A Cost-efficient Air-Filled Substrate Integrated Ridge Waveguide for mmWave Application

This paper introduces the design of an air-filled substrate integrated ridge waveguide (AFSIRW), and a transition design from microstrip line (MSL) to AFSIRW operating at 60 GHz. The proposed structure is cost-efficient since it is realized on traditional printed circuit board (PCB) technology. An equivalent circuit model of the proposed MSL-AFSIRW transition is presented and verified by full-wave simulation. To verify the proposed idea, a back-to-back transition is designed, fabricated and measured. After calibration, the measured return loss is higher than 15 dB from 54 to 69 GHz. The minimum of measured insertion loss is 0.25 dB at 65 GHz. The measured results show that the proposed design can provide low insertion loss around 60 GHz with low circuit fabrication cost.