The Design and Manufacturing of a Small Monopole Antenna with Minimized Electromagnetic Radiation Health Effects

Both the antenna miniaturization and bandwidth account for recent trends in designing modern antennas. This research is about the design of an ultra-wideband (UWB) planar monopole antenna, examining the specific absorption rate (SAR) induced by that antenna on a simplified human head model. The motives of the research are to miniaturize the antenna, targeting the UWB performance with minimized electromagnetic interference with the human brain fluid. An UWB small monopole antenna was designed, manufactured and tested (as a prototype); both the SAR and the electric field were simulated on a basic human head model. During the design process, as the antenna is grounded on one side, the performance is enhanced through impedance matching with the feed; electromagnetic (EM) far-field is strengthened too. Results from the grounded and ungrounded models at 3 GHz helped on the final prototype selection. A grounded monopole was selected, manufactured and the measured results proved the correctness of simulation results. The existing works in this area showed that computer simulation is a reliable method in studying electromagnetic radiation effects: sizing parameters and design properties are flexibly changed in simulation software. For main results, apart from the manufactured and tested prototype, the nearly zero SAR was achieved by simulation using the highfrequency structure simulator (HFSS) as a software tool; the brain fluid was directly placed in the main radiation near field beam of the antenna. The EM interference was studied on the modeled head and brain, in this research work; however, the same interference seriously affects the body's organs which contain a big quantity of fluid, such as the heart, the cheeks, etc. Therefore, both the users and manufacturers of EM energy radiating devices are recommended to refer to their SAR design specifications before utilization, especially when those devices are intended to be used in closeness with the human body.