Accession Number:

AD0743994

Title:

An Automatic Antenna Impedance Compensator for Reentry Vehicles.

Descriptive Note:

Technical rept. Jul 67-Jun 70,

Corporate Author:

NEW MEXICO UNIV ALBUQUERQUE BUREAU OF ENGINEERING RESEARCH

Personal Author(s):

• Potts,John S.
• Bocian,Edward S. , Jr

Report Date:

1972-03-01

Pagination or Media Count:

226.0

Abstract:

The plasma sheath that surrounds a vehicle on reentry into the earths atmosphere at hypersonic speeds is a lossy, reflective, and time varying medium. Consequently, an on-board transmitting antenna that is tuned to an acceptable VSWR before launch becomes mismatched by the plasma and heating encountered during reentry. The report presents a device which will maximize automatically the power radiated from an X-band antenna immersed in a time varying reflective medium. This device, called an automatic antenna impedance compensator, consists of a reflectometer for sensing the complex reflection coefficient of the antenna, an electronic equivalent of a slide screw tuner that employs two variable ferrite phase-shifters for maintaining a matched condition, and a feedback control circuit that processes the signals from the reflectometer for use by the electronic tuner. Author

Descriptors:

• (*ANTENNA COMPONENTS
• *IMPEDANCE MATCHING)
• (*REENTRY VEHICLES
• *BLACKOUT(PROPAGATION))
• PLASMA SHEATHS
• ATTENUATION
• PHASE SHIFT CIRCUITS
• REFLECTOMETERS
• TUNING DEVICES
• FEEDBACK
• X BAND

Subject Categories:

• Unmanned Spacecraft
• Telemetry

Distribution Statement:

APPROVED FOR PUBLIC RELEASE