Variable Focus Microwave Antenna Using Concentric Discs
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Solution Overview
Problem
Existing large microwave antennas face challenges in efficiently focusing megawatt power levels and adapting to variable ranges due to mechanical complexity and the need for numerous individually programmed elements, especially for large apertures and short wavelengths.
Innovation Solution
A variable focus antenna system comprising concentric discs of different dimensions surrounding a central plate, adjustable by actuators to approximate a spherical surface, allowing dynamic focusing and efficient power concentration at specific ranges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a phased array of elements is used to achieve variable focus, then focusing capability is improved, but device complexity increases enormously
Solution Approach 1:
The antenna aperture is divided into a limited number of concentric annular segments that can be independently positioned along the optical axis. This segmentation allows continuous focus adjustment with only a few movable components rather than requiring thousands of individually controlled elements.
Solution Approach 2:
The annular segments are made dynamically positionable along the optical axis through mechanical actuators. By moving these segments to different axial positions, the focal point of the antenna can be continuously adjusted without changing the overall antenna structure or requiring complex electronic beamforming.
2Manufacturing precision
If individually programmed elements are used for large apertures, then focusing precision is improved, but ease of manufacture deteriorates
Solution Approach 1:
Instead of individually programming each element, the patent uses a simplified approach where a small number of annular segments are physically positioned to create the desired focal pattern. This physical copying of the focal requirement through mechanical positioning eliminates the need for complex computer programming of thousands of elements.
3Manufacturing precision
If a spherical surface is approximated with many small elements, then focusing accuracy is improved, but device complexity increases
Solution Approach 1:
The spherical surface is segmented into a small number of concentric annular zones rather than using many small elements. Each annular zone is positioned independently along the optical axis, providing sufficient spherical approximation accuracy with far fewer components than traditional approaches.
Solution Approach 2:
Instead of achieving spherical approximation through lateral arrangement of many small elements in the aperture plane, the patent uses axial positioning of annular segments. This adds the optical axis dimension as the primary degree of freedom for achieving the spherical surface approximation, dramatically reducing the number of components needed.
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 enables efficient focusing and adaptable performance for large antennas, reducing mechanical complexity and cost, while maintaining high power density and reception capabilities, suitable for applications like Active Denial Technology and remote power transmission.
Implementation Method 1
A variable focus antenna system comprising concentric discs of different dimensions surrounding a central plate, adjustable by actuators to approximate a spherical surface
Implementation Method 2
allowing dynamic focusing and efficient power concentration at specific ranges
Data Source
AI summary
Concentric shapes (e.g., discs and rings), are nested and displaced from a central plate. The discs are individually positioned by means of mechanical or electro-mechanical actuators such that the over-all result approximates a spherical surface reflector antenna having an adjustable radius of curvature, with the radii of curvature being equivalent to the focal length of the antenna. Another innovation includes reducing the dimensional positioning of the various discs by a modulo of the wavelength of the operating frequency of the antenna, thus reducing the throw accommodation of the actuators to only one wavelength. Each of the discs and the central plate are designed to have substantially the same area, as a nominal configuration. The accuracy of the approximation is improved as the number of discs is increased; however, very acceptable performance is obtained with as few as ten discs when compared to a perfect spherical surface.