Design of a novel microwave diplexer using slit-top mushroom-like units electromagnetic band gap structure and transmission line layer

This paper presents a multi-bandpass filter using the slit-top mushroom-like on two-layer of electromagnetic band gap (EBG) and transmission line structures. The proposed EBG filter will be utilized as diplexers. The characteristics of this diplexer have been studied by using CST software that was found that it can provide the very good performance. The maximum isolation and minimum insertion loss at the Rx-port when the diplexer operates in Tx-mode are around -40.22 dB and -1.38 dB, respectively. The maximum isolation and minimum insertion loss at the Tx-port in Rx-mode is around -38.42 dB and -0.85 dB, respectively. The bandwidth of Tx-mode and Rx-mode are in the range of 3.646 to 3.715 GHz and 3.141 to 3.214 GHz. This work is the feasibility study of the diplexer design by using EBG technology which can be modified to the other desired frequency bands.