Method and system for time domain antenna holography
AssigneeAgence Spatiale Europeenne (an inter-governmental organization)
InventorsJavier Marti-Canales, Leonardus Petrus Ligthart
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Abstract
A fast, novel method is disclosed which permits to determine the electrical features of an antenna. The antenna is excited with an ultra-short voltage pulse and the far field radiation pattern of the antenna is measured. The resulting time-varying field distribution across the antenna aperture is then reconstructed using time domain holography. A direct analysis of the holographic plot permits the determination a wide range of electrical properties of the antenna.
Claims4
A method for determining the electrical features of an antenna, comprising the steps of:
- (a) Placing and aligning the antenna under in an antenna test range
- (b) Exciting the antenna under test or the range antenna with an ultra-short voltage pulse,
- (c) Measuring the voltage radiation pattern of the antenna under test in the time domain using a digitising oscilloscope,
- (d) Reconstructing the time-varying field distribution across the antenna aperture as a function of time and space,
- (e) Determining electrical characteristics of the antenna directly from the holographic plot.
A method of reconstructing the aperture field distribution of an antenna in the time domain from direct radiation pattern measurements, comprising the steps of:
- (a) Measuring the voltage radiation pattern of the antenna in the time domain,
- (b) Calculate the derivative of the measured far field cut with respect to time;
- (c) Calculate the integral of the derivative over the range extending from −π/2 to π/2;
- (d) Divide the result by π times the speed of light c;
- (e) Recording the final result thus obtained.
A method of reconstructing the aperture field distribution of an antenna in the time domain from direct radiation pattern measurements, comprising the steps of:
- (a) Measuring the voltage radiation pattern of the antenna in the time domain;
- (b) Calculate the wave spectrum associated to the measured radiation pattern;
- (c) Calculate the second derivative of the wave spectrum with respect to time;
- (d) Calculate the double integral of the derived wave spectrum over the propagating space;
- (e) Divide the result by 2*pi.
Dependencies are inferred from the claim text.