This paper presents the design of microstrip antenna with defected ground structure (DGS) for the detection of breast tumor in microwave imaging system at operating frequency of 2.45GHz. Four types of microstrip patch antennas have been designed using microstrip feed inset with grounding patches at 2.45 GHz operating frequency using dielectric substrates, FR4 (ɛr = 4.4 F / m). The results are collected via the intensity of electric (E), magnetic fields (H) and current densities. The antenna is examined with a 3D breast model structure with specific dielectric value and conductivity. From the results, it shows that antenna with design structure, Design 4 produce a good intensities values of both E and H fields respectively with the presence of the tumour, and gives the value of 7083 V/m and 35.5 A/m while without the presence of tumour is 7186 V/m and 35.8 A/m compare to other proposed antennas.

In this paper, square Microstrip Patch Antenna with notch is designed with dumbbell shaped DGS for microwave imaging system. The antenna is designed on dielectric substrate, FR-4 with relative permittivity, ℇ r = 4.7 and thickness, 1.6mm. The dumbbell shaped DGS act as the resonant structures and is placed as the ground layer of the antenna. Different location and size of dumbbell shaped DGS are simulated and analyzed. The result of return loss, radiation pattern and antenna gain are simulated using Electromagnetic Simulation Tools, fabricated and measured using Wave and Antenna Training System (WATS 2002). The design shows better performance with return loss of-38.99 dB and higher antenna gain of 6.20 dB compare to the conventional design, with return loss of-30.21 dB and antenna gain of 5.48 dB respectively.