A Self-Packaged SISL Coupler Using Patterned Ground Structure With Stopband

Abstract

This paper presents a self-packaged branch-line coupler based substrate integrated suspended Line (SISL) platform. Patterned ground structure is designed to achieve good stopband property. As compared with the previous defected ground structure (DGS) which needs additional shielding or supporting structures for practical engineering, the proposed patterned ground structure is embedded inside the self-packaged SISL multi-layer structure, and no additional shielding structure is required. Fabricated by using standard printed circuit board (PCB) process, the implemented SISL branch-line coupler is in a self-packaged form. The measured stopband is up to 3 times of the center frequency of 2.79 GHz. In a bandwidth of 48%, the measured return loss and isolation are better than 14.5 dB. This paper shows a good application method of using the patterned ground structure on SISL platform.