Front-End Module Impedance Reflection for CA Interference Isolation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Front-end modules face challenges in mitigating intermodulation distortion and degradation of reception sensitivity when simultaneously transmitting signals in different frequency bands, particularly when these bands belong to the same frequency band group, due to leakage and interference between antennas.
Innovation Solution
The implementation of a front-end module with a switch and impedance variable circuit that selectively reflects signal components in the second transmission band, combined with phase shifters and matching circuits, to reduce intermodulation distortion by optimizing signal reflection and isolation between frequency bands.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If simultaneous transmission of signals in first band and second band is implemented through two antennas, then two uplinks capability is achieved, but intermodulation distortion occurs in the second quadplexer due to leakage of first-band transmission signals
Solution Approach 1:
A third antenna is introduced as an intermediary element to receive and isolate leakage signals from the first band transmission. This third antenna acts as a mediator that captures the leaked signals before they can interfere with the second quadplexer, thereby preventing intermodulation distortion while maintaining two uplinks capability
Solution Approach 2:
The harmful leakage signals are extracted and isolated from the main transmission path by routing them through a dedicated third antenna. This separation removes the interfering signals from the problematic path between the first and second antennas, eliminating the source of intermodulation distortion
2Reliability
If first-band transmission signals are allowed to flow through both antennas during simultaneous transmission, then signal coverage is improved, but reception sensitivity in the second band degrades due to interference with second-band transmission signals
Solution Approach 1:
The antenna system is segmented into three separate antennas, each dedicated to specific frequency bands. The third antenna is specifically assigned to handle first-band leakage signals, separating them from the second-band reception path. This segmentation prevents interference while maintaining coverage
Solution Approach 2:
The third antenna serves as an intermediary that captures and isolates first-band leakage signals before they can contaminate the second-band reception path. This mediator approach preserves signal coverage benefits while protecting reception sensitivity
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 effectively reduces intermodulation distortion and maintains reception sensitivity by reflecting and canceling interfering signal components, thereby enhancing the performance of carrier aggregation modes in multi-band communication systems.
Implementation Method 1
an impedance variable circuit connected to the second transmission terminal to cause, in the CA mode, reflection of signal components in the second transmission band that are transmitted from the first switch toward the first multiplexer
Data Source
AI summary
A front-end module includes: a first front-end circuit that transmits signals in a first band in a CA mode; and a second front-end circuit that transmits signals in a second band in the CA mode. The second front-end circuit includes a second quadplexer for the first and second bands. The first front-end circuit includes: a first quadplexer for the first and second bands; and an impedance variable circuit that is connected to a transmission terminal that is included in the first quadplexer and corresponds to the second band. In the CA mode, the impedance variable circuit serves as a reflection circuit that causes reflection of transmission waves in the second band. In a non-CA mode, the impedance variable circuit serves as a matching circuit that transmits or absorbs transmission waves in the second band.