Abstract
In case of real aperture microwave radiometers, it is required a large antenna to realize a high spatial resolution. But it is impractical to load a satellite with large antenna.
It is well known that the beam compression by correlation arrays for radars can reduce the beam width equivalently without increasing antenna aperture size. The narrow beam obtained by the beam compression techniques is attractive but the first side-lobe level is very high.
It is also required for microwave radiometers that the directional characteristics has low side-lobe as well as narrow beam width, because a high side-lobe level causes the errors in measurements of antenna temperature.
In this paper, it is proposed a new signal processing method for microwave radiometers to reduce the first side-lobe level as well as beam width. Narrow beam width with low side-lobe is realized by combining the beam compression techniques for radars and aperture synthesis.
A L band prototype radiometer was constructed and its responses to both one and two noise sources were measured.The results showed that 1/2.8 beam compression ratio and low first side-lobe level of -25 dB had been achieved sucessfully.
