Non-Reciprocal RF Co-Designed Filtering Phase Shifters with Continuously Tunable Phase Shift

This paper presents a novel multi-functional RF component that exhibits three distinct RF signal processing functions within its volume. These include: bandpass filtering (BPF), unidirectional transmission/isolation, and continuously-tunable phase shifting. The proposed non-reciprocal filtering phase shifter (NR-FPS) is based on the combination of two concepts, namely reconfigurable passive vector-summation and spatiotemporal modulation of resonator arrays. Whereas the passive-vector summation allows for continuously tunable phase shifting, the STM resonator arrays facilitate RF filtering and directionality. For proof-of-concept demonstration purposes, a NR-FPS with second order RF filtering response and continuously tunable phase shift was manufactured and tested at 680 MHz through a multi-layer PCB-based prototype. It exhibited the following RF measured performance characteristics: continuously tunable phase shift: 340° and unidirectional transmission with directionality exceeding 10 dB across the entire phase tuning range. The proposed NR-FPS allows for multiple RF signal processing actions to be integrated within a single RF component, facilitating the realization of highly-miniaturized RF front-ends.