Design, Fabrication and Test of a TWT Transportable Polarimetric X-band Radar

X-band radars that are lightweight and occupy a small footprint have gained popularity recently as they are suitable for transportable and mobile platform applications. Examples of such systems include the X-Pol from the University of Massachusetts-Amherst, NO-XP from the National Severe Storms Laboratory (NSSL) and Doppler on Wheels (DOW) from the Center for Weather Research, just to name a few. Most X-band radars are magnetron based in which techniques such as phase coding for range unfolding and pulse compression are prohibited. Currently, a Travelling Wave Tube (TWT) based, transportable, dual-polarization X-band radar is being developed at the Atmospheric Radar Research Center (ARRC) at OU. Internally, this radar has been referred to as the PX-1000. It will primarily be used as a platform to test various signal processing techniques, such as pulse compression, waveform studies, polarimetric signal processing, refractivity retrieval and redundant validation. At present, the system-design block diagram has been finalized and major system components have also been acquired. The system features a pair of 2-kW TWT transmitters, a 4-ft parabolic reflector dish with dual-polarization feed, and an azimuth-over-elevation pedestal. The radar is designed in a software defined radio approach for system versatility. Long transmit pulse length of up to 15-us can be applied to compensate for the relatively low peak power while pulse compression techniques (sub-pulse coding or frequency chirping) will be used to achieve high range resolution and sensitivity. The PX-1000 is designed to be autonomous, in which the major components, i.e., the TWT transmitter, transceiver and data acquisition are housed above the elevation axis and raw I/Q time series can be collected and streamed out of the radar system in real time. At the time of the conference, we hope the radar will be completed and a detailed system description and an up-to-date progress will be reported.