Design Of Feed Network For Ku-band Planar Array Antenna

With the development of wireless communications, antennas with high gain and high performance have increasingly attracted people's attention. The proper antenna design is essential for improving communication qualities. This paper has conducted research on array antenna technologies in modern wireless communication systems, including design of microstrip array antenna and its feed network.Basic theories of microstrip antennas and array antennas are briefly introduced. Comman structures of feed network for array antennas are presented. Based on these theories, a novel feed network for microstrip array antennas is designed. Through the adoption of orthogonal feed lines and two-layer feeding structure with air gap, feed network for 2*2 sub array is designed. Simulations demonstrate that new design has greatly enhanced the impedance match and current distribution of feed network, reduced both the internal loss of feed network and the coupling between feed network and radiating elements, which increases the feed network efficiency greatly. Based on the proposed 2*2 structure, feed network for 16-element, 32-element and even larger array antenna is explored. Tapped line technology is adopted to optimize the overall performance of feed network.Based on the proposed feed network, two different elementary antennas, rectangular patch and circular patch with mirror, are adopted to design 32-element microstrip array antennas with wide band and high gain. Simulations and measurements both demonstrate that proposed feed network has enhanced the overall performance of the array antennas. By adjustment of the feed network, unequal magnitude distribution to sub arrays is achieved to suppress the sidelobe. 64-element and 256-element microstrip array antennas are designed. Measurements demonstrate the feasibility and effectiveness of the proposed method of designing low sidelobe array antennas.A summarization is given at the end of this thesis. Future research on microstrip array antenna and its feed network is also discussed.