Acoustic Wave Filter Layout for Stopband Attenuation Control

The patent applies local quality by assigning different impedance values to different interconnect lines within the same circuit. Specifically, the interconnect line connecting the parallel-arm resonator to the switch (third interconnect line) is designed with a lower impedance than the interconnect lines connected to input/output terminals (first and second interconnect lines). This localized impedance differentiation targets the specific region where standing waves cause attenuation degradation, without affecting the overall manufacturability of the device.

The patent employs parameter changes by modifying the impedance parameter of the third interconnect line to be lower than that of the first and second interconnect lines. This parameter adjustment directly addresses the standing wave issue by changing the electrical characteristics of the problematic interconnect line, thereby improving attenuation characteristics in the stop band while maintaining standard manufacturing processes.

The patent limits the complexity increase to a local area by only modifying the impedance of the third interconnect line (connecting the parallel-arm resonator to the switch) while keeping the first and second interconnect lines (connected to input/output terminals) at standard impedance levels. This localized approach improves attenuation characteristics without requiring system-wide impedance matching changes.

The patent applies partial action by selectively lowering the impedance of only the third interconnect line where standing waves cause problems, rather than lowering the impedance of all interconnect lines in the device. This targeted approach achieves the necessary attenuation improvement with minimal additional complexity.