This thesis is designated to enhance the performance of microstrip patch antenna by using dielectric resonator (DR) loading. The impedance bandwidth, antenna gain and the radiation pattern can be improved by using the DR loading in the microstrip patch antennas. The additional DR does not affect the original performance of the patch antenna. The primary objective of using DR loading is to design a smaller size, wider bandwidth and more stable radiation pattern microstrip patch antennas. In the first part, the DR loading technique is implemented in the narrowband and low profile microstrip patch antenna. Typical patch antenna with two shorting pins is used to minimize the size of the antenna and its height is 3mm (0.0245 ). The additional DR is placed at the center of the feeding point to further widen the impedance bandwidth of the original microstrip patch antenna. The original patch antenna has 1.6% impedance bandwidth. The additional DR loading can enhance the impedance up to 7.24% (2.31Ghz to 2.485GHz). That means almost 6% bandwidth increment can be achieved by using DR loading. The cross probe feeding square patch antenna with DR loading is introduced in the second part. The original cross probe feeding square patch antenna has around 50% impedance bandwidth. By using DR loading technique, the impedance bandwidth can be achieved up to 70% (2.44GHz to 5.12GHz). The maximum antenna gain is 4.192dBi. In this case, the additional DR can enhance 20% of the impedance bandwidth, improve the H-plane radiation pattern and cross-polarization. In the last part, the DR loading technique is applied in the wideband monopolar patch antenna design. The DR can also widen the impedance bandwidth from 107% to 128% (0.83GHz to 3.8GHz). The improvement on the radiation pattern and cross-polarization is more significant in this wideband application. Another size minimization technique is introduced in this thesis, the shape of the shorting pin is bended and it can reduce the original height of the patch antenna from 34mm(0.081 ) to 26mm(0.062). The application of DR material is frequently used in antenna design to enhance its performance. In this thesis, the DR loading is applied to improve the performance of the monopolar microstrip patch antenna in different designs.