Inductive Bandpass Filters Based on Half-Mode Groove Gap Waveguide

In this work, Ka-band inductive bandpass filters (BPFs) based on horizontally-polarized half-mode groove gap waveguide (HM-GGW) are proposed. HM-GGW is equivalent to a conventional groove gap waveguide (GGW) and it can be obtained replacing half GGW with a uniform surface of metal pins that acts as a high impedance surface (HIS). Two Ka-band inductive bandpass filters centered at 29.5 and 26.75 GHz and with return loss better than 19 dB, have been designed. The same pins cover is reused for both filters, demonstrating the flexibility and the usefulness of this technology,