Design of Low-Pass Corrugated Filters Based on Half-Mode Groove Gap Waveguide Technology

In this paper, low-pass corrugated filters based on half-mode groove gap waveguide (HMGGW) technology are proposed for the first time. The design process starts from the equivalent classical low-pass implementation in corrugated rectangular waveguide. Then, the final response is achieved after a slight re-optimization of groove widths and lengths. As a proof of concept, two corrugated low-pass filters with upper cutoff frequencies at 27 and 29.5 GHz, and maximum attenuation rejection at 34.5 and 39 GHz, respectively, have been designed and manufactured. In spite of the frequency range of operation, the return losses are better than 19.5 dB for both tuning-less filter prototypes, while measured insertion losses are lower than 0.25 dB and 0.3 dB, respectively, in almost the entire passband. The very good agreement between simulations and measurements fully validates the use of this new emerging technology for the implementation of low-pass filters at high frequency bands.