The design, manufacture, and test results are presented for a 90polarization-rotating Van Atta array reflector with suppressed scattered field for the 1.27-GHz band. The reflector consists of 48 element antennas, half for horizontal polarization and half for vertical polarization. It receives a horizontally or vertically polarized wave and retransmits a vertically or horizontally polarized wave, respectively. The measured cross-polarized radar cross section of the reflector was 15.8 dBm2 on average, which agreed well with a theoretical prediction. Although the suppression of the scattered field was limited to about -20 dB relative to the retransmitted field, we could suppress more the scattered field by accurate positioning and careful characteristics adjustment of element antennas. Theoretical calculations showed that total phase errors of the element antennas including positioning errors and impedance characteristics errors have to be within 7.5to suppress the scattered field by less than -30 dB.

A radio propagation experiment at the Okinawa Radio Observatory of the Communications Research Laboratory is investigating the feasibility of calibrating the spaceborne precipitation radar onboard the Tropical Rainfall Measuring Mission by using the path-averaged rainfall rate estimated from rain attenuation. Because this estimated rainfall rate has errors due to the spatial inhomogeneity of rainfall rate and the variability of raindrop size distribution, we used distrometer data to evaluate both of these errors by computer simulation.