Filter Device Parallel Conductor Lines Isolation
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Solution Overview
Problem
Conventional filter devices, such as duplexers, face challenges with insufficient isolation characteristics between transmission and reception filters, leading to impedance mismatching and increased insertion loss, which cannot be effectively addressed by simply increasing the distance between filter chips or adjusting the impedance of resonators.
Innovation Solution
The implementation of a filter device with a parallel connection area in the conductor line, where multiple conductor lines are connected in parallel, reduces the electrical length and maintains superior isolation characteristics without increasing insertion loss, even when the physical length of the wiring is increased.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the transmission filter chip and reception filter chip are disposed farther away from each other to improve isolation characteristics, then the isolation between filters is improved, but the length of wiring increases which causes impedance mismatching and increases insertion loss
Solution Approach 1:
The conductor line is segmented into multiple parallel conductor lines (first conductor line and second conductor line) that connect the filters to the common connection point. This segmentation allows the wiring to be divided into parallel paths, reducing the electrical length of each path while maintaining the physical separation between filters for isolation characteristics.
Solution Approach 2:
The invention transitions from a single-dimensional conductor line to a multi-dimensional parallel conductor line structure. By utilizing multiple parallel paths in the conductor line, the electrical length is reduced while the physical layout maintains the necessary isolation distance between filters.
2Reliability
If the impedance of resonator in the transmission filter or reception filter is increased to correct impedance mismatching, then the impedance matching is improved, but the insertion loss increases
Solution Approach 1:
The invention extracts the impedance matching function from the resonator impedance adjustment and relocates it to the parallel conductor line structure. Instead of modifying the resonator impedance, the parallel conductor lines provide the necessary impedance matching through their combined electrical characteristics, thereby avoiding the insertion loss penalty.
Data Source
AI summary
In a filter device, a first filter and a second filter are connected to a common connection point by a filter connection conductor line including a first conductor line portion, and a parallel connection area with an electrical length shorter than that in a single conductor line is provided in the first conductor line portion.