Antenna Parasitic Element for Integrated Proximity Sensing
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Solution Overview
Problem
There is a need for smaller size antenna solutions for portable wireless devices that comply with Specific Absorption Rate (SAR) regulations, while also reducing noise levels, by sharing components between Wireless Wide Area Network (WWAN) antenna and proximity sensor systems.
Innovation Solution
An antenna solution with an integrated proximity sensor that includes an antenna feed element, a parasitic element capacitively coupled to the antenna feed element, a capacitor electrically coupled to ground, and a proximity sensor coupled in parallel to the parasitic element, allowing for detection of capacitance changes to adjust output power based on the presence or absence of a human body.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If separate antenna and proximity sensor components are used, then each component can be optimized independently, but the overall device size increases and component integration is reduced
Solution Approach 1:
The patent combines the antenna system and proximity sensor into a single integrated structure where the parasitic element of the antenna serves dual purposes: maintaining antenna radiation patterns and functioning as the sensing element for proximity detection. This merging eliminates the need for separate sensor components while reducing overall system volume.
Solution Approach 2:
The parasitic element is designed to perform multiple functions simultaneously: it acts as a radiating element for the antenna system while also serving as the capacitive sensing element for proximity detection. This multi-functionality reduces the number of components needed and decreases the overall device volume.
2Adaptability or versatility
If the parasitic element is capacitively coupled to the antenna feed element, then the impedance bandwidth is broadened, but the system complexity increases due to additional coupling requirements
Solution Approach 1:
The capacitive coupling between the parasitic element and antenna feed element is implemented by directly utilizing the physical proximity and geometric arrangement of the elements themselves, rather than requiring separate coupling circuits or components. This approach broadens impedance bandwidth while minimizing additional complexity.
3Object-affected harmful factors
If the proximity sensor is coupled in parallel to the parasitic element, then noise levels are reduced, but the circuit design complexity increases
Solution Approach 1:
An ESD/decoupling circuit is introduced as an intermediary component between the parasitic element and the proximity sensor. This intermediary blocks RF signals from entering the sensor while allowing capacitance changes to be detected, thereby reducing noise from RF interference while managing the circuit design through a standardized protection approach.
4Volume of moving object
If component sharing is implemented between antenna and proximity sensor, then space is saved, but the reliability of each function may be compromised
Solution Approach 1:
The ESD/decoupling circuit is extracted as a separate protective function that isolates the proximity sensor from RF signals while maintaining the capacitive coupling necessary for sensing. This extraction protects the sensor function from RF interference, ensuring reliability while maintaining the space-saving integrated design.
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 reduces system noise, saves space by sharing components, and broadens the operating frequency bands, ensuring compliance with SAR regulations and improving antenna performance.
Implementation Method 1
a parasitic element capacitively coupled to the antenna feed element
Implementation Method 2
the proximity sensor configured to detect a change in capacitance in the parasitic element in a presence of a human body
Data Source
AI summary
Wireless wide area network (WWAN) antenna with integrated sensor and methods of using the same. In one embodiment, an antenna subsystem and proximity sensing subsystem share a grounded antenna component/parasitic element. The parasitic element can be used to broaden the operating band of the antenna feeding component and provide an input (via a capacitance change) to a proximity sensor. The parasitic element is, in one embodiment, coupled in parallel to the proximity sensor allowing for a reduction in noise due to increased isolation between the antenna subsystem and the sensing subsystem.