Concentric Isoflux Antenna Module for Low-Profile CubeSat RF Coverage
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Solution Overview
Problem
Conventional antennas for CubeSats are large, heavy, and high-profile, making them unsuitable for small satellites due to size and weight constraints, while also failing to achieve optimal circular polarization and isoflux patterns for effective RF signal coverage.
Innovation Solution
A low-profile circularly polarized isoflux antenna module comprising a stacked structure of an antenna array, substrate, connection plate, and feeding plate, with concentrically distributed antenna elements forming independent circularly polarized apertures through a feeding network, utilizing a combination of circular, annular, and spiral patch antennas with planar inverted-F antennas to achieve efficient radiation performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional circularly polarized patch antennas are used to achieve high gain and circular polarization performance, then the antenna can obtain marginal gain of 6 dBic and axial ratio less than 3 dBic, but the antenna becomes large in size, heavy in weight, and high in profile
Solution Approach 1:
The antenna is divided into multiple concentric circular patches (inner patch, middle patch, outer patch) that are independently fed and controlled. Each patch segment contributes to the overall circularly polarized radiation pattern, allowing the large aperture to be segmented into manageable components that can be integrated on CubeSat surfaces without requiring a single large monolithic structure
Solution Approach 2:
The antenna transitions from a planar two-dimensional patch structure to a three-dimensional configuration by stacking multiple patches at different heights (z-dimension) with varying radii. This vertical stacking enables the achievement of high gain and circular polarization performance in a compact footprint suitable for CubeSat constraints
2Reliability
If dielectric lens is loaded to achieve isoflux pattern and beamforming, then the antenna can obtain angular coverage of ±50° and isoflux pattern, but the loaded dielectric block becomes bulky, heavy-weight, and high-profile
Solution Approach 1:
The dielectric loading is segmented into multiple discrete dielectric blocks positioned at specific locations beneath different patches rather than using a single large dielectric lens. This segmentation allows beamforming and isoflux pattern achievement through distributed phase control while minimizing the overall volume and profile of the dielectric structure
Solution Approach 2:
Different patches are fed with different phase and amplitude characteristics through locally positioned dielectric blocks. Each dielectric block provides localized phase compensation and beamforming for its corresponding patch, enabling the overall antenna to achieve isoflux pattern and wide angular coverage without requiring a bulky uniform dielectric lens
3Length of stationary object
If multiple concentric circular patches are used to form independent circularly polarized apertures, then the antenna achieves low profile and reduced size, but the device complexity increases due to multiple feed networks and patch configurations
Solution Approach 1:
Multiple feeding functions are merged into a single microstrip feed network that distributes signals to all patches through shared transmission lines and power dividers. The feed network is integrated directly on the substrate plane, combining impedance transformation, signal distribution, and phase control functions in one unified structure rather than using separate feeding mechanisms for each patch
Solution Approach 2:
The feeding structure transitions from vertical probe feeds (z-dimension) to planar microstrip transmission lines (x-y plane). This dimensional change allows the feed network to be laid out on the substrate surface, reducing the vertical profile height while managing the complexity through two-dimensional routing and distribution
Data Source
AI summary
A low-profile circularly polarized isoflux antenna module is provided, which relates to the field of microelectronic antennas, and provides a solution to solve the contradiction between size and gain in conventional technology. The antenna module includes an antenna array, a substrate, a connection plate, and a feeding plate that are stacked in sequence. The feeding network on the feeding plate is electrically connected to the antenna array through probe passing through the connection plate and the substrate. The antenna array includes two or more concentrically distributed antenna elements, and each antenna element forms mutually independent concentric circularly polarized apertures through feed control. The structure is simple to assemble and easy to process, light in weight, small in size, and low in profile.