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Monopole calibrations in a GTEM cell.

Knight, D A; Alexander, M J (2001) Monopole calibrations in a GTEM cell. In: BEMC 2001- 10th British Electromagnetic Measurement Conference, 6-8 November 2001, Harrogate, UK.

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Monopole antennas commonly operate anywhere in the range 30 Hz to 100 MHz. One established method for calibrating the antenna is to replace the element with an equivalent capacitor. This models the low frequency performance of the element where the element impedance is mostly reactive, but nearer to the resonant frequency the real component becomes significant and here the model fails. NPL has developed a technique for calibrating monopole antennas, without detaching the element, in a large GTEM cell using calculable passive standard antennas to provide traceability. This method is complemented by an established free-field method which is implemented on a 60 m by 30 m ground plane. This extends the calibration range to cover antennas which operate up to 100 MHz. Estimated measurement uncertainty is ± 1.0 dB for basic designs which have 41 inch elements and ±1.5 dB for more atypical designs.

Item Type: Conference or Workshop Item (UNSPECIFIED)
Subjects: Electromagnetics
Electromagnetics > RF and Microwave
Last Modified: 02 Feb 2018 13:17
URI: http://eprintspublications.npl.co.uk/id/eprint/2222

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