Square Diaphragm CMUT Capacitance Calculation Using a New Deflection Shape Function

Table 2

Comparison of new model-calculated capacitance values using deflection shape functions following [10, 12] and (11) with the FEA results for small diaphragm deflection. 𝑑₀=3 μm, Young’s Modulus, 𝐸=169 GPa, Poisson Ratio, 𝑣=0.3, and Bias Voltage = 12 V for all cases.

𝑎	ℎ	𝜎0	𝑃𝑀	𝑤0	𝐶	𝐶 analytical (fF)			%Δ𝐶 (FEA-analytical)
						[10]	[12]	New model	[10]	[12]	New model
(μm)	(μm)	MPa	(kPa)	FEA	FEA (fF)			𝑁=1			𝑁=1
				(μm)
100	1	100	20	0.43	132.96	130.01	135.06	132.72	2.22	−1.58	0.18
100	2	100	160	1.08	144.84	139.22	154.01	145.5	3.88	−6.33	−0.46
100	3	100	400	1.18	146.08	140.3	156.4	146.3	3.94	−7.05	−0.15
100	1	250	60	0.43	136.64	132.14	139.36	136.03	3.29	−1.99	0.44
100	2	250	320	0.95	149.64	142.25	160.49	150.02	4.94	−7.25	−0.25
100	3	250	700	1.11	151.84	144.48	165.31	152.24	4.85	−8.87	−0.26