Flex Antenna Wire Traces for Wristwatch Wireless Communication
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Solution Overview
Problem
The challenge is to integrate wireless communication capabilities into wristwatch-sized mobile computing devices without increasing their size, as traditional antenna configurations require significant space and can interfere with device-control circuits.
Innovation Solution
A compact antenna system is implemented using a flexible substrate that repurposes user control interface buttons, incorporating bypass capacitors and RF choke circuits to prevent interference, and utilizes existing wire traces as dual-purpose components for both device control and wireless signal transmission/reception, with optional antenna matching circuits for frequency tuning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a traditional antenna configuration is used to provide wireless communication capabilities, then wireless communication functionality is achieved, but the device size increases and space within the wristwatch is consumed
Solution Approach 1:
The wire traces on the flexible substrate are designed to serve dual purposes: functioning as control signal pathways for user interface buttons and simultaneously operating as an antenna for wireless communication. This multi-functionality eliminates the need for separate antenna structures, thereby maintaining compact device size while achieving wireless communication capability
Solution Approach 2:
The antenna structure is merged with the existing flexible substrate that contains wire traces for button control. By integrating the antenna function into the control interface substrate, the patent combines two previously separate functions (control signaling and wireless communication) into a single integrated structure, reducing overall device volume
2Ease of operation
If wire traces are used to couple user control interface buttons to the printed circuit board, then device control functionality is achieved, but RF circuit interference or jamming occurs due to current passing through the wire traces
Solution Approach 1:
RF choke circuits are inserted at strategic points along the wire traces to extract or block RF frequency currents from traveling along the control signal pathways. This separation allows control signals to pass freely while preventing RF interference from coupling into the antenna structure, thus eliminating the harmful interference effect
Solution Approach 2:
Bypass capacitors are introduced as intermediary components connected between the wire traces and ground. These capacitors provide an alternative low-impedance path for RF currents to shunt to ground, preventing them from interfering with the antenna operation while having minimal impact on the control signal functionality
3Reliability
If the wire trace length is adjusted to optimize antenna performance over a specified frequency bandwidth, then wireless communication performance is improved, but the device-control circuit functionality may be affected
Solution Approach 1:
The wire trace geometry is carefully designed and adjusted to achieve the optimal electrical length for antenna operation at the target frequency band. By controlling parameters such as trace length, width, and routing, the trace serves both as a functional antenna element and maintains its role as a control signal pathway, achieving compatibility between wireless communication performance and device-control circuit functionality
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 solution efficiently utilizes space within the wristwatch device, enabling reliable wireless communication across multiple frequency bands while minimizing interference and maintaining device functionality, thus maintaining the compact size of the wristwatch mobile computing device.
Implementation Method 1
an antenna capable of receiving the radio frequency signals of wireless networks
Implementation Method 2
bypass capacitors, and an RF choke circuit, such as an inductor or an inductor-capacitor (LC) filter circuit, may be configured along each wire trace
Implementation Method 3
bypass capacitors, and an RF choke circuit, such as an inductor or an inductor-capacitor (LC) filter circuit
Implementation Method 4
an antenna matching circuit may be implemented such that the existing wire trace may operate as an antenna over a specified frequency bandwidth
Data Source
AI summary
A compact antenna system that provides an antenna capable of transmitting and/or receiving radio signals configured on a flexible substrate material supporting user control interface buttons. In an embodiment, an antenna may be formed on a user control interface button flex between the wire traces used to couple the user control interface buttons to a printed circuit board. In order to prevent the interference on the antenna that may be caused when current passes through the wire traces coupling the user control interface buttons to the printed circuit board, an RF choke (i.e., LC filter) circuit and bypass capacitors may be configured along each wire trace. In another embodiment, the wire trace coupling a user control interface button to the printed circuit board may be configured to serve the dual purposes of coupling the user control interface button to the printed circuit board; and functioning as an antenna capable of transmitting and/or receiving wireless radio signals.