RF Front-End Diplexer Impedance Matching for Narrow-Band CA
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Solution Overview
Problem
Radio frequency circuits face degradation in insertion loss when carrier aggregation is executed between pass bands with a narrow frequency interval, particularly due to the close proximity of pass bands to overlapping frequency bands, leading to degraded signal quality.
Innovation Solution
A radio frequency circuit configuration that includes a diplexer with low and high pass filters and an impedance variable circuit, utilizing switch elements to achieve complex conjugate matching between the filters, thereby reducing insertion loss degradation. The impedance variable circuit, comprising impedance elements and switch elements, adjusts impedance to maintain optimal matching across different frequency bands.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If carrier aggregation is executed between two pass bands with a narrow frequency interval, then the bandwidth utilization is improved, but the insertion loss degrades due to the close proximity to the overlapping frequency band
Solution Approach 1:
The patent applies dynamics by making the impedance of the diplexer adjustable according to the selected pass band combination. The diplexer includes impedance adjustment circuits that can change the impedance values dynamically based on which pass bands are being used for carrier aggregation. This allows the system to optimize performance for different frequency combinations, specifically addressing the insertion loss issue when narrow frequency intervals are used.
Solution Approach 2:
The patent changes physical parameters by adjusting the impedance values of the diplexer components. By modifying the impedance parameters of the low pass filter and high pass filter sections of the diplexer, the system can achieve complex conjugate matching between the pass bands, thereby reducing insertion loss degradation when carrier aggregation is performed on pass bands with narrow frequency intervals.
2Reliability
If the overlapping frequency band is set in the boundary frequency band between two pass bands to ensure isolation, then the isolation between radio frequency signals is improved, but the insertion loss degrades in pass bands close to the overlapping frequency band
Solution Approach 1:
The patent changes the impedance parameters of the diplexer to achieve complex conjugate matching between the pass bands. By adjusting the impedance values in the diplexer's low pass and high pass filter sections, the system maintains effective isolation between frequency bands while minimizing insertion loss in the pass bands, even when they are close to the overlapping frequency region.
Solution Approach 2:
The diplexer's impedance characteristics are made dynamic and adjustable based on the operational mode. The impedance adjustment circuits allow the diplexer to adapt its parameters to different carrier aggregation configurations, ensuring both isolation and low insertion loss are achieved simultaneously by optimizing the impedance match for each specific pass band combination.
3Productivity
If the boundary frequency width between pass bands is reduced to increase bandwidth utilization, then the productivity is improved, but the pass bands become closer to the overlapping frequency band causing insertion loss degradation
Solution Approach 1:
The patent employs parameter changes by adjusting the impedance values of the diplexer components to compensate for the reduced boundary frequency width. By modifying the impedance parameters dynamically, the system maintains low insertion loss characteristics even when pass bands are positioned closer together to maximize bandwidth utilization.
Solution Approach 2:
The system uses dynamic impedance adjustment to adapt to different boundary frequency widths. The diplexer includes control circuits that can modify the impedance characteristics in real-time based on the selected carrier aggregation mode, ensuring optimal insertion loss performance regardless of how closely the pass bands are spaced.
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 proposed configuration effectively reduces insertion loss degradation in radio frequency circuits during carrier aggregation of pass bands with narrow frequency intervals by ensuring complex conjugate matching between low and high pass filters, enhancing signal quality and bandwidth utilization.
Implementation Method 1
a low pass filter connected between the common terminal and the first terminal, allowing a radio frequency signal within a first frequency band to pass through, and attenuating a radio frequency signal within a second frequency band
Implementation Method 2
a high pass filter connected between the common terminal and the second terminal, allowing a radio frequency signal within a third frequency band to pass through, and attenuating a radio frequency signal within a fourth frequency band
Implementation Method 3
the first impedance variable circuit includes a first impedance element, and a first switch element connected to the first impedance element... an impedance of the low pass filter when viewed toward the common terminal from the first terminal and an impedance of the high pass filter when viewed toward the common terminal from the second terminal have a complex conjugate relationship
Data Source
AI summary
A radio frequency circuit includes a filter of a Band A, a filter of a Band B, a filter of a Band C, a low pass filter that is connected between a common terminal and a first terminal, a high pass filter that is connected between the common terminal and a second terminal, and an impedance variable circuit. The frequency interval between the Band A and the Band B is smaller than the frequency interval between the Band A and the Band C. In CA of the Band A and the Band B, the filter is connected to the first terminal, the filter is connected to the second terminal, and an impedance of the low pass filter when viewed from the first terminal and an impedance of the high pass filter when viewed from the second terminal have a complex conjugate relationship.