ESL is home to the one of the largest academic compact antenna test ranges in the world.
ESL's compact range is a state-of-the-art anechoic chamber that can perform antenna pattern measurements for antenna aperture sizes up to eight feet in diameter. It can also be used to measure radar cross section (RCS) and radar scattering characteristics of objects as large as eight feet or as small as a straight pin.
The nominal maximum size of antenna or target that can be tested is 2.4m in diameter with a lowest operation frequency of 500 MHz. The chamber is 40ft wide by 20ft high and 50ft in depth from the vertex of the reflector to the back wall. The reflector was modified from an original Scientific Antenna serrated edge reflector by adding rolled edges around the reflector. The addition of rolled edge allow the measurement capability to be upgraded from 4 GHz lowest frequency and 1.2m quiet zone size to 500 MHz lowest frequency and 2.4m quiet zone size.
The RF measurement system currently includes several vector network analyzers, including Agilent E8362B and Anritsu MS4644B, for transmit and receive up to 40 GHz with in-house developed up/down conversion modules for performing measurement up to 110 GHz. It also includes an automated 4-axis position controller, a roll/azimuth positioner and Styrofoam column mounted on azimuth rotary table for antenna and target support. The roll/azimuth positioner allows complete antenna pattern measurement, including complete spherical pattern coverages and full polarizations.
The Styrofoam column can also be used for antenna and scattering measurements with full polarization matrix as the low-density Styrofoam columns minimize the interaction between the target under test and target support. The measurement system is also equipped with amplifier modules to boost signal levels for increased dynamic range.
The chamber is also equipped with a high-bay door and 1-ton overhead crane for moving large heavy antennas or targets in and out of the chamber.
The ESL compact range was designed by ESL experts, who also helped design anechoic chambers for other institutions, like NASA, Raytheon, Boeing, Ball Aerospace, MIT Lincoln Laboratory and Honda America Research.
The Ohio State ElectroScience Laboratory has contributed three primary innovations to range technology:
The rolled edge on the reflector allows measurement of eight-foot targets as compared to four-foot targets for the same reflector without the rolled edge.
A collection of efforts to improve the sensitivity while lowering the noise of the chamber. A computer-controlled microwave pulsed transmitter and receiver were developed and have very low power (1/2 watt transmitted) yet is stable enough so that very high sensitivity can be achieved. A new technique for time-gating the received signal further improves sensitivity and has been shown to be such a successful technique that it is being commercially manufactured today by Scientific Atlanta and Lintek. In addition, new radar absorbing materials (RAM) layouts were developed to dissipate unwanted energy more efficiently before it can reflect off the walls of the chamber.
A new target support structure that is extremely rigid yet virtually invisible to the radar. Consisting of a tilted tapered-wing shape, its internal target rotation apparatus can accurately locate heavy objects while appearing much less visible to the radar than the thin strings used in the past. The compact range and accompanying data processing capabilities are available for commercial use and use by the Department of Defense.
Interested in using the compact range?
RCS and antenna measurements--relating to current or future research--can be performed for interested parties. Interested in using the compact range? Please email Teh-Hong Lee at firstname.lastname@example.org.