Dual-Channel Balanced-to-Unbalanced Filtering Power Dividers With Equal and Unequal Division Ratios Using Hybrid Coaxial-Dielectric Resonators

In this article, we propose a method to design the dual-channel balanced-to-unbalanced (BTU) filtering power divider with equal and unequal division ratios. The whole circuit consists of one quad-mode dielectric resonator (DR), two single-mode DRs, and two coaxial resonators. By using these hybrid coaxial and DRs, the proposed design integrates two filtering channels into one circuit, where each channel contains functions of the balun, filter, and power divider, achieving high integration. The integration of the balun circuit function for balanced-to-unbalanced signal conversion is enabled by using electromagnetic-field properties of the two single-mode TM01-mode DRs without increasing the circuit complexity. With two rotated L-shape metal probes as nonresonant nodes, the four modes of the quad-mode DR are divided into two sets and then separately coupled to the two single-mode DRs. The metal probe is loaded to each coaxial resonator to enable coupling between the coaxial resonator and quad-mode DR for the dual-channel circuit operation. Moreover, multiple feeding ports are simply arranged to the coaxial resonators to integrate the power divider function with equal and unequal power division ratios. Then, two channels of balanced-to-unbalanced filtering power dividers are realized in one circuit with high integration. For verification, design examples with equal and unequal power division ratios are provided. A 1:1:2 dual-channel filtering power divider is fabricated and measured with a high common-mode (CM) suppression, good bandpass responses, an accurate power division ratio, and high isolation between two-circuit channels.