The smallest admissible number of radiators ARE. Let the sector of scanning of a petal be symmetrized concerning a normal to ARE and makes c. When scanning width of a petal should not exceed the set size. The greatest width of a petal (on scanning sector borders) we will define for ravnoamplitudny inphase ARE, substituting in (13 instead of the L size Le from (13
Existence of phase mistakes leads to distortion of DN of the antenna, reduction of its KND and growth of level of lateral petals. It should be noted that at switching scanning the main petal moves jumps. The size of jump and phase errors of subjects is less, than less diskrt the phases . However, reduction of a diskret of a phase conducts to growth of number of phase shifters and complicates the antenna.
Important parameter of the antenna with frequency scanning is the uglochastotny sensitivity equal to the size of turn of a petal (in degrees or radians) having on relative (for example, for one percent) change of the frequency (wavelength). Differentiating (2, it is possible to receive
DN of the antenna will not change if in any radiator to change a phase of current to an integer of times on 2. Therefore and at a parallel power supply circuit limits of change of phases in each phase shifter can make if to use phase shifters with dumping of a phase on an integer of times on 2l.
Lack of the parallel scheme - not identity of phase shifters and the complexity of a control system following from it. Shortcomings of the consecutive scheme - the lowered electric durability as all power has to pass through the first phase shifter, and small reliability as failure of one phase shifter can break operation of all antenna.
If phase distortions become so great that the phase on a raskryva changes a sign, DN contains more than one main petal. Scanning frequency with which DN breaks up to some main petals, is called critical.
At a large number of radiators feeding power supply circuits differ in complexity and bulkiness and generally find application on decimeter and longer waves. Give preference in a centimetric wave band to a spatial power supply circuit.
Though such electromechanical way of scanning is widely applied, its opportunities are limited to rather small angular speed of movement of a petal because of a mechanical lag effect of mobile part of the antenna (the scanner.