Multiplexer Inductor Magnetic Coupling for Isolation
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Solution Overview
Problem
As the number of frequency bands increases, existing multiplexers face challenges in maintaining isolation between transmission and reception paths, leading to reduced reception sensitivity due to leakage of high-frequency signals, which is difficult to address with inductance components alone.
Innovation Solution
The proposed multiplexer configuration includes a common terminal connected to both transmission and reception filters through inductors that couple via a magnetic field, inverting the phase of leaking high-frequency components to cancel them out, thereby improving isolation between transmission and reception paths while minimizing propagation loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If inductance components are added inside filters to improve isolation, then isolation between transmission and reception paths is improved, but as the number of frequency bands increases, the number of combinations increases and isolation improvement becomes difficult
Solution Approach 1:
The patent merges multiple inductance functions into a single common inductor (L1) that serves multiple frequency bands simultaneously. By coupling this common inductor with transmission path inductors (L2, L3) through magnetic fields, the invention achieves isolation improvement for multiple frequency band combinations using fewer components, directly resolving the contradiction between isolation reliability and device complexity
Solution Approach 2:
The common inductor L1 is designed to provide isolation improvement across multiple frequency bands (Band 25, Band 66, etc.) simultaneously. This multi-functional inductor replaces what would traditionally require multiple separate inductance components for each frequency band combination, reducing overall device complexity while maintaining reliable isolation across all transmission-reception path combinations
2Reliability
If transmission signals with large electric power leak to the reception path, then reception sensitivity is reduced, but adding more inductance components increases device complexity
Solution Approach 1:
The common inductor L1 acts as an intermediary element that mediates between multiple transmission paths and the reception path. By coupling L1 with transmission path inductors L2 and L3 through magnetic fields, it provides a centralized mechanism to prevent leakage of high-power transmission signals to the reception path, improving reception sensitivity without requiring separate inductance components for each transmission-reception pair
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 signal leakage and enhances reception sensitivity by canceling out high-frequency components, improving isolation and cross-isolation between different frequency bands, and allows for reduced size and cost of the multiplexer.
Implementation Method 1
the first inductor and the second inductor couple with each other through a magnetic field
Implementation Method 2
the first inductor and the third inductor couple with each other through a magnetic field
Data Source
AI summary
A multiplexer includes a common terminal, a reception terminal, and transmission terminals; a reception filter between the common terminal and the reception terminal; a transmission filter between the common terminal and the transmission terminal; a transmission filter between the common terminal and the transmission terminal; a first inductor connected in series between the common terminal and the reception filter; a second inductor connected between the transmission terminal and the transmission filter; and a third inductor connected between the transmission terminal and the transmission filter. The first inductor and the second inductor couple with each other through a magnetic field, and the first inductor and the third inductor couple with each other through a magnetic field.