Design of dispersive layered SAW filters with CMOS low noise amplifier

Abstract

Up to now, RF front‐end surface acoustic wave (SAW) filters for mobile communication are mainly fabricated on LiNbO3 and LiTaO3 substrates. A monolithic integration of these filters on Si substrates is highly desirable, but Si is non piezoelectric. One alternative is the deposition of a piezoelectric film on the semiconductor substrate. CMOS technology is very attractive for integrating the radio frequency modules in a single chip. This paper presents the analysis and realisation of a SAW passband filter on silicon substrate based on a piezoelectric ZnO thin film working near 1 GHz , integrated with a CMOS low‐noise amplifier. We propose a modified coupling of modes (COM) approach for a layered ZnO/Si surface acoustic wave filter. The COM parameters in this formulation are the Rayleigh wave velocity, the electromechanical coupling coefficient, the complex reflection coefficient, the transduction coefficient and the inter‐digital capacitance C. This is a dispersive SAW layered filter some parameters of which become frequency dependent due to the phase velocity dispersion. We present the theoretical and experimental results of the filter integrated with a CMOS low noise amplifier.