Company Sponsor: MegaWave Corporation Company Contact: Deliang Wu Faculty Advisor: Rajeev Bansal Group Members: Emanu

1. Automated Wideband Antenna Testing System for Outdoor Use Company Sponsor: MegaWave Corporation Company Contact: Deliang Wu Faculty Advisor: Rajeev Bansal Group Members: Emanuel Merulla (EE) Christopher Mouta (Comp Eng.) Peter Lofaro (EE)

2. Background Introduction Problem Statement Project Specifications Proposed Solution Components Comparisons Final Decision of Components Software Design Antenna Design Budget Timeline Questions Overview

3. Company Background MegaWave Corporation • Located in Boylston, MA. • Founded in 1994. • Develops antennas for radio and television communications technologies. • Customer base includes DARPA, U.S. Army, NASA, DOT, U.S. Navy, SOCOM. • Research areas include development of genetically optimized antennas, direction finding antennas, and detection of portable electronic devices on-board aircraft.

4. Project Introduction Antenna Background: • At MegaWave, in order to test how well an antenna can transmit and receive, they measure antenna radiation patterns. • Antenna radiation is a graphical depiction of the field strength that is transmitted or received by the antenna. • Radiation strength is measured as gain in units of dB (decibels). • Antenna gain is the ratio of the intensity of an antenna's radiation pattern to the intensity of radiation of a reference antenna. • Common types of antennas include: monopole, dipole, Yagi, microstrip, loop, and phased array antennas.

5. Dipole Antenna Radiation

6. Directional Antenna Radiation Azimuth Radiation pattern

7. Problem Statement • Currently, antenna under test must be rotated manually to desired position. • Measurements are taken manually from network analyzer. • The network analyzer will be explained later in the presentation. • This process must be repeated for all data points. • More points = More work = More time

8. Project Specifications • Environmental and Physical: • Testing system will be used outdoors (MegaWave parking lot). • System will only be used in fair weather conditions (no rain/snow). • Entire system should fit through front door (98” x 29”) using a cart system. • System should be able to be moved by one person. • Rotator should be able to rotate 200+ pounds. 

9. Project Specifications cont. Wide Band Antennas • The antennas must have a VSWR of less than 3:1 • VSWR-voltage standing wave ratio. This tells you how much power will be reflected at the input of the antenna • The gain of the antennas are TBD. • Antennas with directional patterns are preferred above 500MHz • These Antennas must be tested thoroughly to obtain the gain within the frequency band

10. Proposed Solution • Create centralized PC interface for antenna testing. • PC controlled antenna rotator • Automated network analyzer setup • Automated data retrieval from said analyzer • Design and build 2 different Antennas for use in project • (30MHz-200MHz) • (1.3GHz-3GHz) • Buy off-the-shelf rotator and controller

11. Proposed System Diagram

12. Network Analyzer Network Analyzers measure complex impedances, VSWR, losses or gains in devices. It measures the gain of an antenna by radiating from a source antenna from port 2 and measures the gain from the antenna under test from port 1.

13. Antenna Rotators • For this project we require an off the shelf rotator that could handle a 200lb load. • These are two of the rotators that we researched: Lintech 300 Series Rotator Prosistel PST-641D

14. Antenna Rotator Comparisons Lintech Rotator Positive • All purpose rotator • Has built-in indexing table • High gear ratio • Low torque requirements • Compatible with any standard stepper motor Negative • More expensive • Requires stepper motor for motion Prosistel Rotator Positive • Inexpensive • Comes with motor • Designed specifically for antennas Negative • Limited software compatibility (not compatible with VB or Labview) • Only couples with limited types of antennas • Requires fabrication of table and stand • Company is located overseas

15. Motion Control System Motion Group SID 2.0 NI PCI-7342 Applied Motion Si3540

16. Motion Control Comparison • NI PCI-7342 • Positive • Can be configured as either stepper or dc motor controller • Interfaces with Labview • Product and software support from same company • Negative • Incompatible with Visual basic • More expensive • Not compatible with laptops • 2 axes (only need 1) • NI does not sell steppers Applied Motion Si3540 Positive • Includes motion controller and stepper motor driver. • Compatible with any standard stepper motor • Includes power supplies and RS-232 serial interface • Simple software included Negative • Incompatible with Labview and Visual Basic • Very expensive Motion Group SID 2.0 Positive • Integrated package • Includes intelligent motion controller, stepper motor and translator/driver • Includes power supplies and RS-232 serial interface • Inexpensive • Easily interfaces with Visual Basic Negative • Incompatible with Labview

17. Software • We need software that controls both the network analyzer and the motion controller system. • Our software choices for the whole project were narrowed down to either Visual basic or Labview due to the GPIB standard connection compatibilities.

18. Software Comparison Labview Positive • Program can be run standalone with Labview runtime engine(free) • Supported by other OS’s • GPIB driver set includes Labview specific libraries • Widely used in industry Negative • Development environment is expensive($1195) • No previous knowledge of language • Not supported by many motion controllers • Code not revisable without expensive development environment Visual Basic Positive • Simple interface design • Inexpensive($100) • GPIB driver set include VB specific libraries • Previous knowledge of language • MegaWave preferred Negative • Not supported by many motion controllers • Not easily portable between OS’s

19. Visual Basic Design Process • Network analyzer flow chart for testing • HP8753A HP-IB reference guide • NI488.2 software package with VB libraries • GPIB command testing through NI Measurement and Automation software • 488.2 VB command implementation into first sample test program

20. Wireless Transceivers • Wireless transceivers were provided by MegaWave. • Digital Wireless Hopnet 1500 transceivers • Operate at 2.4GHz • Will be tested to ensure no interference with gain test • RS232 connection

21. Wireless Transceivers Testing • Transceivers use CSMA for transmission • Transceivers will communicate for our required range (30 feet) • Data was successfully transmitted and received from each unit at a baud rate of 115 kbps • CSMA protocol transmits data by sending random pulses throughout the 2.40 – 2.48 GHz range • Pulses occur less frequently when both transceivers are idle • Measurements will be taken when transceivers are idle • We believe that these random pulses will be averaged out by the network analyzer when it obtains measurements • Further testing will be done with a wired connection in place of the wireless transceivers • Results from wired and wireless measurements will be compared

22. RS232 Antenna Testing System Diagram Source Antenna Antenna Under Test ~ 30 feet Network Analyzer Wireless Transceiver RS232 Port 1 Port 2 Stepper Motor Rotator Table Stepper Motor Controller Wireless Transceiver GPIB

23. Proposed Budget

24. Timeline For Spring 2006

25. Questions