Antenna Device with Segmented Ground Conductors for Miniaturization
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Solution Overview
Problem
Miniaturization and high integration of wireless communication equipment lead to undesired coupling between antenna components, resulting in degraded antenna characteristics due to the proximity of chip components and ground conductors, which cancels out the magnetic field and reduces radiation efficiency.
Innovation Solution
A multilayer substrate with a coil conductor and strategically positioned ground conductors and interlayer connection conductors, where the interlayer connection conductor is only near the side surface, preventing the cancellation of the magnetic field and allowing for high radiation efficiency and miniaturization, while optionally incorporating a magnetic body and unevenly distributed electronic components for improved directivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the module is miniaturized and highly integrated with chip components and ground conductors close to the antenna, then the size and functionality are improved, but undesired coupling occurs and antenna characteristics are degraded
Solution Approach 1:
The ground conductor is segmented into first and second ground conductors positioned on opposite principal surfaces of the coil conductor, with the interlayer connection conductor connecting them only near one side surface. This segmentation prevents the formation of a complete loop around the coil conductor, eliminating the harmful coupling effect while maintaining the miniaturized module structure.
2Volume of moving object
If ground conductors are positioned close to the coil conductor for miniaturization, then the module size is reduced, but the magnetic field is cancelled out and radiation efficiency is reduced
Solution Approach 1:
The interlayer connection conductor is positioned asymmetrically, connecting the first and second ground conductors only near one side surface of the coil conductor rather than symmetrically on both sides. This asymmetric positioning prevents the formation of a symmetric loop that would cancel the magnetic field, thereby maintaining radiation efficiency in the miniaturized structure.
3Adaptability or versatility
If electronic components are mounted on the multilayer substrate for high functionality, then the functionality is enhanced, but the flatness is affected and surface-mounting becomes difficult
Solution Approach 1:
The multilayer substrate is designed with local quality variations, including a magnetic body positioned inside the coil and strategically placed ground conductors and interlayer connection conductors. This local structuring maintains flatness in specific mounting areas while enabling high functionality through the integrated antenna and electronic components.
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 solution achieves good antenna characteristics with increased radiation efficiency and maximum communication distance, reducing loss and enhancing directivity, while maintaining the compact size and functionality of wireless communication devices.
Implementation Method 1
a current in a direction opposed to a current flowing through the coil conductor does not flow into that loop, and a produced magnetic field is not cancelled out
Implementation Method 2
the coil antenna including the magnetic core disposed within the coil winding area is configured, and is miniaturized by the advantage of high magnetic permeability
Data Source
AI summary
A plurality of first linear sections in a coil conductor are disposed on a lower surface of a first resin sheet. A plurality of second linear sections in the coil conductor are disposed on an upper surface of a second resin sheet. A plurality of via conductors in the coil conductor are disposed in the resin sheets. The coil conductor including the linear sections and the via conductors constitutes an antenna section. A first ground conductor is disposed on the lower surface of a third resin sheet. A second ground conductor is disposed on the upper surface of a fourth resin sheet. The first ground conductor and the second ground conductor are connected to each other by a interlayer connection conductor including a plurality of via conductors. The interlayer connection conductor does not define a closed loop surrounding the coil conductor.