Millimeter Wave Wideband Filtering Balun Based on LCP Self-Packaged Suspended Coplanar Waveguide Microstrip Hybrid Structure

In this report, a millimeter wave wideband filtering balun based on LCP multi-layer suspended coplanar waveguide (CPW) and microstrip hybrid structure is proposed, which is composed of four two-stage folded SIRs. The differential filtering path is constructed by using the inherent common mode suppression of symmetrical resonators and the electromagnetic coupling among resonators, realizing the integrated design of balanced-unbalanced signal conversion and filtering function. This filtering balun is designed centering at 32 GHz, with a 15dB bandwidth of 17.9 GHz (55.9%), an excellent phase imbalance in the passband of less than 4.9° and an amplitude imbalance of less than 0.68 dB. The whole circuit also has the advantages of simple structure, small size and self-packaged.