Concentric Waveguide Antenna Array for Efficient Concurrent Tx/Rx
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Solution Overview
Problem
Existing directional antenna systems, such as multi-arm sinuous or spiral antennas, suffer from low feed efficiency (50% or less) due to radiation in both hemispheres, requiring a cavity and absorber disk, which increases complexity and cost while reducing maximum power handling.
Innovation Solution
The use of an array of aperture antenna elements, such as circular waveguide apertures, that do not require a cavity backed absorber to shape the radiation pattern, allowing for higher efficiency and gain patterns, improved manufacturability, and reduced cost.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If multi-arm sinuous or spiral antennas are used to achieve mode 1 and mode 2 patterns, then directional radiation patterns are obtained, but feed efficiency decreases to 50% or less due to radiation in both hemispheres
Solution Approach 1:
The antenna system is segmented into multiple independent feed structures, each responsible for specific radiation patterns. The feed assembly is divided into multiple arms (e.g., four-arm configuration) where each arm can be independently controlled to generate specific polarization modes, eliminating the need for complex phase shifting networks and improving feed efficiency.
Solution Approach 2:
Multiple radiation patterns (mode 1 and mode 2) are merged into a single feed assembly by integrating multiple feed arms within one structure. This unified approach allows simultaneous generation of different polarization modes from one location, reducing the need for separate antenna systems and improving overall efficiency.
2Reliability
If cavity and absorber disk are added beneath the lower hemisphere, then pattern performance in the upper hemisphere is maintained, but device complexity and cost increase
Solution Approach 1:
The problematic lower hemisphere radiation is extracted and eliminated by designing feed arms that naturally direct energy upward. The feed structure geometry is configured so that radiation patterns are inherently directed into the upper hemisphere, removing the need for cavity and absorber disk components while maintaining pattern performance.
Solution Approach 2:
Instead of allowing bidirectional radiation and then suppressing the lower hemisphere with absorbers, the design inverts the approach by configuring feed arms to naturally radiate only in the desired upper hemisphere direction from the outset, eliminating the need for suppression components.
3Loss of energy
If cavity and absorber disk are used to shape radiation pattern, then unidirectional radiation is achieved, but maximum power handling capability is reduced
Solution Approach 1:
The feed arms are configured with specific geometric curvature and orientation (e.g., conical or curved arm structures) that naturally direct radiation in desired directions. This geometric control of radiation patterns eliminates the need for power-limiting absorber materials while achieving unidirectional radiation and maintaining high power handling capability.
4Manufacturing precision
If antenna array with multiple elements is used to achieve constant beamwidth over wide bandwidth, then beamwidth stability is improved, but device complexity increases
Solution Approach 1:
The antenna array elements are designed with specific geometric parameters (aperture sizes, spacing, orientations) that are optimized to maintain constant beamwidth across wide bandwidth. By carefully selecting and configuring these parameters, the system achieves broadband beamwidth stability without requiring excessive complexity in the array structure.
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 solution achieves efficiencies of 90% or greater, enabling higher gain patterns, improved cross-polarization performance, and reduced complexity and cost, while allowing for multi-beam applications and concurrent transmit and receive operations.
Implementation Method 1
an antenna array including a plurality of antenna elements formed by waveguide structures embedded within a substrate
Data Source
AI summary
Provided herein are various enhancements for antenna systems and directed radio frequency energy structures. In one example, an apparatus includes an antenna array comprising a plurality of antenna elements formed by waveguide structures embedded within a substrate and positioned about a longitudinal axis of the substrate to form at least two concentric ring arrangements of antenna elements. Apertures of the waveguide structures are configured to emit or receive radio frequency (RF) energy generally along the longitudinal axis. Feed elements are coupled to each of the waveguide structures on an end opposite of the apertures, and configured to couple the RF energy for the antenna array.