Flat Antenna Segmentation Eliminates Loop Current
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Solution Overview
Problem
Conventional flat antennas have poor antenna gain in the VHF range and are affected by loop current issues, which impact image quality and are sensitive to the positioning of conductors like coaxial cables.
Innovation Solution
A flat antenna design featuring a pair of radiation units with a main radiating body of triangular shape and an auxiliary radiating body extending towards a symmetrical axis, eliminating physical connections between units to prevent loop currents and optimizing dimensions for enhanced gain across VHF and UHF frequency ranges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a conventional flat antenna uses a folded dipole antenna configuration with an auxiliary radiating body connected between main radiating bodies, then the bandwidth and impedance matching are improved, but the antenna gain in the VHF range becomes poor and loop current is generated
Solution Approach 1:
The antenna is divided into independent radiation units, each comprising a main radiating body and an auxiliary radiating body. The radiation units are spaced apart and do not form a continuous folded dipole structure, thereby eliminating loop current while maintaining broadband capability through the combination of different radiating elements.
Solution Approach 2:
The harmful loop current path is extracted by removing the direct connection between the auxiliary radiating body and the main radiating bodies that characterizes the folded dipole configuration. The auxiliary radiating body remains connected to one main radiating body only, breaking the closed loop that causes current circulation and gain degradation.
2Adaptability or versatility
If the conventional flat antenna uses a folded dipole antenna configuration, then the bandwidth is increased, but the antenna becomes sensitive to the positioning of conductors like coaxial cables
Solution Approach 1:
By segmenting the antenna into separate radiation units with spacing between them, the patent eliminates the continuous conductive path that makes the folded dipole sensitive to external conductors. Each radiation unit operates more independently, reducing the overall sensitivity to coaxial cable positioning while maintaining the broadband characteristics through the combined structure.
3Reliability
If the auxiliary radiating body is connected between the main radiating bodies in a folded dipole configuration, then the impedance matching is improved, but loop current is generated that affects performance
Solution Approach 1:
The harmful loop current is extracted by removing the configuration that creates it. The auxiliary radiating body is no longer connected between the two main radiating bodies in a way that forms a closed loop. Instead, it is connected to one main radiating body only, eliminating the circular current path while preserving the impedance matching benefits through the remaining radiating structure.
Solution Approach 2:
The patent converts the potential harm of the auxiliary radiating body (which could create loop current) into a benefit by configuring it to extend toward the symmetrical axis without forming a closed loop. This configuration eliminates loop current while the auxiliary body still contributes to impedance matching and broadband operation, turning a potential problem into a solution.
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 design significantly improves antenna gain in the VHF range by up to 7 dB and reduces noise interference, maintaining performance across digital television frequency bands without being influenced by nearby conductors.
Implementation Method 1
Each of the radiation units includes a main radiating body, an auxiliary radiating body and a feed-in point. The main radiating body has a substantially triangular shape... the auxiliary radiating body is connected to the main radiating body, and extends from the first edge toward the symmetrical axis.
Data Source
AI summary
A flat antenna includes a pair of radiation units that are spaced apart from each other and that are symmetrical with respect to a symmetrical axis. Each of the radiation units includes a main radiating body, an auxiliary radiating body and a feed-in point. The main radiating body has a substantially triangular shape and includes a first angle close to the symmetrical axis, a second angle far from the symmetrical axis with respect to the first angle, and an edge between the first and second angles and obliquely facing the symmetrical axis. The auxiliary radiating body is connected to the main radiating body, and extends from the first edge toward the symmetrical axis. The feed-in point is formed on the first angle of the main radiating body.