Compact Ka-Band Doppler radar MIRA 35C mobile NF
A compact cloud radar MIRA35C (designed by METEK GmbH), has been operating at CIAO since April 2021.It is a mono-static pulsed Ka-band Doppler radar for unattended long term observation of clouds and fog. Linear polarized pulses are transmitted in the atmosphere, while co- and cross polarized backscatter signals are received simultaneously to detect the profiles of Doppler spectrum and related moments, such as the reflectivity factor and Linear Depolarization Ratio (LDR). These moments are used to determine hydrometeors’ properties, such as their density, shape and type.
MIRA-35C uses a transmitter with a lower peak power as compared to the high-end MIRA-35. This loss is partly compensated as the lower peak power causes less attenuation in the transmit-receive switch. Further, the compact design of the MIRA-35C reduces internal waveguide losses, so in total the sensitivity is only 9 dB less than for the MIRA-35. Due to the smaller power, the heat dissipated in the transmitter is 10 times smaller.
The radar has a 1,2 m diameter antenna emitting microwave pulses at 35.1 GHz, with a peak power of 2.4 kW, duration of 200 ns and repetition rate of 5 KHz. The antenna beam width is 0.52° x 0.52°, the antenna gain is 50 dBi, while the radar sensitivity is -44 dBZ at 5 km 10 sec time resolution. The Doppler velocity resolution is 0.08 m/s, the LDR accuracy is within +/- 2.0 dB, while the receiver calibration accuracy is within +/- 1 dB. A clutter fence around the antenna strongly suppresses the ground clutter echo.
Radar profiles typically measured at CIAO have a vertical resolution of 30 m and a temporal resolution of 10 seconds. The typical measurement range is from 100 m to about 12 km above the ground.