Acoustic Wave Multiplexer Layout for Lower Intermodulation Distortion
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Solution Overview
Problem
Multiplexers with acoustic wave filters face challenges in reducing Intermodulation Distortion (IMD) due to nonlinearity, especially with Carrier Aggregation, where increasing the resonator area to minimize IMD is constrained by impedance variations affecting filter characteristics.
Innovation Solution
Designing multiplexers with acoustic wave filters where the relative permittivity of the resonator closest to the common terminal is set to be the lowest, increasing the resonator area and reducing power consumption per unit area, thereby minimizing IMD without optimally varying impedance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If the area of the resonator near the ANT end is increased to reduce IMD, then the occurrence of IMD is reduced, but the impedance of the resonator varies and affects the characteristics of the filter to which the resonator is commonly connected
Solution Approach 1:
The patent applies local quality by assigning different relative permittivity values to different resonators based on their position and function. Specifically, the resonator with the lowest relative permittivity is placed at the ANT end where it can increase in area to reduce IMD without significantly affecting filter impedance, while other resonators maintain higher relative permittivity values to preserve filter characteristics. This localized differentiation resolves the contradiction between reducing IMD and maintaining filter reliability.
Solution Approach 2:
The patent changes the relative permittivity parameter of the resonator near the ANT end to be the lowest among all resonators. This parameter change allows the resonator area to be increased for IMD reduction while the lower relative permittivity compensates for impedance variations, thereby maintaining filter characteristics. This parameter modification directly addresses the technical contradiction.
2Use of energy by stationary object
If the resonator area is increased to decrease power consumption per unit area, then power efficiency is improved, but the impedance variation affects filter characteristics
Solution Approach 1:
The patent applies local quality by differentiating the relative permittivity of resonators based on their positions. The resonator near the ANT end has the lowest relative permittivity, allowing its area to be increased for better power efficiency, while other resonators maintain higher relative permittivity values to preserve filter impedance characteristics. This localized approach resolves the contradiction between power efficiency and filter reliability.
Solution Approach 2:
The patent modifies the relative permittivity parameter of specific resonators to enable area expansion for power efficiency improvement. By setting the relative permittivity of the ANT-end resonator to the lowest value, the patent allows area increase that reduces power consumption per unit area while the parameter change compensates for potential impedance variations, maintaining filter characteristics.
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 IMD occurrences while maintaining optimal capacitance and power efficiency, improving the performance of multiplexers in handling multiple frequency bands.
Implementation Method 1
acoustic wave resonator
Implementation Method 2
acoustic wave filter
Data Source
AI summary
A multiplexer includes a first filter on a first path, a second filter on a second path, and a third filter on a third path. A frequency of intermodulation distortion generated by a transmission signal within a pass band of the first filter and a transmission signal within a pass band of the second filter is within a pass band of the third filter. The first filter includes one or more series resonators on the first path and one or more parallel resonators on one or more paths connecting one or more nodes on the first path to a ground. A relative permittivity of a resonator of the one or more series resonators and the one or more parallel resonators that is closest to a common terminal is lowest among relative permittivities of the resonators.