Stacked Dual-Frequency Antenna Aperture for Radar Systems
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing radar surveillance systems face challenges in achieving an increased aperture for low-frequency IFF/SSR antennas without degrading the performance of high-frequency PSR antennas, while also managing complex feeding networks and interference between different frequency bands.
Innovation Solution
The solution involves a stacked antenna structure with first and second antenna apertures, where the first antenna elements operate in the high-frequency band and second antenna elements operate in the low-frequency band, with perpendicular polarizations and a common feeding structure for the second antenna elements, minimizing interference and allowing for electronic scanning without increasing the overall system size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If two separate antenna apertures are used for PSR and IFF/SSR functions, then the aperture for IFF/SSR can be increased, but the overall antenna system size increases substantially
Solution Approach 1:
The patent combines the PSR antenna and IFF/SSR antenna into a single integrated antenna structure. The PSR antenna elements (slots) and IFF/SSR antenna elements (dipoles) are arranged in the same aperture plane, allowing both functions to share the same physical space. This merging eliminates the need for separate antenna apertures while maintaining the required aperture size for IFF/SSR operation.
Solution Approach 2:
The patent resolves the spatial conflict by utilizing different dimensional characteristics - specifically, arranging elements with different polarizations (horizontal slots for PSR, vertical dipoles for IFF/SSR) in the same aperture plane. This orthogonal arrangement in the polarization dimension allows both antenna types to coexist without interfering with each other's radiation patterns, effectively packing two separate antenna systems into one aperture.
2Area of stationary object
If dipoles and slots are located in the same plane, then the aperture is efficiently utilized, but interference between the two types of antenna elements increases
Solution Approach 1:
The patent employs asymmetric positioning of the dipole and slot elements within the aperture. The dipoles are arranged in specific patterns (e.g., staggered or offset positions) relative to the slots, creating an asymmetric layout that minimizes mutual coupling and interference. This asymmetric arrangement breaks the symmetry that would otherwise cause constructive interference between the two antenna types.
Solution Approach 2:
The patent applies different local characteristics to different regions of the aperture. By carefully selecting the positions, orientations, and dimensions of individual dipole and slot elements at specific locations, the design optimizes the local electromagnetic environment to reduce interference. Each element's local properties are tuned to minimize its interaction with neighboring elements of the other type.
3Ease of operation
If a complex feeding network is used to feed each antenna element independently, then beam steering capability is improved, but the feeding structure complexity and interference with the other antenna function increases
Solution Approach 1:
The patent designs the feeding network to serve multiple functions simultaneously. The same feeding structure provides power to both the dipole elements and slot elements, and enables beam steering for both antenna types. By making the feeding network universal, the patent reduces the total number of separate feeding components needed while maintaining full electronic beam steering capability for both PSR and IFF/SSR functions.
Solution Approach 2:
The patent introduces intermediary feeding structures that act as mediators between the power source and the antenna elements. These intermediary components (such as feed networks with phase shifters) are designed to distribute signals to multiple antenna elements while providing the necessary phase control for beam steering. The intermediary feeding structure simplifies the overall system by consolidating multiple feeding functions into a single integrated network.
Data Source
Figure 1
Figure 2
Figure 3a~4
AI summary
The invention provides an antenna structure comprising at least two stacked antenna apertures, a first antenna aperture with first antenna elements and at least a second antenna aperture with second antenna elements. The antenna structure is arranged for operation in at least a high and a low frequency band. The first antenna elements are arranged for operation in the high frequency band and said second antenna elements for operation in the low frequency band. The first antenna elements are arranged to have a polarization substantially perpendicular to the polarization of the second antenna elements. The second antenna elements are arranged in at least one group and each of said group, comprises a number of second antenna elements coupled in series and arranged to have a common feeding point on a straight feeding structure. One feeding structure is located adjacent to each group of second antenna elements. The direction of the feeding structure is substantially perpendicular to the polarization of the first antenna elements. The invention also provides a corresponding method and a radar system comprising the antenna structure.