BLC) is based on microwave planar circuit operating at ۹۰۰ MHz. a combination of two coupled open-circuit microstrip lines to create electrical coupling, and a single quarter-wave length is proposed to increase isolation between BLC’s ports. The equivalent circuit of the proposed model is synthesized from L-C circuit and simulated by using a full-wave electromagnetic (EM) simulation tool. A compact branch-line coupler (BLC) is designed, analyzed, and tested using this technique. The size reduction is about ۸۶% with comparable performance. The measurement results are in good agreement with the theoretical ones.

Keywords:

microstrip , Branch Line Coupler (BLC) , Coupled Transmission lines