Recently, reconfigurable antennas have attracted significant interest to implement several operating characteristics by using a single antenna. Various methods are reported in the literature to achieve reconfigurability in frequency, polarization, and radiation pattern. Printed microstrip antennas are widely preferred in reconfigurable antenna applications because of their low profile and easy integration with active devices.
Beam steering refers to the changing of the direction of the wave lobe that contains the maximum power of a radiation blueprint. This is the lobe that displays the greatest field strength, which basically means the one with the best reach and the strongest of signals. Typically, beam steering with reflective apertures is performed using mechanical rotation of the reflecting surface. Limited electronic steering can be accomplished using a focusing reflective surface by changing the feed location or direction of incidence. To achieve beam steering more than 10 degrees, different phase shifting mechanisms using varactors can be used such as 90 hybrid loaded by the varactor diodes. Furthermore, the use of MEMS capacitors will also increase the overall efficiency of the antenna because the insertion loss of MEMS capacitances is small compared with varactor diodes.
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