Self-Packaged All-Port CM Reflectionless Balanced Filtering Power Divider Based on SISPSL Structure With Broadband CM Absorption

Abstract

In this article, a self-packaged all-port common-mode (CM) reflectionless balanced filtering power divider (FPD) with high CM suppression and broadband CM absorption is proposed based on substrate-integrated suspended parallel stripline (SISPSL) for the first time. A ring resonator is utilized to provide differential-mode (DM) filtering and power division response based on the Wilkinson power-divider structure. Two transmission zeros (TZs) are generated by employing a ring resonator, significantly improving DM frequency selectivity. Based on the anti-phase-fed double-sided parallel-stripline (DSPSL) structure, a high CM suppression without affecting the DM performance is achieved in the proposed balanced FPD. Furthermore, the CM energy is absorbed by the resistors loaded between the transmission lines, thereby achieving broadband CM reflectionless characteristics. To validate the design, a prototype of the CM reflectionless balanced FPD was designed and fabricated. The measured results show good consistency with simulated data, confirming the feasibility and effectiveness of the proposed approach.