Performance Evaluation of A Directional Beam Forming Circular Antenna for ISM Band Application

Wireless communication is one of the most crucial technologies to build up a smart global society on the earth. An antenna is the fundamental element of that communication system. This paper proposes a circular microstrip patch antenna (CMPA) for industrial scientific and medical (ISM) frequency band. The antenna is comprised of a miniaturized size with a circular shape of radius 20mm and thickness 2.6mm. It obtained 2.4GHz resonant frequency that pertains as appropriate for the application of the 2.4-2.48GHz frequency band. A silicon layer having relative permittivity and loss tangent 11.9 and 0.000012, respectively is considered as substrate material of the antenna. 4.2728dB gain, polarizing most of the radiation towards the front direction of the antenna and avoiding the undesirable radiation, is found from the presented CMPA. It has minimum value of reflection coefficient (RC) -12.3557dB, with more than 53.3MHz wide bandwidth determined at -5dB RC that increases significantly at higher RC. It also has remarkable radiation efficiency of approximately 93.8%. Performance of the CMPA is fixed both in a free space and on a three layers human phantom model to determine the value of specific absorption rate, a measuring factor to have the impact of radiation on human body.