UWB Self-Compensating Antennas: Numerical Demonstration of the Electromagnetic Working Principle

To achieve a dispersionless channel, the receiver must counteract the dispersion caused by the transmitter, assuming that the propagating medium is dispersionless. If identical antennas are used for transmission and reception, constraints are placed on the antenna of interest, since the temporal transmit and receive responses of an antenna are linked through reciprocity and related by a time derivative. By invoking the concept of a half-derivative, it was proposed in Tyo´s 2008 paper, that a half-differentiator transmitter in the time domain (TD) will operate as a half-integrator receiver over some range of frequencies. In the frequency domain (FD) this corresponds to a transfer function that behaves in a similar fashion as the 2D Green´s function due to a line source. The required antenna should transmit and receive cylindrical waves efficiently. When used in UWB applications, a receiving antenna with this property will counteract its dispersion effect as a transmitter, providing a flat overall channel gain. In this work, a numerical model for a rotationally symmetric structure with a dielectric lens is used as a transmitter to verify the above proposition. We start by a brief explanation of the principle on which the antenna works as cylindrical source. A study of FD and TD parameters of the model are provided. The limitations due to the dielectric lens are also addressed, and other geometries of similar characteristics are modeled. In these examples, we demonstrate how the information contained in the radiated fields can help in predicting the flatness of channel gain.