Antenna Array in Metal Housing Cavity with Parasitic Elements
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Solution Overview
Problem
Forming electronic device antenna structures with desired attributes is challenging due to antenna coupling and cavity modes caused by conductive device structures, which can adversely affect wireless communication performance.
Innovation Solution
The use of metal housing walls forming an antenna cavity with planar inverted-F antennas and parasitic resonating elements, arranged in a circular array with different polarization orientations to minimize coupling and broaden frequency response, is proposed. These antennas are mounted on a carrier within the cavity, with parasitic elements extending inward from the metal walls to isolate adjacent antennas and enhance performance across multiple frequency bands.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple antennas are placed in a conductive housing cavity, then wireless communication capability is enhanced, but antenna coupling and cavity modes adversely affect performance
Solution Approach 1:
A parasitic antenna element is introduced as an intermediary component between the active antenna and the conductive housing cavity. This parasitic element acts as a mediator that manipulates electromagnetic fields to reduce cavity mode excitation and improve antenna performance without requiring changes to the housing structure or the active antenna itself.
Solution Approach 2:
The problematic interaction between the antenna and the conductive housing cavity is extracted and addressed separately by introducing a dedicated parasitic antenna element. This element specifically targets and mitigates the cavity mode issues without affecting the primary antenna's function, effectively separating the problem-solving function from the main antenna system.
2Volume of moving object
If antennas are arranged closely in an array, then device size is reduced, but coupling between adjacent antennas increases
Solution Approach 1:
The parasitic antenna element serves as a mediator placed between adjacent active antennas in the array. It creates electromagnetic isolation by manipulating the field distribution, allowing antennas to be positioned closer together while maintaining adequate isolation through the mediating effect of the parasitic element.
Solution Approach 2:
The parasitic antenna element converts the potentially harmful near-field coupling between adjacent antennas into a beneficial isolation mechanism. By strategically positioning and dimensioning the parasitic element, the strong electromagnetic interaction that would normally cause coupling is transformed into a shielding effect that improves antenna isolation.
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 improves antenna performance by reducing coupling between antennas, enhancing frequency response, and minimizing cavity mode excitation, leading to better wireless communication efficiency and bandwidth.
Implementation Method 1
The planar inverted-F antennas may be configured to resonate in upper and lower frequency bands
Implementation Method 2
Each planar inverted-F antenna may have an associated parasitic antenna resonating element. The parasitic elements may each extend inwardly from the metal walls and may broaden the frequency response of the planar inverted-F antennas in the lower frequency band
Implementation Method 3
Each antenna in the array may have a different respective polarization orientation to minimize antenna coupling
Data Source
AI summary
Metal housing walls may form an antenna cavity. Antenna structures may be formed from metal traces mounted on a carrier in the antenna cavity. The antenna structures may form an array of antennas such as an array of planar inverted-F antennas. The housing may have an inner cavity wall such as a circular inner cavity wall. The planar inverted-F antennas may lie between the inner cavity wall and the metal walls of the housing. Each planar inverted-F antenna may have an associated parasitic antenna resonating element. The planar inverted-F antennas may be configured to resonate in upper and lower frequency bands. The parasitic elements may each extend inwardly from the metal walls and may broaden the frequency response of the planar inverted-F antennas in the lower frequency band. Parasitic elements may be used to isolate antennas from each other.