Yu. N. Kalinin - Ph.D. (Eng.), Deputy General Director at Scientific Research, Scientific and Production Enterprise TRIM (Saint Petersburg) E-mail: kalinin@trimcom.ru M. A. Chavdar - Head of Test Department, Scientific and Production Enterprise TRIM (Saint Petersburg) E-mail: maxim@trimcom.ru

A conventional method of measuring the gain of passive antennas in the near field is the method of comparison using the reference antenna. This method is applied in planar, cylinder and spherical scanners and requires additional measurement of the distribution of the reference antenna near field. Direct method of gain measurement based on using the calibrated (standard) probe allows reducing the measurement time significantly. Methods for measuring the equivalent isotropic radiated power (EIRP) in the far field and in the compact range (collimator) follow directly from Friis equation and are also based on using the reference antenna (standard collimator feed). Methods for measuring EIRP in the near field are less obvious. Direct methods of measuring gain and EIRP in the planar scanners of the near field are successfully tested and implemented in the algorithm software of the automated measurement and computing complexes (AIVK) produced by the research and production en-terprise TRIM (Saint Petersburg, Russia). Methods of direct measurement of gain and EIRP in spherical scanners are insufficiently covered in the literature. The article reviews the algorithms of forward calculation of gain and EIRP directly by measuring antenna near field on spherical surface without using the reference antenna. The algorithms have been experimentally tested during measurements of antenna horn with frequency range 5,85-8,2 GHz. The gain measurement accuracy was less than 0,2 dB, EIRP measurement accuracy was less than 0,5 dB, which doesn-t exceed the accuracy of the signal source power level setting. Using this method the gain measurement time is reduced by more than half.

 

1. Bakhrakh L.D. i dr. Metody izmerenijj parametrov izluchajushhikh sistem v blizhnejj zone. L.: Nauka. 1985.
2. Parini C., Gregson S., McCormic J., Daniel J. Theory and practice of modern antenna range measurements // Electromagnetic waves series. V. 55. Institution of Engineering and Technology, London. 2015.
3. Newell A., Ward R., McFarlane J. Gain and power parameter measurements using planar near-field techniques // IEEE Trans. on Antennas and Propagation. 1988. V. 36. № 6.
4. IEEE recommended practice for near-field antenna measurements. Antenna Standards Committee of the IEEE Antennas and Propagation Society. IEEE Std 1720Ô. 2012.
5. Hansen J. Spherical near-field antenna measurements. London, UK: Peter Peregrinus, Ltd. 1988.
6. Doren W. Measurement of EIRP and antenna response for active antennas with spherical near-field scanning // Antenna Measurements and SAR. 2004.
7. Brian B. Spherical near-field antenna measurement note: insertion loss gain measurement // 30th Antenna Measurement Techniques Association Annual Symposium (AMTA 2008).