Loop Antenna for In-Ear Audio Device
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Electrically small loop antennas in in-the-ear audio devices, such as hearing aids, face challenges with limited bandwidth due to space constraints, which restrict their efficiency and impedance characteristics.
Innovation Solution
Transforming a two-dimensional micro strip loop structure into a three-dimensional structure by raising the broad side of the strip orthogonally to the loop plane, increasing the loop area while maintaining the same cross-sectional area and outer circumference, thereby utilizing the available space more efficiently.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the loop area is increased to improve antenna efficiency and bandwidth, then the antenna performance is improved, but the antenna outer dimensions would need to be enlarged which is not feasible in ITE hearing aids
Solution Approach 1:
The patent transforms the traditional planar loop antenna into a three-dimensional structure by folding the strip back on itself. The strip is bent at approximately 90-degree angles to form a rectangular loop where two opposite sides are raised vertically from the battery drawer surface. This dimensional transformation allows the antenna to enclose a larger volume (47mm² effective area) while maintaining a compact footprint that fits within the existing hearing aid housing dimensions.
2Adaptability or versatility
If the loop area is increased to improve bandwidth, then the bandwidth is improved, but the cross section would need to be increased which would increase inductance and reduce bandwidth
Solution Approach 1:
The patent resolves this contradiction by utilizing the third dimension (vertical height) to increase the effective loop area. The strip is folded to create a rectangular loop with height approximately equal to the battery drawer thickness (4-6mm). This allows the antenna to achieve 47mm² effective area with a compact cross-section, maintaining low inductance while achieving the required bandwidth through increased loop area in three-dimensional space.
3Adaptability or versatility
If a thin wire is used to maintain low inductance, then the inductance is kept low, but the bandwidth is reduced
Solution Approach 1:
The patent uses a thin strip (0.01-0.15mm thickness) folded into a three-dimensional rectangular loop structure. The vertical folding creates additional loop area without requiring increased wire thickness. The strip width (2-4mm) is optimized to balance inductance and bandwidth requirements, while the three-dimensional configuration provides the necessary effective area (47mm²) for adequate bandwidth performance.
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 results in an electrically small loop antenna with increased bandwidth and efficiency, effectively addressing the limitations of prior art by doubling the loop area without enlarging the antenna's outer dimensions, thus enhancing the overall performance of in-the-ear audio devices.
Implementation Method 1
an antenna for radiating and/or receiving electromagnetic energy is arranged with a first surface turned towards the surroundings and a second surface located in close proximity of the battery
Data Source
AI summary
The invention regards a communication device which is adapted for placement in a users ear and comprises a shell part enclosing an input transducer for receiving an input signal, a signal processing device and an output transducer for providing a signal perceivable as sound, a battery located at a surface part of the shell which is facing away from the head of the user, a transmission and reception circuit for transmission and/or reception of electromagnetic energy, and where an antenna for radiating and/or receiving electromagnetic energy is arranged with a first surface turned towards the surroundings and a second surface located in close proximity of the battery whereby the antenna forms a loop with a loop axis pointing away from the ear and head, whereby the loop material has a wider extension in the direction of the loop axis than in the direction perpendicular to the loop axis.