Rigorous analysis and investigations of the scan antennas on a ferroelectric substrate

In this paper, the radiation characteristics of a new microstrip electrically controllable scan antenna are investigated theoretically and experimentally. Both longitudinal and transverse currents are taken into account. The substrate of this antenna consists of a ceramic-polymer composite with modified ferroelectric powder Ba_0,65 Sr_0,35TiO₃ and an appropriate polymer. The permittivity of the substrate can be varied by an applied electric control dc-bias field. It allows to change electrically phase constant of the propagation wave and, in turn, changes the main beam direction. It is shown that the main beam position changes over 30deg when dc-bias field is applied up to 200 V. The comparison with experimental results has fully confirmed the usefulness of the scan-antenna concept and method of analysis. Presented results of the electrical scanned antenna investigation are promising for various fixed-frequency applications where frequency scanning is impossible