Filtering couplers based on multi-layer self-packaged suspended coplanar waveguide hybrid and coupled techniques

Abstract

In this paper, new 3 dB/10 dB filtering couplers using branch line loading, multi-line hybrid coupling, and electromagnetic coupling, which are based on self-packaged suspended coplanar waveguide-microstrip (SCPW-MS) hybrid and broadside coupled suspended coplanar waveguide (BC SCPW) techniques, have been proposed. The filtering function is achieved by the branch line loaded resonator, multi-line hybrid coupling and electromagnetic coupling of the SCPW resonator. All of the proposed filtering couplers have been fabricated and measured, and the experimental results approach to the predictions. The advantages of the new designs with low insertion loss of no more than 0.82 dB, favorable isolation of more than 18 dB, phase imbalance of no more than ± 5°, and multiple transmission zeros in some works to introduce high frequency selectivity, and self-packaging have been demonstrated. The dual-layer routing of the core circuit not only retains the advantages of SCPW, but also improves the design flexibility.