RF Front-End Module Shared Reception Filter
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Solution Overview
Problem
Conventional RF front-end modules with a common antenna for multiple communication signals have large circuit dimensions due to the need for separate duplexers and switch ICs for each frequency band, making miniaturization difficult.
Innovation Solution
The RF front-end module design incorporates a switch element with individual ports connected to a common port, and a reception-side filter that filters both reception signals, eliminating the need for separate reception filters for each communication signal, and using SAW filters and an unbalanced-balanced converting function to reduce circuit dimensions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If separate duplexers are used for each communication signal type, then communication functionality is ensured, but circuit dimensions increase
Solution Approach 1:
The patent merges the reception filter functions of multiple duplexers into a single shared reception filter. The switch element selectively connects different transmission paths to this common reception filter, eliminating the need for separate reception filters for each communication signal type. This combining approach maintains full communication functionality while significantly reducing the overall circuit area.
Solution Approach 2:
The common reception filter is designed to handle multiple communication signal types simultaneously. By making the reception filter universal rather than dedicated to a single signal type, the system achieves the same communication reliability as separate duplexers would provide, while occupying less circuit space.
2Reliability
If a double-pole four-through switch IC is used for balanced signals, then reception signal requirements are met, but circuit dimensions increase
Solution Approach 1:
The patent combines multiple switch functions into a single single-pole double-throw (SPDT) switch element. This switch selectively connects the common reception filter to different transmission paths, replacing the need for a larger double-pole four-through switch IC. The simplified switch configuration meets all reception signal requirements while reducing circuit footprint.
3Measurement precision
If separate reception filters are used for each communication signal, then signal filtering is optimized, but device complexity increases
Solution Approach 1:
The common reception filter is designed with universal filtering capability that handles multiple communication signal types. The switch element manages the selective connection of different transmission paths to this single filter, maintaining optimized signal filtering performance while significantly reducing device complexity compared to multiple dedicated filters.
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 significantly reduces circuit dimensions while maintaining equivalent communication characteristics, facilitating miniaturization and simplifying design by integrating filters and using a single-pole double-throw switch IC.
Implementation Method 1
the first transmission-side filter 211 whose pass band is a frequency band of the first transmission signal and whose attenuation band includes a frequency band of the first reception signal
Data Source
AI summary
An RF front-end module includes power amplifiers, transmission-side filters, a reception-side filter, and a switch IC. A first transmission signal is output from a first transmission signal input terminal to a first common terminal via the power amplifier and the transmission-side filter. A second transmission signal is output from a second transmission signal input terminal to a second common terminal via the power amplifier and the transmission-side filter. A first reception signal input from the first common terminal and a second reception signal input from the second common terminal are input via the switch IC to the reception-side filter, common to the first and second reception signals, and are output from the reception-side filter to a reception signal output terminal.