Dual Circularly Polarized Antenna Array for Isolation and Axial Ratio
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Solution Overview
Problem
Achieving good isolation between orthogonal polarizations and maintaining a desired axial ratio in dual circularly polarized antennas sharing the same aperture is a significant technical challenge, especially in compact and integrated designs suitable for phased arrays with aggressive scanning possibilities.
Innovation Solution
The use of orthogonally rotated and integrated dipoles with differential excitation in antenna arrays, where dipoles of receive antennas are geometrically orthogonal to dipoles of transmit antennas, helps achieve desirable isolation between orthogonal polarizations and co-polarizations, resulting in a stable antenna impedance during beam scanning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If dual circularly polarized antennas share the same aperture in a compact integrated design, then the device complexity and space requirements are reduced, but the isolation between orthogonal polarizations deteriorates
Solution Approach 1:
The antenna aperture is segmented into distinct regions: transmit dipoles are positioned in a first region while receive dipoles are positioned in a second region. This spatial segmentation allows each polarization to occupy a dedicated zone, improving isolation while maintaining compact integration. The segmentation principle enables the dual-polarized antenna to achieve good isolation without requiring separate apertures.
Solution Approach 2:
Different regions of the antenna structure are assigned different functional qualities: the transmit region is optimized for transmitting polarization while the receive region is optimized for receiving polarization. This local differentiation of functional properties allows each region to perform its specific function with high efficiency while maintaining overall system integration and compactness.
2Volume of moving object
If dual circularly polarized antennas share the same aperture, then the antenna size is reduced, but maintaining a desired axial ratio becomes more difficult
Solution Approach 1:
The antenna is segmented into transmit and receive sections with spatially separated dipoles. This segmentation allows each section to be independently optimized for its specific polarization function, making it easier to maintain the desired axial ratio for each circular polarization while keeping the overall antenna size compact.
Solution Approach 2:
The antenna employs asymmetric dipole orientations and positioning: transmit dipoles are oriented in one direction while receive dipoles are oriented orthogonally. This asymmetric arrangement enables independent optimization of each polarization's radiation pattern and axial ratio, achieving precise polarization control within a compact integrated structure.
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 approach enables dual circularly polarized antennas to achieve high isolation between orthogonal polarizations, maintain a low axial ratio, and operate in a compact, integrated design suitable for phased arrays, even under aggressive scanning conditions.
Implementation Method 1
An antenna can transmit and/or receive radio frequency (RF) signals that propagate as electromagnetic waves through space
Implementation Method 2
The first pair of conductive elements can be connected to each other by a half wavelength delay line
Data Source
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AI summary
Aspects of this disclosure relate to an antenna array. An antenna array may include a first circularly polarized dipole antenna that includes a first pair of conductive elements. The antenna array may include a second circularly polarized dipole antenna that includes a second pair conductive elements, the second pair of conductive elements being geometrically orthogonal to the first pair of conductive elements. The antenna array may include a beamformer integrated circuit configured to drive the second circularly polarized dipole antenna such that the second circularly polarized dipole antenna transmits a first radio frequency signal while the first circularly polarized dipole antenna receives a second radio frequency signal. The first radio frequency signal can have a different polarization and be in a different frequency band than the second radio frequency signal.