Self-adaptive Antenna Systems for Foldable Devices
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Solution Overview
Problem
Foldable electronic devices experience a shift in RF antenna resonant frequencies when changing form factors, leading to poor RF communication performance as the resonant frequencies move outside target frequency bands, impacting the ability to maintain satisfactory communication standards.
Innovation Solution
Incorporating an antenna adaptation element that is positioned closer to the RF antenna in the folded mode to counteract the frequency shift, ensuring the resonant frequencies remain within target bands by modifying the performance characteristics of the RF antenna.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the electronic device transitions from unfolded mode to folded mode, then the compactness and portability are improved, but the RF antenna resonant frequency shifts outside target frequency bands causing poor RF communication performance
Solution Approach 1:
The antenna adaptation element is positioned dynamically relative to the RF antenna based on device configuration. In unfolded mode, the adaptation element is positioned at a first location that does not significantly affect antenna resonance. In folded mode, the adaptation element moves to a second location closer to the antenna to counteract frequency shifts, enabling the system to adapt to changing form factors while maintaining RF performance
Solution Approach 2:
The system changes the physical parameters of the antenna system by adjusting the position of the antenna adaptation element. This positional parameter change modifies the electromagnetic characteristics of the antenna, counteracting the frequency shifts that occur when the device transitions between unfolded and folded states, thereby maintaining resonant frequencies within target bands
2Reliability
If an antenna adaptation element is added to counteract frequency shifts, then the RF communication performance is improved, but the device complexity increases
Solution Approach 1:
The antenna adaptation element serves multiple functions: it acts as a parasitic radiator to counteract frequency shifts, functions as a positioning mechanism that moves with device configuration changes, and integrates into the existing device structure without requiring separate complex tuning systems. This multi-functionality improves RF performance while minimizing added complexity
Solution Approach 2:
The antenna adaptation element automatically adjusts its effectiveness based on device configuration. As the device transitions between unfolded and folded modes, the relative positioning of the adaptation element and RF antenna changes naturally, providing self-adjusting frequency compensation without requiring external control systems or complex tuning mechanisms
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 self-adaptive antenna system maintains acceptable RF communication performance across different form factors by automatically adjusting the resonant frequencies, ensuring consistent performance in both unfolded and folded modes without the need for tuning.
Implementation Method 1
The capacitance and inductance of an RF antenna are determined by its physical properties and the environment in which it is located. Most RF antenna designs are operated around the resonant point. This means that there is only a limited bandwidth over which an RF antenna design can operate efficiently. Outside this, the levels of reactance rise to levels that may be too high for satisfactory operation.
Implementation Method 2
The first antenna and the parasitic radiator are positioned on their respective housings such that they are parasitically coupled when the housings are collapsed and are not coupled when the housings are extended.
Data Source
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AI summary
An electronic device (400) is described that is configurable to be transitioned from a first operating mode having a first form factor to a second operating mode having a second form factor. The electronic device includes a first device portion (408) and a second device portion (410) that is connected to the first device portion. The second device portion includes an RF antenna (412). The first device portion includes an antenna adaptation element (416). The antenna adaptation element is positioned more closely to the RF antenna in the second operating mode than in the first operating mode. The antenna adaptation element is configured to, in the second operating mode, passively counteract or mitigate a shifting of a resonant frequency of the RF antenna that would otherwise occur as a result of the electronic device being transitioned from the first operating mode to the second operating mode.