Nested Cavity Multiband Antenna for Stable Radiation
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Solution Overview
Problem
Existing antennas for spacecraft and mobile platforms face challenges in maintaining hemispherical coverage and circular polarization across multiple frequency bands due to unstable radiation patterns, complex arrangements, and high coupling between radiating elements, which affect communication quality.
Innovation Solution
A multi-cavity antenna design with distinct resonant cavities and optimized distances and orientations between radiating elements, allowing for separate frequency bands and reduced mutual interaction, ensuring single-mode or predominantly single-mode operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single-port ultra-wideband or multi-band circularly polarized antenna is used to cover all useful bands, then the number of antennas is reduced, but the radiation pattern becomes unstable and varies with frequency
Solution Approach 1:
The antenna system is divided into multiple independent radiating elements, each designed for a specific frequency band with its own resonant cavity. This segmentation allows each element to maintain stable radiation characteristics at its designated frequency while collectively covering multiple bands, resolving the contradiction between reducing antenna数量 and maintaining radiation pattern stability.
Solution Approach 2:
The patent implements a nested cavity structure where resonant cavities for different frequency bands are arranged concentrically, with higher frequency cavities positioned inside lower frequency cavities. This nesting approach allows multiple frequency bands to be accommodated in a compact structure while maintaining proper isolation and stable radiation patterns for each band.
2Adaptability or versatility
If multiple radiating elements are arranged to cover four frequency bands, then the frequency coverage is improved, but the arrangement becomes complex and coupling between elements increases
Solution Approach 1:
The patent uses a nested cavity arrangement where four resonant cavities for different frequency bands are positioned concentrically. This nesting provides a systematic and compact structure that simplifies the overall arrangement while achieving wide frequency coverage, and the natural spacing between nested cavities helps reduce coupling between elements.
Solution Approach 2:
The patent transitions from planar arrangements to a three-dimensional nested cavity structure. By utilizing the vertical dimension and arranging cavities at different radial positions and heights, the design achieves four-band coverage with reduced element coupling and simplified overall architecture compared to traditional planar configurations.
3Volume of stationary object
If radiating elements are placed close together to reduce bulk, then the antenna size is reduced, but wave diffraction effects between elements increase
Solution Approach 1:
The nested cavity structure allows radiating elements to be positioned at optimized distances from each other in three-dimensional space. Each cavity acts as an isolated resonant chamber that contains and directs electromagnetic energy, reducing diffraction effects between elements while maintaining a compact overall antenna volume.
Solution Approach 2:
The resonant cavity walls serve as intermediary structures between adjacent radiating elements. These cavity boundaries act as electromagnetic shields that reduce direct coupling and diffraction effects between elements, allowing closer spacing while maintaining 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 antenna achieves high-quality circular polarization and hemispherical coverage across multiple frequency bands with reduced bulk, minimizing dimensions while maintaining optimal performance and reducing polarization reversals.
Implementation Method 1
The antenna 100 comprises four resonant cavities 110, 120, 130 and 140... each radiating element can therefore function correctly and can therefore produce a quality polarization and hemispherical radiation pattern
Data Source
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AI summary
An antenna (100) comprising at least a first resonant cavity (110) and a second resonant cavity (120), each resonant cavity (110, 120) being closed off by a base (112, 122) at one end and comprising a radiating element (111, 121) superimposed on the base of the resonant cavity, the radiating element (111) of the first cavity (110) being able to emit a signal in a first frequency band and the radiating element (121) of the second cavity (120) being able to emit a signal in a second frequency band separate from the first frequency band, characterized in that a first distance between the base (112) and the radiating element (111) of the first cavity (110) is different from a second distance between the base (122) and the radiating element (121) of the second cavity (120).