Multiband Demultiplexing Circuit With Matching Paths for Tx/Rx Isolation
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Solution Overview
Problem
In demultiplexing apparatuses used in communication machines, supporting multiple communication bands leads to degraded reception sensitivity and isolation between transmission and reception terminals due to common amplifiers, making it difficult to adjust phase correctly and suppress noise components.
Innovation Solution
A demultiplexing apparatus with an amplifier for multiple communication bands, featuring multiple signal paths and transmission-reception filters that isolate transmission and reception signals, and a common matching circuit with individual matching circuits on each path to adjust load impedance and phase for improved impedance matching and reduced noise leakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If common amplifiers are used to support multiple communication bands, then the device can handle multiple frequency bands, but isolation between transmission and reception terminals degrades and reception sensitivity worsens
Solution Approach 1:
The patent divides the common amplifier into multiple independent amplifier units, with each amplifier dedicated to a specific communication band. This segmentation prevents signal leakage between bands and maintains proper isolation between transmission and reception terminals while still supporting multiple communication bands simultaneously.
Solution Approach 2:
The patent introduces transmission-reception filters as intermediary components between the amplifiers and the antenna terminal. These filters act as mediators that selectively pass transmission signals in their designated bands while blocking reception signals, thereby maintaining isolation even when multiple bands are active.
2Reliability
If impedance matching-phase adjustment circuits are provided for each signal path to improve isolation, then transmission-reception isolation improves, but device complexity increases significantly
Solution Approach 1:
The patent assigns one impedance matching-phase adjustment circuit to each dedicated amplifier and its corresponding signal path. This segmentation allows each adjustment circuit to be optimized independently for its specific band without affecting other bands, achieving good isolation while keeping the overall system manageable through modular design.
3Reliability
If multiple transmission-reception filters are provided on multiple signal paths, then isolation between transmission and reception signals improves, but device complexity and cost increase
Solution Approach 1:
The patent designs transmission-reception filters that can handle multiple communication bands with a single filter unit. Each filter is configured to pass transmission signals in its designated band while blocking reception signals across multiple bands, reducing the total number of filters needed compared to having dedicated filters for each band.
Data Source
AI summary
A demultiplexing apparatus according to the present disclosure includes an amplifier that amplifies transmission signals in three or more communication bands having different frequency bands; multiple signal paths which are commonly provided for an output terminal of the amplifier and on which the signals in the corresponding communication bands are propagated; and multiple transmission-reception filters which are provided on the multiple signal paths, and each of which isolates a transmission signal and a reception signal of the corresponding communication band from each other. The gains of the amplifier in the frequency bands of multiple reception signals are smaller than the gains of the amplifier in the frequency bands of multiple transmission signals.