This preview has intentionally blurred parts. Sign up to view the full document

View Full Document

Unformatted Document Excerpt

Near-field Spherical Training McGill University NSI-700S-30 SNF/FF/CTIA System 9 September 2009 NEARFIELD SYSTEMS, INC. NSI Copyright 2009 Page 1 Overview G Introduction G Basics of antenna testing Definition of concepts G G Far-field antenna testing Near-field antenna testing G SNF theory overview G G Hardware overview Software overview & demonstration NEARFIELD SYSTEMS, INC. NSI Copyright 2009 Page 2 1 Measurement Objective I Basic Concept: Rotate antenna under test in azimuth and elevation coordinates Record far-field data 60.00 50.00 40.00 30.00 Elevation (deg) 20.00 10.00 0.00 -10.00 -20.00 -30.00 -40.00 0 -2 -4 -6 -8 -10 -12 -14 -16 -18 -20 -22 -24 -26 -28 -30 -32 -34 -36 -38 -40 -42 -44 -46 -48 -50 -52 -54 -56 -58 -60 -50.00 NEARFIELD Azimuth (deg) Copyright 2009 NSI SYSTEMS, INC. -60.00 -60.00 -50.00 -40.00 -30.00 -20.00 -10.00 0.00 10.00 20.00 30.00 40.00 50.00 60.00 Page 3 Measurement Objective II Antenna Examples NEARFIELD SYSTEMS, INC. NSI Copyright 2009 Page 4 2 Reaction Theorem I < 1,2 >=< 2,1 > < 1,2 >= E1 J 2 - H1 M 2 dv V < 2,1 >= E2 J1 - H 2 M 1dv V 1 V 2 V NEARFIELD SYSTEMS, INC. NSI Copyright 2009 Page 5 Reaction Theorem II + " Measured _ Voltage" = ^ z' e - 2 E J dl 1 2 e 2 ^ z l + 2 ^ y V - d l 2 + V e 2 R ^ y' - e 2 NEARFIELD SYSTEMS, INC. NSI Copyright 2009 Page 6 3 Practical Restrictions & Potential Solutions G Restrictions G G G G G G Antenna size and weight Frequency (i.e. Positioning accuracy & RF losses) Available space Funding Security Environmental control Measurement systems suitable for antenna type Distributed conversion RF sub-systems Compact or near-field ranges Indoor instead of outdoor G Potential Solutions G G G G NEARFIELD SYSTEMS, INC. NSI Copyright 2009 Page 7 Distance Restriction Commonly used rule : R > ^ z' 2D 2 = 2l 2 A high gain AUT. This rule assumes: ^ z + l 2 An electrically small receiver. ^ y That d=0. V - d l 2 + V e 2 R ^ y' - e 2 NEARFIELD SYSTEMS, INC. NSI Copyright 2009 Page 8 4 Far-field Criteria G G G Sufficient antenna separation for flat phase front <22 of phase taper across aperture <0.25 dB of amplitude taper across aperture Phase front AUT Tx Antenna D 8 Rx Antenna 2 <22 D = aperture diameter = test frequency wavelength NSI Copyright 2009 Page 9 > NEARFIELD SYSTEMS, INC. 2D Far-field Separation Distance 2xD**2/Lambda Far Field Criteria Separation Distance (m) 1000.00 AUT Diameter 0.5m 1.0m 1.5m 2.0m 2.5m 100.00 10.00 1.00 1 3 5 7 9 11 13 15 17 19 Frequency (GHz) NEARFIELD SYSTEMS, INC. NSI Copyright 2009 Page 10 5 Far-field Distance Effects NEARFIELD SYSTEMS, INC. NSI Copyright 2009 Page 11 FF Measurement High Gain Antenna Max & Average Error in Measured Far-field D = l = 5.4 d = 0, 0.1 & 0.2 Error level [dB] -20 -25 40 60 80 100 120 140 160 180 200 50 < R < 200 e = 0.25 ^ z' 7D 2 -30 -35 -40 -45 -50 -55 -60 -65 d=0 Max d=0.1 Max d=0.2 Max ^ z + l 2 -70 ^ y Mea sured DIsta nce [m ] V - d l 2 + V e 2 R ^ y' NEARFIELD SYSTEMS, INC. NSI Copyright 2009 e - 2 Page 12 6 FF Measurement High Gain Antenna Far-Field Radiation Patterns 0 0 -10 Relative Amplitude [dB] -20 -30 -40 -50 Relative Amplitude [dB] -60 -70 -80 Theta [deg[ Ref Measured Error 0 Max 0 error 30 -10 Avg error -20 -30 -40 -50 -60 -70 -80 Theta [deg[ Ref Measured Error Max error Avg error 60 90 120 150 180 210 240 270 300 330 360 30 60 90 120 150 180 210 240 270 300 330 360 R= 2D 2 Far-Field Radiation Patterns d = 0.1 d = 0 NEARFIELD SYSTEMS, INC. NSI Copyright 2009 Page 13 FF Measurement Low Gain Antenna Max & Average Error in M easured Far-Field D = l = 0.45 d = 0, 0.1 & 0.2 Error level [dB] 0 0 -10 1 2 3 4 5 6 7 0.4 < R < 6 e = 0.25 ^ z' 15D 2 -20 -30 -40 -50 -60 -70 d=0 Max d=0.1 Max d=0.2 Max ^ z + l 2 ^ y Mea sured Dista nce [m] V - d l 2 + V e 2 R ^ y' NEARFIELD SYSTEMS, INC. NSI Copyright 2009 e - 2 Page 14 7 FF Measurement Low Gain Antenna Far-Field Radiation Patterns 0 -5 -10 Relative Amplitude [dB] -15 Ref -20 -25 -30 -35 -10 Relative Amplitude [dB] 0 30 60 90 120 150 180 210 240 270 300 330 360 R= Measured Error 0 Max error 0 30 -5 Avg error 2D 2 Far-Field Radiation Patterns 120 150 180 210 240 270 300 330 360 60 90 -40 -45 -50 Theta [deg[ -15 Ref -20 -25 -30 -35 -40 -45 -50 Theta [deg[ Measured Error Max error Avg error d = 0.1 d = 0 NEARFIELD SYSTEMS, INC. NSI Copyright 2009 Page 15 Far-Field Range Types G Outdoor Ranges G Ground reflection N Control or characterize reflection Reduce reflection G Elevated N G Indoor Ranges G Tapered Chamber N Chamber forms part of radiation aperture control reflection G G Rectangular Chamber Compact Ranges N Reduce far-field distance and control reflection Reduce far-field distance using defocused feed and correction G Intermediate Field Ranges N NEARFIELD SYSTEMS, INC. NSI Copyright 2009 Page 16 8 Outdoor Far-field Ranges NEARFIELD SYSTEMS, INC. NSI Copyright 2009 Page 17 Indoor Far-Field Range Chamber: 6m x 6m x 15m Frequency range: 0.5 GHz - 40 GHz Far-field range: measurement distance: max. 7.5m Spherical near-field range NEARFIELD SYSTEMS, INC. NSI Copyright 2009 Page 18 9 Indoor Far-Field Range Size app. 6m x 6m x 15m Far-field range: 7.5m NEARFIELD SYSTEMS, INC. NSI Copyright 2009 Page 19 Far-field Ranges NEARFIELD SYSTEMS, INC. NSI Copyright 2009 Page 20 10 Far-field Trade-offs Advantages G G G G Limitations G G G G G Low frequency Real-time measurement results No post processing required Manual measurement capability (no automation software required) Simplified measurement setup Requires large foot print AUT must be rotated More susceptible to multi-path