Application of Comb Beam Transmission to C-band Phased Array Weather Radar

A preliminary study for developing a future C-band weather radar is summarized. Along with the recent significant innovation of X-band weather radars, which is the introduction of a phased array technology (specifically, simultaneous observation for multiple angles by using digital beam forming, resulting in several times faster scan), it is natural for C-band weather radars to adopt the similar concept to achieve faster scan and to enable early detection and alarm of hazardous weather and improvements of weather predictions. An existing X-band weather radar utilized the wide beam transmission scheme, and the comb beam transmission scheme has recently been proposed. While the former forms a broad mainlobe in transmission and resolve the mainlobe digitally in reception, the latter transmits multiple mainlobes (comb beam). With respect to two-way antenna patterns, the comb beam scheme can produce sharper mainlobes and lower sidelobes than the wide beam scheme. Comparing the designed volume scan schedules of the comb and wide beam schemes, both of which take an equivalent scan time, the comb beam scheme is estimated to accomplish 1.5 times sharper mainlobe and 5–15 dB lower sidelobes, which can give significant advantages in qualities of weather radar observables.