Table 3.

Summary table for the comparison of acoustic sensors with the advantages and limitations.

Factors	BAW		SAW
	QCM	FBAR
Advantages	Easy to fabricate and use Suitable to operate in the liquid medium due to shear mode Better Q factor Low-cost device Better commercial availability	Miniature device with reduced sample volume Higher sensitivity due to higher operating frequency Operating frequency in the range of lower GHz to few tens of GHz Lower LOD in the range of picograms to femtograms Compatible with CMOS processing due to the use of piezoelectric thin films	Lower power consumption due to high surface energy density Low-cost device and easy to fabricate Higher sensitivity due to high operating frequency Operating frequency in the range of a few MHz to hundreds of MHz LOD in the range of nanomolar to hundreds of picomolar Wireless capability enabling POC devices Commercially available biosensors Ability to operate in liquid medium for all modes except R-SAW
Limitations	Lower sensitivity due to lower operating frequency Operating frequency in the range of 5 MHz to 30 MHz Comparatively lower LOD in the range of µg/mL Incompatible with CMOS processing Inability to batch produce due to bulk quartz substrate Difficult to scale down dimension	Difficulty in manufacturing fragile free-standing structures for FBAR with a back cavity Longer fabrication time and cost for SMR structures Not commercially made on a large scale Higher noise components while making measurements	Higher attenuation of acoustic waves in liquid medium for R-SAW Difficulty in exciting pure shear mode in SH-SAW and Love mode devices Impact of guiding layer to insertion loss for Love mode sensor Breakable structure for Lamb wave devices due to thin membranes