BULK ACOUSTIC WAVE (BAW) FILTER HAVING REDUCED SECOND HARMONIC GENERATION AND METHOD OF REDUCING SECOND HARMONIC GENERATION IN A BAW FILTER
First Claim
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.
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Abstract
In 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. 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. 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. By this method, the filter'"'"'s second harmonic emissions are reduced.
19 Citations
20 Claims
- 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.
- 15. A method of reducing a harmonic emissions within a BAW 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, the method comprising configuring at least one series branch or one parallel branch of the filter as a BAW device comprising a first BAW resonator and a second BAW resonator connected either antiparallel or antiseries, and configuring the first BAW resonator and the second BAW resonator such that 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.
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16. The method of claim 16, further comprising electrically connecting a first electrode of the first BAW resonator to a second electrode of the second BAW resonator and to a first electrical terminal of the BAW device, and electrically connecting a second electrode of the first BAW resonator to a first electrode of the second BAW resonator and to a second electrical terminal of the BAW device, wherein, the first and second BAW resonators have the same polarizations with regard to their first electrode and their second electrode.
Specification