RF Front-End Switching Layout for Multi-Band Linearity
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Solution Overview
Problem
Existing radio frequency front end modules cannot effectively meet the different requirements of radio frequency signals in various frequency bands under different modes, leading to power loss, increased working current, heating, and poor signal linearity due to the series connection of single-pole M-throw switches and parasitic capacitance.
Innovation Solution
A multi-mode and multi-frequency radio frequency front end module is designed with an output matching unit comprising a first and second output matching module and switch modules, where switches are independently connected to radio frequency transmission paths, allowing the control unit to manage switch states and impedance matching, reducing parasitic capacitance and power loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single-pole M-throw switch is used in series connection in the signal path, then the device complexity is reduced, but power loss increases and working current significantly increases causing heating
Solution Approach 1:
The patent divides the single switching unit into multiple independent switching units (first switching unit, second switching unit, third switching unit), each handling different frequency bands or transmission paths. This segmentation allows parallel signal paths, reducing the need for series connection and thereby reducing power loss while maintaining manageable device complexity through modular design.
2Device complexity
If a single-pole M-throw switch is used in series connection, then the device complexity is reduced, but signal linearity deteriorates due to parasitic capacitance
Solution Approach 1:
By segmenting the switching function into multiple independent switching units, each operating in parallel for different frequency bands, the patent reduces the parasitic capacitance effect on any single signal path. Each switching unit handles a specific frequency band with minimized parasitic effects, thereby improving signal linearity while keeping the overall structure manageable.
Solution Approach 2:
The patent introduces matching circuits (input matching circuit and output matching circuit) as intermediary elements between the switching units and the signal paths. These matching circuits compensate for parasitic capacitance effects and optimize impedance matching, thereby improving signal linearity and reducing the negative impact of parasitic elements.
3Adaptability or versatility
If broadband amplifier covering multiple frequency bands is used, then the adaptability is improved, but the manufacturing precision and signal matching effect deteriorate
Solution Approach 1:
The patent segments the frequency band coverage by assigning different switching units to different frequency bands (e.g., first switching unit for TDD-LTE, second switching unit for FDD-LTE, third switching unit for 5G NR). This allows each amplifier and matching circuit to be optimized for specific frequency bands, improving signal matching effect while maintaining overall adaptability through the switching network.
Solution Approach 2:
The patent implements dynamic switching between different frequency bands and transmission paths based on communication modes. The control unit dynamically configures which switching units are active and which transmission paths are used, allowing the system to adapt to different frequency bands while maintaining optimal signal matching for each specific band through dedicated matching circuits.
Data Source
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AI summary
Disclosed in the present invention are a multimode and multi-frequency radio frequency front end module, a chip, and a communication terminal. The radio frequency front end module comprises an input matching unit, an amplification unit, a first output matching module, a first switch module, a second matching module, and a control unit. The control unit is connected to the first switch module and is used for controlling a switch state of the first switch module, so as to input a radio frequency signal to one or more radio frequency transmission paths. According to the present invention, radio frequency transmission paths matching the radio frequency front end module can be selected according to different frequency bands under different modes and the control unit controls corresponding switches to be in switch-off and switch-on states, thereby implementing output of radio frequency signals at the different frequency bands under the different modes.