Orthogonal Polarization Antenna Arrays for Multipath Fading
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Solution Overview
Problem
Designing an omnidirectional antenna system with multiple polarization directions is challenging in indoor environments due to signal reflection and multipath fading, especially in limited spaces of wireless access points.
Innovation Solution
The antenna system comprises a system ground plane, a first antenna array with orthogonal polarization directions, and a second antenna array, allowing for simultaneous signal processing in various polarization directions. The first antenna array includes dipole or folded dipole antennas with directors and reflectors, while the second array uses PIFAs or monopole antennas with reflectors, enabling operation in both omnidirectional and directional modes through switch circuits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple antenna elements with different polarization directions are arranged in limited space, then the antenna system can process signals in various polarization directions simultaneously, but the device complexity increases
Solution Approach 1:
The antenna system is divided into multiple independent antenna elements (first through eighth antenna elements) with different polarization directions. Each element can be independently controlled through switch circuits, allowing the system to selectively activate specific elements based on communication requirements, thereby managing complexity while maintaining versatility
Solution Approach 2:
The patent utilizes three-dimensional spatial arrangement by placing antenna elements at different positions and orientations within the access point housing. The first and second antenna arrays are positioned at different locations with orthogonal polarization directions, effectively using spatial dimensionality to achieve multi-polarization capability without increasing planar footprint
2Area of stationary object
If antenna elements are densely arranged to achieve omnidirectional coverage, then the wireless communication area is expanded, but signal reflection and multipath fading increase due to indoor environment
Solution Approach 1:
Different antenna elements are assigned different polarization directions (horizontal and vertical) and spatial positions, creating local quality variations in the radiation pattern. This allows the system to adapt to different indoor reflection characteristics by selecting appropriate elements, thereby expanding effective coverage while mitigating environment-specific harmful effects
Solution Approach 2:
The switch circuits enable dynamic changing of operational parameters by selecting different antenna elements based on detected signal conditions. When signal reflection or multipath fading is detected in certain polarization directions, the system switches to elements with orthogonal polarizations, effectively changing the transmission parameters to overcome harmful effects
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 system achieves an almost omnidirectional radiation pattern, effectively receiving and transmitting signals in multiple polarization directions, improving communication quality by overcoming signal reflection and multipath fading issues in indoor environments.
Implementation Method 1
The first antenna array has a first polarization direction. The second antenna array has a second polarization direction. The first polarization direction and the second polarization direction are orthogonal to each other.
Implementation Method 2
a first reflector, a second reflector, a third reflector, and a fourth reflector, which are configured to respectively reflect electromagnetic waves of the first antenna element, the second antenna element, the third antenna element, and the fourth antenna element outwardly
Data Source
AI summary
An antenna system includes a system ground plane, a first antenna array, and a second antenna array. The first antenna array includes a first antenna element, a second antenna element, a third antenna element, and a fourth antenna element. The second antenna array includes a fifth antenna element, a sixth antenna element, a seventh antenna element, and an eighth antenna element. The second antenna array is disposed between the first antenna array and the system ground plane. The first antenna array has a first polarization direction. The second antenna array has a second polarization direction. The first polarization direction and the second polarization direction are orthogonal to each other.