OAM Multiplexing MIMO Antenna for High Data Rate Wireless Links
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Solution Overview
Problem
Conventional line-of-sight communication systems face challenges in increasing bandwidth efficiently, as traditional methods using multiple spatially separated transmitter antennas are costly and require extensive infrastructure, limiting their ability to achieve high data rates.
Innovation Solution
The system employs orbital-angular-momentum (OAM) multiplexing and spatial multiplexing in combination with Multiple-Input-Multiple-Output (MIMO) processing to transmit and receive data, utilizing spiral phase plates to convert Gaussian beams into OAM beams and back, allowing for orthogonal data channels to be transmitted and received with reduced crosstalk.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple spatially separated transmitter antennas are used to increase bandwidth, then data rates are improved, but system cost and device complexity increase significantly
Solution Approach 1:
The patent transitions from conventional spatial multiplexing using multiple separated antennas to OAM multiplexing that utilizes the angular momentum dimension of electromagnetic waves. By encoding data in different OAM modes (different values of orbital angular momentum quantum number l), the system achieves multiple data channels through a single antenna aperture, fundamentally changing the dimension of multiplexing from spatial separation to wave property differentiation.
Solution Approach 2:
The patent enables a single transmit antenna to simultaneously transmit multiple independent data streams through different OAM modes, and a single receive antenna to simultaneously receive and separate these modes. This multi-functional capability replaces the need for multiple specialized antennas, reducing system complexity while maintaining high data rates.
2Productivity
If multiple spatially separated transmitter and receiver antennas are used to increase bandwidth, then data rates are improved, but implementation cost increases
Solution Approach 1:
The patent exploits the orbital angular momentum dimension of electromagnetic waves to create multiple orthogonal data channels. By using spiral phase plates or holographic elements to impose different OAM modes on a single beam from one antenna, the system achieves multiplexing without requiring multiple physical antenna elements, thereby significantly reducing hardware costs.
Solution Approach 2:
The patent uses computer-generated holograms and spiral phase plates to create virtual copies of the transmitted signal in different OAM modes. These holographic elements act as低成本 (low-cost) means to generate multiple orthogonal channels from a single antenna, replacing expensive multi-antenna arrays while maintaining channel separation.
3Productivity
If OAM multiplexing is used to increase data rates, then bandwidth is improved, but signal interference between channels may increase
Solution Approach 1:
The patent changes the fundamental parameter used for channel separation from spatial position to orbital angular momentum quantum number. By carefully controlling and maintaining the orthogonality of different OAM modes through precise phase and amplitude management, the system achieves channel separation without significant crosstalk, as orthogonal modes with different angular momentum values do not interfere with each other during propagation.
Solution Approach 2:
The patent employs MIMO signal processing with feedback mechanisms to detect and compensate for any residual interference between OAM channels. The receiver uses knowledge of the transmitted OAM modes to separately process and decode each channel, actively managing and reducing crosstalk through adaptive signal processing.
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 significantly increases data rates by enabling efficient multiplexing and demultiplexing of data channels, achieving a 16 Gbit/s millimeter-wave communication link with improved bit error rate performance and compatibility with traditional spatial multiplexing methods.
Implementation Method 1
orbital-angular-momentum (OAM) multiplexer coupled to the first transmit antenna. The first OAM multiplexer is designed to receive a first input signal and a second input signal. The first OAM multiplexer is also designed to convert the first input signal to a first OAM beam
Implementation Method 2
The first OAM multiplexer is also designed to convert the first input signal to a first OAM beam, and to convert the second input signal to a second OAM beam that is orthogonal to the first OAM beam
Data Source
AI summary
A system includes a transmitter having a first transmit device having a first transmit antenna and a first OAM multiplexer designed to receive two input signals and to convert the input signals to orthogonal OAM beams. The first transmit antenna is designed to transmit a first output signal that includes the OAM beams. The transmitter also includes a second transmit device that functions in a similar manner as the first transmit device. A receiver includes a first receive device having a first receive antenna designed to receive the first output signal and a first OAM demultiplexer designed to convert the first output signal to received signals corresponding to the input signals. The receiver also includes a second receive device having similar features as the first receive device. The receiver also includes a MIMO processor designed to reduce interference between the received signals.