Solid-State Pulse Compression Radars in Japan

Solid-state weather radars have recently gained popularity in Japan because of its capability for pulse shaping, which allows for a precise control of the actual bandwidth usage. Because electromagnetic emission is strictly regulated by Ministry of Internal Affair and Communication in Japan, weather radars must minimize their interference to neighboring bands. In addition, the use solid-state based weather radar promises lower peak power, which reduces the operational costs of the weather radar, as the financial burden is directly proportional to the peak power in Japan. Using long transmit waveform and pulse compression, weather radars can achieve similar sensitivity performance of a high-power system, while linear solid-state amplifiers allows for minimal electromagnetic interference. In a joint effort between Toshiba Corporation and the Meteorological Research Institute (MRI), we developed a parabolic dish-type C-band solid-state weather radar, which is currently installed at the MRI research facility in Tsukuba, Japan, in order to study the efficacy of a weather radar system using solid-state transmitter. Recently, we implemented the optimized frequency modulation (OFM) waveform, which was developed by the Advanced Radar Research Center (ARRC). The OFM waveform does not require mismatch filtering and, thus, increases the system sensitivity compared to a mismatched filtering pulse compression technique. A set of meteorological events to illustrate such sensitivity gain will be presented. Polarimetric variables of the datasets will also be accompanied to show the soundness of high-quality measurements using solid-state weather radars.

Keywords: Solid-state transmitter, pulse compression, polarimetric weather radar, phased array, digital beamforming

Acknowledgement: The authors would like to acknowledge support from the Advanced Radar Research Center of the University of Oklahoma.