Dual-Band Dual-Mode Dielectric Resonator Filtering Power Divider With Flexible Output Phase Difference and Power Split Ratio

The design of dual-band filtering power divider based on dual-mode dielectric resonator (DR) is investigated. The external quality factors ( $Q_{e})$ of two modes can be controlled independently, which makes the design procedure for arbitrary power split ratio simple and efficient. Meanwhile, the phase difference between the output ports can be adjusted to be in-phase or out-of-phase by altering the quadrants where the feeding probes are located. To improve the band-to-band isolation, the generation mechanism of the transmission zero between the two bands has been analyzed. Based on the analysis, the dual-band filtering power dividers with in-phase/out-of-phase outputs and equal/unequal power split ratio are proposed. All of them can be easily built by properly changing the location or the length of the feeding probes without increasing the circuit size. To verify the design concept, the above-mentioned prototypes are simulated. Some of them are implemented and measured. The measured results match well with the simulated responses, showing good performance, such as low loss and good band selectivity.