Personnel
Tommi Laitinen
Sergey Pivnenko
Olav Breinbjerg
Jeppe M. Nielsen
Period
August 2004 - August 2006
Funding
European Space Agency
Description
Radiation properties of antennas can be determined accurately by a probe-corrected spherical near-field antenna measurement. Performing probe correction requires the receiving (or transmitting) pattern of the probe to be known. It is typical to express the receiving pattern of the probe in spherical near-field antenna measurements in terms of the spherical vector wave expansion. In this expansion the azimuthal dependence of the radiated field of a probe (reciprocity assumed) is expressed in terms of the weighted sum of exponential functions exp(jmf), where m is an integer, and f is the azimuthal angle. Traditionally, first-order probes, for which the m index can be restricted to values m = ±1, have been used for accurate probe-corrected spherical near-field antenna measurements. The advantage of the first-order probes over more general probes is that they offer both a practical measurement procedure and a computationally efficient way to perform the necessary data processing.
Current research
Current project on probe-corrected spherical near-field antenna measurements consists of developing both a high-order probe correction technique and a suitable high-order (|m| > 1) probe for accurate spherical near-field antenna measurements for the frequency range 1 - 3 GHz for the use at DTU-ESA Spherical Near-field Antenna Test Facility. A high-order probe correction offers a greater flexibility to choose the probe type compared to the first-order probe correction. This may then allow the use of a reasonably wideband probe for accurate spherical near-field antenna measurements instead of a traditionally used, relatively narrowband conical horn, which is a first-order probe. Especially, a possibility to perform the probe correction for odd-order (odd m) probes [1] would be advantageous, since these probes consitute a wide and important class of probes [2].
Publications
[1] Laitinen, T. , Pivnenko, S. , Breinbjerg, O. , Development of odd-order probe correction for spherical near-field antenna measurements, 2004 [Published]
[2] Laitinen, T. , Pivnenko, S. , Breinbjerg, O. , Aspects of probe correction for odd-order probes in spherical near-field antenna measurements, AMTA 2004, Antenna Measurement Techniques Association, 26th Annual Meeting & Symposium, Atlanta, GA, USA, pp 98-103, 2004 [Published]
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