Spectral and Spatial Properties of Antennas for Transmitting and Receiving UWB Signals

The spectral and spatial properties of antennas for transmitting and receiving ultrawideband (UWB) pulses and the corresponding filter response designs for receiving such pulses over severe multipath are studied in this paper. Based on the transmit and receive transfer functions of a UWB antenna, we analyze the UWB link behavior. A metric that is based on the receiver output signal-to-noise ratio (SNR) in multipath is used as a criterion to design an appropriate receive filter response. A lower bound on this metric allows for a tractable maximization. The solution is a linear combination of incoming pulses from all directions, which are weighted by their relative intensity. A simpler best candidate solution for the receive filter response is shown to provide a performance close to that of the linear combination solution. These results are given for a diamond planar antenna and a Gaussian monopulse at the transmitter side. For this case, the impact of direction angle on the receiver output SNR is also shown.