RF signal sensitivity may degrade measurement accuracy NEARFIELD SYSTEMS, INC. NSI Copyright 2009 Page 21 Fundamental Compact Range Principles Transmission Compact Ranges Reflection Compact Ranges NEARFIELD SYSTEMS, INC. NSI Copyright 2009 Page 22 11 Near-field Technology NEARFIELD SYSTEMS, INC. NSI Copyright 2009 Page 23 Measurement Objective Antenna Examples NEARFIELD SYSTEMS, INC. NSI Copyright 2009 Page 24 12 Near-field Scan Types G Planar near-field G G G Planar Directional antennas Gain > 15 dBi Max angle < 70 Fan beam antennas Wide side/ backlobes Cylindrical G Cylindrical near-field G G G Spherical near-field G G Spherical Low gain antennas Wide or omnidirectional patterns on any antennas NEARFIELD SYSTEMS, INC. NSI Copyright 2009 Page 25 The Vector Wave Equation Maxwells Equations for a loss-less source free region are: H = j E E = - j H These equations can be re-written in vector wave equation form as: 2 E = - 2 E = - k 2 E 2 H = - 2 H = - k 2 H These second order PDF's are not coupled and a solution to them will also provide a solution to Maxwells equations. Note that the form given here is only valid for source free loss-less regions. In what follows, valid solutions for these vector wave equations are considered in rectangular, cylindrical and spherical coordinate systems. A jt time dependence is assumed. NEARFIELD SYSTEMS, INC. NSI Copyright 2009 Page 26 13 Solutions to the Vector Wave Equation If we express the electric and magnetic fields in terms of the vector potentials we can write: A j 1 1 E= A - F j and from the derivation of these potentials, we know that they also have to satisfy the vector wave equation: H= 1 F + 1 2 F + k 2 F = 0 2 A + k 2 A = 0 NEARFIELD SYSTEMS, INC. NSI Copyright 2009 Page 27 Solutions to the Vector Wave Equation Since the vector potentials consist of orthogonal vector components, one may also require each scalar component to satisfy the scalar wave equation as: 2 + k 2 = 0 By finding solutions to this equation we can ultimately construct solutions to the vector wave equation. Since one can express any arbitrary electric field in a source free loss-less region as the sum of a transverse electric (TE) and transverse magnetic (TM) component [Harrington, p.131], we therefore select: ^ z in rectangular : zA & zF ^ z in cylindrical : zA & zF ^ in spherical : r rA & r rF r NEARFIELD SYSTEMS, INC. NSI Copyright 2009 Page 28 14 Solutions to the Vector Wave Equation Rectangular Coordinates In rectangular coordinates a solution for the scalar wave equation is: = e - j k r ^ TM : A = z ^ TE : F = z From which the electric field can be found: E= 1 j 1 ^ ^ Az z - Fz z NEARFIELD SYSTEMS, INC. NSI Copyright 2009 Page 29 Solutions to the Vector Wave Equation Cylindrical Coordinates In cylindrical coordinates a solution for the scalar wave equation is: = Z ni (k ) e jn e - jk ^ TM : A = z ^ TE : F = z TM part From which the electric field can be found as: z z TE part E= 1 j ^ ^ Az z - Fz z 1 NEARFIELD SYSTEMS, INC. NSI Copyright 2009 Page 30 15 Solutions to the Vector Wave Equation Cylindrical Coordinates The variables and functions shown on the previous slide are: i = 1, 2, 3 or 4 k = k 2 - k z2 1 Z n (k ) = J n (k ) = Bessel function of the first kind. 2 Z n (k ) = Yn (k ) = Bessel function of the second kind. 3 1 Z n (k ) = H n (k ) = Hankel function of the first kind. 4 Z n (k ) = H n2 (k ) = Hankel function of the second kind. NEARFIELD SYSTEMS, INC. NSI Copyright 2009 Page 31 Bessel Functions I NEARFIELD SYSTEMS, INC. NSI Copyright 2009 Page 32 16 Bessel Functions II NEARFIELD SYSTEMS, INC. NSI Copyright 2009 Page 33 Hankel Functions Can be generated from the Bessel functions shown on the previous slides. 1 H n (k ) = J n (k ) + jYn (k ) 2 H n (k ) = J n (k ) - jYn (k ) NEARFIELD SYSTEMS, INC. NSI Copyright 2009 Page 34 17 Solutions to the Vector Wave Equation Spherical Coordinates In spherical coordinates a solution for the scalar wave equation is: i = z n (kr ) Pnm (cos )e jm ^ TM : A = r r ^ TE : F = r r From which the electric field can be found as: E= 1 j 1 ^ ^ Ar r - Fr r NEARFIELD SYSTEMS, INC. NSI Copyright 2009 Page 35 Solutions to the Vector Wave Equation Spherical Coordinates The variables and functions shown on the previous slide are: 0n -n m n 2 z n (k ) = y n (k ) = Spherical Bessel function of the second kind. z 1 (kr ) = jn (kr ) = Spherical Bessel function of the first kind. n 4 z n (k ) = hn2 (k ) = Spherical Hankel function of the second kind. 3 1 z n (k ) = hn (k ) = Spherical Hankel function of the first kind. Pnm (cos ) = (1 - x ) 2 m/2 2 n n! d n+m x 2 - 1 = Legendre functions. dx n + m NSI Copyright 2009 Page 36 ( ) n NEARFIELD SYSTEMS, INC. 18 Spherical Bessel & Hankel Functions Can be generated from the Bessel & Hankel functions. jn (x ) = y n (x ) = 1 hn (x ) = 2x J n +1 / 2 ( x ) Y n +1 / 2 ( x ) ( H n1)1 / 2 ( x ) + ) H n( 2 1 / 2 ( x ) + 2x 2x h n2 ( x ) = NEARFIELD SYSTEMS, INC. 2x NSI Copyright 2009 Page 37 Legendre Polynomials NEARFIELD SYSTEMS, INC. NSI Copyright 2009 Page 38 19 Examples of Planar Systems NSI Model 200V-3x3 3'x3' Vertical Planar NF NSI Model 300V-8x8 8'x8' Vertical Planar NF NSI Model 500H-22x22 22'x22' Horizontal Planar NF NEARFIELD SYSTEMS, INC. NSI Copyright 2009 Page 39 Toshiba 400V-108x52 (33m x 16m) G G G Largest Planar Scanner in the world. Successfully installed and validated 1-50 GHz with pulse capability NEARFIELD SYSTEMS, INC. NSI Copyright 2009 Page 40 20 NSI 650 GHz mm-wave System 1.0 G Elevation (deg) Application Microwave Limb Sounder (MLS) G G 0 0.5 -10 -20 -30 G JPL Earth Observing Satellite Measurements of Earth's ozone layer and related chemistry 1.6m antenna