Antenna Coil Wound in Casing Clearance for Compact Wireless Devices
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Solution Overview
Problem
Antenna modules in electronic devices face challenges with large fluctuations in resonance frequencies and difficulty in adjusting distributed capacity between wirings, leading to variations in inductance and requiring numerous manufacturing steps to set resonance frequency, especially when using flexible cables.
Innovation Solution
An antenna apparatus with a coil wound in a clearance between a conductive body and the inner peripheral wall of the casing, allowing inductive coupling with a transmitter without surrounding the outer peripheral portion, enabling favorable communication properties and downsizing of the electronic device casing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the antenna coil is disposed to surround the outer peripheral portion of the conductive body, then the communication properties are improved, but the size of the casing increases
Solution Approach 1:
The patent extracts the antenna coil from the conventional position that surrounds the entire conductive body and repositions it to be wound only in the clearance between the end portion of the conductive body and the inner peripheral wall of the casing. This extraction of the unnecessary surrounding function while retaining the essential magnetic field reception function achieves downsizing of the casing while maintaining communication properties
Solution Approach 2:
The patent transitions the antenna coil configuration from a two-dimensional planar loop surrounding the conductive body to a three-dimensional winding structure in the clearance space. By utilizing the vertical clearance dimension between the conductive body end portion and the casing wall, the antenna coil achieves effective magnetic field reception without requiring horizontal space to surround the conductive body, thereby reducing casing size
2Volume of stationary object
If the antenna coil is wound in the clearance between the conductive body and casing wall, then the casing size is reduced, but the communication properties may deteriorate
Solution Approach 1:
The patent applies local quality by concentrating the antenna coil winding in the specific local region of the clearance between the end portion of the conductive body and the inner peripheral wall of the casing. This localized placement optimizes the magnetic field reception at the critical interface region, ensuring effective communication properties while utilizing minimal space
Solution Approach 2:
The clearance space between the conductive body and the casing wall serves as an intermediary region that is utilized for winding the antenna coil. This intermediary space, previously unused, is transformed into a functional area that provides both magnetic field reception capability and magnetic shielding, thereby maintaining communication properties while enabling downsizing
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 achieves downsizing of the electronic device casing while maintaining favorable communication properties by optimizing magnetic field reception and utilization, with improved coupling coefficients and Q values, enhancing communication efficiency.
Implementation Method 1
an antenna coil which is wound in a clearance between an end portion of a conductive body opposing the transmitter within a casing of an electronic device and an inner peripheral wall of the casing so as not to surround an outer peripheral portion of the conductive body and which is inductively coupled with the transmitter
Data Source
Figure 1
Figure 2A~2B
Figure 3
AI summary
The present invention provides an antenna apparatus which can realize favorable communication properties while achieving downsizing of a casing of an electronic device when incorporated in an electronic device. An antenna module (1a) which is incorporated in a mobile phone (130) and which is enabled to perform communication by receiving a magnetic field transmitted from a reader/writer (120) comprises an antenna coil (11a) which is wound in a clearance (132) between an end portion (133b) of a metallic plate (133a) opposing the reader/writer (120) within a casing (131) of the mobile phone (130) and an inner peripheral wall (131a) of the casing (131) so as not to surround an outer peripheral portion of the metallic plate (133a) and which is inductively coupled with the reader/writer (120).