Tunable Dielectric Filter and Filtering Power Divider With Multilevel Transfer Function Tunability

In this article, compact tunable filter and filtering power divider (FPD) with multilevel transfer function tunability based on dual-mode dielectric resonators (DRs) are presented. Two metallic screw pairs (SPs) are arranged on the DR puck, allowing for flexible control of frequencies of the resonant modes and their couplings. Thus, filtering devices with multilevel transfer function tunability can be realized. In addition, the DR puck can switch between single- and dual-mode operations, which is suitable for designing band-switchable filtering devices. Characteristics of the dual-mode DR and control mechanisms are provided in detail. Furthermore, several RF filtering devices are explored to validate the proposed structure: 1) filter with band-switchable capability; 2) filter with self-equalized and elliptic function reconfiguration capability; 3) filter with reconfigurable asymmetric transmission zeros (TZs); and 4) band-switchable FPDs with common-mode (CM) suppression. Good agreement between simulation responses and measured results validates the proposed design concept. Regardless of the reconfiguration transfer function ability, all devices can be center frequency (CF) tuned.