RF Module Antenna Switch Variable Filter Attenuation
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Solution Overview
Problem
Existing radio frequency modules face challenges in managing multiple communication bands, leading to increased size and potential signal loss due to the need for separate low pass filters to attenuate spurious waves like harmonic waves, which can result in inefficient signal transmission.
Innovation Solution
A radio frequency module with an antenna switch and a filter circuit that includes a variable reactance element, allowing the attenuation band to shift based on the communication band, ensuring both fundamental and harmonic waves are properly attenuated without increasing module size or causing signal loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If separate low pass filters are provided for each communication band to attenuate spurious waves, then the spurious wave attenuation performance is improved, but the module size increases
Solution Approach 1:
The patent implements a single low pass filter that serves multiple communication bands (e.g., Band 1 and Band 2) simultaneously. This universal filter design allows the same filter component to attenuate spurious waves across different bands, eliminating the need for separate filters for each band and thereby reducing module size while maintaining effective spurious wave suppression.
Solution Approach 2:
The patent merges the spurious wave attenuation function for multiple communication bands into a single low pass filter. By combining what would traditionally require separate filters into one unified filter component, the design achieves space efficiency and reduces the overall module size while still providing the necessary attenuation performance across different bands.
2Volume of stationary object
If a single low pass filter is used to attenuate spurious waves across multiple bands, then the module size is reduced, but signal loss increases due to inability to selectively attenuate specific harmonic waves
Solution Approach 1:
The patent introduces a variable reactance element into the low pass filter design, enabling the filter's characteristics to be dynamically adjusted. This dynamic capability allows the filter to selectively attenuate specific harmonic waves (such as second and third harmonic waves) while preserving the fundamental transmission signals across multiple communication bands, thereby reducing signal loss while maintaining effective spurious wave suppression.
Solution Approach 2:
The patent changes the electrical parameters of the low pass filter by incorporating a variable reactance element. This allows the filter's cutoff frequency and attenuation characteristics to be adjusted according to the specific communication band in use, enabling selective attenuation of harmful harmonic waves while minimizing impact on useful transmission signals, thus reducing overall signal loss.
3Device complexity
If the attenuation band is fixed to cover all communication bands, then spurious wave attenuation is simplified, but transmission signals in certain bands are attenuated causing signal loss
Solution Approach 1:
The patent makes the filter's attenuation band dynamic rather than fixed. By using a variable reactance element, the filter can adjust its attenuation characteristics in real-time based on which communication band is currently in use. This dynamic adjustment ensures that only the necessary harmonic waves are attenuated while transmission signals pass through with minimal loss, resolving the contradiction between simplified configuration and signal preservation.
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 the size of the radio frequency module and minimizes signal loss across multiple communication bands by dynamically adjusting the attenuation band, ensuring efficient signal transmission.
Implementation Method 1
The filter circuit includes a variable reactance element. When the second connection terminal and the common terminal are in connection with each other, the variable reactance element shifts the attenuation band of the filter circuit to a higher band than that when the first connection terminal and the common terminal are in connection with each other.
Data Source
AI summary
An antenna switch of a radio frequency module selectively switches at least between connection between a first connection terminal and a common terminal and connection between a second connection terminal and the common terminal. A first connection terminal receives a signal in a first communication band. A second connection terminal receives a signal in a second communication band. When the second connection terminal and the common terminal are in connection with each other, a variable capacitor (C1, C2) of a filter circuit shifts the attenuation band of the filter circuit to a higher band than that when the first connection terminal and the common terminal are in connection with each other.