Table 7.

A summary of studies of PMUTs for air-borne applications.

Reference	Piezoelectric Material	Diaphragm Structure	Center Frequency	Element Size	Array Size
Przybyla et al. [152]	AlN	Circular	214 kHz	Diameter 400 µm	None
Zhou et al. [153]	PMnN-PZT	Circular	150 kHz	Diameter 700 µm	None
Robichaud et al. [154]	AlN	Circular	1.4 MHz	Diameter 400 µm	128 × 4
Gijsenbergh et al. [158]	P(VDF-TrFE)	Circular	150 kHz/240 kHz	Diameter 800 µm/600 µm	4 × 4 7 × 7
Feng and Liu [159]	PZT	Circular	11 kHz	Diameter 750 µm	None
Liu and Wu [155]	PVDF	Circular	200 kHz	Diameter 750 µm	None
Luo et al. [156]	PZT	Circular	40–50 kHz	Diameter 1250 µm	2 × 2
Sun et al. [157]	AlN	Circular	500 kHz/1 MHz	Diameter 170 µm/120 µm	15 × 15
Billen et al. [160]	AlN	Circular	685 kHz	Diameter 400 µm	20 × 20