RF Front-End Circuit Layout for Multi-Band Intermodulation Suppression
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Solution Overview
Problem
Simultaneous transmission of radio-frequency signals with different frequencies in radio-frequency front-end modules leads to intermodulation distortion, deteriorating signal quality due to superimposition of signals.
Innovation Solution
A radio-frequency circuit design that includes transfer circuits with band-elimination filters and multiplexers to separate and amplify signals of non-overlapping frequency bands, preventing intermodulation distortion by blocking unwanted frequency signals from reaching transmission filters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If simultaneous transmission of multiple radio-frequency signals with different frequencies is performed, then communication capability is improved, but intermodulation distortion is generated causing signal quality to deteriorate
Solution Approach 1:
The patent segments the frequency bands by introducing a band-elimination filter that divides the signal path into different frequency components. The filter separates the third frequency band signal from the first frequency band signal, allowing them to be processed independently without causing intermodulation distortion, thus enabling simultaneous transmission of multiple bands while maintaining signal quality
Solution Approach 2:
The band-elimination filter acts as an intermediary component between the multiplexer and the transmission filter. It mediates the interaction between different frequency band signals by selectively eliminating the third frequency band from the signal path before it reaches the transmission filter, preventing harmful intermodulation while allowing the desired first frequency band to pass through
2Reliability
If band-elimination filter is introduced to reduce intermodulation distortion, then signal quality is improved, but device complexity increases
Solution Approach 1:
The band-elimination filter is integrated into the existing transfer circuit architecture, sharing the common signal path with the multiplexer and transmission filter. This multi-functional integration allows the filter to perform band elimination while coexisting with other circuit components, reducing the overall device complexity compared to having completely separate processing paths for different frequency bands
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
The solution effectively reduces intermodulation distortion and in-band spurious emission, improving the quality of radio-frequency signals and satisfying the in-band spurious emission specification in 3GPP, while maintaining reception sensitivity.
Implementation Method 1
a first band-elimination filter that is disposed between the first multiplexer and the first transmission filter, and has, as an attenuation band, a transmission band of the third communication band
Implementation Method 2
a first transmission power amplifier configured to amplify a radio-frequency signal of the first communication band
Data Source
AI summary
A radio-frequency circuit is capable of simultaneously transmitting a radio-frequency signal of a middle high band group (MHB) including B1 and B3, and a radio-frequency signal of a ultra-high band group (UHB) including n77, and includes: a first transfer circuit that transfers the MHB radio-frequency signal and a radio-frequency signal of a low band group (LB); and a second transfer circuit that transfers the UHB radio-frequency signal. The first transfer circuit includes: a power amplifier for B1 signals; a diplexer that demultiplexes and/or multiplexes the MHB radio-frequency signal and the LB radio-frequency signal; a transmission filter that is connected to the power amplifier and has, as a passband, a transmission band of B1; and a band-elimination filter that is disposed between the diplexer and the transmission filter, and has, as an attenuation band, a transmission band of n77. The second transfer circuit includes a power amplifier for n77 signals.