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Technology Trade –offs: Mid band Array and Elements Prof. A. K. Brown 1. 1 School of Electrical and Electronic Engineering The University of Manchester, PO Box 88, Manchester, M13 9PL, U.K. AA-mid. 400MHz-1.4GHz Wide angle , high sensitivity, multiple beam forming: ~100’s square degrees
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Technology Trade –offs: Mid band Array and Elements Prof. A. K. Brown1 1School of Electrical and Electronic Engineering The University of Manchester, PO Box 88, Manchester, M13 9PL, U.K.
AA-mid • 400MHz-1.4GHz • Wide angle , high sensitivity, multiple beam forming: ~100’s square degrees • High survey speeds • High dynamic range capability • Polarimetry
Element size/type Array Geometry Antenna Array (Array Geometry ,element type) Mutual Coupling Element Impendence , variation with frequency and scan Balanced/unbalanced feed Low Noise Amplifier Coupled noise (relates to geometry and LNA S11 LNA) Beamformer design Frequency sensitive weights “Calibratability”
Bandwidth Minimise Cost /Power Sensitivity scan angle Dynamic Range Sidelobe level Stability/calibration (scan angle and sensitivity) Sidelobe level Minimise N Infrastructure cost Data transport Through life costs: MTBF/MTCF/MTTR etc Polarimetry Calibration accuracy Frequency/angular effect
EMBRACE Antenna development Mechanics evolved toward trustworthy and producible antenna element.
Planar structure • The rings are attached to the surface of the expanded polystyrene foam (EPS) with a defined separation between two layers and the groundplane
Polarimetry- frequency/scan angle dependance • LNA selection- noise, balance/unbalanced, power requirements etc • Cost reduction/production engineering/environmental analysis • Tie down the reliability analysis, LRU policy etc
Come a long way during SKADS • Downselected to two basic types, one at a more advanced stage of technological readiness, the other offering possibly further cost reductions and different detailed electro-magnetics • Choice and design of LNA critical – eg shielding requirements, physical size etc • 1st quarter next year technology review • EMRACE development plus background research programme will prove a crucial tool
COBRA DANE Mid1970’s
Dual Polarization Vivaldi Good radiation Anomaly