The reflection behaviours of elliptical cylinder-loaded monopole antenna with cylindrical balun

In this paper, a small elliptical cylinder-loaded monopole antenna having a cylindrical balun inside the radiator is studied. The frequency and power ranges of the proposed antenna are aimed from 824 MHz to 894 MHz and average power 100 W, respectively. The reflection coefficients are investigated by using the CST MW Studio version 3.2. The validity of the software has been confirmed by analysing many canonical structures related to the monopole antenna problem. The given structure subsumes the scattering problem that is considered in the existing literature, dealing with special cases. The simulated results of this antenna system are obtained for various values of the length of an elliptical cylinder-wall loaded at the top and the contact point of a cylindrical balun at the top-hat disk, through which the effects of these parameters on the reflection coefficients are studied. The typical blade antenna can be obtained by using the /spl lambda//4 cylindrical balun such as proposed in this paper.