Ground brightness temperature measurement by crossed antenna with a negative sidelobe compensation

The effect of negative sidelobe compensation is studied, based on experimental and theoretical analysis. The crossed antenna with the two arms perpendicular to each other (Mills cross) is considered. The signal of the unbroken arm is connected with the signal of the broken arm in the microwave device. The efficiency of the system for this compensation method is 90% when the break width is 7% of the arm length. In the experiment a radiometer receiver with the sensitivity 0.5 K/s was designed. The measured brightness temperature variation was 250 K. For checking the same measurements were performed by an aperture antenna with the same angle resolution. The difference between the two results obtained is about 5 K.