High-Frequency Front-End Circuit for Leakage Reflection Suppression
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Solution Overview
Problem
High-frequency front-end circuits experience degradation in reception sensitivity due to excessive intermodulation distortion (IMD) caused by multiple reflections of leakage signals between duplexer and low pass/high pass filters, especially during 2UL_CA (2-uplink carrier aggregation), leading to interference with communication signals.
Innovation Solution
Incorporating a multiple reflection prevention unit, such as a peak filter or band pass/high pass filter, between the duplexer terminals and the ground to attenuate leakage signals, reducing or preventing multiple reflections and IMD, while maintaining low transmission loss for communication signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a diplexer and duplexers are used to separate communication signals in different bands, then signal separation is achieved, but multiple reflections of leakage signals occur between the diplexer and duplexers causing degradation in reception sensitivity
Solution Approach 1:
A multiple reflection prevention unit is introduced as an intermediary component between the diplexer and the duplexers. This unit acts as a mediator to suppress multiple reflections of leakage signals without interfering with the normal signal transmission path, thereby resolving the contradiction between maintaining signal separation and preventing harmful reflections
Solution Approach 2:
The multiple reflection prevention function is extracted as a separate, dedicated unit rather than being integrated into the existing diplexer or duplexer structures. This allows the prevention unit to specifically target and eliminate leakage signal reflections without affecting the primary signal separation function of the existing components
2Power
If the power of transmission signals is increased for high-frequency communication, then communication quality is improved, but leakage signals are generated that cause intermodulation distortion and degrade reception sensitivity
Solution Approach 1:
The multiple reflection prevention unit converts the harmful leakage signals into a beneficial configuration by providing a controlled impedance path. Instead of allowing uncontrolled reflections to cause intermodulation distortion, the leakage signals are channeled through the prevention unit where they are dissipated in a controlled manner, transforming a harmful effect into a manageable situation
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 or prevents multiple reflections and IMD, thereby enhancing reception sensitivity and maintaining signal integrity across various communication bands during 2UL_CA.
Implementation Method 1
Incorporating a multiple reflection prevention unit, such as a peak filter or band pass/high pass filter, between the duplexer terminals and the ground to attenuate leakage signals
Data Source
AI summary
A high-frequency front-end circuit includes a diplexer, a duplexer, and a low-band-side multiple reflection prevention unit. The diplexer includes an antenna connection terminal, a low-band-side terminal, and a high-band-side terminal, and separates a low-band communication signal and a high-band communication signal. The duplexer separates a transmission signal and a reception signal of the low-band communication signal. The multiple reflection prevention unit is disposed between the low-band-side terminal and the duplexer and reduces or prevents multiple reflections of a leakage signal of the high-band communication signal which leaks to the low band side.