Parametric analysis of a broadband Archimedean spiral antenna with cavity

In this article an Archimedean spiral antenna is designed and analyzed that has good operation in broadband application. By analyzing this design, the effects that different parameters have on antenna operation will be studied and ways of optimization will be found.  Influences of cavity height and number of turns to obtain good matching and gain in a frequency interval of 4 to 18 GHz will be discussed. In addition, using cavity wall around the antenna, side lobes are decreased or deleted. By tapering the arms at feeding center, better matching will be attained. For making S11 bandwidth better, increasing the cavity height or reducing the number of turns can be used. Changing number of turns does not have a significant effect on the gain. To improve the antenna gain, the cavity height needs to be adjusted such that the reflected wave from cavity and radiated wave from spiral arms are constructing.