The beaconless acquisition tracking and pointing (ATP) technology use the signal beam to establish the laser communication link, which can decrease the total weight and power consumption of laser communication terminal (LCT). In this paper, we mainly present the error range correction process and the calculation of acquisition time, the link budget is also calculated. Beaconless ATP technology is used in Low Earth Orbit(LEO), the transmit power is 0.5w, and the maximum communication distance is 4000km. Uncertain area results from the radom and fixed factors is analyzed, and is decreased from 2.5mrad to 865μrad through correction. The correct time of the uncertain area is less than 0.5 hour. The scanning strategy, considered with the vibration of the satellite platform, is proposed, the overlap factor is selected as 0.47 for complete coverage, and thus the acquisition time is less than 51s with a probability of 98%, which can meet the use of LEO laser communication.
In this paper, a miniaturized highly-selective six-pole filter with wide stopband is reported. For this purpose, a triple-mode resonator loaded with stub and patch is proposed, which is characterized both by theoretical analysis and full-wave simulation. The designed six-pole filter is composed of two identical triple-mode resonators. The two resonators are coupled to each other to increase the selectivity. There are two transmission zeros at each side of the passband, which increase the stopband attenuation. The other two transmission zeros suppress the harmonic frequencies, which extend the 20dB stopband rejection levels up to 6GHz. The center frequency of the filter is 2.2GHz, the fractional passband is 13%, and the 30dB regular coefficient is better than 0.6.