Chip Scale Micro-Acoustic Radio Frequency Gyrator

This paper reports on the first demonstration of a micro-acoustic radio frequency (RF) gyrator. The proposed circuit architecture is fully passive, with two micro-acoustic filters being periodically modulated by RF switches to achieve the non-reciprocity. Compared to the conventional passive gyrators based on either transmission lines (TLs) or lumped elements (LCs), the use of high-Q micro-acoustic filters guarantees a low modulation frequency, which allows the use of highly-linear RF switches and improves the linearity of the system. The system requires only two miniaturized micro-acoustic filters and two double-pole, double-throw (DPDT) switches, therefore shows small form factor (device size 6×6 mm²). The demonstrated system shows low insertion loss (IL=3.6 dB), broad bandwidth (1dB BW=15 MHz), high linearity (P1dB=27 dBm; IIP3=35 dBm) and ultra-low modulation frequency (13 MHz) at the same time, addressing all the challenges for the real-world application of RF gyrators.