Notched Ground Element Antenna for Slim Mobile Devices
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Solution Overview
Problem
Designing a wideband antenna for mobile communication devices is challenging due to the need to reduce thickness while maintaining effective bandwidth, especially when the system circuit board and battery are integrated on the same non-rectangular plane.
Innovation Solution
A communication device with a shaped ground element featuring a notch that increases surface currents, allowing the antenna to operate effectively across a broader frequency range, and includes a conductive battery element integrated within the notch to minimize interference with these currents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If the system circuit board and battery element are integrated on the same plane to decrease thickness, then the device thickness is reduced, but the ground element becomes non-rectangular which makes it difficult to design a wideband antenna
Solution Approach 1:
The ground element is segmented by introducing a notch that divides it into multiple regions. This segmentation creates distinct current paths and resonant modes, enabling the antenna to operate across multiple frequency bands (GSM850/900 and LTE700/GSM850/900) despite the non-rectangular overall shape caused by battery integration
Solution Approach 2:
The ground element uses an asymmetric L-shaped or C-shaped configuration with a strategically positioned notch. This asymmetric geometry creates unequal current distribution patterns that enhance bandwidth by supporting multiple resonant modes, resolving the contradiction between the non-rectangular shape requirement for thinness and the need for wideband operation
2Length of moving object
If the ground element is made non-rectangular to accommodate battery integration, then the device can be made thinner, but the antenna radiation performance and bandwidth are degraded
Solution Approach 1:
The notch is positioned at a specific location on the ground element where it locally modifies the current distribution without disrupting the overall radiation mechanism. This local modification creates additional resonant paths while maintaining effective radiation, thereby improving bandwidth and radiation performance despite the non-rectangular shape
Solution Approach 2:
The notch acts as an intermediary structure that mediates between the conflicting requirements of thinness (non-rectangular shape) and radiation performance. By introducing this intermediate feature, the design achieves both goals: the non-rectangular shape enables battery integration for reduced thickness, while the notch compensates for the performance degradation by creating additional current paths
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 effectively increases the bandwidth of the antenna while reducing the device's thickness, enhancing radiation performance and covering multiple communication bands such as GSM850/900 and LTE700/GSM850/900, making it suitable for slim communication devices.
Implementation Method 1
The notch of the ground element increases surface currents flowing in a direction parallel to the second edge on the ground element such that the bandwidth of the antenna element is increased
Implementation Method 2
The battery element further comprises a conductive portion which is electrically coupled to a specific position of the ground element such that the battery element has little impact on the surface currents on the ground element
Data Source
AI summary
A communication device including an antenna element, a ground element and a battery element is provided. The ground element has a short edge as a first edge and a long edge as a second edge. The antenna element is close to the first edge or at a dented section of the first edge. There is a notch in the ground element, and an open edge of the notch is at the second edge. The length of the notch is at least 0.3 times the maximum length of the ground element, and the width of the notch is at least 0.4 times the maximum width of the ground element.