Acoustic Wave Filter Resonance Tuning for Lower Insertion Loss
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Solution Overview
Problem
Existing acoustic wave filters face challenges in reducing insertion loss within the pass band due to the resonant frequency of the cancel circuit being located far away from the pass band, making it difficult to strengthen signals within this band.
Innovation Solution
The acoustic wave filter incorporates an additional resonant circuit with IDT electrode groups and resonant frequencies within the pass band of the filter circuit, ensuring signal phases are aligned to reduce insertion loss and enhance attenuation characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the resonant frequency of the cancel circuit is located far away from the pass band, then attenuation characteristics and isolation characteristics are improved, but insertion loss within the pass band increases
Solution Approach 1:
The patent changes the resonant frequency parameter of the additional resonant circuit from being far away from the pass band (prior art) to being within the pass band (new invention). This parameter change allows the additional resonant circuit to generate signals that constructively interfere with the filter circuit output within the pass band, reducing insertion loss while maintaining attenuation characteristics through the specific configuration of resonant frequencies.
2Object-affected harmful factors
If the resonant frequency of the cancel circuit is located far away from the pass band, then isolation characteristics are improved, but signal strength within the pass band decreases
Solution Approach 1:
The patent adjusts the resonant frequency parameter of the additional resonant circuit to fall within the pass band, enabling the generated signal to constructively interfere with and strengthen the filter circuit output within the pass band. This parameter optimization maintains isolation characteristics while enhancing signal strength through resonant frequency alignment.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration effectively reduces insertion loss within the pass band and improves attenuation characteristics by aligning signal phases, thereby enhancing signal strength and reducing adverse effects outside the pass band.
Implementation Method 1
an IDT electrode group including a plurality of IDT electrodes positioned along an acoustic wave propagation direction
Implementation Method 2
acoustic wave filter including an acoustic wave resonator
Implementation Method 3
At least one resonant frequency of one or more resonant frequencies of the additional resonant circuit is included within the pass band of the filter circuit
Data Source
AI summary
An acoustic wave filter includes a first filter circuit with a predetermined frequency band as a pass band and provided on a first path connecting first and second signal terminals, and an additional resonant circuit connected in parallel with at least a portion of the first filter circuit. The additional resonant circuit includes an IDT electrode group including IDT electrodes positioned along an acoustic wave propagation direction. At least one resonant frequency of one or more resonant frequencies of the additional resonant circuit is included within the pass band of the first filter circuit.