Research On Millimeter Dual-Band Co-Aperture And Conformal Microstrip Antenna Array

As the rapid development of communication systems nowadays, the requirement for antenna becomes higher whether in military or civilian aspects. Co-aperture technology puts two or more antennas with different working frequencies in the same aperture to reduce occupied space and more information can be got at the same time. Conformal technology makes the antenna the same shape of the carrier surface to keep the carrier's aerodynamic performance, which can expand the beam scanning range for phased array. So conformal and co-aperture antenna meets the current development of antennas. In this thesis, the research of E/Ka dual-band conformal and co-aperture printed antenna is described.First, the co-aperture antenna unit is studied. Four E-band antenna units are placed in one Ka-band perforated patch according to the size. The whole structure uses three substrates and the two bands antennas are fed in different planes. Then the simulated and measured results of the antenna unit are compared and analyzed. In order to reduce the computation complexity, small array arranged in the form of rectangle grid is studied here. Considering the narrow space in the array, the feed network combines series-fed and parallel-fed. Then the simulated and measured results of the antenna array are also compared and analyzed.Second, as the mutual coupling and surface wave is serious between antenna units especially in high frequency, several structures able to suppress surface wave are described and compared here. At last EBG structure is chosen and the simulation models are discussed. Then mushroom EBG and UC-EBG structures are studied and mutual coupling is decreased obviously when applied between two antenna units. After that, UC-EBG structure is placed around four units antenna array to suppress the diffraction of surface wave, that improves the antenna pattern. And the influence of the number of UC-EBG is also analyzed.Finally, conformal phased array and plane phased array are introduced. Then cylindrical conformal antenna unit model is simulated and comparison is made with plane unit. The influence of the cylinder radius on antenna's performance is also discussed. At last, as the antenna array is large which results in complex computation, matlab is used here to simulate and analyze beam scanning performance of the plane antenna array.