SU1415203A1 - Method of determining aerial frequency-band directional pattern - Google Patents

Abstract

The invention relates to antenna technology. The purpose of the invention is to improve the accuracy of determining the directivity pattern of the antenna in the frequency range. The essence of this method consists in the fact that in the discovery of the investigated antenna using a source of 5 broadband pulsed signals form a broadband pulsed electromagnetic field. In this case, the antenna 1 is irradiated with the probe 3 by a broadband pulsed signal, which is used as a reference. Then, the registrar 2 registers, with respect to the temporal position of the reference signal, the time dependences of the field amplitudes corresponding to the selected spatial points of the near zone of the antenna 1. Next, the processing unit 8 converts these time dependencies into the frequency domain by means of a spatial Fourier transform. In this case, using the data acquisition and conversion unit 6, the instability of the temporal position of this time dependence is compensated. Then using the processing unit 8 is determined at the required frequencies of the antenna pattern I. I. 2 Il. with "(L

Description

 ate

tpt / f.f

The invention relates to antenna technology and can be used to determine the spatial directivity characteristics of radiating devices and scattering objects in the frequency range in radio astronomy, radio communications, etc.

The purpose of the invention is to improve accuracy.

FIG. 1 shows a structural electrical block diagram of a device that implements a method for determining the antenna radiation pattern in a frequency band; in fig. 2 - mutual temporary position of the time dependences of the amplitudes of the signal at the output of the investigated and reference antennas.

A device for determining the antenna radiation pattern in the frequency range contains the antenna 1 under test, a recorder 2 (for example, a two-channel stroboscopic oscilloscope), a probe 3 mounted for movement in the near zone of the antenna under study 1, a reference antenna 4, a source of wide-band pulse signals 5, a block 6 collect and convert data, scan unit 7, processing unit 8. Registrar 2 is connected to the output of source synchronization 5.

The device works as follows.

The broadband pulsed signal is formed with the help of the source 5. The antenna under investigation 1 is irradiated with a broadband pulsed electromagnetic field with the help of the probe 3. With the aid of the scanning unit 7, install this probe with the coordinates (x, y) and orient the E- the plane of probe 3 is parallel to the x-axis of the scanning surface. At the output of the studied antenna 1, the temporal dependence of the amplitude of the pulsed signal S (t) corresponding to a given point (x, y) of the scanning surface is recorded with the aid of the recorder 2. During registration, a fixed fixation of the mutual temporal position of the temporal dependences of the amplitudes of the pulse signal S (T) at the output of the antenna being extended and the reference signal — HJ la S ° (t), which is a radiated broadband pulse signal.

, A, 1

For this, the signal S, (t) from the output of the investigated antenna 1 is fed to the first input of the recorder 2, and the reference signal S (t) of the reference antenna 4 to its second input. In this case, the recorder 2 is synchronized with both inputs by a single clock pulse arriving at the recorder 2 synchronization input from source 5. This ensures a rigid temporary fixation of the time dependences of the amplitudes of these signals at the registrar 2 outputs regardless of the arrival of the synchronization pulses.

Then, using the processing unit 8, transforms the time dependence of the amplitude of the pulse signal at the output of the antenna 1 under investigation into the frequency domain using the Fourier transform. In this case, the instability of the temporal position of this time dependence is compensated.

For this, the signals are digitized using. A unit 6 for collecting and converting data. Then, in one particular case, it is determined. the initial time position of the time dependence of the amplitude of the reference signal and use it as a reference point of the time dependence of the amplitude of the pulse signal at the output of the antenna under study. To do this, for example, programmatically determine the position t of the front of the time dependence of the amplitude of the reference signal S Ct) (Fig. 2)

H - 2 /

where S (t ;,) К S (t;), t., t ;,; i-th and (i + 1) are the points in time at which the signal S (t) is converted into digital form; K - specified threshold level

(Fig. 2).

After that, the Fourier transform of S (t) signals is performed:

ic + T

A.I. ju (i-te)

- A.lr A. JQlt-te

S ,. (W) J S (t) l dt

L; A, 1

where S, n (ti) are the spectral components of the signal S, u (t) on the recorder 2, In this case, the mutual temporal position of the time dependences of the signal amplitudes at the output of the antenna under study and the reference signal is fixed. Then convert the time dependence of the amplitude of the pulse signal (t) at the output of the antenna I under study to

the course of the antenna 1 under study in the frequency range when the E-plane of probe 3 is oriented parallel to the X axis of the scanning surface; t is the position of the front of the time dependence of the amplitude of the reference-signal frequency domain to determine

spectral component of S (c). In this case, the instability of the temporary position is compensated in the same way as for the initial position of the probe 3.

