Asymmetric Chebyshev Array Antenna for Side Lobe Suppression
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Solution Overview
Problem
Existing array antennas for vehicle radars face challenges in achieving high main beam directivity and low side lobes due to radiation effects from the ground plane and power divider, leading to reduced target detection resolution.
Innovation Solution
An asymmetrical Chebyshev array antenna design that compensates current values of radiating elements at the ends of serial antenna units, resulting in an asymmetric distribution of current values to improve detection resolution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If an idealized symmetrical Chebyshev array antenna is used, then the main beam has the highest directivity and all side lobes have the same level, but the ground plane and power divider generate radiation effects that disrupt the radiation field pattern, creating two peaks and reducing main beam directivity
Solution Approach 1:
The patent applies asymmetry by intentionally designing different current values for radiating elements at different positions. Specifically, radiating elements closer to the power divider are assigned different current values than those farther away, creating an asymmetric current distribution that compensates for the harmful radiation effects from the power divider and ground plane, thereby maintaining a single main beam peak and improving measurement precision
Solution Approach 2:
The patent implements local quality by applying different current values to radiating elements based on their specific positions in the array. Each radiating element's current value is locally optimized to compensate for position-dependent interference from the power divider and ground plane, rather than using a uniform current distribution across all elements
2Power
If more radiating elements are added to increase peak gain, then the peak gain increases, but the printed circuit board size increases proportionally
Solution Approach 1:
The patent applies parameter changes by optimizing the current values assigned to each radiating element. By carefully adjusting these current parameters, the system achieves enhanced peak gain without needing to increase the number of radiating elements or the overall array size, thus improving power while keeping the printed circuit board area constrained
3Measurement precision
If the side lobe level is reduced to improve target detection resolution, then the main beam directivity decreases and peak gain is reduced
Solution Approach 1:
The patent resolves this contradiction by introducing asymmetric current distribution among radiating elements. This asymmetry allows the system to suppress side lobes while maintaining a strong main beam, as the different current values create destructive interference in side lobe directions while constructive interference is maintained in the main beam direction, thereby improving target detection resolution without sacrificing main beam directivity
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 asymmetrical design enhances main beam directivity and reduces side lobe gain, improving the identification rate of object detection by maintaining a single peak in the main beam and decreasing side lobe gain.
Implementation Method 1
The antenna usually uses the principle of Frequency Modulated Continuous Wave (FMCW) to detect the distance and speed of the target
Implementation Method 2
The radiation pattern synthesized by the array antenna includes the main beam (also called the main lobe) and side beam (also called the side lobe)
Implementation Method 3
the ground plane material is metal, leading to current flow and the generation of radiation effects, which can disrupt the radiation field pattern of the array antenna
Data Source
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AI summary
Provided is an asymmetric Chebyshev array antenna, comprising a substrate, a power divider, a ground plane, and a serial antenna unit. The serial antenna unit includes at least one middle radiating element, a plurality of first radiating elements, and a plurality of second radiating elements. An original current value of the middle radiating element is defined as A, original current values of the first radiating elements from a first end toward a second end of the serial antenna unit are defined as B1, B2, ... , Bn, original current values of the second radiating elements from the second end toward the first end of the serial antenna unit are defined as C1, C2, ... , Cn, a sum of original current values of the power divider and the ground plane is defined as D, current compensation values of the second radiating elements from the second end toward the first end of the serial antenna unit are defined as δ1, δ2, ... , δn, n ≥ 1 and n is a positive integer, Bn = Cn , D < B1 < B2 < ··· < Bn < A, D < C1 + δ1 < C2 + δ2 < ··· < Cn + δn < A, and ∑i=1nδi=δ1+δ2+⋯+δn≅D.