High frequency monolithic crystal filters (MCF) using piezoelectric elements operating at the fundamental frequency 30-150 MHz and their adjustment method

摘要

The application of ion-plasma technology enabled us to develop and put into production MCFs using piezoelectric elements with reverse mesa structure operating at the fundamental frequency over the range from 30 to 50 MHz. The filters are manufactured in flat enclosures with the dimensions 12.0/spl times/12.0/spl times/4.2 mm. The advantage of this adjustment method consists in a practically maskless technology because no necessity exists in the mask alignment with the electrode configuration, which would be difficult with a gap of 0.05-0.18 mm. The parameters of 2nd order MCF FP2P-486 operating at the frequencies of 34338, 68736 and 149950 kHz and their frequency attenuation characteristics are given, including frequency attenuation characteristic of 4th order-MCF at 149950 kHz, synthesized from two 2nd order MCFs.