Infrared thermography for electromagnetic field pattern recognition

The visualization of electromagnetic field intensity can be easily achieved by infrared thermography using an absorption screen of carbon loaded polymers. The electromagnetic waves falling on the absorption screen increase its temperature which is monitored by an infrared camera. The measured temperature profile can further be correlated to the electric field intensity. Measurement of electromagnetic field distribution is typically done by a small scanning antenna and is a time consuming process. Furthermore the scanning antenna will itself disturb the measurement process which is not the case with an absorption screen, even if the screen is kept very near to the electromagnetic wave source. Therefore fields very near to the source can also be visualized and measured. Also the length of the scanning antenna depends on wavelength of electromagnetic field to be measured, therefore it is improper to apply it to measure various fields. In order to show the utility of the above technique, an example of a patch antenna operating at a frequency of 2.45 GHz is given. Initial experiments show good agreement between simulated and measured results.