Measurement and computer simulation of resonant frequency for TM g mode of annular ring microstrip antenna covered with lossy dielectrics

The analysis of an annular ring microstrip antenna covered with lossy dielectrics is presented in this paper. It has been reported in the literature that due to dielectric loading the resonant frequency in the rectangular microstrip antenna changes. The absolute value of the change increases with operating frequency, the relative permittivity and the thickness of dielectric layer. This change may cause degradation in performance due to inherent narrow bandwidth of microstrip antennas if the effect of loading is not considered in the design. Using variational method fractional change in the resonant frequency has been calculated for annular ring microstrip antenna and stacked annular ring microstrip antenna. Experimental results are compared with numerical results and also with the rectangular microstrip antenna. Eventually results are simulated on computer