AAVP meeting Cambridge December 2010

Technology Trade –offs: Mid band Array and Elements

Prof. A. K. Brown1

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• High survey speeds• High dynamic range capability• Polarimetry

Element size/type

Array Geometry

Antenna Array (Array Geometry ,element type)

Element Impendence , variation with frequency and scan Balanced/unbalanced feed

Low Noise Amplifier

Frequency sensitive weights“Calibratability”

Coupled noise (relates to geometry and LNA S11 LNA)

Beamformer design

Mutual Coupling

Sensitivityscan angle

Dynamic RangeSidelobe levelStability/calibration

(scan angle and sensitivity)

PolarimetryCalibration accuracyFrequency/angular

effect

Minimise Cost /Power

Minimise NInfrastructure costData transportThrough life costs: MTBF/MTCF/MTTRetc

Sidelobe level

Bandwidth

0.8 0.9 1 1.1 1.2 1.3 1.4100

110

120

130

140

150

160

170

180

190

200

210

220

230

240

250

High frequency (GHz)

Ma

xim

um

ele

me

nt s

pa

cin

g (

mm

)

/(1+sinmax

),max

=30o

ORA element spacing/(1+sin

max),

max=45o

ORA element spacing

EMBRACE Antenna development

Mechanics evolved toward trustworthy and producible antenna element.

Printed Vivaldi

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

Thank you!

COBRA DANEMid1970’s

Dual Polarization Vivaldi

Good radiation

Anomaly