Investigation of Wide Band mm-Wave Radome

Abstract: “Radome” is a necessary shield for any type of antenna. Itsshape, thickness, mechanical and electrical properties defineits application. This thesis mainly revolves around thetechniques, used for radome analysis in W-band with thehelp of electromagnetic solvers of High Frequency StructureSimulator (HFSS) and CST Microwave Studio. Measurementof permittivity of many materials is not made atsuch high frequencies and hence one is not sure about itsmaterial characteristics. This thesis includes a survey onmaterials which are applicable in W-band regime and givea sturdy performance with single type of material or commonlyknown as ‘Style A’ radomes. The thesis further describes,the shape and thickness modification of the radome.It contemplates on the the choice of solver involved and thedifferent advantages and disadvantages of the electromagneticsolvers with respect to this particular case. Severaltrials have been done on each of these platforms and onlythe relevant results have been presented. The antenna studiedis a “Travelling Wave Microstrip Patch Antenna” whichis subjected to different sizes of ground plane in order toobtain the realistic environment for it to be simulated in.It was observed that as the thickness of radome increased,the gain through the radome enclosed antennas decreasedbut the side lobe level performances improved. The simulationsdone in HFSS have a closer resemblance to theoryof radome performance.From the perspective of measurement, the return lossand insertion loss has been recorded for the radome in theW-band. A radome piece having different thicknesses hasalso been measured using the Rhode & Shwarz VNA. Asa step further, to study the radome pattern characteristic,Fabry perot periodic resonating dipoles are simulated ona radome of desired thickness. The height of the radomefrom the ground plane is optimized in order to get a 3-dB gain at the region of interest. After implementationit was observed that, around 76.5 GHz the setup which isdescribed later on acquired a gain of 20.33 dB. Althoughit is a high gain and low profile solution, it comes witha cost of narrow beam-width. Thus one has to optimizethe number of periodic elements along with phase taperingin order to achieve the desirable beam characteristics. Inshort, the thesis outlines the theory and thinking behinddesigning a radome, its effect on the antenna and how onecan resolve the issues.