Pattern descriptors for UWB antennas

Three descriptors of antenna performance appropriate for ultrawide-band (UWB) applications are proposed and described: energy pattern, correlated energy pattern, and correlation coefficient pattern. The parameters are indicative of how a particular antenna will behave with a receiver employing correlation detection of broadband pulses. Numerical simulations of canonical dipole antennas demonstrate the significance of these parameters. In particular, there are substantial differences between total energy quantities and correlated energy quantities, showing that consistency of radiated pulse shape is a critical issue in UWB antenna performance. A further numerical example using crossed linear dipoles shows that even an antenna system exhibiting an isotropic radiation pattern at all frequencies does not provide an isotropic correlated energy pattern and hence cannot provide truly onmidirectional performance when pulse fidelity is considered.