PCB Ground Plane Isolation for Antenna Interference
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Solution Overview
Problem
In wireless communication repeaters, achieving high isolation between closely packed antennas is challenging due to physical proximity, leading to interference issues, especially in duplex operation, where simultaneous transmission and reception occur, and existing solutions like signal cancellation are costly and complex.
Innovation Solution
A multiple-antenna device is designed with a printed circuit board (PCB) featuring a ground plane for electromagnetic isolation, non-conductive support members, and orthogonal antenna configurations to minimize energy coupling and interference, using a PCB with a ground plane to separate and isolate antennas electrically and physically.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If antennas are placed close together in a compact package, then manufacturing cost and convenience are improved, but electromagnetic isolation between antennas deteriorates
Solution Approach 1:
The ground plane is segmented into multiple isolated ground regions, each serving a specific antenna. This segmentation prevents electromagnetic coupling between antennas by creating electrical isolation barriers, while maintaining the compact overall structure for cost-effective manufacturing.
Solution Approach 2:
A ground plane structure is introduced as an intermediary element between the antennas. This ground plane acts as an electromagnetic barrier that isolates the antennas from each other, preventing harmful electromagnetic coupling while allowing the antennas to remain in close proximity for compact packaging.
2Volume of moving object
If antennas are placed close together, then device size is reduced, but signal isolation and receiver sensitivity deteriorate
Solution Approach 1:
The isolation problem is solved by transitioning from two-dimensional planar separation to three-dimensional vertical separation. The ground plane is positioned vertically between antennas at different heights, creating electromagnetic isolation in the vertical dimension while maintaining horizontal compactness for reduced device size.
Solution Approach 2:
The ground plane serves as an intermediary electromagnetic barrier that physically and electrically separates the antennas. This intermediary structure provides the necessary signal isolation and protects receiver sensitivity while allowing the antennas to be positioned close together for compact device dimensions.
3Length of moving object
If directional antennas are used to increase range, then transmission distance is improved, but alignment complexity and ease of operation deteriorate
Solution Approach 1:
Multiple directional antennas with different polarizations are merged into a single compact array structure. This combination provides the transmission distance benefits of directional antennas while the integrated design and orthogonal polarization configurations reduce alignment complexity and improve ease of operation.
Solution Approach 2:
The antenna array is designed to perform multiple functions simultaneously - providing directional transmission for extended range while also offering polarization diversity for improved signal reliability. The compact integrated design makes the system universally applicable without requiring precise manual alignment.
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 effectively reduces electromagnetic interference between antennas, maintaining acceptable gain and directivity while enabling efficient, cost-effective operation in duplex modes without the need for complex cancellation circuits.
Implementation Method 1
a ground plane formed between the first antenna and the second antenna, the ground plane configured to provide electromagnetic isolation between the first and second antennae
Data Source
AI summary
A multiple-antenna device is provided, comprising: a printed circuit board having a ground plane configured to provide electromagnetic isolation between a first side of the printed circuit board and a second side of the printed circuit board; a first non-conductive support member formed over the first side of the printed circuit board; a second non-conductive support member formed over the second side of the printed circuit board; a first antenna formed over the first non-conductive support member; and a second antenna formed over the second non-conductive support member, wherein the first antenna is electrically connected to a first feed point on a first portion of the printed circuit board that is not connected to the ground plane, and wherein the second antenna is electrically connected to a second feed point on a second portion of the printed circuit board that is not connected to the ground plane.