Foldable Antenna Matching Circuit for Parasitic Resonance Control
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Solution Overview
Problem
Foldable electronic devices face challenges in maintaining radiation performance due to parasitic resonance occurring through conductive sheets, such as copper sheets, in the flexible display, which degrades the antenna's radiation performance.
Innovation Solution
The electronic device incorporates a design where the first housing and conductive portions, including a conductive support member, the ground of the flexible display, the conductive side surface, and the metal frame, are used to guide parasitic resonance frequencies to a band outside the operating frequency band of the antenna, utilizing a matching circuit to induce a second surface current with an opposite phase to the first surface current.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a metal frame is used to reinforce rigidity in foldable electronic devices, then structural strength is improved, but parasitic resonance occurs through conductive sheets which degrades radiation performance
Solution Approach 1:
The patent converts the harmful parasitic resonance into a beneficial effect by intentionally designing conductive portions (side portions and corner portions) that generate second surface currents with opposite phase to cancel the first surface currents causing parasitic resonance. This transforms the harmful resonance phenomenon into a useful cancellation mechanism, improving radiation performance while maintaining the metal frame structure for rigidity.
Solution Approach 2:
The patent introduces conductive portions on the second housing as intermediary elements that mediate between the metal frame structure and the antenna system. These conductive portions act as intermediaries that generate compensating currents to cancel parasitic resonance, allowing the metal frame to maintain structural rigidity without degrading radiation performance.
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 solution effectively improves the radiation performance of the foldable electronic device by shifting the parasitic resonance frequency out of the operating band, thereby enhancing the antenna's efficiency and performance.
Implementation Method 1
planar parasitic resonance may occur through a conductive sheet (e.g., a copper (Cu) sheet) of the flexible display provided therein. Such a parasitic resonance may degrade radiation performance of the foldable electronic device.
Implementation Method 2
a first matching circuit provided on the second support member, electrically coupled with the sixth side portion, and configured to induce a second surface current having a second phase opposite to a first phase of a first surface current induced on the first housing, the second housing, and the hinge structure
Data Source
AI summary
An electronic device includes: a first housing; a second housing; a hinge structure coupled with the first and second housings so that the first and second housings are foldable relative to each other; and a wireless communication circuit on the second housing, wherein the second housing includes: a sixth side portion; a fifth side portion facing the sixth side portion; a fourth side portion facing the hinge structure; a third corner portion between the sixth side portion and the fourth side portion; a fourth corner portion between the fifth side portion and the fourth side portion; and a first matching circuit coupled with the sixth side portion and configured to induce a second surface current having a second phase opposite to a first phase of a first surface current induced on the first and second housings and the hinge structure based on the electronic device being in a folded state.