SU1628017A1 - Method for measuring reflector-type antenna beam patterns - Google Patents

Abstract

The invention relates to antenna measurements. The purpose of the invention is to measure the gain factor of a mirror antenna with increased efficiency. The method of measuring the directional pattern of a mirror antenna consists in measuring the surface shape of the reflector by measuring the coordinates of its surface points with a step of no more than 20 wavelengths, followed by restoring the surface shape, as well as the coordinates of the irradiator and the direction of its axis in the coordinate system associated with the reflector ;. In addition, the normalized vector pattern of the irradiator and its irradiation coefficient are measured. The parameters of the irradiator are measured at a distance equal to the focal length of the mirror antenna, then the gain of the mirror antenna is determined from the data obtained. y

Description

The invention relates to antenna measurements and can be used to measure the parameters of mirror antennas during their tuning.

The purpose of the invention is to measure the gain factor of a mirror antenna with increased efficiency.

The method of measuring the radiation pattern of the reflector antenna is implemented as follows.

The gain of the antenna is determined by the ratio

4 P Real (0, p)

basement

0)

where RISL (v, p) is the power radiated in the direction v and p;

Rpv - power supplied to the antenna.

Rizl (0, Vl E I2. (2) where E (b, f) is the intensity of the electric field;

W is the wave impedance of the medium, W 120 tt.

| (0, p) ..Ko.

where I, N is the current on the surface S of the reflector:

, 2U60Rpodv-Sobl i.M) d / p 1 J v

where n is the normal vector at a given point of the reflector surface; About 143 00 About

V4

Co - ort in the direction of determining KU

F fv (v.Ј) fy + W V-H ®

vector DN irradiation;

Sobl - measured KU irradiator in the direction of the maximum of its DN;

p is the distance from the phase center of the irradiator to the given point of the surface of the reflector;

K 2 l / I is the wave number;

I am the working wavelength.

Substituting (5) and (4) in (3), then (3) and (2) in (1), we get:

(/ 01t

(Pim (rZt

Ko M „. ) K 6) K) K

pim, / Эзт distance from the phase center of the irradiator to the 1st, 2nd and 3rd vertices of the mth triangular region on the reflector;

Fri, G2t, gzt - vectors from the beginning of the selected coordinate system to the 1st, 2nd and 3rd vertices of the m-ro triangle:

l A1m + A2m + Azt

Sobl

, x

eiK (/ 3-K,)

(6)

The technique of calculating the two-fold integral in formula (6) by the method of trining of the area of integration and linearization of the amplitude and phase of the integrand is known and is as follows.

To integrate, the surface of the mirror (reflector) is divided into triangular areas so that each triangle is formed by three adjacent measured points of the surface, adjacent triangles do not intersect and all triangles overlap the reflector.

As a result, to determine the QA of the mirror antenna, from formula (6) go to formula

Sobl

2

{ll,}

where I An is the contribution of the mth triangular area on the reflector to the total antenna radiation:

lAn- T1me m + T2te t +

+ Tzte t,

where45

(- plm) (- f2t)

S D - the area of the projection of the triangle

on the aperture plane;

T2m -2SA.

(- plm) ((pirn rZt) 25D

Tet

(W1t -) (plm "/ Urn)

15

0

with

five

0

0

five

0

five

Thus, as follows from formula (6), to determine the QA of a mirror antenna, it is necessary to measure the surface shape of the reflector by measuring the coordinates of its surface points, followed by restoring the surface shape, as well as the coordinates of the irradiator and the direction of its axis in the coordinate system associated with the mirror antenna , vector DN irradiator and its KU. The measurement of these parameters of the irradiator should be made at a distance equal to the focal length of the reflector antenna, which usually does not exceed several meters. The latter circumstance makes it possible to perform these measurements in laboratory conditions with a significant reduction in the time spent.

In addition, the measurement of the QA of the irradiator allows the use of standard model antennas, whose QA is known with high accuracy and whose value is comparable to the value of the KU of the irradiator, instead of using large model antennas when determining the QA mirror antennas by the comparison method. This ensures the use of cheap model antennas.

Claims (1)

The formula of the invention ° A method of measuring the directivity pattern of a mirror antenna, including measuring the coordinates of points on the reflector surface with a step of not more than 20 wavelengths, coordinates of the irradiator and the direction of its axis, in the coordinate system associated with the reflector, measuring the normalized vector radiation pattern of the irradiator, In order to measure the gain of the mirror antenna, the gain factor of the Unsolder is additionally measured and the gain of the mirror antenna is determined by the formula  Sobl H2 // iUffi.utfo x 516280176 K 2 / I is the wave number; iK ()) S, 2p is the distance from the phase center of the edge of the beam to the given point of the surface of the region A-working wavelength; Ko - ort in the direction of determination 5 the gain factor of the mirror antenna g is the radius vector from the beginning of the system us; coordinates associated with the reflector, in  the normal vector at a given point is the given point of the surface of the limiter; reflector surfaces; S is the area of the mirror antenna, F - normalized vector diagram Yu-integration is carried out over the surface direction of the irradiator;