End-Fire Array Antenna Using Thin Electromagnetic Surface
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Solution Overview
Problem
Conventional end-fire array antennas face limitations in antenna gain due to mutual coupling between elements, which also restrict their size and weight, making it difficult to achieve both wide beam coverage and aerodynamic efficiency for airborne radar systems and other applications.
Innovation Solution
A spatial feeding end-fire array antenna utilizing a single-layer or multi-layer medium-metal combination surface to convert electromagnetic waves into an end-fire focused beam, reducing mutual coupling and enhancing gain, while maintaining a lightweight and compact structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If a large aperture is used to achieve wide beam coverage and high gain, then the radar coverage area is improved, but the aircraft maneuverability and aerodynamic performance deteriorate due to increased weight and size
Solution Approach 1:
The patent employs a thin flexible electromagnetic surface with thickness much less than one percent of the working wavelength, replacing traditional rigid large-aperture structures. This thin film surface can be conformally mounted on aircraft with minimal impact on aerodynamics and weight, while still achieving the required beam coverage area through electromagnetic wave manipulation.
Solution Approach 2:
The patent transitions from a conventional planar array structure to a curved conformal surface structure that follows the aircraft fuselage contour. By utilizing the curvature and three-dimensional geometry of the surface, the antenna achieves wide beam coverage without increasing the projected aperture area, thereby maintaining aircraft maneuverability.
2Area of stationary object
If a large aperture is used to ensure 360° omnidirectional coverage, then the scanning beam coverage is improved, but the aircraft maneuverability deteriorates due to the large radial array aperture
Solution Approach 1:
The thin flexible electromagnetic surface allows the antenna to be mounted conformally on the aircraft fuselage without extending the radial aperture. The surface wraps around the aircraft body, achieving 360° omnidirectional coverage through the circumferential arrangement of elements on the curved surface rather than through radial extension.
Solution Approach 2:
The patent utilizes a curved conformal surface structure that follows the cylindrical geometry of the aircraft fuselage. This curvature enables the antenna elements to be distributed around the entire circumference, achieving omnidirectional scanning beam coverage without increasing the radial dimension of the array aperture.
3Power
If conventional end-fire array elements are used to form focused beams, then the beam focusing capability is improved, but mutual coupling between elements occurs which limits array dimensions and antenna gain
Solution Approach 1:
The patent extracts and eliminates the mutual coupling problem by using space wave feeding instead of direct element-to-element coupling. Each antenna element is independently fed by space waves from the curved surface, removing the harmful mutual coupling interactions between adjacent elements that normally limit array size and gain.
Solution Approach 2:
The patent introduces space waves as an intermediary medium to feed the antenna elements. Instead of direct electromagnetic coupling between adjacent elements, the curved surface generates space waves that illuminate each element independently, acting as a mediator that eliminates mutual coupling while still providing the necessary excitation for focused beam formation.
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 significantly improves antenna gain, reduces size and weight, and simplifies the structure, allowing for high-gain end-fire beams with increased aperture, addressing the limitations of conventional end-fire arrays.
Implementation Method 1
a single-layer and/or multi-layer medium-metal combination surface is configured to convert the electromagnetic waves emitted from the primary feed to an end-fire focused beam
Implementation Method 2
concentrate space waves received in an end-fire direction into the primary feed
Data Source
AI summary
The present disclosure provides a spatial feeding end-fire array antenna based on electromagnetic surface technologies, including: a primary feed, configured to transmit and/or receive electromagnetic waves; and a single-layer and/or multi-layer medium-metal combination surface, configured to convert the electromagnetic waves emitted from the primary feed to an end-fire focused beam, or to concentrate space waves received in an end-fire direction into the primary feed. The single-layer and/or multi-layer medium-metal combination surface has a thickness that is equal to or less than one percent of working wavelength of the antenna.