US 7,548,140 B2
Bulk acoustic wave (BAW) filter having reduced second harmonic generation and method of reducing second harmonic generation in a BAW filter
Tiberiu Jamneala, San Francisco, Calif. (US); and Paul D. Bradley, Los Altos, Calif. (US)
Assigned to Avago Technologies General IP (Singapore) Pte. Ltd., Singapore (Singapore)
Filed on Apr. 16, 2007, as Appl. No. 11/735,768.
Prior Publication US 2008/0252398 A1, Oct. 16, 2008
Int. Cl. H03H 9/54 (2006.01); H03H 3/02 (2006.01)
U.S. Cl. 333—189  [310/357] 20 Claims
OG exemplary drawing
 
1. A filter having a half-ladder structure comprising an alternating series of series branches and shunt branches, including a signal input and a signal output related to a common ground, wherein at least one series branch or one parallel branch of the filter is configured as a BAW device comprising a first BAW resonator and a second BAW resonator connected either antiparallel or antiseries, wherein a second harmonic emission generated by the first BAW resonator substantially cancels a second harmonic emission of the second BAW resonator and a second harmonic emission of at least one other series branch or one other parallel branch of the filter.