The Effect of Nonlinear Characteristics of an Electric Field Probe on Detection Response to OFDMA Signal

To improve the accuracy of probe calibration in the non-linear response region of the probe for modulated signals, a method using the continuous wave calibration curve and the probability distribution function of the modulated signal was proposed. This method can be applied when the bandwidth of the signal is sufficiently wide. However, when this method is applied to multicarrier signals such as orthogonal frequency division multiplexing signals, the result estimated by this method appears higher than the measured result, especially in the region of the non-linear response of the probe. In this study, we examined the difference between the output voltage estimated by the proposed method and the measured result in the non-linear region of the probe using orthogonal frequency division multiplexing access (OFDMA) signals as an example. To clarify the characteristics of the signal after diode detection, the envelope spectrum of the OFDMA signal was investigated. As a result, the OFDMA signal contains many low frequency components, and the low frequency component of the OFDMA signal is a factor which lowers the output voltage of the probe.