MTT - APS - Eng. in Medecine & Biology joint meeting: Auto-Tuning Antennas For Small Systems
Raoul Ouedraogo
Mr. Douglas W. White from Draper Laboratory will be our guest speaker for our November 6th 2013 meeting.
Title:Auto-Tuning Antennas For Small Systems
Abstract:
The drive to miniaturize RF systems usually requires that the antennas be reduced in size as well. This degrades a number of antenna performance parameters, with bandwidth near the top of the list. The diminishing passband of small antennas becomes increasingly difficult to keep on frequency in the presence of environmental de-tuning effects. These can be compensated for with an automatic tuning system. Conventional auto-tuning systems use an impedance bridge followed by a variable matching network between the radio and the antenna, but both introduce loss in the signal path.
The primary focus of this presentation will be an auto-tuning antenna system for thin GPS patch antennas. By embedding the tuning and detection features directly in the antenna, series losses can be eliminated, and polarization can be controlled as well. Techniques for minimizing the impact of tuning on antenna efficiency will be covered.
Auto-tuning issues for transmit applications will also be discussed. High efficiency power amplifiers can be especially sensitive to impedance mismatch, resulting in unacceptably large variations in transmit power and efficiency. Mismatches acceptable for a receiver can seriously degrade the performance of a high efficiency transmitter, and auto-tuning can be very beneficial. Tuning component issues for moderate power levels (up to 5 Watts) will be explored. Copyright © 2013 by The Charles Stark Draper Laboratory, Inc. all rights reserved.
Douglas W. White received B.S. degrees in electrical engineering and in physics in 1975, and the M.S. and Engineers degrees in E.E. & C.S. in 1978, all from M.I.T. in Cambridge, MA. He is presently a Principal Member of the Technical Staff at the Charles Stark Draper Laboratory in Cambridge, MA. Mr. White has worked on a wide range of communications and radar systems, including mixed-signal, analog, RF and microwave circuits operating from VLF to W-band. His work in recent years has primarily focused on high efficiency power amplifiers, and ultra-miniature auto-tuning antenna systems. He currently holds three US patents. Before joining Draper Laboratory in 2000, he worked for 18 years in the Communication Systems Division at M.I.T. Lincoln Laboratory in Lexington, MA. From 1978 to 1982 he was a Development Engineer at Hewlett Packard in Santa Clara, CA.
Meeting is being held at MIT Lincoln Laboratory is located at 244 Wood St., Lexington, MA 02420. The cafeteria is open to the public and visitor parking is available adjacent to the main entrance (in front of the parking structure). The Laboratory is also accessible via MBTA Bus route 76. When entering the Wood St. gate and the Main Cafeteria entrance, please tell the guard on duty that you are a visitor attending the IEEE meeting. Refreshments are served at 5:30PM.
(Thanks to the Boston Photonics Society for the following directions.)
From interstate I-95/Route 128: Take Exit 31B onto Routes 4/225 towards Bedford - Stay in right lane; Use Right Turning Lane (0.3 mile from exit) to access Hartwell Ave. at 1st Traffic Light.; Follow Hartwell Ave. to Wood St. (~1.3 miles); Turn Left on to Wood Street and Drive for 0.3 of a mile.; Turn Right into MIT Lincoln Lab, at the Wood Street Gate.
From Exit 30B: Take Exit 30B on to Route 2A - Stay in right lane; Turn Right on to Mass. Ave (~ 0.4 miles - opposite Minuteman Tech.).; Follow Mass. Ave for ~ 0.4 miles.; Turn Left on to Wood Street and Drive for 1.0 mile.
Turn Left into MIT Lincoln Lab, at the Wood Street Gate.
This is a joint meeting with MTT, APS and AES.
Date: November 6 2013
Time: 6pm
Location: MIT Lincoln Laboratory A-cafe