Hybrid Planar Array Element for Zenith-to-Horizon ESA Scanning
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Solution Overview
Problem
Conventional active electronically scanned array (ESA) antennas face challenges in scanning to the horizon due to the cosn(θ) nature of radiating elements, resulting in poor gain at the horizon and high gain at the zenith, while end-fire arrays have poor gain at the zenith.
Innovation Solution
An ESA with radiating elements that combine normal mode and superimposed end-fire mode elements, utilizing feed layer circuitry with attenuators, variable gain amplifiers, and phase shifting to produce a hemispherical radiation pattern through constructive interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If end-fire arrays are used to scan toward the horizon, then horizon scanning capability is improved, but gain at the zenith becomes extremely poor or null
Solution Approach 1:
The patent merges normal mode radiating elements (which provide zenith gain) with end-fire mode radiating elements (which provide horizon scanning capability) into a single hybrid element. The feed layer circuitry dynamically adjusts the contribution of each mode based on the desired scan angle, enabling the antenna to achieve both horizon scanning capability and zenith gain that neither mode could provide alone.
2Adaptability or versatility
If multiple panels are used to achieve horizon-to-horizon scanning, then scanning coverage is improved, but cost and device complexity increase
Solution Approach 1:
The patent makes a single radiating element perform multiple functions by integrating both normal mode and end-fire mode capabilities into one hybrid element. This universal element can produce useful gain for any scan angle from zenith to horizon, eliminating the need for multiple specialized panels and reducing overall device complexity while maintaining full hemispherical scanning coverage.
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 enables a single panel ESA to achieve useful gain from the zenith to the horizon, overcoming the limitations of conventional ESA antennas by producing a composite radiation pattern that effectively scans across the entire hemisphere.
Implementation Method 1
produce radiation patterns that constructively interfere through complex summation of the two adjusted radiation patterns
Data Source
AI summary
An ESA includes radiating elements having a normal mode radiating element and a superimposed end-fire mode radiating element. The combined normal mode radiating element and and-fire mode radiating element attenuators or variable gain amplifiers for amplitude adjustment, phase shifting, and time delay circuitry and algorithms to drive the normal mode radiating element and end-fire mode radiating element simultaneously to produce radiation patterns that constructively interfere. Alternatively, the radiating elements are fed by a radio frequency (RF) feed and switching integrated circuitry timed to drive the normal mode radiating element and end-fire mode radiating element to effectively produce hemispherical radiation patterns as a function or time/scan angle.