aperture 0.0 -40 -50 -0.5 -60 -70 -1.0 -1.0 -0.5 0.0 0.5 1.0 Azimuth (deg) G NSI Solution Sub-millimeter wave system G G G 2.4 m x 2.4 m precision granite scanner - 4 m rms Thermal compensation via NSI Motion Tracking Interferometry (MTI) 118 to 650 GHz operation using Agilent 8530A receiver, 104 GHz to 110 GHz Gunn oscillator and 6X frequency multiplier NEARFIELD SYSTEMS, INC. NSI Copyright 2009 41 Spherical Near-field Systems G NSI 700S-30 Spherical NF System G G G NSI 700S-70 Spherical NF System Testing X-band SGH AUT's up to 10 Kg, 1m dia Testing cellular base antenna AUT's up to 136 Kg, 2m dia NEARFIELD SYSTEMS, INC. NSI Copyright 2009 Page 42 21 EADS UK - Spherical System G G G G Large satellite production test capability Satellite on azimuth positioner with probe scanning via overhead swing arm NSI spherical data acquisition and processing software HP 8530A receiver system NEARFIELD SYSTEMS, INC. NSI Copyright 2009 Page 43 Far-field Technology NEARFIELD SYSTEMS, INC. NSI Copyright 2009 Page 44 22 Far-field Positioning Systems 5 Axis Positioner Roll/ Slide/ Azimuth/ Elevation/ Slide NEARFIELD SYSTEMS, INC. NSI Copyright 2009 Page 45 Ramet Far-field Range Czech Republic G G G G NSI Electronics and s/w upgrade Existing customer outdoor positioners ACC 9030 Positioner Controller Agilent PNA NEARFIELD SYSTEMS, INC. NSI Copyright 2009 Page 46 23 Antenna Field Boundaries NEARFIELD SYSTEMS, INC. NSI Copyright 2009 Page 47 Radiation Patterns I Rectangular format 0 -5 Polar format Far-field amplitude of 1.7-2.6 Gain Horn 4.nsi 345 330 0 15 30 315 45 Far-field amplitude of 1.7-2.6 Gain Horn 4.nsi -10 -15 300 60 -20 Amplitude (dB) -25 -30 270 285 75 -35 -40 255 -50 -40 -30 -20 -10 dB 90 105 -45 -50 -55 -60 -150 -100 -50 0 50 Elevation (deg) 100 150 240 120 225 135 210 195 180 165 150 NEARFIELD SYSTEMS, INC. NSI Copyright 2009 Page 48 24 Radiation Patterns II 0 Far-field amplitude of 1.7-2.6 Gain Horn 4.nsi Far-field amplitude of 1.7-2.6 Gain Horn 4.nsi 345 330 0 15 30 -5 315 45 300 60 -10 285 75 Amplitude (dB) -15 270 -25 -20 -15 -10 -5 dB 90 -20 255 105 240 120 -25 225 135 210 150 195 180 165 -30 -150 -100 -50 0 50 Elevation (deg) 100 150 0 -5 Far-field amplitude of 1.7-2.6 Gain Horn 4.nsi Far-field amplitude of 1.7-2.6 Gain Horn 4.nsi 345 330 0 15 30 -10 315 45 -15 300 60 -20 Amplitude (dB) -25 -30 270 -50 -40 -30 -20 285 75 -35 -40 -45 240 255 -10 dB 90 105 120 -50 225 135 -55 210 150 195 180 165 -60 -150 -100 -50 NEARFIELD SYSTEMS, INC. 0 50 Elevation (deg) 100 150 NSI Copyright 2009 Polar format: Differing scales Page 49 Radiation Patterns III 0 Far-field amplitude of 1.7-2.6 Gain Horn 4.nsi Main lobe First side lobe -5 First null -10 Amplitude (dB) -15 -20 -25 -30 -150 -100 -50 0 50 Elevation (deg) 100 150 NEARFIELD SYSTEMS, INC. NSI Copyright 2009 Page 50 25 Radiation Patterns IV 3dB Beamwidth 330 315 345 0 15 30 45 300 60 285 75 270 -25 -20 -15 -10 -5 dB 90 255 105 240 120 225 135 210 195 180 165 150 NEARFIELD SYSTEMS, INC. NSI Copyright 2009 Page 51 Spherical Coordinate System z E Variables & are independent and orthogonal. E r E & E are orthogonal unit vectors. Variable r denotes the distance to the observer. y x NEARFIELD SYSTEMS, INC. NSI Copyright 2009 Page 52 26 Gain & Directivity PAvailable Radiation efficiency or loss AUT PRAD PIN PReflected Directivity Gain G Directivity is given by, Realized Gain G Gain is given by, G In practice, many people measure realized gain which is affected by VSWR and internal Ohmic losses. NEARFIELD SYSTEMS, INC. NSI Copyright 2009 Page 53 Directivity Directivity = 4 U [dBi] Prad U = Radiation Intensity [W/Steradian] 2 r2 U ( , ) = E ( r , , ) 2 Prad = Total radiated power [W] 2 Prad = U sin d d 0 0 NSI Copyright 2009 Page 54 NEARFIELD SYSTEMS, INC. 27 Gain Gain = 4 U [dBi ] Pin U = Radiation Intensity [W/Steradian] 2 r2 U ( , ) = E ( r , , ) 2 Pin = Total input power [W] 2 Pin ecd = Prad = NEARFIELD SYSTEMS, INC. U sin d d 0 0 Page 55 NSI Copyright 2009 Efficiency ecd = AUT loss efficiency er = AUT reflection efficiency e0 = AUT total efficiency e0 = er ecd Gain = ecd Directivity er = 1 - 2 = AUT Voltage reflection coefficient NEARFIELD SYSTEMS, INC. NSI Copyright 2009 Page 56 28 Polarization Polarization is defined as the direction of the E-field: E-field horizontal, antenna is horizontally polarized. E-field vertical, antenna is vertically polarized. E-field rotates, antenna is circularly polarized. NEARFIELD SYSTEMS, INC. NSI Copyright 2009 Page 57 Slant Linear Polarization NEARFIELD SYSTEMS, INC. NSI Copyright 2009 Page 58 29 Circular Polarization I NEARFIELD SYSTEMS, INC. NSI Copyright 2009 Page 59 Circular Polarization II NEARFIELD SYSTEMS, INC. NSI Copyright 2009 Page 60 30 Polarization Ellipse y E2 Major axis OB OA x E1 Minor axis NEARFIELD SYSTEMS, INC. NSI Copyright 2009 Page 61 Polarization Notes G G G G G In reality LHCP and RHCP is never circular, always elliptical. LHCP and RHCP are orthogonal. Axial ratio is an indication of cross-polar isolation. CP can always be expressed as the sum of two LP components. LP can always be expressed as the sum of two CP components. NEARFIELD SYSTEMS, INC. NSI Copyright 2009 Page 62 31 RHCP Example I Far-field amplitude of RHCP Test Case.nsi - Rotating Linear Pattern & Pol Ellipse Axes G 10 Pol ellipse max Pol ellipse min Rotating linear 0 -10 Amplitude (dB) -20 G -30 Linear co- and crosspol patterns from ellipse major & minor axes and rotating linear pattern for measured RHCP antenna. Rotating linear pattern is bound by linear pol patterns. -40 -50 -60 -20 -15 -10 -5 0 5 Elevation (deg) 10 15 20 NEARFIELD SYSTEMS, INC. NSI Copyright 2009 Page 63 RHCP Example II Far-field