Experimental Study on Propagation Characteristics of P-Band Narrow Pulse in Coal Seams

In order to study the change rule of attenuation during the penetration of P-band narrow pulse into coal samples, a time-domain test scheme based on P-band narrow pulse is proposed. The time-domain narrow pulse test of coal seam media with thickness of 20,35,50,80,100 cm is carried out by using an antenna with frequency band of 300 MHz to 1GHz. The receiving antenna is directly connected to the oscilloscope to store the received signals. The received signal data were processed by intercepting time window, background cancellation, wavelet denoising, and analyzing the changes of positive and negative peaks in the signals, and the transmission characteristics of narrow pulses passing through different thickness coal seams and the relative dielectric constant of coal samples are obtained. This conclusion has certain guiding significance for studying the transmission characteristics of P-band electromagnetic wave in coal and life detection in underground.