Transient calibration of electric field sensors

An electric field sensor calibration system that operates in the time-domain is described and its accuracy is assessed. The system makes use of a broadband, unterminated transient test cell that is simple to construct by comparison with matched TEM or GTEM cells. An advantage of the transient technique is that the frequency response of the test equipment does not have to be characterised. Furthermore, given sufficient signal-to-noise ratio, the calibration frequency range can be extended well above the 3 dB bandwidth of the measurement equipment. The transient measurement depends for its accuracy on a model for the frequency response of a monopole probe, which is used as a reference. A model for this transfer function is presented. Results for a probe calibrated independently using the swept-frequency method are compared with those measured on the transient calibration system. The level of agreement between the two measurements validates both the transient technique and the model of the reference probe's transfer function. The transient calibration technique offers an alternative means of calibrating non-resonant electric field sensors.