OAM Full-Duplex Antenna Arrays for Self-Interference Cancellation
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Solution Overview
Problem
Conventional OAM electromagnetic wave communication systems face challenges such as beam divergence, energy holes in beam centers, and off-axis states, making it difficult to implement self-interference cancellation and multiplexing due to strict antenna alignment requirements and energy distribution issues.
Innovation Solution
A full-duplex communication method using uniform circular antenna arrays (UCAs) for transmit and receive beams in different OAM states, with equal antenna quantities and orthogonal OAM states, and a feeding network for self-interference cancellation, allowing simultaneous transmission and reception.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If conventional OAM electromagnetic wave communication is used, then channel capacity can be increased through multiplexing, but performance deteriorates due to beam divergence, energy holes, and off-axis states
Solution Approach 1:
The patent applies local quality by designing different antenna types at specific positions in the antenna array. Specifically, a first antenna (e.g., dipole or patch antenna) is placed at the center position while second antennas (e.g., omnidirectional antennas) are placed at surrounding positions. This local differentiation allows the center antenna to handle OAM mode 0 efficiently while surrounding antennas handle other OAM modes, thereby resolving the energy hole problem and improving overall communication performance without sacrificing channel capacity
Solution Approach 2:
The patent employs asymmetry by breaking the traditional symmetric circular arrangement of identical antennas. The hybrid antenna array uses asymmetric antenna configurations where the center antenna differs from surrounding antennas in both type and function. This asymmetric design enables different radiation patterns and OAM mode capabilities at different positions, effectively addressing beam divergence and energy distribution issues while maintaining high channel capacity through multiplexing
2Object-generated harmful factors
If strict antenna alignment is required for OAM communication, then self-interference cancellation can be achieved, but device complexity and alignment difficulty increase
Solution Approach 1:
The patent applies parameter changes by utilizing the inherent properties of different OAM modes, particularly the orthogonality between OAM mode 0 and other OAM modes. By designing the hybrid antenna array to efficiently generate and receive specific OAM modes with controlled radiation patterns, the system achieves self-interference cancellation through modal orthogonality rather than strict geometric alignment. This parameter-based approach (using OAM mode characteristics) replaces the need for precise physical alignment, reducing device complexity while maintaining effective self-interference cancellation
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
Enables efficient self-interference cancellation and beamforming, overcoming energy holes and alignment issues, thereby enhancing spectral efficiency and channel capacity.
Implementation Method 1
An orbital angular momentum (Orbital Angular Momentum, OAM) is an inherent attribute of an electromagnetic wave, and corresponds to a spiral phase wavefront of a beam in space. Electromagnetic waves carrying different OAM states are orthogonal to each other when transmitted coaxially in space.
Implementation Method 2
A relatively convenient method for implementing high isolation between transmit and receive ports is designing a placement manner of an antenna array for passive superposition elimination in a propagation domain, so that self-interference signal cancellation in the full-duplex technology can be implemented.
Data Source
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AI summary
Embodiments of this application relate to a full-duplex communication method and apparatus, to implement self-interference cancellation and avoid a problem of an energy hole in a beam center in a full-duplex communication process. The full-duplex communication method includes: transmitting transmitted beams in different orbital angular momentum OAM states by using a transmit antenna array, where the transmit antenna array is a uniform circular array UCA; receiving received beams in different OAM states by using a receive antenna array, where the receive antenna array is a UCA, a quantity of transmit antennas of the transmit antenna array is equal to a quantity of receive antennas of the receive antenna array, and the OAM states of the transmitted beams are not equal to opposite numbers of the OAM states of the received beams; and feeding the transmit antenna array and synthesizing signals of the receive antenna array by using a feeding network.