Design of a Bandpass Rectangular Waveguide Filter Based on Direct Coupled Technique

Abstract

This paper presents how to design and simulate two different topologies of a bandpass (BP) rectangular waveguide filter using a direct coupled resonator technique operating at 12 GHz. The filters are characterized by a cross coupling (CM) which produces a single attenuation pole at finite frequency used to realize the bandpass response. The filter resonators provide3rd and 4th order designs with a pseudo-elliptic response using High Frequency Structure Simulator (HFSS) simulator. Transmission zeros are obtained through coupling between the fundamental mode and high mode. The filter structures are validated leading to obtain transmission zeros close to the bandpass. The simulated waveguide filters with a central frequency exhibit an insertion loss of 0.4/0.3dB and a return loss of 20/23dB for the whole bandwidth ranging from 11.85GHz to 12.15GHz that show good electromagnetic responses for the simulated rectangular waveguide filters.