amplitude of RHCP Test Case.nsi - Rotating Linear Pattern & Pol Ellipse Axes Far-field amplitude of RHCP Test Case.nsi - Axial Ratio 20 Axial ratio NSI2000 axial ratio 10 Pol ellipse max Pol ellipse min Rotating linear 0 15 10 -10 5 Amplitude (dB) -20 Amplitude (dB) -20 -15 -10 -5 0 5 Elevation (deg) 10 15 20 0 -30 -5 -40 -10 -50 -15 -60 -20 -20 -15 -10 -5 0 5 Elevation (deg) 10 15 20 Linear co- and cross-pol patterns from ellipse major & minor axes and rotating linear pattern for measured RHCP antenna - Left. Axial ratio Right. NEARFIELD SYSTEMS, INC. NSI Copyright 2009 Page 64 32 Near-field Scan Types G G G Planar Planar Near-field G Directional antennas G Gain > 15 dBi G Max angle < 70 Cylindrical Near-field G Fan beam antennas G Wide side/ backlobes Spherical Near-field G Low gain antennas G Wide or omni-directional patterns on any antennas Cylindrical Spherical NEARFIELD SYSTEMS, INC. NSI Copyright 2009 Page 65 Spherical Scanning NEARFIELD SYSTEMS, INC. NSI Copyright 2009 Page 66 33 Spherical NF Coordinate System NEARFIELD SYSTEMS, INC. NSI Copyright 2009 Page 67 Spherical System Configuration AUT mounting position for minimum MRE Maximum Radial Extent (MRE) NEARFIELD SYSTEMS, INC. NSI Copyright 2009 Page 68 34 Spherical Near-field Sampling Criteria It is found that for an AUT contained in a sphere of radius MRE, centered around the spherical coordinate system origin, the sample spacing required is: 0 = 0 < k MRE = 2 MRE NEARFIELD SYSTEMS, INC. NSI Copyright 2009 Page 69 Spherical Near-field Sampling Criteria Distance from theta-axis to pol-stage face plate = X mm. Length of WR_xxx probe assembly = Y mm Radius = distance from probe tip to theta-axis = X Y mm. MRE = distance from theta/phi intersection to sphere enclosing AUT. AUT support d AUT D Phi axis of rotation Radius Probe M RE Azimut axis of rotation 0m NEARFIELD SYSTEMS, INC. NSI Copyright 2009 Page 70 35 Spherical Truncation Truncated Near-field Resulting Far-field Measuring less than full 360 degree spherical data can result in ripple errors in the main beam region. Recommend measuring data down to at least 30 dB from max near-field amplitude NEARFIELD SYSTEMS, INC. NSI Copyright 2009 Page 71 Hardware Overview NEARFIELD SYSTEMS, INC. NSI Copyright 2009 Page 72 36 Chamber Layout [mm] NEARFIELD SYSTEMS, INC. NSI Copyright 2009 Page 73 Far-Field Configuration NEARFIELD SYSTEMS, INC. NSI Copyright 2009 Page 74 37 SNF Configuration NEARFIELD SYSTEMS, INC. NSI Copyright 2009 Page 75 40 67 GHz Far-Field Configuration NEARFIELD SYSTEMS, INC. NSI Copyright 2009 Page 76 38 CTIA/OTA Configuration NEARFIELD SYSTEMS, INC. NSI Copyright 2009 Page 77 Antenna Range Controller (ARC Box) G G G Provides stepper drivers for 4 axes Interfaces for AUT and probe port switches (TTL) Options: G G Scanner safety system interlock Linear axis brake NEARFIELD SYSTEMS, INC. NSI Copyright 2009 Page 78 39 System Controller G G Software G Real time motor control G Timing G Triggering G Data collection and buffering G Fault detection G Safety Hardware G I/O card (may be multiple cards) G Serial interface (communication with Windows computer) G 3.5" FDD Diagnostic and set-up functions require use of a monitor and keyboard on the system controller (2 x Scroll Lock). NEARFIELD SYSTEMS, INC. NSI Copyright 2009 Page 79 Software Overview NEARFIELD SYSTEMS, INC. NSI Copyright 2009 Page 80 40 NSI Software Description G G G G Industry Leading NSI2000 Software Runs on Windows XP & Vista (32 bit) based systems. Field Tested Daily by NSI's More than 300 Customers Worldwide Advanced scripting features: G Measurement & Processing Automation G Direct import to MS Office programs G Interface to customer-written data reduction programs and DLLs G Complete program control with macro language NEARFIELD SYSTEMS, INC. NSI Copyright 2009 Page 81 NSI 2000 Software Overview NEARFIELD SYSTEMS, INC. NSI Copyright 2009 Page 82 41 NSI 2000 Menu Operation G G G G G G Software is Windows-menu based Built-in aids to help in operator test design and test set-up Fault diagnostics for common system errors with recommendations for resolution Right click options available for many menus Help pop-ups available for some fields On-line help is available NEARFIELD SYSTEMS, INC. NSI Copyright 2009 Page 83 NSI 2000 Main Window Measurements Menu -show/hide Select Processing Menu Items Select Plot Type Script Editor - show/hide Stop Process Automatically prints plots when checked Select Filename Display Beam List NSI 2000 Window Status Bar - click to show/hide history File-read Progress Bar NEARFIELD SYSTEMS, INC. NSI Copyright 2009 Page 84 42 Typical Test Process G G G G G G Align antenna Verify good RF performance Set up scan Make measurement Data processing/analysis Reports and output NEARFIELD SYSTEMS, INC. NSI Copyright 2009 Page 85 Verifying RF Performance G Stability, Linearity, Sensitivity, Leakage G NSI2000 options include: N N N N Real-time stability plot Signal-to-noise monitor Drift check MTI monitoring and correction NEARFIELD SYSTEMS, INC. NSI Copyright 2009 Page 86 43 Receiver Stability Display G Select Measurements Stability plot 0 -1 0 -2 0 -3 0 Phase (deg) -4 0 -5 0 -6 0 -7 0 -8 0 0 2 0 0 4 0 0 6 00 T im e e la p se d 8 0 0 sin c e 1 0 0 0 s ta r t (m in ) 1 2 0 0 1 4 0 0 1 6 0 0 NEARFIELD SYSTEMS, INC. NSI Copyright 2009 Page 87 Setting Up the Scan G G G G Easy scan setup. User enters: G Height and width of antenna G Probe-to-antenna separation G Maximum scan angles Auto scan computes: setup G Scan size, #pts and spacing Multi-beam G Multi-frequency, Multi-switch, Dual-pol Reference measurements G Drift check, MTI NEARFIELD SYSTEMS, INC. NSI Copyright 