Mobile Device Metallic Casing Stub Line Antenna Interference
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Solution Overview
Problem
Metallic strips in mobile device casings deteriorate antenna performance by interfering with electromagnetic waves, leading to poor signal reception both when the device is in use and in free space environments.
Innovation Solution
The implementation of a ground plane connected to metallic members via specific connection points, forming stubs that resist electric current flow at desired frequencies, and the use of resonance circuits to adjust the phase of antenna currents, thereby minimizing antenna characteristic degradation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If metallic strips are disposed around the casing to increase mechanical strength and durability, then the structural strength is improved, but the antenna performance deteriorates due to electromagnetic wave interference and electric current transmission
Solution Approach 1:
A ground plane is introduced as an intermediary component between the metallic strips and the antenna system. The ground plane is directly connected to the metallic strips at specific connection points, serving as a mediator that controls electromagnetic field distribution and prevents direct interference between metallic strips and antenna signals, thereby resolving the contradiction between structural strength and antenna performance
Solution Approach 2:
The patent changes the electrical parameters of the metallic strips by controlling their connection to the ground plane at specific points. By adjusting the connection points and ground plane configuration, the electrical characteristics (impedance, current distribution) of the metallic strips are modified to reduce their harmful electromagnetic effects while maintaining their mechanical support function
2Reliability
If metallic strips are connected to ground plane at multiple points to suppress antenna deterioration, then the antenna performance is improved, but the device complexity increases
Solution Approach 1:
Instead of uniformly grounding all metallic strips at multiple points, the patent applies grounding selectively at specific local positions (connection points) on the metallic strips. This localized grounding approach targets the specific areas that cause antenna interference while avoiding unnecessary grounding connections, thereby improving antenna performance without significantly increasing device complexity
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 configuration effectively suppresses antenna performance deterioration to levels comparable to devices without metallic strips, maintaining optimal signal reception both when the device is in use and in free space without altering the metallic strip arrangement.
Implementation Method 1
a transmission path between the first connection point and an open end of the metallic member has a resonant frequency within a first frequency band, in which performance deterioration of an antenna of the communication device is large when the communication device is being held by a user
Data Source
AI summary
Embodiments described herein relate a mobile communication device and techniques to suppress deterioration of antenna characteristics. The mobile device includes metallic members that are disposed around, or in portions of a casing of the mobile device. The metallic member is grounded directly to a ground plane of the mobile device at a first predetermined position. The grounded metallic member forms a stub line that cancels a flow of electric current though the metallic member. Furthermore, the metallic member is also connected to the ground plane, at a second predetermined location, via a resonant circuit. The mobile device is capable of adjusting a phase of the antenna current flowing through the device, when the mobile device is being operated by a user, and thus suppresses deterioration of antenna characteristics in certain desired frequency bands.