Research On Slotted Waveguide Antenna Design In Millimeter Wave Band

Slotted Waveguide Antennas(SWAs) have been greatly developed from World War II. Geometric simplicity, high efficiency, polarization purity and conformal installation make SWAs ideal solutions for many radar, communications, and navigation applications.Firstly, the backgrounds, fundamental theory and design methods of SWAs are introduced briefly in this thesis.Secondly, travelling-wave SWAs with low sidelobes operating in V band are presented. An improved method for millimeter-wave non-resonant slotted Waveguide Antenna(SWA) design is presented. This method introduces a modified factor which multiplies the traditional Stevenson formula for longitudinal shunt slots cut in the broad face of a waveguide by a constant for more accurate slot displacement calculation. After the modification, a good performance in low-sidelobe design can be obtained. Based on analytical computing of slot displacement, this method is simpler and faster than other numerical computing methods. The SWAs presented here are also featured with wide slots. Typically, narrow slots have an aspect ratio(length to width) of 10:1. The slots used in the simulation and experiments have an aspect ratio of approximately 4:1. A theoretical explanation of the modification is provided. Non-resonant SWAs operating in 60 GHz band have been designed with the improved method and numerically validated by Ansoft HFSS. A prototype is realized by aluminum in 60 GHz band. Good agreement between the simulation results and measured data indicate the effectiveness of this improved method.Thirdly, broad-band SWAs with slots of spiral shape cut in the broad wall operating across the X band are researched and deisgned in this thesis. Equiangular and Archimedean waveguide-fed spiral slot antennas are presented and analyzed in detail.The-10 dB return-loss bandwidth is greater than 35% and almost covers the entire TE10 mode bandwidth of WR-90 rectangular waveguide. The bandwidth of the conventional rectangular slot based on its total efficiency is narrow while for the spiral shaped slot the antenna efficiency is relatively uniform across the bandwidth. Based on the design results of waveguide-fed spiral slot antennas operating in X band, Slotted WaveguideAntenna using spiral shaped slot cut in the broad wall of a WR-14 rectangular waveguide operating in 60 GHz band has been designed and analyzed. The frequency response is simulated by Ansoft HFSS. The-10 dB return-loss bandwidth is greater than40% and covers the entire TE10 mode bandwidth of WR-14 rectangular waveguide. The spiral shaped slotted waveguide antennas are manufactured from aluminium and the carbon fiber reinforced polymer(CFRP). The bandwidth of the conventional rectangular slot based on its total efficiency is narrow while for the spiral shaped slot the antenna efficiency is relatively uniform across the bandwidth. What’s more, the rectangular slot manufactured by CFRP cannot radiate effectively while the spiral slot still can radiate effectively.Finally, isolation between transmitting/receiving SWAs designed in Chapter four is discussed. Simulation results of the isolation between antennas are exhibited, which shows high isolation between two SWAs below-100 dB.