Antenna Perimeter Plate with Truncated Cone Bands for Radiation Attenuation
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Solution Overview
Problem
Conventional methods for attenuating antenna back-lobe and side-lobe radiation often result in undesirable changes to the antenna's physical profile, mechanical, aerodynamic, and aesthetic qualities, and are limited in effectiveness due to their dependence on the orientation and polarization of the signal.
Innovation Solution
A perimeter plate with concentric bands of truncated cones or other EM-field-suppressing features, such as fins, is used around the antenna to attenuate back-lobe and side-lobe radiation, providing polarization-independent surface-wave suppression and maintaining the antenna's structural integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If microwave-absorbing materials and metal shielding are added to attenuate back-lobe and side-lobe radiation, then radiation attenuation is improved, but the physical profile and structure of the antenna are adversely affected
Solution Approach 1:
The perimeter plate is segmented into multiple concentric bands, each band containing discrete truncated cone elements spaced apart from each other. This segmentation allows the structure to attenuate radiation effectively while maintaining an open profile that does not significantly alter the antenna's aerodynamic or aesthetic qualities, unlike solid shielding materials.
Solution Approach 2:
The invention transitions from two-dimensional planar shielding to three-dimensional truncated cone structures extending perpendicular to the antenna aperture. These cones create multiple reflection and absorption paths for electromagnetic waves in the backward hemisphere, achieving superior attenuation with minimal impact on the antenna's forward-facing profile.
2Object-generated harmful factors
If conventional choke plates with continuous parallel grooves are used, then some radiation attenuation is achieved, but effectiveness is limited by the orientation and polarization of the signal
Solution Approach 1:
The truncated cones are oriented with their bases aligned to the antenna aperture and their apexes extending outward, creating an asymmetric structure that effectively interacts with electromagnetic waves regardless of their polarization state. This asymmetric geometry provides consistent attenuation performance across different signal orientations, overcoming the limitation of conventional parallel groove choke plates.
Solution Approach 2:
The concentric bands of truncated cones create a universal attenuation structure that functions effectively for all polarization states and signal orientations. The multi-band configuration ensures broad frequency coverage and consistent performance across varying operational conditions, making the solution universally applicable rather than orientation-dependent.
3Reliability
If radiation-absorbing materials are added to reduce back-lobe and side-lobe radiation, then regulatory compliance is improved, but the antenna's mechanical and aerodynamic qualities are adversely affected
Solution Approach 1:
The truncated cone elements are strategically positioned only at the perimeter of the antenna aperture in concentric bands, concentrating the radiation attenuation function at the edges where it is most effective. This localized approach achieves regulatory compliance while leaving the central antenna structure and its critical mechanical and aerodynamic properties unchanged.
Solution Approach 2:
The invention replaces traditional mechanical shielding materials (metal plates, foam absorbers) with a geometrically-engineered perimeter structure that achieves attenuation through electromagnetic interaction with the truncated cone shapes. This substitution eliminates the need for bulky absorbing materials that would compromise mechanical strength and aerodynamic performance.
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 solution effectively reduces radiation strength in the backward hemisphere, improving compliance with regulatory requirements and maintaining the antenna's mechanical and aesthetic qualities by providing enhanced radiation suppression across a range of frequencies.
Implementation Method 1
The perimeter plate is designed to attenuate at least one of back-lobe and side-lobe radiation generated by the antenna
Data Source
Figure 1A~1B
Figure 2~3
Figure 4A~4C
AI summary
In one embodiment, an antenna system includes a device for attenuating undesirable radiation from an antenna. The device includes a perimeter plate adapted to be located around the perimeter of the antenna. The perimeter plate has one or more concentric perimeter bands, where each perimeter band comprises an array of distinct EM-field- suppressing features. The surface of each suppressing features is metallic. The dimensions, arrangement, and number of the suppressing features are such that the features form a meta- material and the perimeter plate attenuates back-lobe and/or side-lobe radiation generated by the antenna.