Next, the probe 3 is moved using the scan unit 7 to the next

T is the implementation interval of the specified point of the scanning surface with x + their coordinates, y & y,

la), which is the origin on the time axis, determined by the mutual temporal position of the time dependences S, (t),

s Ct);

the implementation interval of the Fourier integral, determined by the recorder 2; In this case, the mutual temporal position of the time dependences of the amplitudes of the signal at the output of the antenna under study and the reference signal is fixed. Then convert the time dependence of the amplitude of the pulse signal (t) at the output of the antenna I under study to

frequency domain to determine

legible by a given step

2TG UQ - on the frequency

axes, as well as the need to eliminate the influence of parasitic reflections caused by objects in the measurement zone. Another particular case after the Signals are digitized 30 spectral components S h (oJ)

simultaneously with the temporal dependence of the amplitude of the pulse signal at the output of the antenna being studied, the temporal dependence j of the amplitude of the reference signal is transformed into the frequency domain and multiplied at each frequency the spectral components of the signal at the output of the antenna with the complex-matched components of the reference signal

d h I - / kch

S m (o) in x, y coordinates:

H

 +

 with t

Sc)

If

.n

Sv (C0) 1

if (

a azimuthal and elevation angle radiation patterns FU (p, tf), F (J (| 5, Cf) for each frequency are in the form

(p, () - - c08 5 Pj; Vc08i

§;:; () (p, () - - c08 5 Pj; Vc08i5ei

r t ,, -icoi -irr t -I. tgs L. f -. Г- (t) l S (t) .dtj,) + sin (58inCf92 co8 / ieinCf,

45-1

as a result of multiplication, the spectral components of the signal (sd) at the output of the antenna 1 under study are determined in the frequency range when the E-plane of the probe 3 is oriented parallel to the X-axis of the scanning surface.

After that, using the scanning unit 7, the probe 3 is rotated so that its E-plane is parallel to the axis at the scanning surface, and the time dependence of the amplitude of the pulsed signal S, | u (t) corresponding to a given point of the surface of the scans, is recorded;

F. Sin

4 (coep ei

50

sin

fi),

where the azimuth (f is located from the axis in the ZX plane, and the elevation angle | S from 55 is from the zx plane of the Cartesian coordinate system x, y, z, whose xn axis coincides with the x and y axes of the previously introduced coordinate system; .

20 and, similarly to this, the spectral components D,. (БЗ), хЛх, ч4 & h in the frequency range For this point. At the end of the tour, the entire scanning surface Q is determined

25, the radiation pattern of the antenna 1 at the required frequencies using the processing unit 8. For this, a spatial Fourier transform is performed at each desired frequency.

30 spectral components S h (oJ)

d h I - / kch

S m (o) in x, y coordinates:

H

 +

 with t

Sc)

If

.n

Sv (C0) 1

if (,)

dxdy

n-1,2

The azimuthal and elevation components of the radiation pattern FU (p, tf), F (J (| 5, Cf) for each frequency value are found by the formulas

(p, () - - c08 5 Pj; Vc08i5einif

 with -I. tgs L. f -. ,) + sin (58inCf92 co8 / ieinCf,

-one

infi);

sin

4 (coep ein (f

50

sin

fi),

where is the azimuth (f is from the t axis in the ZX plane, and the elevation angle | S is from the zx plane of the Cartesian coordinate system x, y, z, whose xnu axis coincides with the x axis, y axis of the previously entered coordinate system; c is the speed Sveta.

Claims (1)

Invention Formula The method of determining the antenna pattern in the frequency range, which consists in forming a pulsed electromagnetic field in opening the antenna under investigation, registers the time dependences of the field amplitudes relative to the selected spatial points of the near zone of the antenna being investigated relative to the time position of the reference signal, and converts them into frequency band (i) io.4afw ofTjcf efrfa ti fpu, 2 VNUTI Order 3872/44 Production polygr, pr-tie, Uzhgorod, st. Project, 4 power through spatial Fourier transform, and the antenna pattern of the antenna under investigation is determined at the required frequencies, characterized in that, in order to improve the accuracy, the pulsed electromagnetic field in the undercut of the antenna being studied is formed by a wideband antenna, while the irradiated antenna is being irradiated with a broadband pulse signal that is used as reference. Supporting Circulation 772 Subscription