Antenna and pulse designs for meeting UWB spectrum density requirements

Antenna design in ultra-wideband (UWB) systems is a major challenge. For, in contrast to conventional systems, wherein waveform distortion by the antenna is negligible, there is potentially significant waveform distortion by UWB antennas. A further challenge to UWB system design is posed by mandated limits on power spectrum density, such as the FCC emission mask. In this paper, we join these two issues for the case of impulse radio (IR)-type UWB, showing how antenna design, transmit pulse design, filter design and attainable output signal-to-noise ratio (SNR) are intertwined. In particular, through software simulation, several antenna frequency responses are calculated, and a modified inversely-positioned bowtie antenna ('rounded diamond') is found to give the broadest frequency response. An integrated design of antenna, transmit pulse shaping and receive filtering is presented that gives near-maximal SNR under the FCC mask constraint, and comparisons are made to alternative designs.