Antenna Test RangeCSU ECE Senior Design Project 2009

Professor Branislav Notaros

Ryan Koenig, Aaron Kim, Michael Turner

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PRESENTATION TOPICS• Aaron Kim

• Introduction• System Overview

• Michael Turner• Antenna Positioning System• Antenna Test Software

• Ryan Koenig• ATRCamApp• Planar/Source Scanner• Budget• Next Semester Plans

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Why do we need to measure antennas?

• Numerical analysis are complex

• Validation of theoretical models

• Environmental effects

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Antenna Test Ranges• Reflection Ranges• Free Space Ranges

• Elevated Ranges• Slant Ranges• Anechoic Chambers

• Used in this project

• Compact Ranges

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Field Methods• Near Field

• λ/2π < r < 2D2/λ• Attenuation• Polarization

• Far Field• r < 2D2/λ• Attenuation

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Near Field/Far Field Techniques

• Three techniques• Planar Scanner• Spherical Scanner• Cylindrical Scanner

• Mathematical simplicity

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Example System

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Antenna Positioning System• Multi-axis antenna positioning system used

for the AUT (antenna under test)

• Designed and analyzed in SolidWorks and Cosmos FEA.

• The movement is accomplished via precision stepper motors, controlled through a custom PCB previously created

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Antenna Test Software

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Home screen of the test software

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Antenna Test Software

10This screen allows the user to configure the motor sweep parameters

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Antenna Test Software

11This screen allows the user to configure the VNA settings

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Antenna Test Software

12This screen shows the scan progress and the approximate scan time

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Antenna Test Software

13This screen displays the scan data and parameters

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Antenna Test Software - Code

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Program Flowchart

Programming done with LabView 8.6

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Antenna Test Software - Code

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• Queue driven state machine with events

• States • Initialize• Open Error Log• About• Home• Motor Sweep• VNA Setup• Run Measurement• Array To Listbox• Update Graph• Export Data• Default• Clean Up• Exit

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Antenna Test Software - Code• Events

• Timeout• “Exit”: Value Change• “Cancel”: Value Change• “Configure Measurement”:

Value Change• “Start”: Value Change• “Next”: Value Change• “Export Data”: Value Change• “Multicolumn Listbox”:

Double Click

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Antenna Test Software - Code

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“Run Measurement” Sub-VI

• This VI is located within the “Run Measurement” state of the main code• A state machine of its own, its responsible for performing the measurement collecting the data from the VNA

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Antenna Test Software - Code

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“Array to Listbox” state

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Multiple Camera Capture

Demand: Single Application that displays image capture from two identical webcams.

Solution: ATRCamApp

• Programmed in Microsoft Visual Studio• Written C++ .Net• Implements Microsoft DirectShow (API)• Tutorial and Example given at

http://www.codeproject.com/KB/audio-video/Cpp_DShowNET_FrameCap.aspx

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ATRCamApp Program Flow

Start Cameras

Grab Raw Data

USB

Logitech Software

Raw Image Data

Filter Raw DataSet Locations

for Imagesin window

Select Image Sources

(ie USB Port)

Cam

era Capture

Enable Visibilty in window

Logitech QuickCam® Orbit AF

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XY Planar Scanner with Polarization

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XY Planar Scanner with Polarization

Three movements:• Horizontal: Belt drive• Vertical: Screw drive shaft powered by stepper motor• Polar: Linear actuator to arm and lever. (smaller)

Structural Material: Machined Delrin• low friction coefficient• excellent dimensional stability• excellent insulator 22

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Bipolar Stepper Motor

1a and 2a 2b and 2a Clockwise

Pulse Width Modulation

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PWM & Microstepping

Quarter Increment Microstepping

Atmel ATMega168 Microprocessor

Allegro A3979 Microstepper

Pulse Width Modulation (PWM)

USB to FT232R Motor

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Budget Estimates

Description Quantity Estimated PricePCB Board 1 $50PBC Components Multi $100Machined Delrin Multi $1,000Fasteners Multi $200Screw Drive 1 $300Belt Drive 1 $200Misc. Costs Multi $200Antenna Mounting Plate1 $10Shaft Extention 1 $35Anodizing Positioner 1 $150Shelf Plate 1 $200Linear Actuator 1 $100

Total: $2,545

Sphe

rical

Plan

ar

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What’s Next

• CAD Design and testing of the Planer Scanner• Modify LabView Application for Planar Scanner• Write Planar Scanner Microprocessor Code• Manufacture Planar Scanner and remaining

Spherical Positioner parts• Create Cylindrical Scanner Concept

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Thank you for your time, any Questions?

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