This work presents the results of numerical simulations and parametric studies of dielectric loaded wire monopole antenna, of which the main advantage is bandwidth enhancement. Introducing dielectric loading makes it possible to tune antenna to operate over a frequency range not covered with unloaded antenna, while maintaining an omnidirectional radiation pattern. The simulations are performed when loading is done with lossy as well as lossless dielectric and the results are compared. The observational frequency range is extended up to 40 GHz. In addition, the simulated results are compared with the measured S11 of four fabricated antennas loaded with lossy dielectric and a good agreement is obtained.