Receiving Filter Isolation via Capacity Coupling
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Solution Overview
Problem
Existing multiplexers face challenges in achieving effective isolation between transmission and receiving filters due to leakage of electric and magnetic fields, which affects signal integrity and filtering performance.
Innovation Solution
A receiving filter configuration utilizing a longitudinally coupled double-mode type acoustic wave filter with capacity-coupling between the reception terminal and a reference potential terminal, improving isolation through strategic conductor patterns and capacity element placement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a longitudinally coupled resonator type filter is surrounded by a grounded shield electrode, then isolation between receiving and transmission filters is improved, but device complexity and manufacturing difficulty increase
Solution Approach 1:
The patent extracts the isolation function from the traditional grounded shield electrode and relocates it to the reception terminal wiring structure. By configuring the reception terminal wiring to extend in the direction away from the transmission filter and increase spacing, the isolation function is achieved without requiring additional shield electrodes, thus simplifying the device structure while maintaining filter isolation performance
Solution Approach 2:
The reception terminal wiring is designed to serve dual purposes: it provides the necessary electrical connection for signal reception while simultaneously functioning as an isolation structure against the transmission filter. This multi-functional design eliminates the need for separate shield electrodes, reducing device complexity while achieving the isolation effect
2Reliability
If grounded shield electrodes are used to short-circuit leaked electric and magnetic fields, then isolation is improved, but manufacturing precision requirements increase
Solution Approach 1:
The patent removes the grounded shield electrode component entirely and extracts its isolation function into the reception terminal wiring configuration. This eliminates the need for precise positioning of separate shield electrodes, as the isolation is achieved through the inherent spacing and orientation of the reception terminal wiring relative to the transmission filter
Solution Approach 2:
The patent changes the isolation mechanism from active electromagnetic shielding (requiring precise positioning) to passive geometric spacing. By increasing the spacing between the reception terminal wiring and transmission filter, and orienting the wiring away from the transmission filter, the isolation effect is achieved through parameter optimization rather than precise component positioning
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
Enhances isolation between the receiving and transmission filters, reducing signal leakage and improving filtering performance across various frequency bands, as demonstrated by simulation calculations.
Implementation Method 1
a reception terminal conductor configured by the reception terminal and reception terminal wiring and a first reference potential conductor configured by the first reference potential terminal and the first reference potential wiring are mutually adjacent and capacity-coupled
Implementation Method 2
a first filter which is a longitudinally coupled double-mode type acoustic wave filter
Implementation Method 3
longitudinally coupled double-mode type acoustic wave filter
Data Source
AI summary
A receiving filter includes a reception terminal which outputs reception signals from an antenna terminal, a second DMS filter configured by a longitudinally coupled double-mode type acoustic wave filter which is located in a signal path from the antenna terminal to the reception terminal, a fourth GND terminal given a reference potential, and a fourth GND wiring connected to the fourth GND terminal and to the second DMS filter. A reception terminal conductor configured by the reception terminal and the reception terminal wiring connected to the reception terminal and A fourth GND conductor configured by the fourth GND terminal and the fourth GND wiring are adjacent and are capacity-coupled with respect to each other.