Beam reconfiguration of capacitor-based square patch antenna array

In this paper, a beam reconfiguration of antenna array composed of four elements microstrip square patch antenna is proposed by use of capacitor chips. The array of antenna which is deployed on an FR4 Epoxy dielectric substrate is intended to operate at center frequency 2.4GHz for wireless communication application. The four patch antennas are arranged in a horizontal array employing microstrip line as its feeding network. There are two configurations of capacitor chips incorporated into the antenna array, the first with capacitances of 1pF, 10pF, 10pF, 1pF and the second with capacitances of 0.5pF, 1.5pF, 1.5pF, 0.5pF for each feeding line connected the antenna patch. The beam reconfiguration is shown by characterizing the antenna array and comparing the result for an array without and with capacitor chips. From the measured results, it shows that the magnitude and phase of reflection coefficient as well as the radiation pattern of proposed antenna array are influenced by the presence of capacitor chips. The first configuration of capacitor chips changes the reflection coefficient at frequency of 2.46GHz from -17.18dB to -9.68dB, the phase shift into 81.48°, and a slight deflecting beam maximum angle of 10°. Whilst from the second configuration, the result shows the reflection coefficient of -7.46dB at frequency of 2.48GHz, shift of antenna phase into 73.89°, and deflection of beam angle up to 20°.