Curved Omnidirectional Antenna for Low-Attenuation Hemispherical Coverage
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Solution Overview
Problem
Existing omnidirectional antennas do not generate a true omnidirectional radiation pattern, especially at low attenuation levels, which is required for applications like hemispherical array antennas where high background noise levels are present.
Innovation Solution
A hemispherical omnidirectional antenna with a three-dimensional radiating element, shaped on the outer surface of a dielectric support layer, is designed to achieve hemispherical radiation by adapting the curvature of its edges, thereby optimizing diffraction phenomena.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional omnidirectional antennas (dipole, monopole, collinear, helical) are used, then the antenna structure is simple and easy to manufacture, but the radiation pattern deviates from true omnidirectional especially at low attenuation levels
Solution Approach 1:
The patent applies spheroidality by shaping the radiating element as a spherical cap on the outer surface of a hemispherical dielectric support layer. This curved geometry enables the antenna to achieve a true omnidirectional radiation pattern with hemispherical coverage, resolving the contradiction by using geometric curvature to improve radiation pattern accuracy while maintaining a relatively simple single-element structure.
Solution Approach 2:
The patent transitions from conventional planar or linear radiating elements to a three-dimensional spherical cap geometry. This dimensional change allows the antenna to achieve omnidirectional radiation in the hemispherical space, improving radiation pattern accuracy by utilizing spatial curvature rather than relying on complex multi-element arrangements.
2Object-affected harmful factors
If the radome carries a metal layer that confines electromagnetic waves, then the structure provides shielding and support, but the background noise level inside the cavity becomes high
Solution Approach 1:
The patent extracts the radiating function from the metal layer cavity structure and places it on the outer hemispherical surface. By positioning the radiating element on the external surface rather than inside the noisy cavity, the antenna achieves omnidirectional radiation while being isolated from the high background noise generated by confined electromagnetic waves within the radome.
3Adaptability or versatility
If the antenna main lobe opening angle is increased to achieve omnidirectional coverage, then the radiation coverage improves, but the attenuation increases
Solution Approach 1:
The spherical cap geometry of the radiating element naturally provides omnidirectional radiation coverage in the hemispherical space without requiring excessive beam spreading. The curved surface area of the spherical cap allows efficient radiation distribution, achieving both wide coverage and acceptable attenuation levels by utilizing geometric curvature for directional control.
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 antenna achieves a low attenuation omnidirectional radiation pattern with an angular aperture of approximately 165° to 200°, effectively operating above background noise levels and maintaining compactness for integration within a hemispherical radome.
Implementation Method 1
The support layer 24 is made of a dielectric material whose relative permittivity is adapted
Implementation Method 2
adapting the curvature of its edges, thereby optimizing diffraction phenomena
Data Source
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AI summary
The present invention relates to an omnidirectional antenna (20) comprising a radiating element (26), a metal layer (22) brought to a reference potential so as to constitute a ground layer, and means (40) for exciting the radiating element, the radiating element being arranged above the ground layer, which is characterized in that the radiating element (26) is constituted by a metal strip conforming to a curved surface, the curved surface having a strictly positive Gaussian curvature at each of its points.