ATDS-HOWLAND NOVEL SPHERICAL NEAR-FIELD ANTENNA ...
ATDS-HOWLAND NOVEL SPHERICAL NEAR-FIELD ANTENNA ...
ATDS-HOWLAND NOVEL SPHERICAL NEAR-FIELD ANTENNA ...
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<strong>ATDS</strong>-<strong>HOWLAND</strong><strong>NOVEL</strong> <strong>SPHERICAL</strong> <strong>NEAR</strong>-<strong>FIELD</strong> <strong>ANTENNA</strong>MEASUREMENT TECHNIQUES ADVANCESTATE-OF-THE-ARTA. Ray Howland, P.E; Carl W. Sirles; Michael H. SewellPresented By: Carl W. Sirles<strong>ATDS</strong>-<strong>HOWLAND</strong>4540 Atwater Court; Suite 107Buford GA USA 30518Email: info@atds-howland.comWeb: www.atds-howland.com
Background<strong>ATDS</strong>-<strong>HOWLAND</strong>! Consumer demand for wireless devices isrevitalizing interest in electrically qualifyingradiation characteristics of antennas! Near-field measurement techniques becomingmore popular– 3D representation of the radiating sphere can begenerated
<strong>ATDS</strong>-<strong>HOWLAND</strong>Market Watch! Millions of low-gain, omnidirectional antennasnow produced each year! Enormous demand has manufacturers concernedover Quality & Cost! Lots of time spent designing electronics andsoftware, but not much time allocated to theradiating aspects! Poor antenna design causing undesirable signaldrop-outs
Problem<strong>ATDS</strong>-<strong>HOWLAND</strong>! Device engineers, mostly with digital or circuitdesign backgrounds, now faced with employingtechniques to measure complex, radiatingelements of their designs! Challenge of the experienced antenna engineer isto educate the wireless manufactures on thevarious measurement techniques
Solution<strong>ATDS</strong>-<strong>HOWLAND</strong>! <strong>ATDS</strong>-<strong>HOWLAND</strong> recently developed twodifferent types of test ranges– Outdoor drive-on type– Indoor test-inin-a-boxtype– both employ Spherical Near-fieldmeasurementtechniques
<strong>ATDS</strong>-<strong>HOWLAND</strong>! Solution 1Outdoor Drive-on SNF rangeParameterFrequencyRangeProbe RotationRadiusBoom WidthRotation VelocityTravel LimitsSpecification100 MHz – 2 GHz27 feet (8.23m)24 feet (7.31m)0.5 deg/sec max0-90 degFeatures φ-axis turntable; dualgantry structural fiberglass near-fieldprobe θ-axis; helical-woundfiberglass probe boomPositioning+/- 0.1 degAccuracyWind Speed 40 mph (64.8Km/h) max
!Solution 1Outdoor Drive-on SNF range<strong>ATDS</strong>-<strong>HOWLAND</strong>• Probe assembly lowersbelow grade level toallow same real estate toperform as a groundreflection range• Employs, time-saving,drive-on grease rackstyle, self-centeringvehicular guide• Uses AgilentInstrumentation
!Solution 1Outdoor Drive-on SNF range<strong>ATDS</strong>-<strong>HOWLAND</strong>
!Solution 2Indoor test-in-a-box SNF range<strong>ATDS</strong>-<strong>HOWLAND</strong>ParameterTurntable(φ)Travel +/- 200degProbe (θ)200 degSpeed 72deg/secAccuracy +/-0.05deg10deg/sec+/-0.05degResolution 0.01 deg 0.01 degCapacity80 lb,36.3kg30 lb, 13.6kg60 dB shielded box (16’ cube);scanning mechanisms allow fullsphere data collection; scanner &turntable made of dielectric materialsProbeRadialPositionErrorθ Cross-ArmRadius0.05” with10 lb., 4.5kg probe72”,1.82m
!Solution 2Indoor test-in-a-box SNF range<strong>ATDS</strong>-<strong>HOWLAND</strong>• 16 ft cubicle chamber• Robust θ axis drivesystem• θ boom and φ turntablemade of dielectric
!Solution 2Indoor test-in-a-box SNF range<strong>ATDS</strong>-<strong>HOWLAND</strong>• Contains unique swing-downcross-bridge platform for easy UUTaccess & handling• Turntable is centered within thetest chamber• Chamber may be used as SNF orFar-field test range• Uses Agilent Instrumentation &NSI 2000 Professional Editionsoftware
!Solution 2Indoor test-in-a-box SNF range<strong>ATDS</strong>-<strong>HOWLAND</strong>• φ-axis turntable madewith Delrin dielectricmaterial• Original orientationplaced turntable atopdielectric support structure• Test data indicatedunwanted reflections;turntable later relocated tojust above floor level (seedata slide)
WR-430 SGH / 2.4 GHzE-Plane Pattern Comparison<strong>ATDS</strong>-<strong>HOWLAND</strong>0Horizontal OrientationVertical Orientation-5-10-15Amplitude (dB)-20-25-30-35-40-45-50-150 -100 -50 0 50 100 150Theta (deg)
WR-430 SGH / 2.4 GHzH-Plane Pattern Comparison<strong>ATDS</strong>-<strong>HOWLAND</strong>0Horizontal OrientationVertical Orientation-5-10-15Amplitude (dB)-20-25-30-35-40-45-50-150 -100 -50 0 50 100 150Phi (deg)
Elev TT / Ref Dipole / 824 MHz<strong>ATDS</strong>-<strong>HOWLAND</strong>0NF DataTransformed FF Data-5-10Amplitude (dB)-15-20-25-300 25 50 75 100 125 150 175Theta (deg)
Floor TT / Ref Dipole / 824 MHz<strong>ATDS</strong>-<strong>HOWLAND</strong>0Measured NF Data Interpolated NF Data Transformed FF Data-5-10Amplitude (dB)-15-20-25-300 25 50 75 100 125 150 175Theta (deg)
Floor TT / Ref Dipole / 824 MHzTruncation v Interpolation<strong>ATDS</strong>-<strong>HOWLAND</strong>0Truncated NF DataInterpolated NF Data-5-10Amplitude (dB)-15-20-25-300 25 50 75 100 125 150 175Theta (deg)
Ref Dipole / 824 MHz / FF Transformed DataElev TT v NF Data Truncation<strong>ATDS</strong>-<strong>HOWLAND</strong>0Elev TT / Full NF DataFloor TT / Truncated NF Data-5-10Amplitude (dB)-15-20-25-300 25 50 75 100 125 150 175Theta (deg)
Conclusions<strong>ATDS</strong>-<strong>HOWLAND</strong>!Analytically complex techniques employingSpherical Near-field technology to assesselectrical performance of radiating devicesbecoming more commonplace!Two methods (one indoor & one outdoor)that simplify the measurement process aredescribed
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