Folded Rear-Wall Antenna Layout for Low-Coupling Devices
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Solution Overview
Problem
Challenging to provide small form factor electronic devices with antennas that exhibit satisfactory wireless performance despite the presence of nearby antennas and/or other components, which can interfere with each other.
Innovation Solution
Incorporating a first antenna with a segment of peripheral conductive housing structures and a second antenna with a folded element on a dielectric substrate, where the folded antenna element follows a meandering path and is shorted to a conductive chassis, minimizing electromagnetic coupling and optimizing radiation through a rear housing wall.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If antennas are incorporated into a small form factor electronic device, then the device size is reduced, but wireless performance deteriorates due to interference between antennas and components
Solution Approach 1:
The second antenna element is folded into a compact configuration that utilizes three-dimensional space efficiently. The element is disposed on multiple sides of a dielectric substrate, creating a folded structure that fits within the limited device volume while maintaining adequate electrical length for wireless operation
Solution Approach 2:
A dielectric substrate is introduced as an intermediary between the antenna elements and the rear housing wall. This dielectric layer serves as a mediator that controls electromagnetic coupling between the antennas and manages the radiation pattern, allowing the antennas to operate effectively in the constrained space
2Volume of moving object
If a folded antenna element is placed near the rear housing wall, then space is saved, but electromagnetic coupling with nearby antennas increases
Solution Approach 1:
The antenna element is configured to exhibit minimum peak current magnitude at the surface of the dielectric substrate facing the rear housing wall. By controlling the current distribution parameter, electromagnetic coupling with nearby antennas is minimized while maintaining radiation efficiency
Solution Approach 2:
The antenna element follows a meandering path along multiple sides of the dielectric substrate, utilizing three-dimensional routing to achieve the required electrical length while keeping the physical footprint compact and controlling current distribution to reduce coupling
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
Minimizes electromagnetic coupling between antennas, optimizing radiation patterns and ensuring satisfactory wireless performance in compact electronic devices.
Implementation Method 1
The folded antenna element may be configured to exhibit minimum peak current magnitude at a surface of the dielectric substrate facing the rear housing wall. This may serve to minimize electromagnetic coupling between the first and second antennas to optimize a radiation pattern of the second antenna through the rear housing wall.
Data Source
AI summary
An electronic device may be provided with peripheral conductive housing structures, a rear wall, a first antenna, and a second antenna. The first antenna may have a resonating element formed from the peripheral conductive housing structures. The second antenna may have a folded antenna element overlapping the first antenna. The folded element may be disposed on at least three sides of a substrate. The folded element may follow a meandering path along at least two of the sides. A first end of the folded element may be coupled to a positive feed terminal. A second end of the folded element may be shorted to a conductive chassis. The folded element may exhibit minimum peak current magnitude at a surface of the substrate facing the rear wall, minimizing electromagnetic coupling between the first and second antennas and optimizing a radiation pattern of the second antenna through the rear wall.