2009 Page 88 44 NSI 2000 Measurement Setup Other Set-up Tabs Enter Test Title & Comments (256 characters max) Enter Monitor Frequency Real Time display of amplitude and phase Create New Scan Enter AUT Test Parameters Open Beam Table Select Reference Type Enter Scan Parameters (or use Auto scan Set-up) Automatically Generate Scan Set-up Start Acquisition Measurement Type V or H Scan Options Measurement modes NEARFIELD SYSTEMS, INC. NSI Copyright 2009 Page 89 NSI 2000 Probe Setup Select Probe Axis Select Probe Type Select Probe Mode (OEWG, Cos model, or Pattern File) Select Probe-1 Sense (1st pol measured) Select Probe-2 Sense (2st pol measured Enter None for single pol measurement) Probe Dimensions (set automatically by choosing probe type above) CosN coefficients for matching function Az and El NEARFIELD SYSTEMS, INC. NSI Copyright 2009 Page 90 45 NSI2000 Multi-beam Setup Features such as "Use suggested dwell" and "Maximize scan speed" improve throughput NEARFIELD SYSTEMS, INC. NSI Copyright 2009 Page 91 NSI 2000 Beam Table Inner Loop Outer Loop Data taking axis Dwell Time - fixed field Single Pol Data Set-up for 4 inner-loop frequencies Frequency list is repeated for 2nd Z-position Note: dwell times in this table apply for fast switching synthesizers, not for HP 8360-series sources NEARFIELD SYSTEMS, INC. NSI Copyright 2009 Page 92 46 Inner-Loop Timing Displays Check to enable Amplitude and Phase columns Check for continuous Amplitude & Phase readings Example of optimized dwell times for HP 8360 series sources NEARFIELD SYSTEMS, INC. NSI Copyright 2009 Page 93 Multi-Frequency Beam Table G NSI 2000 software includes a powerful beam table generator for multi-beam and multi-frequency measurements: Easy setup & automatic dwell time optimization Using Agilent PNA NEARFIELD SYSTEMS, INC. Beam table Continuous real-time save/recall & Excel compatibility NSI Copyright 2009 display of amp/phase and S/N ratio Page 94 47 Reference Measurements NEARFIELD SYSTEMS, INC. NSI Copyright 2009 Page 95 Making Measurements G G G Automatic file naming G Increments filenames: (Test.nsi becomes Test01.nsi) Measurement monitoring G Drift check, MTI (RF cable drift, pointing errors) Scan recovery G Overcoming errors during measurement without retaking the complete scan NEARFIELD SYSTEMS, INC. NSI Copyright 2009 Page 96 48 Data Processing & Analysis G G G G Far-field transform Probe correction Coordinate and Polarization transform Pattern analysis G Pointing, 3 dB beamwidth, Sidelobes Directivity, Gain, efficiency G Gain analysis G NEARFIELD SYSTEMS, INC. NSI Copyright 2009 Page 97 NSI 2000 Far-field Processing NEARFIELD SYSTEMS, INC. NSI Copyright 2009 Page 98 49 NSI 2000 Plots G Cartesian Polar Contour Image Surface ASCII File Output G G G G G NEARFIELD SYSTEMS, INC. NSI Copyright 2009 Page 99 NSI 2000 Plots 3D VR G G G G G Interact Rotate Zoom Pan Tilt NEARFIELD SYSTEMS, INC. NSI Copyright 2009 Page 100 50 Multiple Plot Overlays Far-field amplitude of Nrf001.dat 0 -5 -10 -15 -20 -25 -30 -35 -40 -45 -50 -25 -20 -15 -10 -5 0 5 Azimuth (deg) 10 15 20 25 H-Cut V-Cut Far-field H-Cut Far-field V-Cut Amplitude (dB) Drag & Drop Plot Overlays NEARFIELD SYSTEMS, INC. NSI Copyright 2009 Page 101 Plot Subtraction Process Far-field amplitude of WR28 antenna test006.nsi - Far-field amplitude of WR28 antenna test006.nsi G Amplitude (dB) G G Plot Comparisons can be made using `drag and drop' from one plot to another. This method is useful but is not able to show small differences NSI has developed a script named `plot subtraction' that is used to provide a standard way to show the differences in plots as an `error level' A low `error level' indicates a good match between the plots 0 -5 -10 -15 -20 -25 -30 -35 -40 -45 -50 -55 -60 -60 -50 Plot 1 Plot 2 Plot 1 - Plot 2 -40 -30 -20 -10 0 10 Azimuth (deg) 20 30 40 50 60 NEARFIELD SYSTEMS, INC. NSI Copyright 2009 Page 102 51 Plot Subtraction Result G G G Run NSI plot subtraction script Select plots to subtract Click OK to proceed - = NEARFIELD SYSTEMS, INC. NSI Copyright 2009 Page 103 Reporting and Output G Documentation G G Plot text includes the documentation of significant processing options Copy and Paste to windows program Printing, Listing to file Net-posting shows scan and script progress G Data output G G In-process monitoring G NEARFIELD SYSTEMS, INC. NSI Copyright 2009 Page 104 52 Listing to File G G G G G G Select Near-field, Far-field or Hologram display mode Click Listing Toolbar button Select File Print pull-down menu Check Print to file checkbox Enter a filename when prompted. Default file extension is .txt Listing contains data for all cuts (amplitude and phase) of the selected beam, including plot annotation. NEARFIELD SYSTEMS, INC. NSI Copyright 2009 Page 105 Customization - Scripting G G Scripting is a macro-like language that can do anything one can do from the menus G Setting parameters, selecting options, pressing buttons Scripting uses the Basic language to give a VBA-like capability for programming and debugging G Arrays, type definition G If...then...else, Do...loop etc NEARFIELD SYSTEMS, INC. NSI Copyright 2009 Page 106 53 Script Editor NEARFIELD SYSTEMS, INC. NSI Copyright 2009 Page 107 Sample Script NEARFIELD SYSTEMS, INC. NSI Copyright 2009 Page 108 54 Adding Button Bars Buttons invoking custom scripts can be added to the tool bar by renaming the script as follows scriptlabel.MacroX Where X= position on the tool bar Enable the button bar by selecting View Toolbars Macrobar Example: To add a button in the 3rd position called Subtract, rename the script that performs this task Subtract.Macro3 Button Location NEARFIELD