A Design Approach for Asymmetric Coupled Line In-Phase Power Dividers with Arbitrary Terminal Real Impedances and Arbitrary Power Division Ratio

In this paper, we first introduced asymmetric coupled lines (ACLs) into both the transmission path and isolation path in traditional in-phase Gysel power dividers and proposed the single-resistor asymmetric coupled line in-phase Gysel power dividers (ACPDs). Utilizing the decoupled branch-line model of ACLs, a generalized design approach for ACPDs with arbitrary terminal real impedances and arbitrary power division ratio was innovatively proposed. Design formulas relating terminal real impedances, power division ratio, and image impedances of ACLs, for simultaneously satisfying the perfect port isolation and match conditions, are presented. ACPDs achieved a large in-phase power division ratio of 100:1 (20 dB) and offered significant advantages, including impedance transformation, high design freedom, and miniaturization. To automatically determine accurate initial values of geometric parameters for ACLs, a solution software based on MATLAB-HFSS co-simulation and multi-layer perception neural networks was developed, significantly reducing subsequent optimization iterations. To verify the proposed analysis theory and design approach, three ACPDs with different power division ratios of 1:1 (3 dB), 10:1 (10 dB), and 100:1 (20 dB) were implemented. Comparisons of the measured and simulated results showed great accordance, and the three ACPDs achieved good frequency bandwidth, high isolation, excellent port match, and compact size.