Microwave Imaging Sparse Antenna Array Sidelobe Suppression
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Microwave imaging systems using sparse antenna arrays face challenges with signal loss and reduced signal-to-noise ratio due to increased sparseness, leading to inefficient sidelobe suppression.
Innovation Solution
A microwave imaging system with an illumination network capable of operating in multiple modes to suppress sidelobes by using complementary subarray patterns and complex multipliers to constructively enhance the main scanning lobe and destructively cancel sidelobes, optimizing the sparse geometry of the antenna array.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a sparse antenna array is used to reduce cost and complexity, then the number of antenna elements is reduced, but signal loss increases and signal-to-noise ratio deteriorates
Solution Approach 1:
The antenna array is divided into multiple subarrays with different sparseness factors. The first subarray has a first sparseness factor and the second subarray has a second sparseness factor, allowing different regions of the array to have different density characteristics. This segmentation enables optimization of both complexity and signal quality by having different subarrays serve different functional roles.
Solution Approach 2:
Different portions of the antenna array are given different local characteristics through varying sparseness factors. The first subarray and second subarray have different sparseness factors, creating local quality variations that optimize both cost and signal-to-noise ratio. This allows certain regions to be denser for better signal reception while other regions can be sparser for cost reduction.
2Device complexity
If a sparse antenna array is used to reduce cost, then the number of antenna elements is reduced, but sidelobe suppression becomes inefficient
Solution Approach 1:
The antenna array is segmented into multiple subarrays with different sparseness factors, allowing independent optimization of main lobe and sidelobe characteristics. By having the first subarray with a first sparseness factor and the second subarray with a second sparseness factor, the system can control sidelobe levels while maintaining cost reduction benefits.
Solution Approach 2:
The sparseness factors of the subarrays are carefully selected and optimized to control the radiation pattern characteristics. By changing the sparseness parameter between different subarrays, the system achieves efficient sidelobe suppression while maintaining the cost advantages of sparse arrays.
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 effectively captures microwave images with suppressed sidelobes, improving signal-to-noise ratio and reducing signal loss, while maintaining a reduced number of antenna elements and cost.
Implementation Method 1
an array of microwave detectors to capture either passive microwave energy emitted by the target or reflected microwave energy reflected from the target in response to active microwave illumination of the target
Implementation Method 2
reflected microwave energy reflected from the target in response to active microwave illumination of the target
Implementation Method 3
an illumination system including a transmitter for transmitting microwave illumination to the antenna array and a receiver for receiving reflected microwave illumination from the target through the antenna array
Data Source
AI summary
A microwave imaging system suppresses sidelobes in a microwave image captured using a sparse antenna array using an illumination system that operates in two different illumination modes. The antenna array including subarrays of antenna elements arranged in a sparse geometry to form complementary subarray patterns. The illumination system operates in a first mode to transmit microwave illumination to both of the complementary subarray patterns of the antenna array and receive reflected microwave illumination from both of the complementary subarray patterns of the antenna array to produce a first receive signal. The illumination system further operates in a second mode to transmit microwave illumination to a first one of the complementary subarray patterns of the antenna array and receive reflected microwave illumination from a second one of the complementary subarray patterns of the antenna array to produce a second receive signal. Sidelobes are suppressed using a linear combination of the first and second receive signals.