BULK ACOUSTIC WAVE (BAW) FILTER HAVING REDUCED SECOND HARMONIC GENERATION AND METHOD OF REDUCING SECOND HARMONIC GENERATION IN BAW FILTER

摘要

PROBLEM TO BE SOLVED: To provide a filter structure which relaxes the occurrence of unwanted harmonic components in an output signal when driving a filter circuit using BAW resonators at a high power level.;SOLUTION: In a filter having a half-ladder structure, at least one series branch or one parallel branch of the filter is configured as a BAW device including first BAW resonators 1052/1062 and second BAW resonators 1054/1064 connected antiparallel or antiseries. Second harmonic emission generated by the first BAW resonators 1052/1062 substantially cancels second harmonic emission of the second BAW resonators 1054/1064 and the second harmonic emission of at least one other series branch or one other parallel branch of the filter. By this method, the filter's second harmonic emissions are reduced.;COPYRIGHT: (C)2009,JPO&INPIT