Physical description for the reception of short pulses by antennas

The finite difference time domain (FDTD) method has been successfully used to analyze and optimize a number of simple transmitting antennas for pulse radiation. These antennas have mainly been rotationally symmetric structures (cylindrical and conical monopoles, both metallic and resistively loaded). In all cases, excellent agreement was obtained with experimental measurements. We discuss the reception of a plane wave pulse (1 V, differentiated Gaussian) by these antennas. This is done using a direct application of the FDTD method. Unlike the case for transmission, for reception there is no rotational symmetry, so a fully three-dimensional FDTD grid must be used. Information about the reception by these antennas could be obtained using the results for transmission with reciprocity relations. However, reciprocity applies to terminal quantities, e.g., the received voltage, and says little about the physical processes occurring when the pulse interacts with the antenna structure. A knowledge of the latter is particularly helpful when one is optimizing the antenna.