## Ielts Task 2 Five Points To Start A Speech

The efficiency of the area of a raskryv of a mirror completely is defined by nature of distribution of a field in a raskryva. It is known that for any platforms excited inphase its size is defined by a formula.

The mirror is usually produced from aluminum alloys. Sometimes for windage reduction the mirror becomes not continuous, but trellised. The surface of a mirror is given the form providing formation of the necessary directional pattern. Mirrors in the form of a paraboloid of rotation, the truncated paraboloid, the parabolic cylinder or the cylinder of a special profile are the most widespread. The irradiator is located in focus of a paraboloid or along the focal line of a cylindrical mirror. Respectively for a paraboloid the irradiator has to be dot, for the cylinder – linear. Along with one-mirror antennas also the two-mirror are applied.

As it was shown above, each n-y the field component in a raskryva represented by a polynom creates in a distant zone intensity of electric field, where, S – the area of a raskryv, E0 – amplitude of intensity of electric field in the center of a platform, - lambda-function (n +-go about.

Obviously, than the corner is more, i.e. the mirror, the most part of the radiated energy is deeper gets on a mirror and, therefore, the more K.P.D. Thus, nature of change of function is opposite to nature of change of function.

In this case as knots of interpolation take points in the center of a raskryv of a mirror, on the edge of a mirror and approximately in the middle between these extreme points. Coefficients of this polynom are defined by system of the equations:

The surface limited to an edge of a paraboloid and the plane is called raskryvy mirrors. Radius of this surface is called as the radius of a raskryv. The corner under which the mirror from focus is visible, is called as a corner of a raskryv of a mirror.

Any section of a paraboloid the plane containing axis Z is a parabola with focus in F point. The curve which is turning out at paraboloid section the plane parallel to axis Z is as well a parabola with the same focal length of f.

In interpolation knots, i.e. points where the polynom coincides with earlier found function, we will consider the points of a raskryv of a mirror corresponding to values: Then coefficients of a polynom is defined from system of the equations: