900 MHz/1.8 GHz thin-film microwave bandpass filter

Abstract

900 MHz and 1.8 GHz microwave thin-film bandpass filters on Al/sub 2/O/sub 3/ substrates are designed, fabricated and characterized. Based on the high-Q values of passive components, spiral inductors and MIM capacitors for example, a low insertion loss of thin-film bandpass filter can be realized with a minimized chip area. The insertion loss was 3 dB for a 1.8 GHz filter, and was 5 dB for a 900 MHz filter.