Half-Mode Buried Corrugated Substrate Integrated Waveguide

A half-mode buried corrugated substrate-integrated waveguide is proposed. Its dominant mode propagation behavior is almost identical to that of the half-mode substrate-integrated waveguide but offers a floating top conductor thereby permitting active devices connected to its longitudinal open-edge to be biased without the need for extra biasing chokes. The corrugations comprise open-circuit stubs buried in the substrate that are connected to the top wall of the waveguide by vias. These stubs are quarter-wave in length at a frequency twice the dominant mode cut-off frequency. The corrugations and vias are used to obtain an electric wall. Burying stubs in the substrate results in a low stub input impedance over a wide bandwidth which allows a monomode bandwidth of 3:1 to be obtained. Experiments for waveguides with a TE0.5,0 mode cut-off frequency of 2.8 GHz demonstrate its effectiveness.