Bar-Shaped Horn Antenna Layout for Coupling and Sampling Balance
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Solution Overview
Problem
Conventional passive security checking devices using horn antennas face a contradiction between coupling efficiency and sampling interval due to the large aperture required for higher efficiency, leading to reduced sampling rate and imaging quality, with low coupling efficiency with lenses typically below 50%.
Innovation Solution
The use of a bar-shaped horn antenna with a long-to-short side ratio greater than 1.2, arranged in one dimension or an arc, increases the gain and coupling efficiency while maintaining adequate sampling rate, and a grid-type reflecting plate aligns with the polarization direction of the receiving antennas to enhance signal-to-noise ratio and image quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the antenna aperture is increased to improve coupling efficiency, then the coupling efficiency improves, but the number of horn antennas that can be arranged per focal spot decreases
Solution Approach 1:
The patent employs asymmetric horn antenna designs with different aperture dimensions in orthogonal directions. By making the horn antenna aperture asymmetric (different lengths in x and y directions), the system can achieve high coupling efficiency in one direction while maintaining adequate sampling rate in the other direction, thus resolving the contradiction between coupling efficiency and sampling rate
Solution Approach 2:
The patent applies different aperture characteristics to different spatial directions. The horn antenna is designed with optimized aperture dimensions specifically tailored for each direction's requirements - larger aperture where high coupling is needed, and smaller aperture where high sampling rate is needed, achieving local optimization in different spatial zones
2Loss of energy
If the antenna aperture is increased to improve coupling efficiency, then the coupling efficiency improves, but the imaging quality deteriorates due to reduced sampling rate
Solution Approach 1:
The asymmetric horn antenna design allows the system to achieve high coupling efficiency in the direction where imaging quality is most sensitive, while maintaining sufficient sampling rate in the orthogonal direction. This directional asymmetry prevents degradation of overall imaging quality
Solution Approach 2:
The patent optimizes specific geometric parameters of the horn antenna (aperture dimensions, length, flare angles) to achieve the desired balance between coupling efficiency and sampling rate. By carefully adjusting these parameters, the system maintains both high coupling efficiency and adequate sampling rate for good imaging quality
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 improves the power coupling efficiency to nearly 50% in one direction and over 90% in another, enhancing the signal-to-noise ratio and imaging quality, while reducing hardware costs and compensating for spatial resolution asymmetry.
Implementation Method 1
the coupling efficiency of the antenna with the lens is low, usually less than 50%
Implementation Method 2
The use of a bar-shaped horn antenna with a long-to-short side ratio greater than 1.2, arranged in one dimension or an arc, increases the gain and coupling efficiency
Implementation Method 3
a grid-type reflecting plate aligns with the polarization direction of the receiving antennas to enhance signal-to-noise ratio and image quality
Data Source
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Figure 3
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AI summary
A passive security checking device and a receiving antenna unit thereof are disclosed. The receiving antenna unit includes at least one horn antenna (410) including a horn body (411) and a waveguide (412) connected thereto. A ratio of a long side to a short side of a horn opening of the horn body is greater than 1.2. The passive security checking device and receiving antenna unit thereof can solve the problem, faced by normal horn antennae, of contradiction between a sampling interval and coupling efficiency.