An Approach To A Narrow Beam Antenna For Microwave Scanning Of Stroke Affected Brain Cells

The purpose of this study was to reduce the beamwidth of broadside quarter-wave dipole array antenna which has been proposed to scan the stroke affected brain model. Since the inhomogeneities in complex permittivity in different cells in human brain is of the order of millimeter range, the beamwidth of the scanning signal should be as narrow as possible in the near field region of the transmitting system to achieve resolution required for medical purpose. Two different techniques have been undertaken here for the curtailment of beamwidth of near field pattern of broadside quarter-wave dipole array antenna. In the first method, beamwidth of the interrogating wave is studied for different values of transmitting frequency of the system from 2.4 GHz to 8 GHz keeping the number of array element fixed that results in reduction of beamwidth with increase in frequency. In the 2ndapproach, decrease of beamwidth is observed with increase in the number of array elements when the transmitting signal frequency is kept constant at 5 GHz.