Frequency-Variable Multiplexer Filters for Carrier Aggregation Loss Control
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Solution Overview
Problem
Existing multiplexers experience increased insertion loss and degradation of demultiplexing characteristics when carrier aggregation mode is used, particularly when frequency bands from different groups are combined, leading to poor signal quality due to changes in frequency intervals and boundary bands.
Innovation Solution
A multiplexer design with frequency-variable filters, including a first filter with a switching element that adjusts its pass band and attenuation band based on the connection or disconnection of the switching element, allowing for optimization of pass bands and attenuation bands to maintain signal quality across different frequency combinations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a fixed pass band and attenuation band are used in the filter, then the filter structure is simple, but insertion loss increases and demultiplexing characteristics degrade when frequency bands are combined in carrier aggregation mode
Solution Approach 1:
The patent applies the dynamics principle by making the filter's pass band and attenuation band variable rather than fixed. A switching element is introduced that can dynamically adjust the filter characteristics based on the operating frequency band. When carrier aggregation is detected or when switching between different frequency bands, the switching element changes the filter's frequency response to maintain optimal signal quality and minimize insertion loss across different carrier aggregation configurations.
2Adaptability or versatility
If the pass band is widened to accommodate multiple frequency bands, then frequency band coverage is improved, but insertion loss increases at the band edges
Solution Approach 1:
The patent applies the local quality principle by providing different filter characteristics for different frequency regions. The switching element enables the filter to have optimized pass band characteristics for each specific frequency band or carrier aggregation configuration. Instead of using a single wide pass band with high insertion loss at edges, the filter dynamically adjusts to provide narrow, optimized pass bands with minimal insertion loss for the currently active frequency bands.
3Ease of manufacture
If fixed attenuation bands are used to separate frequency bands, then the filter design is straightforward, but demultiplexing characteristics degrade when frequency intervals change in carrier aggregation mode
Solution Approach 1:
The patent applies the parameter changes principle by making the attenuation band parameters variable rather than fixed. The switching element changes the filter's attenuation characteristics based on the detected frequency band configuration. When carrier aggregation uses different frequency intervals, the switching element adjusts the attenuation band position and shape to maintain effective separation between aggregated carriers, ensuring consistent demultiplexing performance across different configurations.
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 suppresses the increase in insertion loss and degradation of demultiplexing characteristics during carrier aggregation, ensuring stable signal quality even when frequency bands from different groups are combined.
Implementation Method 1
The first filter includes a first frequency-variable circuit including a first switching element. In accordance with connection or disconnection of the first switching element, at least one of the pass band and the attenuation band of the first filter is changeable.
Data Source
AI summary
A multiplexer capable of concurrently sending a radio-frequency signal in one of Band A and Band B belong to a low band group and a radio-frequency signal in a Band C belongs to a high band group that includes: a common terminal and input/output terminals; a low-pass filter arranged between the common terminal and the input/output terminal and whose pass band is frequencies in the low band group and whose attenuation band is frequencies in the high band group; and a high-pass filter arranged between the common terminal and the input/output terminal and whose pass band is the frequencies in the high band group and whose attenuation band is the frequencies in the low band group. The low-pass filter includes a first frequency-variable circuit including a switch, and at least one of the pass band and the attenuation band of the low-pass filter is changeable.