Mobile Terminal Antenna Filter Unit for Audio Interference
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Solution Overview
Problem
Conventional mobile terminal designs face significant interference issues between antennas and audio components due to the placement of antennas in areas with large radiation, such as the GSM antenna, which is not effectively mitigated by existing isolation methods in lightweight and thin-profile devices.
Innovation Solution
The implementation of a mobile terminal design that includes a diplexer connected to multiple antennas and filter units between these antennas and external interface bodies, such as earphone sockets, to reduce interference by filtering out radio frequencies and routing parasitic currents to ground, thereby minimizing radiation coupling and improving audio and charging signal integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If conventional isolation methods (ground isolation, trace design) are used to reduce antenna-audio interference, then device weight and profile can be kept light and thin, but the interference between antenna and audio components remains significant
Solution Approach 1:
The patent introduces a filter unit as an intermediary component between the antenna and the audio interface body. This filter unit includes a first circuit element connected to the antenna, a second circuit element connected to the audio interface body, and a filter connected between these two circuit elements. The filter acts as a mediator that blocks harmful radio frequency interference while allowing audio signals to pass through, thus resolving the contradiction between maintaining light weight and reducing interference.
Solution Approach 2:
The patent segments the signal path into distinct sections: the antenna section, the filter unit section, and the audio interface body section. By dividing the system into separate functional blocks with the filter unit positioned between the antenna and audio components, the interference is isolated and blocked without requiring the entire device structure to be redesigned, thus maintaining device simplicity while improving audio signal integrity.
2Area of stationary object
If the earphone socket is disposed in the antenna clearance area to save space, then device profile can be reduced, but parasitic current from the antenna couples to the audio signal line causing interference
Solution Approach 1:
The filter unit serves as an intermediary that blocks parasitic current generated by the antenna from coupling to the audio signal line. The filter is connected between the antenna and the audio interface body, allowing audio signals to pass through while blocking radio frequency parasitic currents, thus enabling close proximity placement without interference.
Solution Approach 2:
The patent converts the harmful parasitic current into a controlled signal path by routing it through the filter unit. The filter unit includes a third circuit element that provides a dedicated path for parasitic current to reach ground, converting the harmful interference into a controlled electrical path that does not affect audio signals, thus turning the harmful proximity coupling into a manageable design feature.
3Power
If GSM antenna with large radiation is used to ensure communication coverage, then signal coverage is improved, but mutual interference between antenna and audio components increases
Solution Approach 1:
The filter unit acts as an intermediary that allows the GSM antenna to maintain its large radiation power for good signal coverage while blocking the resulting interference from affecting audio components. The filter is positioned between the high-power antenna and the sensitive audio interface, allowing audio frequencies to pass through while blocking radio frequency interference, thus enabling high-power antenna operation without audio degradation.
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
This design effectively reduces interference between antennas and audio components, enhancing the performance and reliability of mobile terminals by minimizing parasitic current impact on RF signals and audio quality.
Implementation Method 1
filter units between these antennas and external interface bodies, such as earphone sockets, to reduce interference by filtering out radio frequencies
Implementation Method 2
routing parasitic currents to ground, thereby minimizing radiation coupling and improving audio and charging signal integrity
Data Source
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AI summary
A mobile terminal includes an external interface body, an antenna assembly, and a first filter unit. The antenna assembly includes a first antenna, a second antenna, and a diplexer. The external interface body is disposed in an antenna clearance area defined by the first antenna and the second antenna. The diplexer is connected to the first antenna, the second antenna, and a feed of a board of the mobile terminal. The first filter unit is disposed between the first antenna and the external interface body and is connected to a first circuit element of the external interface body to reduce interference from the external interface body to the antenna assembly.