A Compact G-Band Diplexer Based on Quasi-Elliptical Filter

With the development of military and consumer electronics applications, the demand for high-data-rate wireless communications is growing synchronously. Terahertz bands, which have many advantages of large bandwidth, high penetration etc., are attractive in high-speed satellite data link, ultrashort-range interface of portable device, and wireless local area networks (WLANs)1. However, full-duplexer terahertz communication technology has rarely been reported, due to the lack of high-performance terahertz duplexers. To solve this problem, we propose a compact G-band diplexer based on quasi-elliptical filter. Through by-pass coupling, each filter generates a transmission zero in stop bands, which greatly improves the isolation between the two channels, reduces the guard band width, and improves the spectrum utilization. Two quasi-elliptic filters are connected by a T-junction to form the proposed diplexer. By using common junction as a part of filters, the optimization parameters are reduced and the simulation efficiency is greatly improved. Simulation results show that the proposed diplexer has a return loss greater than 15dB in channel 1(200-208GHz) and channel 2 (212-220GHz), and the isolation between the two channels is better than 50dB. This compact, high-isolation diplexer has great potential in G-band terahertz communication systems.