Parasitic Antenna Resonating Element for Near-Field Radiation Reduction
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Solution Overview
Problem
Incorporating effective antennas into electronic devices with small form factors and conductive housings is challenging due to space constraints and electromagnetic interference, which can lead to radiation hotspots and non-compliance with regulatory limits for radio-frequency signal emission.
Innovation Solution
The use of parasitic antenna resonating elements and proximity sensors to reduce near-field radiation hotspots by adjusting transmit power levels and employing dielectric antenna windows and ferrite materials to manage electromagnetic radiation, while utilizing conductive housing portions as antenna grounds and feed terminals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If conventional antennas are used in electronic devices with conductive housings, then wireless communication functionality is provided, but radiation hotspots occur and regulatory limits for radio-frequency signal emission may not be met
Solution Approach 1:
A parasitic antenna resonating element is introduced as an intermediary component between the main antenna and the conductive housing. This parasitic element acts as a mediator that redistributes electromagnetic energy and reduces the concentration of electric fields at hotspot locations, thereby lowering near-field radiation while maintaining communication functionality and regulatory compliance
Solution Approach 2:
The conductive housing is selectively modified by introducing a parasitic antenna resonating element at specific locations where radiation hotspots occur. This creates localized modifications to the electromagnetic field distribution without changing the overall conductive housing structure, addressing the harmful radiation issue at specific problem areas while preserving the general design
2Power
If antenna resonating elements are mounted adjacent to antenna windows in conductive housings, then radio-frequency signals are transmitted effectively, but localized currents are induced in the conductive housing creating radiation hotspots
Solution Approach 1:
The parasitic antenna resonating element is designed to interact with the localized currents induced in the conductive housing by the main antenna. Instead of allowing these currents to create harmful radiation hotspots, the parasitic element is tuned to resonate at the same frequency, effectively absorbing and redistributing the electromagnetic energy that would otherwise be radiated as hotspots, thereby converting the harmful localized currents into useful resonant coupling that enhances overall antenna performance
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 enhances antenna performance, reduces radiation hotspots, and ensures compliance with regulatory limits for radio-frequency signal emission, even in compact devices with conductive housings.
Implementation Method 1
an antenna having a parasitic antenna resonating element formed from one or more conductive structures
Implementation Method 2
employing dielectric antenna windows and ferrite materials to manage electromagnetic radiation
Implementation Method 3
a dielectric antenna window in the conductive housing, an antenna resonating element mounted in the conductive housing so that radio-frequency signals are transmitted through the dielectric antenna window
Data Source
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AI summary
Antennas are provided for electronic devices such as portable computers. An electronic device may have a housing in which an antenna is mounted. The housing may be formed of conductive materials. A dielectric antenna window may be mounted in the housing to allow radio-frequency signals to be transmitted from the antenna and to allow the antenna to receive radio-frequency signals. Near-field radiation limits may be satisfied by reducing transmit power when an external object is detected in the vicinity of the dielectric antenna window and the antenna. A proximity sensor may be used in detecting external objects. A parasitic antenna resonating element may be interposed between the antenna resonating element and the dielectric antenna window to minimize near-field radiation hotspots. The parasitic antenna resonating element may be formed using a capacitor electrode for the proximity sensor. A ferrite layer may be interposed between the parasitic element and the antenna window.