Balanced Acoustic Wave Filter Layout for Lower Insertion Loss
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Solution Overview
Problem
Existing acoustic wave filter apparatuses with multiple passbands suffer from increased insertion loss and deteriorated balancing due to parasitic capacitances, inductances, or resistances of wiring lines when first and second balanced terminals are commonly coupled.
Innovation Solution
The acoustic wave filter apparatus includes first and second acoustic wave filter sections with balance-unbalance conversion functions, where the first and second balanced terminals are commonly coupled with acoustic wave resonators having different resonant frequencies, and wiring lines are configured to cross each other on the piezoelectric substrate, reducing the influence of parasitic effects and insertion loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If first and second balanced terminals are commonly coupled with long wiring lines, then the filter apparatus can process multiple passbands, but parasitic capacitances, inductances, or resistances increase causing insertion loss to increase and balancing to deteriorate
Solution Approach 1:
The patent applies dimensionality change by making wiring lines cross each other on the piezoelectric substrate rather than extending in parallel. This spatial reconfiguration reduces the effective length of wiring lines connecting first and second balanced terminals to multiple passband filter sections, thereby reducing parasitic effects and insertion loss while maintaining multiple passband processing capability.
2Adaptability or versatility
If first and second balanced terminals are commonly coupled with long wiring lines, then the filter apparatus can process multiple passbands, but parasitic capacitances, inductances, or resistances increase causing balancing to deteriorate
Solution Approach 1:
The patent applies dimensionality change by making wiring lines cross each other on the piezoelectric substrate rather than extending in parallel. This spatial reconfiguration reduces the effective length of wiring lines connecting first and second balanced terminals to multiple passband filter sections, thereby reducing parasitic effects and insertion loss while maintaining multiple passband processing capability.
3Loss of energy
If wiring lines are configured to cross each other on the piezoelectric substrate, then parasitic effects and insertion loss are reduced, but wiring line layout complexity increases
Solution Approach 1:
The patent merges the routing paths of multiple wiring lines by configuring them to cross each other on the piezoelectric substrate. This consolidation approach allows multiple signal paths to share the same physical space efficiently, reducing the overall wiring line length and parasitic effects while the crossing configuration itself manages the layout complexity through systematic routing.
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 minimizes the impact of parasitic effects, reduces insertion loss, and maintains balanced signal quality, allowing for smaller chip sizes and improved balancing characteristics.
Implementation Method 1
acoustic wave resonators having different resonant frequencies are coupled between a first balanced input/output terminal of the first acoustic wave filter section and a first balanced terminal
Implementation Method 2
acoustic wave filter sections formed on one piezoelectric substrate
Implementation Method 3
first and second acoustic wave filter sections formed on one piezoelectric substrate
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
There is provided an acoustic wave filter apparatus that is allowed to improve the balancing and reduce the insertion loss in a structure where first and second acoustic wave filter sections are formed on one piezoelectric substrate, first balanced terminals of the first and second acoustic wave filter sections are commonly coupled to each other, and second balanced terminals thereof are commonly coupled to each other. An acoustic wave filter apparatus (1) where first balanced input/output terminals of first and second acoustic wave filter sections (3 and 4) are commonly connected to each other and then connected to a first balanced terminal (7), second balanced input/output terminals thereof are commonly connected to each other and then connected to a second balanced terminal (8), the first and second balanced output terminals of the first acoustic wave filter section (3) are connected to first and third acoustic wave resonators (12 and 13), respectively, via first and third wiring lines (31 and 33), respectively, and then coupled to the first and second balanced terminals (7 and 8), respectively, via the first and third acoustic wave resonators (12 and 13), respectively, the first and second balanced output terminals of the second acoustic wave filter section (4) are coupled to the first and second balanced terminals (7 and 8), respectively, via second and fourth wiring line (32 and 34) and second and fourth acoustic wave resonators (16 and 18), respectively, and the second wiring line (32) and second wiring line (33) cross each other on a piezoelectric substrate (2).