1973 Technical Papers

Antenna Gain Calibration on a Ground Reflection Range

Authors: Leland H. Hemming, Raymon A. Heaton
Publication: IEEE Transactions on Antennas and Propagation
Copyright Owner: IEEE

The absolute gain of wide-beam antennas may be accurately measured using the method described. Both the theoretical and practical aspects of gain calibration on a ground reflection antenna range are presented. The measurement procedures developed were used to calibrate a log-periodic antenna at selected frequencies from 250 to 400 MHz. Measured data at 300 MHz is tabulated and error contributions are analyzed, yielding a measurement accuracy of ±0.27 dB with a 95 percent confidence interval.

Determination of Far-Field Antenna Patterns from Near-Field Measurements

Authors: Richard C. Johnson, H. Allen Ecker, and J. Searcy Hollis
Publication: Proceedings of the IEEE
Copyright Owner: IEEE

In many cases, it is impractical or impossible to make antenna pattern measurements on a conventional far-field range; the distance to the radiating far field may be too long, it may be impractical to move the antenna from its operating environment to an antenna range, or the desired amount of pattern data may require too much time on a far-field range. For these and other reasons, it is often desirable or necessary to determine far-field antenna patterns from measurements made in the radiating near-field region; three basic techniques for accomplishing this have proven to be successful. In the first technique, the aperture phase and amplitude distributions are sampled by a scanning field probe, and then the measured distributions are transformed to the far field. In the second technique, a plane wave that is approximately uniform in amplitude is created by a feed and large reflector in the immediate vicinity of the test antenna. And in the third technique, the test antenna is focused within the radiating near-field region, patterns are measured at the reduced range, and then the antenna is refocused to infinity. Each of these techniques is discussed, and various advantages and limitations of each technique are presented.