Wearable NFC Antenna Segmentation for On-Body Communication
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Solution Overview
Problem
Conventional wearable electronic devices with NFC functionality cannot perform near field communication while being worn due to the placement of NFC components, requiring the device to be removed for functionality.
Innovation Solution
An antenna arrangement featuring a primary antenna with a conductive sidewall and a loop antenna separated from the NFC chip, where the loop antenna is magnetically coupled to the case to form a secondary magnetic field, enabling NFC functionality without removing the device.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the NFC components are placed on the back surface of the wearable device, then the device structure is simple, but the device cannot perform near field communication while being worn
Solution Approach 1:
The antenna system is segmented into two independent parts: a primary antenna integrated into the case and a loop antenna integrated into the wearable device. This segmentation allows each antenna to serve specific functions - the primary antenna for generating the magnetic field and the loop antenna for receiving signals - enabling NFC communication while worn without requiring complex integration of all components in one location
Solution Approach 2:
The patent introduces an intermediary magnetic field coupling mechanism between the primary antenna and loop antenna. The primary antenna generates a magnetic field that couples with the loop antenna, acting as an intermediary that transfers energy and enables communication between the case and wearable device even when separated by the wrist or body part
2Reliability
If the loop antenna is integrated inside the case, then the magnetic field radiation efficiency is improved, but the waterproof design and aesthetic appearance are compromised
Solution Approach 1:
The loop antenna is extracted from the case and integrated into the wearable device instead. This extraction maintains the magnetic field radiation efficiency by preserving the magnetic coupling relationship between the primary antenna (in the case) and loop antenna (in the wearable device), while simultaneously protecting the case's waterproof integrity and aesthetic appearance by removing the antenna structure from the case
Solution Approach 2:
The patent transitions the antenna arrangement from a two-dimensional planar layout (both antennas in the case) to a three-dimensional distributed configuration (primary antenna in case, loop antenna in wearable device). This spatial redistribution maintains electromagnetic coupling effectiveness while resolving conflicts with waterproofing and aesthetics by placing components in different physical locations
3Productivity
If the wearable device is removed to perform NFC communication, then the NFC function can be executed, but the convenience and portability are reduced
Solution Approach 1:
The system is pre-configured with two antennas positioned and coupled in such a way that NFC communication capability is already established before use. The primary antenna in the case and loop antenna in the wearable device are arranged to maintain magnetic coupling, so when the user wears the device, NFC communication is immediately available without requiring any additional setup or removal actions
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 configuration allows for efficient near field communication while the device is worn, improving magnetic field radiation efficiency and maintaining a waterproof and aesthetically pleasing design.
Implementation Method 1
The case is configured to generate a first magnetic field based on an electrical signal from the NFC chip
Implementation Method 2
The loop antenna is configured to magnetically couple to the case such that the loop antenna forms a second magnetic field in response to the first magnetic field
Data Source
AI summary
In one embodiment, the antenna arrangement includes a primary antenna having a conductive sidewall; and a loop antenna disposed in and physically separated from the primary antenna. The loop antenna includes a first conductive loop and a capacitor electrically connected between ends of the first conductive loop.