Method of designing acoustic wave RF filter to be robust to variation in frequency response in pass band through resonance frequency modulation of IDT
AssigneeWiPAM, Inc.
InventorsDae Kyu Yu, Kyoung Joon Min, Kyung Oh Kim
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Abstract
The present invention provides a method for design acoustic wave RF filter robust against variations of frequency response in passband by resonance frequency modulation of IDT enabling to improve the skirt characteristics in the passband of the filter by resonance frequency modulation with respect to the IDT electrodes of the resonators constituting the acoustic wave filter and determining the design parameters for the IDT electrodes based on the resonance frequency modulation so as to compensate for variations in frequency response due to effects of temperature variations as well as other factors.
Claims4
A method of designing an acoustic wave RF filter to be robust to variation in frequency response in pass band through resonance frequency modulation of an interdigital transducer (IDT) electrode, the method comprising:
- modulating resonance frequency of the IDT electrode having periodic structure to resonance frequency of a modulated IDT electrode having non-periodic structure by allowing the IDT electrode to have non-periodic fingers;
- determining parameters for the modulated IDT electrode of non-periodic structure from changes of resonance frequencies of the acoustic wave resonators having the modulated IDT electrode parallel-connected and the modulated IDT electrode series-connected;
- and
- constructing the acoustic wave RF filter by connecting the acoustic wave resonators having the modulated IDT electrode according to the determined parameters in parallel and series.
A method of designing an acoustic wave RF filter to be robust to variation in frequency response in pass band through resonance frequency modulation of an interdigital transducer (IDT) electrode, the method comprising:
- configuring the IDT electrode with a plurality of fingers having a period length p into m sub-IDTs having different period lengths p1 to pm;
- generating the resonance frequencies fr1 to fm into which are divided according to modulating a resonance frequency fr of the IDT electrode having period length p to the plurality of sub-IDTs having period lengths p1 to pm;
- generating the anti-resonance frequency fa(m) which is shifted according to modulating an anti-resonance frequency fa(p) of the IDT electrode having period length p to the plurality of sub-IDTs having period lengths p1 to pm;
- determining the period length of each of the plurality of sub-IDTs when the difference between the resonance frequency fr and the divided resonance frequency for the resonator having the plurality of sub-IDTs connected in parallel and the difference between the anti-resonance frequency fa(p) and the shifted anti-resonance frequency fa(m) for the resonator connected in series is maximized;
- constructing the acoustic wave RF filter by connecting the acoustic wave resonators having the sub-IDTs according to the determined period lengths in parallel and series.
Dependencies are inferred from the claim text.