Deployable AMC Antenna With Inflate-to-Latch Ground Plane Spacing
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Solution Overview
Problem
Traditional antennas over ground planes require a quarter wavelength spacing, resulting in a thick profile at low frequencies, and artificial magnetic conductor (AMC) antennas, while thinner, are stiff and cumbersome for large aperture antennas below 1 GHz.
Innovation Solution
An AMC antenna apparatus with a retaining structure to coil the antenna element, ground plane, and inflatable bladder system for stowage, and actuators to deploy the antenna by inflating the bladder and latching the ground plane, allowing for a compact and efficient deployment mechanism.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional antenna spacing of λ/4 is used, then directivity performance is improved, but antenna thickness increases significantly at low frequencies
Solution Approach 1:
The patent changes the fundamental parameter of ground plane behavior by introducing an artificial magnetic conductor (AMC) structure with frequency selective surface (FSS) patches. This transforms the ground plane from a simple reflector into an active component that creates magnetic wall conditions, enabling sub-λ/4 spacing while maintaining directivity performance through constructive interference of reflected signals.
Solution Approach 2:
The patent employs a composite structure combining conductive FSS patches, dielectric substrate, and feeding network to create the AMC ground plane. This composite material approach enables the ground plane to exhibit magnetic conductor properties at specific frequencies, allowing reduced spacing while preserving antenna performance.
2Length of stationary object
If AMC ground plane with FSS is used, then antenna thickness is reduced, but structural stiffness and portability deteriorate
Solution Approach 1:
The patent divides the AMC antenna structure into separable components: the rigid FSS ground plane assembly and the flexible inflatable support structure. This segmentation allows the antenna to be transported in a compact stowed configuration and deployed to its full operational size at the destination, combining thin profile with improved portability.
Solution Approach 2:
The patent introduces an inflatable bladder system that transitions the antenna structure from a compact stowed state to a deployed operational state. This dynamic mechanism allows the antenna to change its physical configuration, providing both portability during transport and structural stability during operation.
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
Enables thinner, more portable AMC antennas with efficient directivity performance and easy deployment, addressing the stiffness and size issues of traditional antennas.
Implementation Method 1
the bladder system is configured to transition from an unlatched state to a latched state when the AMC antenna is deployed from a stowed configuration
Data Source
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AI summary
An AMC antenna apparatus includes a ground plane and a flexible antenna element layer above the ground plane. The ground plane includes a conductive base surface, a plurality of flexible conductors, and a frequency selective surface (FSS) layer above the base surface, where the FSS layer includes a plurality of conductive patches separated from one another. Each of the flexible conductors electrically connects one of the conductive patches to the base surface. A latch mechanism is arranged between the base layer and the FSS layer. An inflatable bladder system between the base layer and the FSS layer is configured to receive a gas input during deployment of the antenna apparatus and inflate to produce force sufficient to cause the latch mechanism to transition from an unlatched state to a latched state in which the conductive base surface is fixedly separated from the FSS layer at a predetermined distance.