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An efficient technique to realize dual‐band multi‐polarized shared‐aperture slot antenna array is proposed in this paper, featuring in all‐metal, low‐profile, light‐weight and high radiation efficiency. The cavity‐backed longitudinal slots are used at L‐band for vertical polarization, while horizontal and vertical polarizations are both achieved at C‐band, by utilizing interleaved ridged waveguides with two different kinds of slots. A coaxial‐feed end‐grounded metallic bridge is developed to excite the L‐band cavity‐backed slots, so the volume and weight of the L‐band cavity can be obviously reduced. To further make the whole antenna structure compact and tight, the reduced L‐band cavity is embedded into the serration, surrounding by two adjacent C‐band ridged waveguides for vertical polarization and one for horizontal polarization. An array prototype, which consists of two L‐band single‐polarized antennas and four pairs of C‐band dual‐polarized antennas, is fabricated and measured. Experimental results are well consistent with the simulated ones, showing a satisfying impedance bandwidth of 12% in L‐band and 5.5% in C‐band, and besides high radiation efficiency above 85% for both bands. The all‐metallic structure of this proposed array provides the thermal and mechanical advantages for space‐borne synthetic aperture radar (SAR) application. [ABSTRACT FROM AUTHOR]

Underground coal mining activities are likely to cause changes in surface structure, resulting in damage to buildings, which seriously threaten the safety of life and property of the residents within the mining area. In this paper, the synthetic aperture radar time-series analysis method is combined with the building damage level empirical model to conduct a health assessment of the residential buildings in the Panji mining area of Huainan. Through the processing of 50 Sentinel-1A satellite radar images from April 2015 to May 2018, it is indicated that the residential areas in Huainan Panji Mining Area continued to be affected by underground coal mining during this period, and severe settlement occurred. Large areas of buildings in residential areas were damaged. Until May 2018, 202,000 m2 of buildings in the residential area of Panji mining have reached the Class II damage and 41,575 m2 have reached the Class III damage. After field investigation, the actual damage situation of the building is in good agreement with the results of this paper. Therefore, synthetic aperture radar time-series analysis combined with building damage level empirical model can be used as an effective tool for rapid and efficient deformation monitoring and health assessment of buildings. It is of great significance for the identification, early warning and disaster prevention decision making of such disasters. [ABSTRACT FROM AUTHOR]