Design of a Compact and Efficient Monopole Antenna for ISM Band Applications

In this paper, a low cost, highly efficient and compact monopole antenna for Industrial, Scientific, and Medical (ISM) applications is presented. A new spiral coil rectangular shape structure possessing meander lines is designed to achieve a resonance at 0.915 GHz response with an Omni-directional radiation pattern. The proposed architecture makes the miniaturization by turning the conducting transmission lines as coil to both left and right part of the feedline to follow symmetry in current distribution. The ground plane has been adjusted in such a way to get proper impedance because if the area of ground plane increases input impedance shift to inductive region and resonant frequency decreases respectively. Ansys HFSS 3D High Frequency Simulation Software has been used to carry out the analysis of the presented antenna. The overall volume of the proposed antenna is 4.5 X 4.5 cm
²
whereas the FR4 material is used as a substrate with a relative permittivity and loss tangent of 4.4 and 0.025, correspondingly. The peak gain of 0.88 dBi is achieved with a radiation efficiency of 80 to 98% for the desired band.