RF Switch Module With Selective Filter Bypass for Carrier Aggregation
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Solution Overview
Problem
In multiband communication systems, carrier aggregation leads to harmonic leakage from low-frequency to high-frequency bands, causing sensitivity degradation and impedance mismatching, which increases insertion loss and requires additional filters or matching circuits, making devices bulkier and less efficient.
Innovation Solution
A switch module with a switch circuit and a filter or matching circuit that selectively switches between connection modes, allowing radio-frequency signals to bypass filters or matching circuits in non-carrier-aggregation mode to minimize insertion loss and impedance mismatching, while using filters or matching circuits during carrier-aggregation mode to reduce harmonics and impedance mismatching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a low pass filter is disposed in a transmit path of a low-frequency band, then harmonics leakage is reduced, but the number of filters increases making the device bulkier
Solution Approach 1:
The patent applies a single low pass filter that serves multiple functions by processing transmit signals across different low-frequency bands (e.g., Band 1, Band 2, Band 4, Band 5, Band 6, Band 8) through a unified filter structure, eliminating the need for separate filters for each band while maintaining harmonics reduction effectiveness
Solution Approach 2:
The patent combines multiple filter functions into a single low pass filter component that handles harmonics reduction for multiple low-frequency bands simultaneously, merging what would traditionally require multiple separate filter units into one integrated solution
2Area of stationary object
If a low pass filter is disposed immediately under an antenna, then space is saved, but insertion loss increases due to broad bandwidth requirements
Solution Approach 1:
The patent segments the signal processing function by placing the low pass filter in the transmit path before the antenna rather than immediately under the antenna, allowing the filter to operate on specific frequency bands without requiring excessive bandwidth that would cause high insertion loss, while still achieving harmonics reduction
Solution Approach 2:
The patent introduces an intermediary low pass filter component in the transmit path that mediates between the signal source and the antenna, reducing harmonics before signal transmission without directly coupling to the antenna in a way that would require broad bandwidth and cause high insertion loss
3Reliability
If a matching circuit is provided to eliminate impedance mismatching in CA mode, then impedance matching is improved, but insertion loss increases in non-CA mode
Solution Approach 1:
The patent employs a dynamically configurable matching circuit that can be selectively activated or deactivated based on the operating mode (CA or non-CA), allowing the system to optimize impedance matching only when needed in CA mode while avoiding unnecessary insertion loss in non-CA mode
Solution Approach 2:
The patent changes the operational parameters of the matching circuit by controlling its activation state based on communication mode, adjusting the circuit's electrical characteristics to provide impedance matching only when CA mode is detected, thereby avoiding energy loss in other modes
4Object-affected harmful factors
If multiple low pass filters are provided for different low-frequency bands, then harmonics reduction is effective for each band, but device complexity increases
Solution Approach 1:
The patent designs a universal low pass filter that can effectively reduce harmonics for multiple low-frequency bands (Band 1, Band 2, Band 4, Band 5, Band 6, Band 8) through a single filter structure, eliminating the need for multiple band-specific filters and simplifying the overall device configuration
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 reduces insertion loss and impedance mismatching in non-carrier-aggregation mode, maintains desired performance in carrier-aggregation mode, and saves space by eliminating the need for multiple filters or matching circuits, thereby enhancing the efficiency and compactness of communication devices.
Implementation Method 1
The filter is connected between the first and second bypass terminals and reduces harmonics of a radio-frequency signal which passes through the filter
Data Source
AI summary
A switch module includes a switch circuit and a filter. The switch circuit includes two or more selection terminals, a common terminal provided for the two or more selection terminals, and first and second bypass terminals. The filter is connected between the first and second bypass terminals and reduces harmonics of a radio-frequency signal which passes through the filter. The switch circuit is selectively switched between a first connection mode and a second connection mode. In the first connection mode, the common terminal is connected to any of the two or more selection terminals. In the second connection mode, the common terminal is connected to the first bypass terminal and the second bypass terminal is connected to any of the two or more selection terminals.