SYSTEMS, INC. NSI Copyright 2009 Page 109 Scripting User Interface G Scripting has a built-in user-interface for simple interaction NEARFIELD SYSTEMS, INC. NSI Copyright 2009 Page 110 55 Advanced Scripting G Active-X interface G Allows calling NSI2000 from other programs like Word, Excel or Visual Basic Word documents can talk directly to NSI2000 Powerful interface capability can change the look and feel of NSI2000 G Active Documents (Word and Excel) G G Visual Basic Interface G G http://www.nearfield.com/sales/Scripts.htm NEARFIELD SYSTEMS, INC. NSI Copyright 2009 Page 111 Visual Basic Interface Visual Basic Interface G Simplified NSI2000 UI via VB6 Interface NEARFIELD SYSTEMS, INC. NSI Copyright 2009 Page 112 56 Advanced Functions G G G G Data Averaging Aperture truncation and Tapering Hologram diagnostics Side lobe analysis NEARFIELD SYSTEMS, INC. NSI Copyright 2009 Page 113 Data Averaging G G G G Select Beam List and click on beams to be averaged. Press and hold Ctrl and click on the beam number of the beams to perform averaging on. Beams will be highlighted in purple. Select plot type. Plot data will be an average of the selected files. NEARFIELD SYSTEMS, INC. NSI Copyright 2009 Page 114 57 Holographic Imaging G G NSI software includes ability to calculate fields at arbitrary distance from the antenna, including on the antenna aperture Holographic Imaging can be used for: G Aperture diagnostics for faulty array elements G Aperture tuning for phased array antennas G Radome system performance and diagnostics G Reflector surface error mapping NEARFIELD SYSTEMS, INC. NSI Copyright 2009 Page 115 Membrane AUT- Hologram Focusing Hologram Backprojection during JPL Customer Test at NSI showed clear evidence of defective element in the membrane antenna NEARFIELD SYSTEMS, INC. "Membrane Antenna Photo Courtesy of NASA/JPL-Caltech" NSI Copyright 2009 Page 116 58 NSI Software Side Lobe Analysis G G G NSI script for RMS side lobe level and null depth Works on last cut plotted Can exclude main beam region for RMS sidelobe calculation NEARFIELD SYSTEMS, INC. NSI Copyright 2009 Page 117 Interfacing with RF Equipment G G A wide variety of models G NSI: Panther 6000, Panther 9000 G Agilent: PNA, ENA, 8530, 8720, 8753, 8360, PSG, VXI G R&S: ZVM models, CMU200 (OTA) G Anritsu: MT8820 (OTA) A wide variety of configuration G VNA G External mixers N PNA/PSG, 8530/8360, Panther/7020 NEARFIELD SYSTEMS, INC. NSI Copyright 2009 Page 118 59 NSI2000 Limit Switches for Rotary Stages NSI Rotary stages have hardware and software limits. Software limits: Are used as "intelligent" limits for deceleration of stages. Angles can be changed by user. Reliability is dependent on axis indexing and maintaining position. Hardware limits: Are switches and are used as "hard" limits and index references. Can be bypassed in software by user. Do NOT allow for full 360 rotation without software option. Note: Any setup changes made have to be saved as default (Options/Save settings as default) if they are to be retained after software has been shut down. NEARFIELD SYSTEMS, INC. NSI Copyright 2009 Page 119 Antenna Measurements NEARFIELD SYSTEMS, INC. NSI Copyright 2009 Page 120 60 Scanner Safety G G G G Turn off ARC power before approaching the scanner Don't leave tools on scanner, especially not on the precision rails! Do not step on cables Disconnecting motor cables with ARC power ON will cause damage to ARC box and/or CIO-DIO cards NEARFIELD SYSTEMS, INC. NSI Copyright 2009 Page 121 Basic Near-field Acquisition Procedure 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. Index scanner if necessary Install and level antenna Install and level probe, set probe distance Set up for new scan Set up parameters for AUT Set up parameters for probe (See Probe Set-up Procedure) Compute sampling parameters (Using auto scan setup) Insure probe horizontal polarization is aligned parallel to floor (Pol = 0 deg) Move scanner to scan center or reference point Verify RF signal SNR is acceptable Enter test title & comments Run scan When acquisition is completed, plot NF pattern and check for truncation NEARFIELD SYSTEMS, INC. NSI Copyright 2009 Page 122 61 Probe Set-up Procedure 1. Mount new probe to probe rotary stage or probe carriage 2. Measure probe distance to center of rotation for cylindrical & spherical NF) 3. Select the probe model 4. Select the probe type 5. Level the probe Insure probe pol stage was indexed Rotate pol stage to level Add/subtract pol position to index offset Re-index pol axis and verify pol stage returns to Co-pol position NEARFIELD SYSTEMS, INC. NSI Copyright 2009 Page 123 Scanner Coordinate System NEARFIELD SYSTEMS, INC. NSI Copyright 2009 Page 124 62 NSI Probe Coordinate System Probe setup convention. Cable. Pol = 90 degrees. y Pol x y Cable. x Pol = 0 degrees. Facing the probe tip. NEARFIELD SYSTEMS, INC. NSI Copyright 2009 Page 125 Common Problems G Probe polarization incorrect G Must set POL=0 for horizontal polarization (parallel to X axis) G Why does amplitude display show red during acquisition? G G G Software normalizes to receiver amp at reference origin (usually scan center) If amp higher than 3 dB at other XY positions, will show red Data is re-normalized later, so can be ignored as long as you are sure receiver or mixer will not be saturated NEARFIELD SYSTEMS, INC. NSI Copyright 2009 Page 126 63 Holographic Imaging & Aperture Diagnostics G NSI software includes ability to calculate fields at arbitrary distance from the antenna, including on the antenna aperture Holographic Imaging can be used for: G G G G G Aperture diagnostics for faulty array elements Aperture tuning for phased array