Ear-Worn Antenna Cutout Layout for Wider 2.4 GHz Bandwidth
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Solution Overview
Problem
The challenge in designing small RF antennas for ear-worn electronic hearing devices is that they often suffer from low feed point impedance, inability to meet total radiated power (TRP) requirements due to low radiation efficiency, and a narrow frequency bandwidth that cannot effectively operate over the 2.4 GHz ISM band.
Innovation Solution
The implementation of an antenna with a multiplicity of cutouts along the antenna periphery and/or along the periphery of one or more interior windows, which increases the electrical length of the antenna without increasing its physical size, thereby enhancing radiation efficiency and impedance bandwidth.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the physical size of the antenna is reduced to fit in ear-worn devices, then the device becomes more compact and wearable, but the radiation efficiency and impedance bandwidth deteriorate
Solution Approach 1:
The antenna periphery is segmented by introducing multiple cutouts (first, second, third cutouts) at different locations. This segmentation increases the electrical length of the antenna by creating additional current paths along the periphery, allowing the small physical antenna to achieve the electrical characteristics of a larger antenna, thereby improving radiation efficiency and impedance bandwidth
Solution Approach 2:
The cutouts are positioned at specific locations along the antenna periphery to create multiple-dimensional current distribution paths. This dimensional approach to current flow optimization allows the antenna to achieve enhanced electrical length and improved radiation efficiency within the constrained physical space of ear-worn devices
2Volume of moving object
If the physical size of the antenna is reduced to fit in ear-worn devices, then the device becomes more compact and wearable, but the impedance bandwidth becomes narrow and cannot operate over 2.4 GHz ISM band
Solution Approach 1:
Multiple cutouts are strategically positioned along the antenna periphery to create segmented current paths. This segmentation increases the electrical length and broadens the impedance bandwidth, enabling the compact antenna to operate effectively across the 2.4 GHz ISM band and other frequency ranges despite its small physical dimensions
Solution Approach 2:
The cutouts are placed at specific locations (first, second, third cutouts at different periphery positions) to create localized variations in current distribution. This local quality modification optimizes the impedance characteristics at different frequencies, enabling broad bandwidth operation within the constrained antenna size
3Reliability
If the antenna size is increased to improve radiation efficiency, then the radiation efficiency improves, but the device size increases and is no longer suitable for ear-worn applications
Solution Approach 1:
The antenna structure is segmented with multiple cutouts that increase the electrical length without proportionally increasing physical size. This segmentation allows the antenna to achieve the radiation efficiency of a larger antenna while maintaining the compact form factor required for ear-worn devices
Solution Approach 2:
The cutouts create additional dimensional paths for current flow along the antenna periphery. This dimensional approach allows the antenna to achieve enhanced radiation efficiency through increased electrical length while maintaining compact physical dimensions suitable for wearable applications
Data Source
AI summary
An ear-worn electronic hearing device comprises an enclosure configured to be supported by, at, in or on an ear of the wearer. Electronic circuitry is disposed in the enclosure and comprises a wireless transceiver. An antenna is disposed in or on the enclosure and operably coupled to the wireless transceiver. The antenna has a physical size and comprises a plurality of cutouts disposed along a periphery of the antenna. The cutouts are configured to increase an electrical length of the antenna without an increase in the physical size of the antenna. The antenna can comprise at least one interior window having a window periphery. A plurality of window cutouts are disposed along the window periphery. The window cutouts are configured to increase a path length of current distribution along the window periphery.