Comprehensive Analytical Synthesis of Star-Junction Multiplexers With Guaranteed Equi-Ripple Responses

This article addresses the limitations in the analytical synthesis of star junction multiplexers, focusing on passband configuration flexibility, maximum achievable multiplexer order, and canonical channel settings, with the aim of eliminating uncertainties in existing approaches. The proposed method provides an optimal design approach by iteratively updating the allocation of reflection zeros (RZs) for various configurations. By introducing a set of techniques to enhance numerical accuracy, the new method significantly expands the order of synthesizable multiplexers to over 200, surpassing existing engineering requirement. Moreover, the new method offers flexibility in accommodating various channel filter configurations, including fully canonical, nonfully canonical filters, and their combinations. The effectiveness and generality of the proposed synthesis technique are validated through three synthesis examples and one design example, which includes fabrication and measurement, demonstrating its capability to address complex challenges in the synthesis of high-order multiplexers.