Slap Band Antenna Structure to Mitigate Body-Worn RF Attenuation
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Solution Overview
Problem
Wearable devices with small form factors face challenges in achieving efficient signal radiation due to the close proximity of their antennas to the human body, limiting the maximum signal radiation range to 1 to 2 meters and compromising performance.
Innovation Solution
Incorporating a detachable conductive slap band made of materials like steel, conductive polymer, or metallic mesh that is capacitively coupled to the antenna array, allowing for tuning of its length, width, and thickness to extend the signal radiation range up to 4 to 8 meters by shielding the antenna from the human body.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the antenna is placed close to the human body in a small wearable device, then the device form factor is reduced, but the signal radiation range is limited to 1 to 2 meters due to body absorption
Solution Approach 1:
A conductive slap band is introduced as an intermediary component between the antenna and the human body. The slap band is capacitively coupled to the antenna array and extends away from the body, serving as a mediator that allows the antenna to maintain close proximity to the body for a small form factor while the extended conductive element projects the signal outward, extending the effective radiation range beyond the immediate body proximity limitation.
Solution Approach 2:
The antenna structure is extended into a third dimension by adding the conductive slap band that projects outward from the body surface. Instead of relying solely on the two-dimensional plane of the wearable device, the conductive element extends in the radial dimension away from the body, creating a three-dimensional antenna structure that overcomes the limited radiation range imposed by body proximity.
2Device complexity
If the antenna array is located solely within the puck portion or wristband portion, then the device structure is simplified, but the signal absorption by the human body cannot be mitigated and the radiation range remains limited
Solution Approach 1:
The antenna system is segmented into two distinct parts: the antenna array located within the puck or wristband portion, and the separate conductive slap band that is capacitively coupled to the antenna array. This segmentation allows the antenna array to remain simple and integrated within the device while the conductive slap band extends outward to mitigate body absorption effects, resolving the contradiction between structural simplicity and absorption mitigation.
Solution Approach 2:
The conductive slap band serves as an intermediary element that is capacitively coupled to the antenna array. This intermediary structure allows the antenna to maintain its simple integrated position within the device while the slap band extends away from the body to reduce the harmful absorption effect, without requiring complex integration of the antenna throughout the entire device structure.
3Shape
If the antenna array is placed close to the body, then the wearable device can be made compact, but the maximum signal radiation range is limited to 1 to 2 meters
Solution Approach 1:
The conductive slap band extends the antenna structure into the radial dimension away from the body surface. While the wearable device itself remains compact and close to the body, the conductive element projects outward in three-dimensional space, effectively extending the radiation range without compromising the compactness of the wearable device form factor.
Solution Approach 2:
The conductive slap band acts as an intermediary that decouples the device compactness requirement from the signal radiation range requirement. The antenna array remains compact within the device, while the slap band extends outward to achieve longer radiation range, allowing both compactness and extended range to coexist.
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 conductive slap band enhances the antenna's performance by directing RF current around the user's body, effectively extending the signal radiation range and maintaining device form factor.
Implementation Method 1
a conductive band capacitively coupled to the antenna array
Implementation Method 2
allowing for tuning of its length, width, and thickness to extend the signal radiation range up to 4 to 8 meters by shielding the antenna from the human body
Data Source
AI summary
Aspects of the disclosure relate to methods, apparatus, and systems for mitigating signal attenuation at a body-worn device transmitting a radio signal. An antenna structure for the body-worn device includes an antenna array configured to radiate at least one radio signal and a conductive band capacitively coupled to the antenna array. The conductive band is configured to detachably couple to a body of a user, and mitigate attenuation of the at least one radio signal when the conductive band is coupled to the body. The conductive band mitigates the attenuation by facilitating a radio frequency (RF) signal current corresponding to the at least one radio signal to flow through the conductive band and preventing absorption of the RF signal current by the body.