SU1277025A1 - Method of determining directivity pattern of aerial - Google Patents

Abstract

The invention relates to radio engineering and provides improved measurement accuracy. In the first focus of the shielded camera 1, having the shape of an ellipsoid of rotation, an irradiating antenna (OA) 2 is installed, and in the second focus, the test antenna (IA) 3 is installed. The OA 2 has a radiation pattern (DN) symmetric with respect to the major axis of the ellipsoid of rotation and having the shape of the cardioid, the minimum of which is directed to the AA 3. The emitted microwave signal OA 2 is reflected from the walls of the shielded chamber 1 and fed to the AA 3. During the sequential rotation of the IA 3 to discrete angles, they are measured & signal: at its output. DN determined (L from the ratio. 1 Il.

Description

The invention relates to radio engineering and can be used to measure the directivity pattern of microwave antennas in shielded cameras.

The purpose of the invention is to improve the measurement accuracy.

The drawing shows the structure of a device that implements a method for determining the antenna radiation pattern.

The device contains a shielded chamber 1 in the form; an ellipsoid of rotation, in the first of whose foci an irradiating antenna 2 is installed, and in the second an antenna under test 3. The forward beam is marked on the drawing as A, and one of the rays reflected from the walls of the shielded camera 1 is A ,,. Circle ABCD of radius, equally large axis of the elliptical cylinder, has a center in the second focus.

The method for determining the antenna pattern is implemented as follows.

When measuring the radiation pattern of the tested antenna 3, the irradiating antenna2 with a cardioid shape symmetrical about the major axis of the ellipsoid of rotation, has a cardioid shape, the minimum of which is directed to the test antenna 3, emits a microwave signal, and this causes the arrival of the microwave signal 3 by the reflected rays, such as, for example, A, and the signal on the direct beam Af does not come. The irradiating antenna 2 is installed in the first focus F, which is equivalent for reflected rays to its location on a circle ABCD of radius equal to the major axis of the ellipsoid of rotation drawn from the center placed in the second focus R. Due to the symmetry, the diagram HanpftHnoHHE E ((nd) irradiating antenna 2 be written as E (-oi), where a is the angle measured from the major axis of the ellipsoid of rotation. With this in mind, the signal at the output of the test antenna

3 is defined by

g

and (0) 1 F (Q-trf) E (.) do,

(one)

where F (0) is the radiation pattern of the test antenna.

The transition to the disjoint angle values of nu8, for which measurements are made, where n 1,253).,. N, al9 discretization step, the ratio (1) can be represented as

and (py9) 2: i (nu0- mu0) E (), (2)

where m 0,1,2, ... M-1, at the same time.

Exposure (2) to the discrete Fourier transform, we obtain

Jirrnk

M-1- ;;

and (K) IlF (K) e

t-, 0

Wherein

u (k)

(four)

ITmK

 E (TBO)

e

nicO

dl to - 1,2,, 3 ,. . . N.

The desired radiation pattern is determined from (4) by means of the inverse discrete Fourier transform, which gives

and (K)

f

2TTTK

M-1

Y. & ECmuG).

where G is the inverse discrete

Fourier transform.,

Claims (1)

Invention Formula The method of determining the antenna pattern by placing it in a shielded camera, having the shape of an ellipsoid of rotation, radiating 5 from its first focus of a spherical electromagnetic wave by means of a radiating antenna and measuring the signal at the output of the test antenna, distinguishing measurements, the test antenna is placed in the second focus of the rotational ellipsoid, the signal at the output of the test antenna is measured at its successive rotation at angles e 0 - n, where n 1,2,3, ... N; d9 - goal between two posledovatelnshi the positions of the antenna under test, and the radiation pattern F (nuS) is determined from the ratio U (K) f fA-1 9-VmK He E (ra40) m-o Where f is the inverse discrete Fourier transform; and (K) E (muS) 312770254 discrete transformations with, l, 2, ..., Fourier of and (pdb) with k 1, N-1; 2.3 ... N; U (nu0) is the value of the output signals, the value of the direction-of-the-antenna diagram at different numbers of the irradiating antenna positions of the antenna.