Dual-Function Antenna Switching Between Phased Array and Low RCS
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Solution Overview
Problem
Aircraft antennas often reflect radar signals back towards the source, increasing detectability, and existing solutions struggle to efficiently switch between communication and low radar cross-section modes.
Innovation Solution
A dual-function antenna structure with a substrate and an array of antenna elements, coupled with a beam forming network and a controller, allows switching between a steerable phased array communication mode and a low radar cross-section (RCS) mode using controllable switches and phase shifters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the antenna operates in maximum power transfer mode for communication, then communication efficiency is improved, but radar cross-section increases making the aircraft more detectable
Solution Approach 1:
The antenna system dynamically switches between two operational modes: maximum power transfer mode for communication and low RCS mode for stealth. The controllable switches and phase shifters enable real-time reconfiguration of the antenna elements' electrical connections and signal phases, allowing the system to adapt its radiation pattern and impedance characteristics based on operational requirements.
Solution Approach 2:
The system changes key electrical parameters including impedance matching (from 50 ohms for power transfer to shorted conditions for low RCS), phase relationships between elements (using controllable phase shifters), and current distribution patterns. These parameter changes transform the antenna's electromagnetic characteristics to achieve either communication efficiency or radar evasion.
2Productivity
If the antenna is designed for directional communication capabilities, then communication performance is improved, but the antenna structure becomes more complex
Solution Approach 1:
The antenna system performs multiple functions using a single integrated structure: it provides steerable beam communication, low RCS stealth mode, and automatic radar detection. The same array of dipole elements, when reconfigured through switches and phase shifters, can function as a communication antenna with directional control or as a low-visibility structure, eliminating the need for separate antenna systems.
Solution Approach 2:
The patent combines the communication antenna function with the radar evasion function into a single integrated structure. The dipole array, feed network, switches, and phase shifters work together as one system that can alternatively provide either communication service or stealth protection, rather than requiring separate dedicated antennas for each function.
3Object-affected harmful factors
If the antenna elements are spaced to provide capacitive coupling for low RCS mode, then radar cross-section is reduced, but communication efficiency decreases
Solution Approach 1:
The electrical coupling between antenna elements is dynamically adjusted through controllable switches. In low RCS mode, the switches configure the elements to provide capacitive coupling with specific spacing that reduces radar reflectivity. In communication mode, the switches reconfigure the same elements to provide optimal impedance matching and current distribution for efficient power transfer, transforming the coupling characteristics as needed.
Solution Approach 2:
The system changes the effective electrical parameters of the antenna elements including their impedance (from matched to shorted), phase relationships, and current magnitudes. These parameter changes allow the same physical structure with fixed element spacing to exhibit different electromagnetic behaviors - either as efficient radiating elements for communication or as coupled structures that present a low radar cross-section.
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 reduces radar detectability by switching to a low RCS mode, while maintaining communication capabilities, thereby enhancing the stealth and operational effectiveness of aircraft.
Implementation Method 1
adjacent legs of adjacent dipole antenna elements including respective spaced apart end portions having shapes and relative positioning to provide capacitive coupling between the adjacent dipole antenna elements
Data Source
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AI summary
A system to be carried by a vehicle may include a dual-function antenna structure that includes a substrate and an array of antenna elements carried thereby. A beam forming network may be coupled to the dual-function antenna structure. A radar detector to be carried by the vehicle may be configured to detect radar signals directed to the vehicle. A controller may be configured to control the dual-function antenna structure to switch between a steerable phased array communication mode and a low radar cross section (RCS) mode responsive to the radar detector.