Hybrid Loop-Dipole Antenna for Orthogonal End-Fire Directivity
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Solution Overview
Problem
Existing miniature loop antennas face challenges in maintaining directivity outside their plane, especially when miniaturized, which affects their ability to be compactly arrayed in an "End-Fire" configuration.
Innovation Solution
The design incorporates a main radiating element of the loop antenna type with a central electric dipole element circumscribed within it. The central element is powered centrally, and the loop's connection ports are optimized to have zero real impedance, allowing for balanced coupling and maintaining radiation orthogonal to the loop's plane.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the loop antenna is miniaturized (low C/λ ratio), then the antenna size is reduced, but the directivity orthogonal to the loop plane deteriorates
Solution Approach 1:
The patent combines a loop antenna with a central dipole element to form a hybrid structure. The dipole is positioned at the center of the loop and both elements are excited together, merging their radiation patterns to achieve orthogonal directivity while maintaining a compact low C/λ ratio structure.
Solution Approach 2:
The central dipole acts as an intermediary element that mediates the radiation pattern of the miniaturized loop. By introducing this intermediate element, the patent restores the orthogonal directivity that would otherwise be lost in a pure miniaturized loop configuration.
2Volume of moving object
If loop antennas are arrayed in End-Fire mode, then the occupied space is minimized, but maintaining good directivity orthogonal to the loop plane becomes difficult
Solution Approach 1:
By merging the loop and dipole elements into a single hybrid radiating structure, the patent enables compact End-Fire array configurations while the dipole component ensures that each element maintains orthogonal directivity, allowing the array to achieve both compactness and directional performance.
3Volume of moving object
If the circumference C of the loop is small compared to the wavelength, then the antenna is compact, but radiation tends to occur in the plane of the loop rather than orthogonal to it
Solution Approach 1:
The patent merges the radiation characteristics of the compact loop with those of the central dipole. The dipole's natural orthogonal radiation pattern compensates for the loop's in-plane radiation tendency, resulting in a combined structure that radiates orthogonally despite the small loop circumference.
Solution Approach 2:
The patent changes the excitation parameters by introducing a third connection port for central dipole excitation. By controlling the amplitude and phase of the dipole excitation relative to the loop excitation, the radiation pattern is transformed to achieve orthogonal directivity while maintaining compact dimensions.
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 enables the antenna to maintain high directivity orthogonal to its plane, even at low C/λ ratios, allowing for compact and directive array configurations in "End-Fire" orientations without compromising directivity.
Implementation Method 1
an antenna comprising a main radiating element of the loop antenna type, a first connection port and a second connection port disposed on either side of the main radiating element, a central element of the electric dipole type, circumscribed in the main radiating element
Data Source
AI summary
An antenna includes a main radiating element of the loop antenna type, a first connection port and a second connection port disposed on either side of the main radiating element, a central element of the electric dipole type, circumscribed in the main radiating element, the central element being formed by two branches disposed symmetrically relative to an axis of symmetry passing through the first connection port and through the second connection port, the central element being powered at a third connection port located in the axis of symmetry, the main radiating element and the central element being coplanar.