Wrist-worn Device Loop Ground for Multi-band Antenna
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Solution Overview
Problem
Wearable communication devices, such as smart watches, face challenges in operating across multiple frequency bands, particularly the low frequency band of 900 MHz, due to their compact design which limits the antenna's performance.
Innovation Solution
A communication device design featuring a device casing, external non-conductive connection element forming a loop structure, and a metal element supported by this connection to increase the equivalent resonant length of the ground element, effectively exciting the antenna element for multi-band operation across GSM900/1800/1900 frequency bands.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the communication device is designed to be compact in size for wearable applications, then the device becomes easy to wear, but the ground plane becomes excessively small causing the antenna element to be unable to operate in low frequency bands
Solution Approach 1:
The patent combines the device casing and external connection element to form a loop structure that serves as an extended ground plane. This merging allows the antenna element to achieve multi-band operation capability while maintaining a compact device size, as the loop structure effectively increases the electrical length without proportionally increasing physical volume.
Solution Approach 2:
The patent extends the ground plane from a two-dimensional surface within the device casing to a three-dimensional loop structure that includes external connection elements. This dimensional transformation allows the antenna to achieve longer resonant lengths and broader frequency coverage while keeping the device body compact.
2Area of stationary object
If the ground plane is made small to fit wearable device constraints, then the device remains compact, but the antenna element cannot be excited effectively in low frequency bands
Solution Approach 1:
The device casing and external connection element are merged to form a continuous loop ground structure. This combined structure provides sufficient ground plane area for effective antenna excitation in low frequency bands while maintaining the compact form factor required for wearable devices.
Solution Approach 2:
The loop ground structure is pre-configured with specific geometric parameters and connection points to ensure proper impedance matching and resonant characteristics across multiple frequency bands, including low frequency bands, before the antenna element is activated.
3Volume of moving object
If the device casing is made compact for smart watch application, then the device is easy to wear, but the antenna element cannot achieve multi-band operation
Solution Approach 1:
The patent merges the device casing with external connection elements to create a loop ground structure that provides multi-band resonant characteristics. This allows the compact device to support multiple frequency bands including GSM900, GSM1800, and GSM1900 without increasing device volume.
Solution Approach 2:
The loop ground structure is designed with specific parameter values including connection point positions, segment lengths, and geometric dimensions that are optimized to achieve resonant frequencies across multiple bands. By carefully controlling these parameters, the compact device achieves multi-band operation capability.
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 enables the antenna to achieve improved impedance matching and radiation efficiency, allowing for effective multi-band operation, including the low frequency band of GSM900, with efficiency ranging from 51% to 87% across various frequency bands.
Implementation Method 1
the ground element effectively increases an equivalent resonant length thereof, so as to effectively excite a resonant mode of an antenna element in the device casing and cover multi-band operation of mobile communication
Data Source
AI summary
A communication device, including a device casing, an external connection element, and a first metal element, is provided. A ground element and an antenna element are disposed in the device casing. The ground element has a first edge, a second edge, and a first connection point. The first edge and the second edge are opposite to each other. The first connection point is disposed near or at the second edge. The antenna element is disposed near the first edge. The external connection element is formed by a non-conductive material and is outside the device casing. The external connection element has a belt-like structure and is combined with the device casing to substantially form a loop structure. The first metal element is supported by the external connection element and is coupled to the first connection point of the ground element.