Acoustic Wave Filter Layout for Low-Loss Balanced Multi-Passband Signals
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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 balance output 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 balance input/output terminals are commonly coupled, and signal phases are opposite, with acoustic wave resonators and wiring lines arranged to minimize the influence of wiring line capacitances, inductances, and resistances, and impedance adjustment is achieved using additional resonators.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If first and second balance output terminals are commonly coupled using wiring lines, then the filter apparatus can process multiple passbands, but parasitic capacitances, inductances, or resistances of the wiring lines increase causing insertion loss to increase and balancing to deteriorate
Solution Approach 1:
The patent introduces acoustic wave resonators as intermediary elements between the filter sections and balance terminals. These resonators act as mediators that transfer signals while minimizing the impact of wiring line parasitics, thereby maintaining balancing performance despite the presence of multiple passbands requiring common coupling.
Solution Approach 2:
The patent converts the harmful effect of wiring line parasitics into a beneficial configuration by strategically positioning acoustic wave resonators. The resonators are designed to compensate for the parasitic effects, transforming the detrimental influence of long wiring lines into an opportunity for optimized signal paths and improved overall filter performance.
2Adaptability or versatility
If first and second balance output terminals are commonly coupled using wiring lines, then the filter apparatus can process multiple passbands, but parasitic capacitances, inductances, or resistances of the wiring lines cause insertion loss to increase
Solution Approach 1:
Acoustic wave resonators are introduced as intermediary elements that transfer signals between filter sections and balance terminals with minimal energy loss. These resonators serve as efficient mediators that reduce the impact of wiring line parasitics, thereby decreasing insertion loss while maintaining multiple passband functionality.
Solution Approach 2:
The patent transitions from a planar wiring layout to a three-dimensional configuration by stacking acoustic wave resonators and wiring lines in multiple layers. This dimensional change allows for shorter effective signal paths and reduced parasitic effects, resulting in lower insertion loss across multiple passbands.
3Device complexity
If wiring lines are arranged to commonly couple balance terminals, then the filter apparatus structure is simplified, but the influence of wiring line capacitances, inductances, and resistances increases
Solution Approach 1:
The patent employs a three-dimensional stacked configuration where acoustic wave resonators and wiring lines are arranged in multiple layers. This dimensional approach simplifies the overall coupling structure by providing direct vertical connections while simultaneously reducing the influence of wiring line parasitics through shorter effective paths and optimized signal routing.
Solution Approach 2:
Acoustic wave resonators serve as intermediary elements that decouple the direct connection between filter sections and balance terminals. This intermediary configuration simplifies the overall structure by providing standardized coupling points while reducing the harmful effects of wiring line parasitics through the resonators' impedance transformation properties.
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 reduces insertion loss and prevents balancing deterioration, allowing for improved amplitude balance characteristics and reduced chip size by minimizing the effects of wiring line stray capacitance, inductance, and resistance.
Implementation Method 1
an acoustic wave filter apparatus includes a piezoelectric substrate; a first acoustic wave filter section disposed on the piezoelectric substrate
Implementation Method 2
a first acoustic wave resonator coupled between the first balance input/output terminal of the first acoustic wave filter section and the first balance terminal; a second acoustic wave resonator coupled between the first balance input/output terminal of the second acoustic wave filter section and the first balance terminal
Data Source
AI summary
An acoustic wave filter apparatus where first balance input/output terminals of first and second acoustic wave filter sections are commonly connected to each other and then connected to a first balance terminal, second balance input/output terminals thereof are commonly connected to each other and then connected to a second balanced terminal, the first and second balance input/output terminals of the first acoustic wave filter section are coupled to the first and second balance terminals, respectively, via first and third wiring lines and first and third acoustic wave resonators, respectively, the first and second balance input/output terminals of the second acoustic wave filter section are coupled to the first and second balance terminals, respectively, via second and fourth wiring lines and second and fourth acoustic wave resonators, respectively, and the second wiring line and the third wiring line cross each other on a piezoelectric substrate.