Tolerance considerations for wireless backhaul diplexer circuits

A novel topology is presented which can relax fabrication tolerances associated with an E-band waveguide diplexer circuit. This is achieved by using a narrow wall short slot coupler/highpass filter configuration, in addition to a low order bandpass filter which reduces the required number of resonating structures by halve when compared to other E-band diplexers in the literature. This is advantageous when tolerance is considered as it is found that resonating structures associated with bandpass filters contribute to fabrication sensitivity. In addition to this, it is found that capacitive iris coupling has benefits over inductive iris coupling due to the positive length of the impedance inverter.