Phase-Reconfigurable Reflectarray Beamforming for Interference Nulling
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Solution Overview
Problem
Conventional anti-jam satellite communication systems using digital receiver arrays are costly and complex due to their high hardware requirements and limited ability to null multiple interference sources, leading to saturation and reduced performance in the presence of numerous radio interference signals.
Innovation Solution
A phase-reconfigurable reflectarray system with a single radio receiver and antenna is used to form beams and nulls by configuring each reflector with appropriate phase-shift states, amplifying desired signals and attenuating undesired signals before they reach the receiver, thereby reducing complexity and cost.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a digital receiver array is used to null multiple interference sources, then the ability to suppress interference improves, but the system complexity and cost increase significantly
Solution Approach 1:
The system segments the interference suppression function into two parts: a single receiver handles signal reception while a separate reflectarray antenna performs the nulling function. This divides the complex digital receiver array into simpler components working in parallel, reducing overall system complexity while maintaining interference suppression capability.
Solution Approach 2:
The reflectarray antenna acts as an intermediary between the incoming radio signals and the single receiver. It pre-processes the signals by forming nulls in interference directions before the signals reach the receiver, thereby protecting the receiver from saturation while allowing it to operate with simpler hardware.
2Object-affected harmful factors
If the number of digital receivers is increased to null more interference sources, then the interference nulling performance improves, but the launch weight and size increase
Solution Approach 1:
The system merges the receive function and the nulling function into a single integrated architecture. The reflectarray antenna elements are positioned to reflect signals toward the single receiver while simultaneously creating nulls in interference directions. This combination eliminates the need for multiple separate receivers, significantly reducing satellite weight while maintaining the ability to null multiple interference sources.
3Device complexity
If a single receiver is used with reflectarray, then the system complexity and cost reduce, but the ability to form multiple nulls may be limited
Solution Approach 1:
The system transitions from spatial diversity (multiple receivers) to angular diversity (reflectarray element positioning) to achieve multiple nulls. By strategically positioning reflectarray elements in specific three-dimensional configurations, the system creates multiple nulls in different directions while using only a single receiver, thus maintaining interference nulling capability without increasing receiver count.
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 effectively suppresses interference power before it reaches the receiver, allowing robust operation in the presence of multiple interference sources while maintaining beamforming performance and reducing system complexity and cost.
Implementation Method 1
configuring each reflector with an appropriate phase-shift state
Implementation Method 2
the amplification (constructive combining) of the desired radio signals and the nulling (destructive combining) of the undesired radio signals
Implementation Method 3
an antenna to receive signals redirected by the phase-reconfigurable reflectarray
Data Source
AI summary
The disclosed system uses a less complex system of a single radio receiver-frontend with a phase-reconfigurable reflectarray and an antenna to form beams in directions of the desired arriving signals while forming nulls in directions of the arriving radio interference signals. This is done by configuring each reflector with an appropriate phase-shift state so that the amplification of the desired radio signals and the nulling of the undesired radio signals happen at the point all reflected radio signals combine at the antenna (before the receiver frontend). In comparison, a conventional digital receive array achieves beams and nulls by taking the sampled radio signal streams at the outputs of the receiver frontends, multiplies each sample stream by a digital weight to shift the stream's phase and/or amplitude and then combines the sample streams into one sample stream in which desired radio signals are amplified and undesired radio signals are attenuated.