antennas Radome system performance and diagnostics Reflector surface error mapping NEARFIELD SYSTEMS, INC. NSI Copyright 2009 Page 127 32 X 32 Element X/Ku-band Array NEARFIELD SYSTEMS, INC. NSI Copyright 2009 Page 128 64 32 X 32 Element X/Ku-band Array A minimum radius sphere of radius 44cm is required to enclose all radiating parts of the antenna (plus some margin). At a frequency of 14.5 GHz an angular sampling interval of 1.2 is required to resolve all the spherical wave expansion coefficients and these were acquired over a span of 240 and a span of 180. Based on the high directivity of the antenna, the near-field data set was truncated beyond this. NEARFIELD SYSTEMS, INC. NSI Copyright 2009 Page 129 Principal Radiation Pattern Cuts - 14.5 GHz Co-polar cuts Far-field amplitude of 856 Prototype-02.nsi 0 -5 -10 -15 -20 Amplitude (dB) Amplitude (dB) Cross-polar cuts Far-field amplitude of 856 Prototype-02.nsi 0 -5 -10 -15 -20 -25 -30 -35 -40 -45 -50 -55 -60 Cross Cross Co Co -25 -30 -35 -40 -45 -50 -55 -60 -30 -25 -20 -15 -10 -5 0 5 Azimuth (deg) 10 15 20 25 30 -30 -25 -20 -15 -10 -5 0 5 Azimuth (deg) 10 15 20 25 30 Higher than designed cross-polar level and a directivity of 30.5 dBi NEARFIELD SYSTEMS, INC. NSI Copyright 2009 Page 130 65 Back Projected Amplitude X (meters) 0.40 X (meters) 0.40 0.30 0 -1 0.30 0 -1 0.20 -2 -3 -4 -5 0.20 -2 -3 -4 -5 0.10 -6 Y (meters) Y (meters) Y (meters) -0.30 -0.20 -0.10 0.00 0.10 0.20 0.30 0.40 Y (meters) -7 -8 -9 -10 -11 -12 -13 -14 -15 -16 0.10 -6 -7 -8 -9 -10 -11 -12 -13 -14 -15 -16 0.00 0.00 -0.10 -0.10 -0.20 -17 -18 -19 -20 -0.20 -17 -18 -19 -20 -0.30 -0.30 -0.40 -0.40 -0.30 -0.20 -0.10 0.00 0.10 0.20 0.30 0.40 -0.40 -0.40 Co-pol X (meters) X (meters) Cross-pol Pre feed network redesign. NEARFIELD SYSTEMS, INC. NSI Copyright 2009 Page 131 Feed Network Redesign Original feed network Redesigned feed network NEARFIELD SYSTEMS, INC. NSI Copyright 2009 Page 132 66 Back Projected Amplitude X (meters) 0.40 0.40 X (meters) 0.30 0 -1 0.30 0 -1 0.20 -2 -3 -4 -5 0.20 -2 -3 -4 -5 0.10 -6 Y (meters) Y (meters) 0.10 -6 Y (meters) -0.30 -0.20 -0.10 0.00 0.10 0.20 0.30 0.40 Y (meters) -7 -8 -9 -10 -11 -12 -13 -14 -15 -16 -7 -8 -9 -10 -11 -12 -13 -14 -15 -16 0.00 0.00 -0.10 -0.10 -0.20 -17 -18 -19 -20 -0.20 -17 -18 -19 -20 -0.30 -0.30 -0.40 -0.40 -0.30 -0.20 -0.10 0.00 0.10 0.20 0.30 0.40 -0.40 -0.40 Co-pol X (meters) X (meters) Cross-pol Post feed network redesign. NEARFIELD SYSTEMS, INC. NSI Copyright 2009 Page 133 Antenna Gain Improvement Far-field amplitude of 856 Prototype-02.nsi 40 35 30 25 20 Amplitude (dB) Amplitude (dB) Far-field amplitude of 856 Prototype-02.nsi 40 35 30 25 20 15 10 5 0 -5 -10 -15 -20 Initial Redesigned Initial Redesigned 15 10 5 0 -5 -10 -15 -20 -30 -25 -20 -15 -10 -5 0 5 Azimuth (deg) 10 15 20 25 30 -30 -25 -20 -15 -10 -5 0 5 Elevation (deg) 10 15 20 25 30 4dB Gain improvement NEARFIELD SYSTEMS, INC. NSI Copyright 2009 Page 134 67 Reference Material NEARFIELD SYSTEMS, INC. NSI Copyright 2009 Page 135 Far-field Angle Conventions THE NSI ELEVATION AND AZIMUTH ANGLE CONVENTIONS Far-field observer kx = k x = sin cos = cos E sin A = sin k ky = k y = sin sin = sin E = cos sin k kz = k z = cos = cos E cos A = cos cos k Elevation = E y x Azimuth = A These angles can be measured on a far-field range using an azimuth over elevation positioner z Antenna Spherical Coordinate Systems And Their Application In Combining Results From Different Antenna Orientations: Allen C. Newell & Greg Hindman, 1999 ESTEC Antenna Measurement Conf. NEARFIELD SYSTEMS, INC. NSI Copyright 2009 Page 136 68 Far-field Angle Conventions THE NSI THETA AND PHI ANGLE CONVENTIONS Far-field observer These angles can be measured on a far-field range using a roll over azimuth positioner y x z NEARFIELD SYSTEMS, INC. NSI Copyright 2009 Page 137 Measurement Coordinate Systems G Coordinate System Defined by Type of 2-Axis Rotators Used (Actual or Implied) Location of Polar Axis G Roll over azimuth - fixed source = Theta/Phi, Z = Polar Roll over azimuth - rotate source = Ludwig-3, Z = Polar Azimuth over elevation = Az/EL, Y = Polar Elevation over azimuth = Alpha/Epsilon, X = Polar Not available in Spherical N-F package. G G G NEARFIELD SYSTEMS, INC. NSI Copyright 2009 Page 138 69 Measurement Coordinate Systems IMPORTANT CONCEPTS -G Coordinate System Is Fixed To Antenna. Sphere Rotates When Antenna Rotates Coordinate Systems Are Used To Define Both Directions And Vector-Components Direction System And Vector Component System May Be Different G G NEARFIELD SYSTEMS, INC. NSI Copyright 2009 Page 139 Measurement Coordinate Systems Y Theta/Phi coordinate system with polar axis = Z-axis, source polarization fixed during measurement Coordinate system and sphere fixed to antenna. Always rotates with antenna for all 4 coordinate systems X Z NEARFIELD SYSTEMS, INC. NSI Copyright 2009 Page 140 70 Measurement Coordinate Systems Y Ludwig-3 coordinate system with polar axis = Z-axis, source polarization rotates during measurement v h X Z NEARFIELD SYSTEMS, INC. NSI Copyright 2009 Page 141 Measurement Coordinate Systems Y Azimuth over elevation coordinate system with polar axis = Y-axis. rotators at (0,0) for on-axis measurement E Z A x NEARFIELD SYSTEMS, INC. NSI Copyright 2009 Page 142 71 Measurement Coordinate Systems Y Azimuth over elevation coordinate system with polar axis = Y-axis. Rotators at (-AZ, -EL) for off-axis measurement E A Z A X NEARFIELD SYSTEMS, INC. NSI Copyright 2009 Page 143 Measurement Coordinate Systems Y Elevation over azimuth coordinate system with polar axis = X-axis. Rotators at (0,0) for on-axis measurement Z X Not available in Spherical N-F