C-band The Narrow Slot Antenna Design

Waveguide slot array antennas are widely used in narrow beam antennas, shaped-beam antennas, microwave communication and radar systems. It is the preferred form in the design of airborne radar antenna because of its small size, light weight, high efficiency and low side lobe characteristics.In this thesis, depth research was done on the design of rectangular waveguide edge slot array at C-band. Due to the complexity of the structure of the narrow arrays, it is difficult to obtain a closed form from theory directly. So far, the basic theoretical research about edge slot array is still at the stage of single-slot and the linear array. Therefore, based on the traditional theoretical analysis, the analysis in this thesis with high-frequency simulation software HFSS, extracted the slots'parameters that include mutual coupling. All of the extracted parameters are exploited to design the travelling-wave fed slot arrays. This method greatly simplifies the design time and costs.,meanwhile it ensure the effectiveness of the design. On the problem of cross polarization in the edge slot arrays, for planar arrays, one of the solutions is to arrange the slots of adjacent waveguide crossing–slots to suppress the cross-polarization. This will make the phase of adjacent waveguide inverse, which bring troubles into feeding system. In this thesis, the structure that the slots of every waveguide have the same direction is introduced. And the cross-polarization was suppressed with the clapboard. This structure greatly simplified the structure of feeding. According to the structure of the antenna, the ET junction was selected as a feed unit. This thesis proposes a method to analyze the error characteristics of the antenna. The method that uses a linear array with a horn to narrow the beam width of this antenna and use the clapboard to suppress the cross-polarization was also researched in this thesis.The planar arrays (the planar array method) and linear arrays with horn and clapboard (the method of linear arrays with horn) were all designed at C-band including the cross-polarization suppression in this thesis. All the outcomes of simulation meet the targets. The advantages and disadvantages of the two antenna forms were also discussed. To investigate the effectiveness and versatility, the method to design slot arrays at C-band was applied to X-band. An edge slot array was designed at X-band using the method of horn. The results basically meet the index requirements through processing test. It shows that the method discussed in this thesis to design the edge slot arrays at C-band can also be used to design edge slot arrays in other bands.