Antenna Signal Pad Margin Region Impedance Matching
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Solution Overview
Problem
Existing antenna structures in thin display devices face impedance mismatching issues due to contact resistance, leading to degraded radiation efficiency, especially when integrated with high-frequency communication systems like 3G, 4G, and 5G, where reliable radiation properties are crucial.
Innovation Solution
The antenna structure incorporates a dielectric layer with a signal pad having a bonding region and a margin region, where the area ratio of the margin region to the bonding region is between 0.05 and 0.5, and a conductive intermediate structure is used to connect the flexible circuit board to the bonding region, while the margin region remains non-bonded, optimizing impedance and radiation efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the signal pad is fully bonded to the external circuit structure to ensure good electrical connection, then the contact resistance is reduced, but the radiation efficiency is degraded due to impedance mismatching
Solution Approach 1:
The signal pad is divided into two distinct regions: a bonding region for electrical connection to the external circuit structure and a margin region that remains unbonded. This segmentation allows the bonding region to provide low contact resistance while the margin region maintains proper impedance matching, thereby resolving the contradiction between good electrical connection and radiation efficiency.
Solution Approach 2:
Different regions of the signal pad are given different properties: the bonding region is designed for optimal electrical contact with the external circuit structure, while the margin region is left unbonded to maintain impedance characteristics. This local differentiation allows each region to fulfill its specific function without compromising the other.
2Reliability
If the area of the bonding region is increased to improve electrical connection, then the contact resistance is reduced, but the impedance matching is degraded
Solution Approach 1:
The signal pad area is segmented into a bonding region and a margin region with specific area ratios. The bonding region provides sufficient area for low contact resistance, while the margin region compensates for impedance matching. This segmentation resolves the contradiction by distributing different functions to different areas.
Solution Approach 2:
The area ratio between the margin region and bonding region is optimized to specific ranges (0.05-0.5 in various embodiments) to achieve both low contact resistance and proper impedance matching. By controlling this geometric parameter, the patent simultaneously satisfies electrical connection reliability and impedance matching requirements.
3Length of moving object
If the antenna is integrated into the thin display device to reduce device thickness, then the device profile is reduced, but the radiation properties are degraded
Solution Approach 1:
The unbonded margin region creates a localized area with different electromagnetic properties compared to the bonded region. This local quality difference helps maintain proper impedance and enhances radiation efficiency even in the thin structure, resolving the contradiction between device thickness and radiation properties.
Data Source
AI summary
An antenna structure according to an embodiment of the present invention includes a dielectric layer, a radiator disposed on the dielectric layer, a transmission line branching from the radiator, a signal pad electrically connected to the radiator through the transmission line on the dielectric layer, and an external circuit structure bonded to the signal pad. The signal pad includes a bonding region that is bonded to the external circuit structure and a margin region that is not bonded to the external circuit structure and is adjacent to the bonding region. An area ratio of the margin region relative to the bonding region in the signal pad is 0.05 or more and less than 0.5.