Dual Acoustic Wave Filter Layout for Band Isolation and Rejection
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Solution Overview
Problem
Existing RF communication systems face challenges in efficiently integrating dual acoustic wave filters with common ground patterns, leading to increased size and cost due to the need for multiple resonator stages, which compromises the rejection of out-of-band signals and increases interference between filter bands.
Innovation Solution
A dual acoustic wave filter design with a common ground trace on a substrate, separating two sections, where shunt resonators are closer to the ground trace than series resonators, enhancing signal rejection and reducing interference without increasing resonator stages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple resonator stages are used to improve filter performance, then out-of-band signal rejection is improved, but device size and cost increase
Solution Approach 1:
The patent applies local quality by creating an asymmetric resonator configuration where shunt resonators are positioned closer to the common ground trace than series resonators. This localized structural differentiation optimizes the electromagnetic field distribution and impedance characteristics at specific points in the filter, achieving improved out-of-band rejection without requiring additional resonator stages. The unequal spacing creates distinct local electrical environments that enhance signal rejection performance.
2Object-generated harmful factors
If multiple resonator stages are added to reduce interference between filter bands, then band isolation is improved, but device area increases
Solution Approach 1:
The patent employs parameter changes by modifying the physical arrangement and spacing of resonators relative to the common ground trace. By adjusting the distance between shunt resonators and the ground trace to be smaller than the distance between series resonators and the ground trace, the electrical parameters (impedance, coupling coefficients) are optimized to enhance band isolation. This parameter optimization achieves reduced inter-band interference within a compact footprint.
3Device complexity
If a common ground pattern is used to reduce device size, then integration density is improved, but manufacturing precision requirements increase
Solution Approach 1:
The patent applies segmentation by dividing the filter structure into distinct functional sections separated by a common ground trace. The asymmetric positioning of shunt and series resonators relative to this ground trace creates clearly defined electrical segments with specific functions. This segmentation approach simplifies the manufacturing process by providing clear reference features (the ground trace) for positioning, thereby reducing precision requirements while maintaining high integration density.
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
The design improves out-of-band signal rejection and reduces interference between filter bands, achieving better performance in a compact form factor while maintaining passband similarity and reducing implementation costs.
Implementation Method 1
a first acoustic wave filter having a plurality of first acoustic resonators arranged in the first section of the substrate and a second acoustic wave filter having a plurality of second acoustic resonators arranged in the second section of the substrate
Implementation Method 2
first series resonators and first shunt resonators and the plurality of second acoustic resonators includes second series resonators and second shunt resonators
Data Source
AI summary
Aspects and embodiments disclosed herein include a dual acoustic wave filter comprising a substrate having a first section and a second section, a first acoustic wave filter having a plurality of first acoustic resonators arranged in the first section of the substrate, a second acoustic wave filter having a plurality of second acoustic resonators arranged in the second section of the substrate, and a common ground trace disposed substantially on a border line running from a first edge of the substrate to a second edge of the substrate opposite to the first edge and separating the first section from the second section of the substrate, the common ground trace providing a ground connection to both the first acoustic wave filter and the second acoustic wave filter.