Radar Grating Lobe Suppression via Null Point Segmentation
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Solution Overview
Problem
Conventional array antenna systems face challenges in precisely detecting targets due to the influence of grating lobes, which cannot be sufficiently suppressed when their width exceeds the null width, leading to reduced detection precision, especially when using the snap-shot technique.
Innovation Solution
A radar apparatus with a transmission array antenna and a reception array antenna, where the control unit sets one array antenna as a grating lobe suppressing antenna with multiple directivities having null points, and the detecting unit produces an average reception signal to suppress the grating lobe influence, allowing for high-precision target detection by differentiating null point positions and combining transmission-reception directivities to reduce grating lobe power.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the null point width is made narrower to improve main lobe detection precision, then the ability to suppress grating lobes deteriorates when grating lobe width exceeds null width
Solution Approach 1:
The patent divides the grating lobe suppression task into multiple segments by setting multiple null points at different positions within the grating lobe area. Each null point suppresses a specific portion of the grating lobe, and by combining multiple null points, the entire grating lobe is suppressed even when its width exceeds the null point width.
Solution Approach 2:
The patent transitions from a single null point approach to a multi-dimensional approach by distributing multiple null points across different angular positions within the grating lobe area. This spatial distribution in the angular dimension enables comprehensive grating lobe suppression while maintaining narrow null point widths for precise main lobe detection.
2Device complexity
If a single null point is used in the reception directivity, then the system complexity is reduced, but the grating lobe suppression becomes insufficient when grating lobe width exceeds null width
Solution Approach 1:
The reception directivity is segmented into multiple null points instead of using a single null point. Each null point is positioned to suppress a specific angular region of the grating lobe, enabling effective suppression across the entire grating lobe width while keeping the overall system relatively simple.
Solution Approach 2:
The patent changes the parameter of null point positions by distributing multiple null points at different angular positions within the grating lobe area. This parameter optimization enables effective grating lobe suppression without requiring excessive system complexity.
3Reliability
If the grating lobe width is reduced to fit within the null width, then grating lobe suppression is effective, but the array antenna configuration becomes more constrained
Solution Approach 1:
Instead of constraining the grating lobe width to fit within a single null width, the patent segments the grating lobe suppression task across multiple null points. This segmentation approach maintains array antenna configuration flexibility while achieving effective grating lobe suppression.
Solution Approach 2:
The patent resolves the configuration constraint by moving from a single null point dimension to multiple null point positions in the angular dimension. This enables the system to handle wider grating lobes without restricting the array antenna configuration options.
Data Source
AI summary
A radar apparatus has a transmission array antenna for radiating electromagnetic waves containing a main lobe and a grating lobe in a transmission directivity, a reception array antenna for receiving electromagnetic waves radiated from the transmission array antenna and reflected from a target, and a microcomputer for setting the reception antenna in reception directivities one after another by placing a null point in a grating lobe receiving area of each directivity and placing the null points of the directivities at different positions. The microcomputer produces a reception signal, produced from the received electromagnetic waves containing the main lobe reflected from the target, every change of the reception directivity and detects the target from the average of the reception signals.