Front-End Module Shared Impedance Matching Circuit
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Solution Overview
Problem
Existing multi-band front-end circuits for mobile communication terminals face increased size and signal transmission loss due to the need for individual impedance matching circuits for each signal path as the number of supported frequency bands increases.
Innovation Solution
A front-end module configuration that uses a single impedance matching circuit connected to multiple selection terminals, allowing for adjustable impedance across different frequency bands by switching between filters and impedance matching circuits, reducing the number of circuit elements and signal transmission loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If an individual impedance matching circuit is provided for each signal path, then impedance matching accuracy is improved, but the number of circuit elements and device size increase
Solution Approach 1:
A single impedance matching circuit is designed to serve multiple frequency bands by switching between different configuration states. The circuit includes switching elements that can connect different components (inductors, capacitors) in series or parallel, allowing the same physical circuit to provide impedance matching for multiple bands rather than requiring separate dedicated circuits for each band
Solution Approach 2:
The impedance matching circuit employs switching elements (such as transistors or diodes) that can dynamically change the circuit configuration based on the operating frequency band. By controlling the switching elements, the circuit topology can be reconfigured to match different impedance requirements for different frequency bands, enabling one circuit to adapt to multiple functions
2Manufacturing precision
If an individual impedance matching circuit is provided for each signal path, then impedance matching accuracy is improved, but signal transmission loss increases
Solution Approach 1:
By using a single shared impedance matching circuit for multiple frequency bands, the number of signal paths is reduced. This eliminates redundant impedance matching circuits that would each introduce additional transmission loss, while the switching mechanism ensures that the same high-precision matching is achieved for all bands
Solution Approach 2:
Multiple impedance matching functions for different frequency bands are merged into a single physical circuit structure. The switching elements allow the same circuit components to be shared across different signal paths, reducing the total number of components and minimizing cumulative signal transmission loss while maintaining matching accuracy
3Adaptability or versatility
If the number of supported frequency bands increases, then multi-band capability is improved, but the number of circuit elements and device size increase
Solution Approach 1:
The impedance matching circuit is designed as a universal structure that can handle multiple frequency bands through configuration switching. Instead of adding a separate impedance matching circuit for each new frequency band, the existing circuit can be reconfigured to support additional bands, allowing multi-band capability to expand without proportionally increasing device complexity
Solution Approach 2:
The circuit incorporates dynamic switching elements that enable it to adapt its configuration for different frequency bands. This dynamic reconfigurability allows the same physical hardware to support multiple bands by changing its electrical characteristics through switching, rather than requiring static dedicated circuits for each band
Data Source
AI summary
A front-end module includes a switch, a first filter including an input end connected to a first selection terminal, a second filter including input end connected to a second selection terminal, and an impedance matching circuit connected to a selection terminal, a pass band impedance when viewing the first filter side from a common terminal in a state in which the common terminal and only the first selection terminal are connected is different from a pass band impedance when viewing the second filter side from the common terminal in a state that the common terminal and only the second selection terminal are connected. When the common terminal and the first selection terminal are connected, the common terminal and the selection terminal are connected, and when the common terminal and the second selection terminal are connected, the common terminal and the selection terminal are not connected.