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一众所周知,无论以何种压电材料为基片作成的金属叉指式声表面波(SAW)器件的等效电路,主要包含叉指静电路C_T和等效电阻R_a(或电导G_a)。所用压电材料不同,等效电路的形式也不同。当器件的叉指数较多,孔径较大时,C_T的值往往较大,而R_a值往往较小。具有较大输入(或输出)电容及较小电阻的器件,在高频应用中,对高频信号的传输极为不利,可以用一个阻抗变换网络,来保证SAW器件工作于对电端具有良好阻
It is well-known that the equivalent circuit of a metal-interdigital surface acoustic wave (SAW) device made of a piezoelectric material as a substrate mainly includes an interdigital circuit C_T and an equivalent resistance R_a (or a conductance G_a). Piezoelectric materials used in different forms of equivalent circuit is also different. When the device’s fork index more, larger aperture, C_T values tend to be larger, and R_a values tend to be smaller. Devices with larger input (or output) capacitance and smaller resistance are extremely detrimental to the transmission of high-frequency signals in high-frequency applications. An impedance transformation network can be used to ensure that the SAW device operates well on the electrical side