Multiport Multifunctional RF Signal-Routing Networks Using Spatiotemporally Modulated Resonator Arrays

This article presents novel multiport multifunctional RF signal-routing networks that functionalize multiport RF switching, bandpass filtering, power division, and RF isolation. They are based on the reconfigurable spatiotemporal modulation (STM) resonator arrays that are arranged in star- and box-type configurations. Specifically, the star-type block supports three modes of operation: 1) a reconfigurable single-pole multithrow (SPMT) co-designed bandpass filtering isolator (BPFI); 2) a power divider bandpass filter isolator (PD-BPFI); and 3) a bandpass filtering circulator (BPFC). The box-type block supports two modes: 1) a channel-reconfigurable (CR) BPFI (CR-BPFI) mode that can support both concurrent two-channel or single-channel transmission and 2) a PD-BPFI mode. The proposed multiport multifunctional STM-based array concept is demonstrated through circuit-level simulations and is validated by two experimental prototypes. Prototype 1 implements the star-type block configuration at 1.12 GHz with a fractional bandwidth (FBW) of 7%, and exhibits: 1) a single-pole multithrow BPFI (SPMT-BPFI) mode of operation with insertion loss (IL) of $5.18\sim 5.5$ dB; 2) a PD-BPFI mode with IL of 4.7 dB; and 3) a BPFC mode, with passband IL of $4\sim 4.2$ dB. In all of these states, isolation was measured higher than $20\sim 30$ dB. Prototype 2 implements the box-type block operating at 1.2 GHz with a 7% FBW, realizing: 1) a CR-BPFI mode with IL of $3.8\sim 4.1$ dB and 2) a PD-BPFI mode with IL of $4.3\sim 4.8$ dB. Furthermore, all of its nonactive paths exhibit more than 20 dB of isolation.