Satellite Jammer Suppression Using Parasitic Elements
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Solution Overview
Problem
Existing anti-jamming solutions for satellite communication systems are costly and offer limited effectiveness, often degrading antenna gain-to-noise-temperature (G/T) across the full frequency band rather than targeting specific jammer frequencies, and can disrupt services during jamming events.
Innovation Solution
A satellite system with a beamforming module that processes RF signals from multiple antenna elements to generate analog signals, including anti-interference signals, which are converted to digital signals and processed to create composite signals with nulls directed towards interference sources at specific frequencies, using a thinned phased array with a low number of elements to achieve high jammer suppression without impacting nearby uplink stations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If existing anti-jamming payloads with additional antenna elements are used, then anti-jamming capability is improved, but device complexity and cost increase
Solution Approach 1:
The patent segments the anti-jamming function into two parts: the main antenna array for normal signal reception and a separate parasitic element array specifically for jammer suppression. This segmentation allows each subsystem to be optimized independently, reducing overall complexity while maintaining effectiveness.
Solution Approach 2:
The patent introduces parasitic elements as intermediary structures that interact with both the main antenna array and the jammer signals. These parasitic elements act as mediators that create nulls in the radiation pattern towards interferers without requiring complex active control systems.
2Reliability
If reflector antennas with active feed arrays are used, then nulls towards interferers are provided, but cost and device complexity increase
Solution Approach 1:
The patent uses passive parasitic elements instead of expensive active feed arrays. These parasitic elements are simpler, cheaper structures that achieve interference suppression through their passive electromagnetic interaction with incident waves, eliminating the need for complex active control systems.
Solution Approach 2:
The patent extracts the interference suppression function from the main antenna system by adding separate parasitic elements. This extraction allows the main antenna array to focus on signal reception while the parasitic elements handle jammer suppression independently.
3Reliability
If existing anti-jamming solutions are implemented, then some jammer suppression is achieved, but G/T degradation occurs over the full frequency band
Solution Approach 1:
The patent applies local quality by designing the parasitic elements to create nulls only in specific directions towards interferers and at specific frequencies, rather than degrading performance across the entire frequency band. This localized approach preserves G/T ratio for legitimate signals while suppressing jammers.
Solution Approach 2:
The patent introduces dynamic control of the parasitic elements' electromagnetic characteristics through varactor diodes, allowing the null positions and depths to be adjusted in real-time based on the location and frequency of interfering signals, thereby maintaining optimal G/T ratio across different operating conditions.
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 greater than 30 dB jammer isolation at specific distances and up to 35-40 dB suppression at the jammer frequency, maintaining service integrity while reducing costs and minimizing scan loss over the coverage area.
Implementation Method 1
A processing module is configured to process the digital signals to generate one or more composite signals that include nulls directed towards an interference source at an interference frequency
Implementation Method 2
a beamforming module that is configured to process radio-frequency (RF) signals originated from multiple antenna elements of an array antenna and to generate a number of analog signals
Data Source
AI summary
A system for interference suppression onboard a satellite includes a beamforming module that processes radio-frequency (RF) signals originated from a plurality of antenna elements of an array antenna to generate multiple analog signals. At least one of the analog signals is an anti-interference signal. Analog-to-digital converters convert the analog signals to a number of digital signals. A processing module processes the digital signals to generate a phase and amplitude control signal. A summation module generates one or more composite signals with reduced interference.