RF Module Two-Stage Switch Segmentation for Multiband Isolation
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Solution Overview
Problem
In radio-frequency modules supporting multiband communication, increased selection terminals lead to higher off-capacitance and transmission loss, particularly when high-power transmission paths are connected, resulting in degraded isolation between transmission and reception paths.
Innovation Solution
The radio-frequency module employs two-stage switches to isolate transmission and reception paths, reducing the number of selection terminals and off-capacitance, with one switch only connected to reception paths to minimize transmission loss and maintain isolation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the number of selection terminals of the switch is increased to support multiband communication, then the adaptability is improved, but the transmission loss is increased due to increased off-capacitance
Solution Approach 1:
The switch is divided into multiple independent switching units, each handling a specific frequency band. By segmenting the signal paths and using multiple switches with fewer terminals each, the off-capacitance per switch is reduced while still supporting multiple bands collectively. This segmentation allows the system to maintain multiband adaptability without the transmission loss penalty of a single high-terminal switch.
2Power
If high-power transmission path is connected to the switch, then the power handling capability is improved, but the isolation between transmission and reception paths is degraded due to reduced voltage resistance
Solution Approach 1:
A duplexer is introduced as an intermediary component between the high-power transmission path and the reception path. The duplexer acts as a mediator that provides galvanic isolation and prevents high-voltage transmission signals from directly affecting the sensitive reception circuitry. This intermediary structure allows high-power transmission while maintaining reliable isolation between transmit and receive paths.
3Adaptability or versatility
If the number of selection terminals is increased, then the adaptability for multiple frequency bands is improved, but the device complexity is increased
Solution Approach 1:
The switching function is segmented across multiple switches rather than concentrated in a single switch with many terminals. Each switch handles a subset of frequency bands, reducing the terminal count per switch and simplifying the overall device architecture. This segmentation strategy maintains full multiband adaptability while reducing individual component complexity and making the system more manageable.
Data Source
AI summary
A radio-frequency module includes a transmission path which has one end connected to a transmission terminal and on which a transmission signal in Band A is transmitted; a reception path (62) which has one end connected to a reception terminal (120B) and on which a reception signal in Band B is transmitted; a reception path (63) which has one end connected to a reception terminal (120C) and on which a reception signal in Band C is transmitted; a switch (11) having a common terminal (11a) and selection terminals (11b and 11c); and a switch (12) having a common terminal (12a) and selection terminals (12b and 12c).