package. NEARFIELD SYSTEMS, INC. NSI Copyright 2009 Page 144 72 Measurement Coordinate Systems Transformation Equations between three different spherical angles and plane-wave vector components: kx , k k sin sin = sin E = cos sin = y , k k cos = cos E cos A = cos cos = z . k sin cos = cos E sin A = sin = NEARFIELD SYSTEMS, INC. NSI Copyright 2009 Page 145 Measurement Coordinate Systems Transformation Equations between - and H-V (Ludwig-3) vector components: Eh ( , ) = E ( , ) cos - E ( , ) sin Ev ( , ) = E ( , ) sin + E ( , ) cos NEARFIELD SYSTEMS, INC. NSI Copyright 2009 Page 146 73 Measurement Coordinate Systems Transformation Equations between - and A-E (Ludwig-2) vector components: E A ( A, E ) = cos cos sin E ( , ) - E ( , ) cos E cos E cos sin cos E ( , ) + E ( , ) cos E cos E E E ( A, E ) = cos E = 1 - (sin sin ) 2 NEARFIELD SYSTEMS, INC. NSI Copyright 2009 Page 147 360 phi vs. 180 phi SNF Scanning AUT points to + and sides of chamber Two different scanning geometries both give a complete AUT data set NEARFIELD SYSTEMS, INC. NSI Copyright 2009 Page 148 74 180 phi SNF Scanning AUT points to + and sides of chamber Two different scanning geometries both give a complete AUT data set NEARFIELD SYSTEMS, INC. NSI Copyright 2009 Page 149 360 phi SNF Scanning Two different scanning geometries both give a complete AUT data set NEARFIELD SYSTEMS, INC. AUT points to only + sides of chamber NSI Copyright 2009 Page 150 75 Illustration of the Effect of Co-ordinate Systems When Plotting Antenna Patterns NEARFIELD SYSTEMS, INC. NSI Copyright 2009 Page 151 MARS G G G G MARS stands for Mathematical Absorber Reflection Suppression MARS is a post-processing algorithm to reduce the effects of scattered signals on the desired antenna pattern MARS can improve performance in a traditional chamber MARS can extend the performance of a chamber to lower frequencies NEARFIELD SYSTEMS, INC. NSI Copyright 2009 Page 152 76 Key MARS Requirements G G G G G Offset AUT from center of rotation Over sampling the data in Theta and Phi helps the process Need to estimate or determine the phase center of the AUT Need to know the radius of the minimum sphere (AKA, minimum radial extent) Not required by MARS: G G G Knowledge of the AUT pattern Knowledge of the test range configuration Not frequency limited NSI Copyright 2009 Page 153 NEARFIELD SYSTEMS, INC. NSI 2000 Tips G G G G G G Use Show/Hide buttons to eliminate screen clutter Click on Status Bar to show/hide history. Can be useful in determining the cause of a problem. Sample scripts can be found in the NSI Help menu Click on the plot data label to change the field value Averaging plots can be done by selecting two or more beams in the beam table then plotting Enable FF analysis routines by setting the number of points to 1 (side lobe level, beamwidth) NEARFIELD SYSTEMS, INC. NSI Copyright 2009 Page 154 77 NSI 2000 Number Conventions G Number entry: G G G Some text boxes require number entry Numbers can be entered using any combination of the following symbols : 0 1 2 3 4 5 6 7 8 9 . - e E E or e represents the exponent as in 3.2e-2 = 3.2x10-2 = 0.0032 All numbers are saved with 32 bit precision (7 digits accuracy), but are displayed to only 3 decimal places Prior to pressing the Enter key or exiting the text box, you can hit the esc key to restore the previous number G Numerical precision: G G Restoring previous entry: G NEARFIELD SYSTEMS, INC. NSI Copyright 2009 Page 155 NSI 2000 Units Conventions G Units convention: G G G Text boxes showing numbers with units, display the numbers in default units It is not necessary to enter the units when entering numbers in default units Numbers may be entered in different units, but the units must be entered along with the number in the same text box, the number will be automatically converted to default units If the units entered do not match a possible unit type, a message box will appear asking you to select from one of the unit types Select one of the possible types and continue G Error handling G G NEARFIELD SYSTEMS, INC. NSI Copyright 2009 Page 156 78 NSI 2000 Supported Units G Distance units: G G G `pm', `nm', `um', `mm', `cm', `m', `meters', `km' `uin', `mil', `in', `ft', `yd', `miles', `au', `lyr' `wvlng', `lambda', `wave' `deg', `arcsec', `arcmin', `urad', `mrad', `rad' `ghz', `mhz', `khz', `hz' `sec', `ms', `us', `ns', `ps', `s', `min', `hr', `day', `yr' G Phase units: G G Frequency units: G G Time units: G NEARFIELD SYSTEMS, INC. NSI Copyright 2009 Page 157 NSI 2000 Real-time Key Commands G Ctrl-s G G Ctrl-u Ctrl-w Saves the current state of options in the menus and dialog box to the default state These settings will be automatically restored on boot-up Toggles between English and Metric units Toggles between distance and wavelength NEARFIELD SYSTEMS, INC. NSI Copyright 2009 Page 158 79 NSI 2000 Saved Settings & Data Files G Saved Settings: G The following options can be selected from the tools menu or by pressing the indicated control key: N N Ctrl-S= Saves current settings into default settings file (`Startup.srt'). Ctrl-R= Restores settings from default settings file (`Startup.srt'). G Data Files: G G G G NSI 2000 data files are created when data is acquired User is prompted to overwrite current data file or create new file NSI 2000 will automatically increment a numbered filename, or user can type in a new filename if desired NSI 2000 data files use .nsi extension NEARFIELD SYSTEMS, INC. NSI Copyright 2009 Page 159 Near-field Antenna Course - 2010 NEARFIELD SYSTEMS, INC. NSI Copyright 2009 Page 160 80 ... View Full Document

End of Preview

Sign up now to access the rest of the document