Compact Radiating Element with Nested Resonant Cavities
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Solution Overview
Problem
Radiating elements for low frequency bands, such as L or S band, face challenges in achieving high surface effectiveness, compactness, and low mass while supporting dual-polarization, as existing solutions like Potter horns are bulky, and alternative sub-arrays suffer from significant losses and complex implementations.
Innovation Solution
A radiating element comprising two concentric resonant cavities with cylindrical or conical lateral walls and corrugations below the upper cavity's earth plane, along with a polarizing radome and dual feeds to filter higher modes and enhance matching, allowing for compact, high-efficiency, and dual-polarization capable designs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of moving object
If Potter horn type radiating elements are used, then high gain and surface effectiveness are achieved, but longitudinal bulkiness and mass increase significantly
Solution Approach 1:
The patent implements nesting by placing the upper resonant cavity inside the lower resonant cavity, with the upper cavity being supported by and nested within the structure of the lower cavity. This nested configuration allows both cavities to occupy overlapping spatial volumes, achieving a compact longitudinal profile while maintaining the required radiating aperture area for high gain performance.
Solution Approach 2:
The patent transitions from a conventional longitudinal horn structure to a stacked cavity configuration where the resonant structures are arranged in a vertical stack with the upper cavity nested within the lower one. This dimensional reorganization maintains the necessary radiating aperture in the horizontal plane while dramatically reducing the longitudinal extent by utilizing vertical stacking and nesting.
2Adaptability or versatility
If conventional sub-arrays with triplate distributors are used, then radiation capability is achieved, but losses increase and dual-polarization capability is difficult to implement
Solution Approach 1:
The patent segments the radiating structure into two independent resonant cavities, each capable of supporting different polarization modes. The lower cavity and upper cavity can be independently excited and designed to support orthogonal polarizations, eliminating the need for complex triplate distributors while reducing losses by removing the lossy distribution network.
Solution Approach 2:
The stacked resonant cavity structure serves multiple functions simultaneously: it provides dual-polarization capability through the two cavities, acts as the radiating element itself without requiring separate distributor components, and achieves compactness through nesting. Each cavity can be excited independently to produce different polarization states, making the structure universally applicable for dual-polarization operations.
3Area of moving object
If radiating apertures of large dimensions are obtained using high reflectivity grids, then cavity field establishment is improved, but signal return to access guide increases and matching becomes difficult
Solution Approach 1:
The patent uses nesting of the upper cavity within the lower cavity to achieve a compact configuration that maintains adequate radiating aperture while controlling the cavity dimensions and field distribution. This nested arrangement allows optimization of the aperture area without requiring excessively high reflectivity grids, thereby improving signal matching by reducing unwanted reflections and standing waves in the access guide.
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 achieves a compact, high-surface-efficiency radiating element with improved matching and reduced higher mode excitation, resulting in axisymmetric radiation patterns and low sidelobe levels, suitable for high-power applications with reduced bulkiness and mass.
Implementation Method 1
corrugations essentially of cylindrical shape and concentric with the resonant cavities, are formed substantially below the first earth plane of the upper resonant cavity
Implementation Method 2
a resonant cavity required to radiate energy representative of these signals according to a chosen wavelength λ0
Data Source
AI summary
A radiating element is provided, for example for array antenna, having stacked resonant cavities of Pérot-Fabry type, of compact structure, a lower cavity being fed by excitation means, the radiating element being characterized in that corrugations are formed substantially below a first earth plane delimiting in its lower part the upper resonant cavity. A radiating element structure of improved compactness is also proposed, whose upper cavity is surmounted by a polarizing radome.