Design a Novel Fully Reconfigurable Nonreciprocal Quasi Reflectionless Microstrip Diplexer

Abstract

In this paper, a novel design of a multifunctional quasi-reflectionless non-reciprocal diplexer is proposed. The reflection less diplexer is necessary to overcome many problems in various parts of communication systems that result from reflective unwanted signals from passive elements. in addition, the nonreciprocal diplexer has many advantages in RF systems as interference elimination. The proposed diplexer consists of two pseudocombline BPFs that work in two channels (2.2, 2.6) GHz, respectively. A T-shaped structure is used in the proposed QR diplexer design in three parts (an absorptive part for each BPF and a matching part between the two BPFs). Also the Spatial Temporal Modulation (STM) is used for achieving the nonreciprocity property for the diplexer. Furthermore, the proposed model achieved a high level of absorption for undesired reflected signals, where undesirable waves in the 1.5–4 GHz frequency band were efficiently absorbed. The proposed QR diplexer demonstrates a wide range of suppression for unwanted signals as well as significant separation between the RX and TX ports. All simulations are performed by Keysight ADS software and fabricated by a CNC machine. The results of the proposed work show good agreement between simulation and fabrication.