Experimental characterisation of planar groove gap waveguide and cavity

A planar implementation of groove gap waveguide is presented at Ka-band. The new structure has similar modal characteristics to air-filled machined groove gap waveguide, but in a low-cost fabrication technology that may be readily integrated with surface mount components. The structure provides two DC isolated conducting planes while still providing a low-loss planar transmission medium. A coplanar waveguide to planar groove gap waveguide transition is designed to excite the medium. Measured results demonstrate the TE10 mode passband inside the artificially created bandgap. These de-embedded results indicate good agreement between simulated and measured results over the usable bandwidth of the waveguide (28 to 40 GHz). A cavity resonator's loss is characterised and the unloaded Q-factor of a 33.5 GHz rectangular cavity resonator is measured to be 209. This is demonstrated by measurement to be comparable to an SIW resonator on the same substrate and frequency band.