A Coaxial Line to Post-Wall Waveguide Transition for a Cost-Effective Transformer between a RF-Device and a Planar Slot-Array Antenna in 60-GHz Band

Interfaces between a coaxial structure and a post-wall waveguide are proposed as the essential components for cost-effective millimeter-wave modules. PTFE substrate is selected in terms of loss and manufacturability. The reflection and the transmission characteristics are investigated. The short-stepped and the short-taper-stepped feeding structures provide 14.7% and 13.2% bandwidths for the reflection smaller than -15 dB, respectively. The 46 40 mm 2 size antenna fed by the shortstepped structure in PTFE substrate gives 27.3 dBi with 58.2% efficiency at 60.0 GHz. Feeding structures in PTFE substrate fulfill electrical and manufacturing demands in millimeter-wave bands.