A Radio Frequency Non-reciprocal Network Based on Switched Low-loss Acoustic Delay Lines

TL;DR

This paper introduces a novel non-reciprocal RF network utilizing switched low-loss acoustic delay lines, achieving high contrast and broadband operation at a low switching frequency, paving the way for advanced chip-scale nonreciprocal systems.

Contribution

The work presents the first non-reciprocal network based on switched low-loss acoustic delay lines with record low switching frequency and high non-reciprocal contrast.

Findings

Achieved 21 dB non-reciprocal contrast

Operates over 8.8% fractional bandwidth at 155MHz

Uses record low switching frequency of 877.22 kHz

Abstract

This work demonstrates the first non-reciprocal network based on switched low-loss acoustic delay lines. A 21 dB non-reciprocal contrast between insertion loss (IL=6.7 dB) and isolation (28.3 dB) has been achieved over a fractional bandwidth of 8.8% at a center frequency 155MHz, using a record low switching frequency of 877.22 kHz. The 4-port circulator is built upon a newly reported framework by the authors, but using two in-house fabricated low-loss, wide-band lithium niobate (LiNbO3) delay lines with single-phase unidirectional transducers (SPUDT) and commercial available switches. Such a system can potentially lead to future wide-band, low-loss chip-scale nonreciprocal RF systems with unprecedented programmability.