Design And Calibration On Antenna Array For 5.8GHz Communication System

In this dissertation, antenna arrays for base station and terminal have been designed, and the calibration method for smart antenna and large-scale phased array has been studied. These antennas are designed for a point to multipoint wireless communication system operating at 5.8GHz.A parallel feed patch antenna array is designed as the omni-directional antenna of the base station antenna. In order to achieve an ideal omni-directional pattern, the antenna consists of three parallel fed sub patch antenna arrays which are arranged in a triangular configuration. Each element of the sub array is a parasitic patch array. By changing the loading resistors of the parasitic elements, the 6-dB beam width of sector antenna can be adjusted to 120°, and the fluctuation of the composite pattern can be suppressed. For terminal, a planar slot antenna array based on substrate integrated waveguide (SIW) technology is also investigated in the dissertation.Compared with the traditional waveguide, SIW is cheaper to manufacture, and easier to be integrated with other circuit blocks. But due to the large width to height ratio, the bandwidth of a slot antenna array fed by SIW is narrower than its waveguide counterpart. In this dissertation, the relationship between the bandwidth, the array scheme and feeding waveguide is studied. As a solution, choke grooves are used to expand the bandwidth. A planar slot array with 8.1% bandwidth and–25~–32dB low sidelobe is implemented.In the phased array,smart antenna and other active antenna array, the amplitude and phase of each antenna element must be calibrated. Based on the classic rotating-element electric-field vector (REV) method, a new combined REV method is proposed for the calibration of large-scale phase array. This method synchronously rotates the sources'phases of more than one antenna element, and makes the signal vary more significantly. So this method overcomes the shortage of classical method in which the amplitude of the test signal changes insignificant and is difficult to detect. The error estimation and simulated results indicate that the new method improved the precision of measurement and effect of calibration. A simple test shows that the new method is feasible.