Reconfigurable Phase-Switched Screen Using Varactor-Loaded AMC
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Solution Overview
Problem
Conventional radar cross section (RCS) reduction technologies, such as radar absorbing materials (RAMs), face limitations in thickness and frequency adjustment, which restrict their ability to effectively absorb electromagnetic waves across a wide bandwidth and provide stealth capabilities.
Innovation Solution
A reconfigurable wideband phase-switched screen (PSS) based on an artificial magnetic conductor (AMC) is developed, comprising centrally symmetrical AMC units with varactors and capacitors, allowing for continuous frequency switching and in-phase reflection states, thereby reducing RCS by controlling the capacitance of varactors to achieve broadband absorption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a conventional PSS is composed of a metal plate, a quarter-wavelength dielectric barrier and a periodic patch array, then the PSS can shift the energy frequency of incident electromagnetic waves, but the thickness becomes large
Solution Approach 1:
The patent changes the electromagnetic parameters of the structure by introducing AMC units with specific impedance characteristics. The AMC structure modifies the boundary conditions and resonance properties, enabling frequency shifting functionality with a much reduced thickness of only 0.05λg compared to the conventional quarter-wavelength dielectric barrier.
Solution Approach 2:
The patent employs a composite structure combining AMC units with varactor diodes and capacitors. This composite design integrates active electronic components with passive electromagnetic structures, creating a reconfigurable system that achieves both thin profile and frequency shifting capability through the synergistic interaction of different material properties.
2Adaptability or versatility
If RAM is used to reduce RCS, then electromagnetic wave energy is converted into electric energy, but the thickness and frequency adjustment capability are limited
Solution Approach 1:
The patent introduces varactor diodes that can dynamically adjust their capacitance values based on applied voltage, enabling real-time frequency tuning and reconfiguration of the AMC structure. This dynamic capability allows the system to adapt to different frequency requirements without changing the physical thickness of the structure.
Solution Approach 2:
By changing the capacitance parameters of the varactor diodes and capacitors, the resonant frequency and impedance characteristics of the AMC units can be continuously adjusted. This parameter control mechanism provides versatile frequency adaptation while maintaining the thin profile of the structure.
3Adaptability or versatility
If varactor capacitance is adjusted to switch surface impedance of AMC, then multiple continuous in-phase reflection points can be generated, but device complexity increases
Solution Approach 1:
The patent divides the AMC structure into discrete periodic units, each containing varactor diodes and capacitors as independent controllable elements. This segmentation allows localized impedance control and simplifies the overall system architecture by repeating modular units across the surface, making the complex functionality manageable through standardization.
Solution Approach 2:
The AMC units are designed as multi-functional modules that simultaneously provide impedance control, frequency selection, and phase control capabilities through the coordinated action of varactors and capacitors. This universal design reduces overall system complexity by consolidating multiple functions into single integrated units.
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 solution achieves a significant reduction in thickness by 80% compared to conventional PSS and allows for adjustable frequency bands with a phase difference of 143°-217°, effectively implementing stealth capabilities across a wide frequency range with high absorption efficiency.
Implementation Method 1
By controlling the capacitance value of a varactor, multiple continuous in-phase reflection points can be generated, thus changing the surface impedance of the AMC
Implementation Method 2
The AMC, as a metamaterial, has the electromagnetic characteristics of in-phase reflection of plane waves in a specific frequency range
Implementation Method 3
The AMC and a PEC were distributed in a checkerboard form, and the reflection phase difference between the two was 180°, so that electromagnetic waves could cancel each other with equal amplitude at the interface
Implementation Method 4
a middle dielectric substrate
Implementation Method 5
through a metalized through-hole in the central position of the unit, the central square metal patch is connected to the metal ground at the bottom surface of the dielectric substrate
Data Source
AI summary
The present invention discloses a reconfigurable wideband phase-switched screen (PSS) based on an artificial magnetic conductor (AMC). Gap capacitance between patches is controlled by changing the capacitance of varactors, so that periodic units have a plurality of continuous frequency points. A phase difference between two adjacent frequency bands is 143°-217°, so that the periodic structure absorbs incident electromagnetic waves in a wide frequency band, and the broadband PSS is implemented with a relative bandwidth of 45.2%. The AMC structure according to the present invention is simple in structure and easy to process, with a thickness less than one twentieth of the working wavelength, and greatly reduces size and costs.