3. Electronically controlled antennas

Combining antennas in arrays can produce special radiation patterns, provided that the phase and amplitude of the feed currents to each element can be controlled. Printed antennas are simple to manufacture and require very little space, making them ideal for use in channel formation using traditional amplification and phase-shifting methods. Printed technology has given rise to the idea of integrating the active amplification and/or phase-shifting elements within the antenna itself, thus simplifying the feed circuits.

Indeed, since the radioelectric quantities of a printed antenna can be modified by inserting localized components, the concept of electronically...