RF Multiplexer Filter Switching to Cut CA Mode Propagation Loss
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Solution Overview
Problem
Existing multiplexers experience significant propagation losses due to the inclusion of a 2P8T switch and additional circuit structures necessary for attenuation characteristics, regardless of whether they are in carrier aggregation (CA) or non-CA mode, which affects the quality of radio frequency signals in mobile devices.
Innovation Solution
A multiplexer design that includes a common terminal with series and parallel arm circuits, featuring acoustic wave resonators and switches, which allows radio frequency signals to bypass the switch in CA mode, reducing switch loss and propagation loss by optimizing the bandpass characteristics and impedance matching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a 2P8T switch is arranged in the preceding stage of all filters to support both CA and non-CA modes, then the multiplexer can selectively pass radio frequency signals in multiple bands, but propagation loss increases due to the switch's ON resistance and additional circuit structures
Solution Approach 1:
The invention divides the multiplexer into multiple independent filter banks, each handling specific frequency bands. Each filter bank contains its own switch and filter circuits, allowing selective activation based on operating mode. This segmentation enables the system to activate only necessary circuits for CA or non-CA mode, reducing overall propagation loss while maintaining versatility.
Solution Approach 2:
The invention implements dynamic circuit configuration where switches can be selectively turned on or off based on the operating mode. In CA mode, multiple filter banks are activated simultaneously; in non-CA mode, only one filter bank is activated. This dynamic switching optimizes signal paths and minimizes propagation loss by avoiding unnecessary switch insertions and circuit engagements.
2Reliability
If attenuation characteristics are optimized for both CA and non-CA modes, then signal quality is maintained, but circuit structure complexity increases
Solution Approach 1:
The multiplexer is segmented into multiple independent filter banks, each with its own attenuation-optimized circuit structure. Each filter bank is designed to maintain signal quality for its specific frequency bands. This segmentation allows each unit to be optimized independently while the overall system maintains versatility through selective combination of filter banks.
Solution Approach 2:
Each filter bank is designed with local optimization of attenuation characteristics tailored to its specific frequency band requirements. The circuit structures within each filter bank are configured to provide optimal signal quality for their designated bands, while the overall system achieves versatility through the combination of these locally optimized units.
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 propagation losses in both CA and non-CA modes by minimizing switch loss and enhancing attenuation characteristics, thereby improving the overall quality of radio frequency signals in mobile devices.
Implementation Method 1
a first series arm resonator that is an acoustic wave resonator having an input terminal and an output terminal connected on the first path
Data Source
AI summary
A multiplexer includes a filter (10) arranged between a common terminal and an input/output terminal (110) and configured to pass a radio frequency signal in a first frequency band, and a filter (20) arranged between the common terminal and an input/output terminal (120) and configured to pass a radio frequency signal in a second frequency band. The filter includes series arm circuits (31 and 32) connected in series, a series arm circuit (33) connected in parallel to the series arm circuit (32), and a parallel arm circuit. The series arm circuit (32) includes a series arm resonator that is an acoustic wave resonator. The series arm circuit (33) includes a switch arranged on a second path connecting nodes. In a CA mode, the switch is OFF. In a non-CA mode, the switch is ON.