Designing of a compact microstrip antenna resonating at 4.8GHz by using size reduction technique

In this work a compact microstrip antenna has been design and developed. This antenna incorporated two symmetrical DMS like etching structure along length on patch surface of the antenna to minimize the size. Unlike normal antenna DGS/DMS introduces discontinuities on the signal plane which in turn disturbs shielded current distribution in signal plane. Due to which apparent permittivity of the substrate varies as a function of frequency and play important role in the performance of the antenna. A size reduction of 40% at 4.8 GHz was observed. We also calculate all other parameters like apparent permittivity, phase velocity of wave, equivalent inductance and capacitance. Here we implement proportional formula of defect in three steps to get compact size of antenna which has higher impedance bandwidth w.r.t conventional patch antenna approximately 23.1 MHz. For this work we care the overall performance like radiation pattern, efficiency, gain, directivity, polarization should not degraded by inserting slot. Here we also observe that performance of antenna is a function of shape, size, and position of DMS which is inserted. We use symmetrical DMS along length to avoid cross polarization. We not prefer here to use DGS because DGS also acts as radiating element which increases the back lobe radiation.