High performance high-temperature superconducting (HTS) filters have been designed and constructed for satellite application. The filters are actually a superconducting integration of an 8-pole band-pass filter with an adjustable band-stop filter onto a single piece of LaAlO 3 substrate (with dimension of 0.5×45×20 mm 3 ). Typical results of the filters, i.e., Filters A (made by YBCO) & B (made by TBCCO) will be reported. The measured responses of Filter A showed excellent specifications, e.g., an insertion loss less than 0.1 dB, a return loss better than −22.5 dB in pass-band, band-edge steepness greater than 12 dB/MHz and out-of-band rejection at a certain band deeper than −110 dB. To satisfy the requirement of rocket launch and space operation, three filters of the above design have undergone mechanical environmental simulation tests for space qualification. Detailed analysis of the response curves of Filter B measured before and after the tests showed that no noticeable change in the performance can be found. All the filters passed the rigorous ground simulation tests, which is the first time in China for HTS devices and provided a solid foundation for satellite applications of high-temperature superconductors in the near future.high temperature superconductor, filter, space qualification test One of the first applications of high temperature superconductors (HTS) was in high performance microwave devices, among which, that of satellite communications seemed very promising, both in terms of advanced technology and economic impact. Narrow-band filters made of HTS thin films showed so excellent performances of small insert loss, deep band rejection and steep skirt slope that it could improve the sensitivity and selectivity of microwave system. On the other hand, compared with conventional components, HTS devices had very obvious superiority in weight and volume.Efforts to use HTS devices in space have been made by many groups. There were some reports on HTS components space experiments. The most famous was "High Temperature Superconductivity Space Experiment" (HTSSE) [1] initiated by the Naval Research Laboratory of the United States. This program was divided into three phases. Even though the HTSSE-I phase (1989 to 1993) was intermitted because of the failure of the launch in 1993, it was still a success by demonstrating that HTS was a robust, radiation hard and survivable

The acoustic field distributions and the convergent beams generated by the planar-structure Fresnel zone transducers on solid surface are investigated. Because only 0 and 180 degree phase transducers are used, an imaging system with the Fresnel zoom lens could work at very high frequency, which overcomes the frequency limit of the traditional phased array acoustic imaging system. Simulation results are given to illustrate the acoustic field distributions along the focal axis and the whole plane as well. Based on the principle of scanning of the focus with the change of frequency for the excited signal, an experimental imaging system is also built. Acoustic Fresnel zone transducers are fabricated at center frequency of 400 MHz. Measurements and detections of the known hole flaws at different depths of the fused quartz sample are presented to show that the imaging system with Fresnel zoom lens could move its focus by only changing the frequency of the excited signal.focusing of acoustic beams, ultrasonic imaging, Fresnel zoom lens