Both ridge and double-ridged horn antennas have generally been preferred in the wideband application such as electromagnetic compatibility (EMC) testing and standard measurements due to their advantages such as high gain and broadband. The geometry of ridge has been a significant factor to specify the characteristics of antenna over the operating frequency band. In this paper, the double-ridged horn antennas for different types of ridge profiles are designed at 8-18 GHz frequency range. Also the performances of antennas having exponential, quadratic and binomial ridged profiles are compared in terms of VSWR, radiation pattern and gain. The simulation results are obtained via CST Studio Suite, a commercially available electromagnetic software program which is based on the finite integral technique. The maximum value of the VSWR having exponential ridged profile is less than 1.5 over the operating frequency band which is better than other two designs.