Back-to-Back Slotted-Waveguide Radar Antennas for False Reflection Control
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Solution Overview
Problem
Existing cavity slotted-waveguide antennas suffer from false reflections between the radiating and receiving antennas, which degrade the signal-to-noise ratio and hinder accurate detection of small targets like birds or UAVs in cluttered environments.
Innovation Solution
A radar system with two back-to-back positioned antenna modules, each comprising a planar slotted waveguide array for radiating and receiving, where the arrays are arranged with their longitudinal directions aligned horizontally and rotated around a vertical axis, and equipped with electromagnetic shields and absorbers to minimize reflections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single antenna module is used for both radiating and receiving radar signals, then the device complexity is reduced, but false reflections from the radiating antenna reach the receiving antenna, degrading the signal-to-noise ratio
Solution Approach 1:
The antenna system is segmented into two separate antenna modules positioned back-to-back, with one dedicated to radiating and the other to receiving. This spatial segmentation prevents false reflections from the radiating antenna from reaching the receiving antenna, thereby improving the signal-to-noise ratio while maintaining relatively simple device architecture.
Solution Approach 2:
The receiving function is extracted from the radiating antenna module and assigned to a separate receiving antenna module. This extraction eliminates the harmful interaction where false reflections from the radiating antenna would reach the same antenna, thus improving detection reliability without significantly increasing overall system complexity.
2Productivity
If the radar system rotates at high speed to increase update rate, then the productivity of target detection is improved, but the radar signal exposure time on the target is reduced, lowering the signal-to-noise ratio
Solution Approach 1:
The back-to-back antenna configuration enables continuous radar signal exposure on targets during rotation. While one antenna module radiates signals during a specific angular position, the other module receives reflected signals, ensuring uninterrupted detection and maintaining high signal-to-noise ratio even at reduced rotation speeds that prioritize exposure time over update rate.
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
This configuration reduces false reflections, increases radar signal exposure time, and enhances the signal-to-noise ratio, allowing for more accurate target classification and detection.
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
Depending on the desired electric field polarization, the slots can be placed on either the narrow or broad wall of the waveguide. At the fundamental TE10 mode, longitudinal slots on the broad wall will produce a field with vertical polarization, while transverse slots on the narrow wall result in a horizontal field polarization.
Implementation Method 3
a radar system comprising a first and a second antenna module, each said antenna module comprising: a first planar slotted waveguide antenna array configured for radiating electromagnetic waves; and a second planar slotted waveguide antenna array configured for receiving electromagnetic waves
Data Source
AI summary
A radar system includes antenna modules that have a first planar slotted waveguide antenna array configured for radiating electromagnetic waves, and a second planar slotted waveguide antenna array configured for receiving electromagnetic waves. A rotation system is configured for supporting and rotating the antenna modules around a vertical axis, with the antenna modules arranged in a back-to-back position on opposite sides of a plane intersecting the vertical axis of rotation. There is also provided another radar system comprising a first radar antenna module that has a first planar slotted waveguide antenna array configured for radiating electromagnetic waves, and a second planar slotted waveguide antenna array configured for receiving electromagnetic waves, where each of the planar slotted waveguide antenna arrays have several longitudinal extending waveguide columns. The waveguide columns have a front side and a rear side with a plurality of cavity slots on the front side.