Multi-Configurable Bandpass Filters with Tune-All Single-, Dual-Band Transfer Functions and Reconfigurable Directionality

Multi-configurable bandpass filters (BPFs) with multiple levels of transfer function tunability and the RF co-designed functionality of a bandpass filter and an RF isolator (BPFIs) are reported. Multiple levels of single- and dual-band tunability, namely center frequency, intrinsic switching off, reconfigurability of the number of passbands by band merging and cancellation and tuning of the out-of-band rejection by transmission zero (TZ) reallocation are obtained by only altering the resonant frequencies of its constituent resonators. Reconfigurability in terms of directionality (i.e., from bi-directional to uni-directional) is also achieved by modulating its resonators with progressively phase shifted low frequency AC signals. For proof-of-concept demonstration purposes, a multi-configurable filter with tune-all transfer function capabilities and reconfigurable directionality based on three cascaded transversal cells was designed, manufactured, and measured at UHF band.