New class microwave antennas, based on the elements of the diffraction quasioptics: advantages and applications

The concept of optical elements using diffraction is quite an old one; for instance, Fresnel\´s zone plate dates from about 1830. The elements of the diffraction quasioptics (EDQ) are intended for transformation of incident wavefronts into the required ones. The EDQ operation principle is based on creation of specifically chosen discrete phase delays over the wave front. There are three main types of EDQ (by the principle of disposition with respect to the propagation direction of the electromagnetic wave): transverse (made mainly on a flat surface), longitudinal-transverse (made on an arbitrary curvilinear surface) and longitudinal (representing a system of screens located along the direction of the electromagnetic wave propagation). The EDQ can operate both in the "transmission regime" and the "reflection regime". According to the application the EDQ can be of amplitude (binary) and phase inversion type. The main physical properties of the EDQ are surveyed in the present work. Different systems based on the EDQ are considered as well.