Slotted Ground Plane Antenna for Compact Wireless Devices
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Solution Overview
Problem
The challenge in designing wireless devices, such as mobile phones, is to create a compact antenna structure that balances size reduction with performance requirements like bandwidth, efficiency, and multiband operation, while avoiding the limitations of small antennas which typically have narrow bandwidth and low efficiency due to their small size and proximity to the ground plane.
Innovation Solution
The implementation of a slotted ground plane with strategically placed feeding and ground connections close to the short end of the slot, allowing for direct excitation and enhanced radiation, which improves the antenna's electrical and mechanical characteristics, enabling reduced size and thickness while maintaining or improving radiation features like bandwidth and efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the antenna size is reduced to make the wireless device more compact, then the device volume is reduced, but the antenna bandwidth and efficiency deteriorate
Solution Approach 1:
The ground plane is segmented by introducing slots that divide it into multiple regions. This segmentation allows the ground plane to support multiple resonant modes and impedance transformations, enabling the small antenna to achieve multiband operation and improved bandwidth without increasing the overall device volume.
Solution Approach 2:
The invention changes the geometric parameters of the ground plane (slot positions, slot dimensions, ground plane shape) to optimize the antenna's electrical characteristics. By carefully adjusting these parameters, the antenna achieves improved bandwidth and efficiency while maintaining a compact size suitable for modern wireless devices.
2Length of stationary object
If the antenna is placed close to the ground plane to reduce thickness, then the device thickness is reduced, but the radiation efficiency deteriorates
Solution Approach 1:
The slots in the ground plane act as intermediaries that facilitate efficient electromagnetic coupling between the antenna and the ground plane. These slots create controlled impedance transitions and resonant structures that enhance radiation efficiency even when the antenna is positioned close to the ground plane, thus reducing device thickness without sacrificing performance.
3Ease of operation
If external antennas are removed to improve device aesthetics and ergonomics, then the device appearance is improved, but the antenna reliability deteriorates
Solution Approach 1:
The antenna is merged with the internal structure of the wireless device, specifically integrated with the ground plane and housing components. This integration eliminates the need for separate external antenna elements while maintaining mechanical reliability through robust internal mounting structures and achieving improved aesthetics and ergonomics.
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 approach allows for a more efficient and compact antenna design that enhances radiation performance, supports multiband operation, and reduces the overall size of wireless devices, such as mobile phones, while maintaining or improving radiation features like bandwidth and efficiency.
Implementation Method 1
The implementation of a slotted ground plane with strategically placed feeding and ground connections close to the short end of the slot, allowing for direct excitation and enhanced radiation
Data Source
AI summary
This invention refers to an antenna structure for a wireless device comprising a ground plane and an antenna element, wherein the ground plane has a slot with at least a short end, an open end and a length substantially close to a quarter wavelength. The feeding and ground connections of the antenna structure are placed at the two different sides of said slot and the distance of at least one of them to the short end of the slot is equal or smaller than an eighth of the wavelength. The invention further refers to an antenna structure for a wireless device comprising a ground plane and an antenna element, wherein the ground plane has a slot with at least two short ends, and a length substantially close to half wavelength. The feeding and ground connections of the antenna structure are placed at the two different sides of said slot and the distance of at least one of them to a short end of the slot is equal or smaller than a quarter of the wavelength. Further the invention refers to a corresponding wireless device, a corresponding mobile phone and to a method for integrating such an antenna structure within a wireless device.