conic hemispherical antennas
The last of two ten years are marked by rapid development of radiators which basis is made with spirals of various updatings. For space flying devices (SFD) the combined methods of use of parts of surface SFD are frequently used as elements of radiating devices. Convex parts of a surface, a cavity of installation of parachute devices concern to such elements, etc. By the Choice of a configuration current-carrying branches it is carried out quadrature excitation of cross-section components of a field of radiation. In article examples of aerials as conductors of the certain configuration, wind on a skeleton conic, hemispherical and other form are resulted. Examples of adjustment of the form of an orientation are resulted. By transition from a continuous reflector to partitioned and increase of efficiency at a premise of the antennas in director of horn, etc. configurations.
Dependence of the form directional pattern is shown. From quantity of calls and ways of excitation of spiral antennas. Efficiency of radiation of tape spirals decreases with increase in diameter of the core, reduction of width of tape and increase in dielectric permeability of a substrate.
For maintenance of steady communication with SFD it is possible to allocate the next ways of creation of antennas:
Modulation of geometrical parameters of a spiral (a step of a spiral, diameter of a coil, a corner of winding, etc.;
Introduction in structure of a spiral of additional elements (the screens, phase-shifting elements);
A combination of several radiators in one design;
Application of screens of the various forms, allowing to carry out redistribution of a field of radiation of a spiral in external space.
For example, the quantity of calls of a spiral influences a direction of a maximum of radiations. Advantage of a conic spiral before flat is that it provides unilateral radiation without application of special additional reflectors. At excitation of the aerial from top of a cone the most active area of radiation is the area of a spatial resonance of a wave such as creating axial radiation in an orientation, the opposite to movement of a wave stimulating structure. At excitation on the part of the basis the areas corresponding to waves of higher orders, creating directional pattern are more effectively raised. Funneled and other forms. At a choice of a way of excitation of concrete designs it is necessary to be guided by a rule: one sites of structure of the aerial are responsible basically for the water drain, others- for radiation Energy the Form directional pattern Depends basically both on a way of excitation of a spiral, and from the form of its external surface.