Peripherally Excited Phased Array Cavity Design
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Solution Overview
Problem
Conventional phased arrays require a large number of active antenna elements, leading to high complexity, power consumption, and cost, which hinders their adoption in commercial applications due to the need for numerous phase shifters or transceivers, and existing reduction techniques either fail to significantly reduce the number of elements or compromise key antenna parameters.
Innovation Solution
A Peripherally Excited (PEX) phased array design where a passive 2D antenna array is excited only by active elements at its periphery, utilizing a metallic cavity with apertures to synthesize interior field patterns, scaling the number of active elements with the circumference rather than the area, and simplifying the feeding network.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If conventional phased arrays use full 2D array excitation to maintain scanning performance, then beam steering capability is preserved, but the number of active elements and system complexity increase dramatically
Solution Approach 1:
The invention extracts only the periphery elements from the full 2D array configuration, using solely the boundary elements to excite the array. This extraction principle reduces the number of active elements from O(N²) to O(N), dramatically lowering system complexity while maintaining the essential beam steering function through controlled excitation of the perimeter elements.
Solution Approach 2:
The invention transitions from a two-dimensional excitation pattern (full 2D array) to a one-dimensional excitation pattern (periphery only). By confining active elements to the boundary and using the interior passive elements as radiating apertures, the system achieves area coverage with linear scaling of active components.
2Device complexity
If the number of active antenna elements is reduced to lower cost and complexity, then system affordability improves, but grating lobes appear and scanning angle range decreases
Solution Approach 1:
The invention introduces a metallic cavity as an intermediary structure between the periphery excitation sources and the radiated fields. This cavity mediates the electromagnetic field distribution, enabling the periphery-excited array to achieve uniform illumination and maintain wide scanning angles without grating lobes, effectively decoupling the reduced element count from performance degradation.
3Device complexity
If periphery excitation is used to reduce active elements, then the number of phase shifters decreases, but achieving uniform field distribution becomes more difficult
Solution Approach 1:
The invention utilizes parameter changes in the cavity characteristics (dimensions, material properties, aperture configurations) to transform the non-uniform periphery excitation into a uniform interior field distribution. By adjusting these cavity parameters, the system achieves controlled field uniformity despite the reduced and geometrically constrained excitation element placement.
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 approach drastically reduces the number of active elements needed, lowers complexity and cost, and maintains a wide scanning angle range while preserving key antenna parameters like directivity and sidelobe levels, making large scanning phased arrays more feasible for commercial use.
Implementation Method 1
These metasurfaces are based on the Huygens/Schelkunoff equivalence principle in which the fields in a given region can be completely controlled by appropriate electric and magnetic currents on the boundary surface of that region
Data Source
AI summary
The present invention introduces a new phased array, called the peripherally-excited phased array (PEX-PA). The PEX-PA comprises an electrically large metallic cavity which is excited by weighted antenna sources only at its periphery. The top surface of the cavity is patterned with a suitable configuration of apertures (slots) whereas the cavity is filled with a dielectric material. The (PEX-PA) is capable of beam scanning, one or multiple beams, over a large number of directions in air but with a drastically reduced number of passive or active phase shifters. Specifically, the PEX-PA scales the number of phase-shifters according to the circumference of the cavity and not its area, as usually the case in a conventional phased array.