Yi Min

Inflatable Antenna for Space-Borne Microwave Remote Sensing

Although inflatable antennas represent a new and untested technology for remote-sensing applications, the advantages of small volume, low cost, and low mass provide an incentive for people to invest in developing this technology. The space-borne inflatable antenna concept was evaluated for passive microwave sensing of ocean temperature, wind, and precipitation. A large-diameter (3 m), on-axis, parabolic-torus antenna, operating in the L/C- and X-band frequency ranges, was designed and measured. This paper describes the system design of the inflatable space-borne antenna, including the mechanical design, the dynamic analysis, the deployment demonstration, and other key technologies. A photogrammetry tool was used to detect the rms accuracy of the antenna reflectors surface. An NSI planar antenna near-field testing system was used to measure the antennas patterns and gain. We also analyzed the possible errors resulting from the measurements.

Potter Horn and Compact Orthomode Transducer at 150 GHz

A Potter horn and a compact orthomode transducer operating at 150 GHz are designed using full wave analysis. The Potter horn patterns have good symmetry within the main beam, the sidelobe level is less than 35 dB, and the cross-polarization level reaches 21 dB. The transmission test results of the orthomode transducer and feed horn show that the bandwidth(S11 <; -20 dB) is 16 GHz. The whole dimension is only (25 mm x 70 mm) , whereas the orthomode transducer dimension is (25 mm x 20 mm x 30 mm).

Ku-band wideband space-borne waveguide slot array antenna

Ku-band wideband high gain space-borne waveguide slot array antenna optimized by genetic algorithms is presented. Wide bandwidth is ensured by utilizing E-T wideband power divider and partition feed distribution of the array. Respects referring to higher modes, slot couplings, slot end shapes and other factors are given fully consideration in design process. Precision processing and salt bath brazing are employed to maintain the good conformity with respect to aperture shape, besides, high strength is also guaranteed. Two factors mentioned above play an important role for the possible coherent measurement. Results obtained by multipaction test, vibration and thermal cycle test verify the good properties of the large dimension fan beam payload array antenna. Measurements acquired by planar near field test show that the gain is 33.8 dB with radiation efficiency up to 76%, and side lobe levels of the two main planes are −19 dB and −20 dB respectively, meanwhile, the VSWR bandwidth better than 1.5 is about 400 MHz.