| 摘要 |
In a filter 50, 60 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, at least one series branch or one parallel branch of the filter is configured as a BAW device 57, 67 comprising a first BAW resonator and a second BAW resonator connected either anti-parallel or anti-series. The second harmonic emission generated by the first BAW resonator substantially cancels the second harmonic emission of the second BAW resonator and the second harmonic emission of at least one other series branch or one other parallel branch of the filter. Alternate filter configurations are shown (figs 8, 10). |
