Back-to-Back Slotted-Waveguide Radar Arrays for False Reflection Control
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Solution Overview
Problem
Existing radar systems face challenges in reducing false reflections from radiating antennas to receiving antennas, which affects the signal-to-noise ratio and accurate classification of small targets in cluttered environments.
Innovation Solution
A cavity slotted-waveguide antenna system with two back-to-back positioned antenna modules, where each module has a planar slotted waveguide antenna array for radiating and receiving electromagnetic waves, is designed to minimize false reflections by using a rotating system that reduces the speed of rotation, and includes electromagnetic shields and absorber materials to enhance signal exposure time and noise ratio.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the radar system uses a single antenna module for both radiating and receiving, then the device complexity is reduced, but the signal-to-noise ratio deteriorates due to false reflections from the radiating antenna reaching the receiving antenna
Solution Approach 1:
The antenna system is segmented into separate radiating and receiving antenna modules. Each module contains its own antenna array, allowing the radiating and receiving functions to be physically separated. This segmentation prevents false reflections from the radiating antenna from reaching the receiving antenna, thereby improving the signal-to-noise ratio while maintaining manageable system complexity through modular design.
Solution Approach 2:
The receiving antenna array is extracted and positioned separately from the radiating antenna module. By taking out the receiving function from the radiating module and placing it in a distinct module with a different spatial orientation, the system eliminates the problem of false reflections while maintaining a relatively simple overall structure.
2Productivity
If the radar system rotates at high speed, then the productivity is improved by faster scanning, but the signal exposure time on target is reduced, lowering the signal-to-noise ratio
Solution Approach 1:
The system merges the functions of multiple antenna modules (both radiating and receiving modules) into a single rotating assembly. This combination allows the radar to maintain high scanning productivity while the integrated multi-module configuration provides redundant signal paths that effectively increase the signal exposure time on target, thereby improving the signal-to-noise ratio.
3Device complexity
If the first and second antenna arrays are positioned close to each other, then the device complexity and size are reduced, but the false reflections from the radiating antenna to the receiving antenna increase
Solution Approach 1:
The first and second antenna arrays are positioned in asymmetric orientations relative to each other, with the second array rotated at an angle (e.g., 45 degrees) compared to the first array. This asymmetric positioning, combined with the back-to-back module configuration, ensures that false reflections from the radiating antenna do not directly reach the receiving antenna, thereby reducing harmful reflections while maintaining compact system size.
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 achieves a higher signal-to-noise ratio and improved target classification by reducing false reflections and increasing radar signal exposure time, allowing for more accurate detection of small targets like birds or UAVs.
Implementation Method 1
slotted-waveguide antennas consist of lengths of waveguides with a multiple number of slots formed in the conducting walls of the waveguides. These slots introduce discontinuities in the conductor and interrupt the flow of current along the waveguide. Instead, the current must flow around the edges of the slots, causing them to act as dipole antennas.
Implementation Method 2
includes electromagnetic shields and absorber materials to enhance signal exposure time and noise ratio
Data Source
AI summary
A radar system with antenna modules that have first and second planar slotted waveguide antenna arrays for radiating and receiving electromagnetic waves. A rotation system supports and rotates the antenna modules around a vertical axis. The modules are arranged back-to-back on opposite sides of a plane intersecting the vertical axis of rotation. Another radar system includes planar slotted waveguide antenna arrays with longitudinal extending waveguide columns. The front side of the columns holding the cavity slots of the first planar antenna array are positioned in a first plane and the front side of the columns holding the cavity slots of the second planar antenna array are positioned in a second plane parallel to the first plane. The arrays may be positioned at a distance to each other in a direction to the first and second planes. The parallel planes may be offset with a minimum perpendicular array distance.