Antenna Parasitic Element Integrated Proximity Sensor
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Solution Overview
Problem
There is a need for smaller size antenna solutions that comply with Specific Absorption Rate (SAR) regulations for mobile devices, while also reducing noise levels, by sharing components between Wireless Wide Area Network (WWAN) antenna and proximity sensor systems, and integrating the proximity sensor in parallel with the RF signal path.
Innovation Solution
An antenna apparatus with an integrated proximity sensor, featuring a parasitic element capacitively coupled to the antenna feed element, a capacitor electrically coupled to ground, and a proximity sensor connected in parallel to the parasitic element, which detects changes in capacitance to adjust the output power based on the presence or absence of a human body, thereby broadening impedance bandwidth and reducing noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the antenna size is reduced to meet mobile device miniaturization requirements, then the device size is reduced, but the impedance bandwidth becomes insufficient
Solution Approach 1:
The patent combines the proximity sensor element with the antenna's parasitic element, making them a single integrated component. This merging allows the same physical structure to serve dual functions: broadening impedance bandwidth for the antenna and detecting capacitance changes for proximity sensing, thereby resolving the contradiction between reduced antenna size and sufficient impedance bandwidth
Solution Approach 2:
The integrated element serves multiple functions simultaneously: it acts as both the antenna's parasitic element for impedance matching and bandwidth broadening, and as a proximity sensor for detecting human body proximity. This multi-functionality allows the antenna to maintain adequate bandwidth even as overall device size is reduced
2Reliability
If a separate proximity sensor is added to detect human proximity for SAR compliance, then SAR regulation compliance is achieved, but the device complexity and noise increase
Solution Approach 1:
The patent merges the proximity sensor functionality into the antenna structure itself by using the parasitic element as the sensing element. This integration eliminates the need for a separate proximity sensor component, thereby maintaining SAR compliance while reducing overall system complexity
Solution Approach 2:
The parasitic element performs dual roles: it contributes to the antenna's impedance characteristics and bandwidth, while simultaneously serving as the proximity sensor element. This multi-functionality achieves SAR compliance without adding separate components or increasing system complexity
3Difficulty of detecting and measuring
If the proximity sensor is connected in series with the RF signal path, then the sensing function is achieved, but the noise level increases
Solution Approach 1:
The patent uses a capacitor as an intermediary element to couple the integrated proximity sensor to the RF signal path. This capacitive coupling allows the proximity sensor to detect capacitance changes while being electrically isolated from the main RF signal flow, thereby enabling proximity detection without introducing significant noise into the RF path
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 provides reduced system noise, space savings, and the ability to operate on multiple frequency bands, ensuring compliance with SAR regulations by dynamically adjusting transmit power based on human proximity.
Implementation Method 1
a parasitic element capacitively coupled to the antenna feed element, the parasitic element configured to broaden the impedance bandwidth of the antenna feed element
Implementation Method 2
the proximity sensor configured to detect a change in capacitance in the parasitic element in the 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.