SU1697019A1 - Method of measuring characteristics of antenna - Google Patents

Abstract

The invention relates to the technique of antenna measurements and can be used to measure the characteristics of antenna systems during their setup and testing. The purpose of the invention is to improve the measurement accuracy. The invention is implemented as follows. In the direction of the probe, a microwave signal is emitted by an emitter located at a distance not less than twice the distance from the antenna under study to the probe from the antenna under study. This signal is received by the auxiliary antenna, installed together with the probe, modulate the phase of the received signal from the 5 5 disk, feed it to the probe input, determine the amplitude and phase of the signal received by the antenna using the formulas: А А02 + А п2 - ПСО3 (Fo -Fp); Acjtsin (Фр) - А sin (Oi) ф Arctg A0 «cos (Ф0) - Atvcos (Fo) -KLo. where AO, Fo are the measured amplitudes and phases of the signal received by the antenna, with phase modulation at 0: A, Fn are the measured amplitudes and phases of the signal received by the antenna, at phase modulation by n; L0 is the optical path length of the beam from the radiator to the antenna being installed through the auxiliary antenna and the unperturbed probe; K is the phase coefficient. Emitter 3, controlled discrete phase shifter 5, auxiliary antenna 4 are additionally introduced into the device for realization of the method. Improvement of accuracy is provided by compensating for the change in position of the measuring probe due to external influences during the measurement process. 1 il. Os yu XS Oh yu

Description

The invention relates to the technique of antenna measurements and can be used to measure the characteristics of antenna systems during their tuning and testing.

The aim of the invention is to improve the accuracy.

The drawing shows an electrical block diagram of a device implementing a method for measuring the characteristics of an antenna.

The device includes a computational unit 1, a generator 2 connected in series, and a power divider 3, the first output of which is connected to the reference input of the amplification meter 4, the measurement input of which is connected to the output of the antenna 5 under study, the output of the amplification display 4 is connected to the input of the computing computational unit 1, the probe b, the emitter 7, whose input is connected to the second output of the power divider 3, the controlled discrete phase shifter 8, the output of which is connected to the probe 6, and the control input to the first output of the computational unit 1, auxiliary antenna 9, the output of which is connected to the input of the controlled discrete phase shifter 8, while the radiator 7 is mounted on the first rotary support unit 10 at a distance not less than twice the distance from the antenna under study 5 to the probe 6, and the auxiliary antenna is mounted on the second turntable unit 11, installed together with the probe 6, and the control inputs of the first and second turntable blocks 10 and 11 are connected to the second and third inputs of the computational block 1, respectively.

The device works as follows.

Let the coordinates of the probe in the unperturbed position (O, O, p), the phase center of the antenna under study (d, 0, 0), and the phase center of the radiator (d, 0, 0). If, due to external influences, the probe moves in space relative to the initial position to a point with coordinates (x, y), then V z h. where h is the height of the tower; d is the distance from the tower to the antenna under study and the distance from the tower to the radiator.

Optical path length of the beam from the probe to the antenna under study

-

Os

with unperturbed probe position

D3fb2dx7c o

with the disturbed position of the probe.

The change in the optical path length of the beam from the probe to the antenna under study due to probe perturbation

Ai - Di - D2 Do (Vl 2dx / D2o 1)

At x 0.2 m d 50 m h 20m, a change in the optical path length of the beam AI 185 mm is obtained.

In the proposed method, the beam travels the path of the radiator — the probe — the antenna under investigation. The variation of the optical path length of the beam due to the instability of the probe position for this case is evaluated.

Optical path length of the beam from the probe to the antenna under study with the unperturbed position of the probe 2D0, and with the disturbed position of the probe

Di + D2,

where D2rr5fid ± il2 + U2 + 2 V + h2 + 2dx DoYTb dxTCTo is the optical path length of the beam from the probe to the radiator due to probe disturbance.

The change in the optical path length of the beam from the probe to the antenna under investigation due to probe disturbance AI D2 + Dt - 2D0 is decomposed in a power series q 2dx / D02: At D0 (q2 / 4 +

+ 0 (q), At x 0.2 m; d 50m; h 20m get the change in the optical path length of the beam Ar 6 mm.

Thus, for the particular case considered, a reduction in phase errors is obtained by a factor of 30.

In order to distinguish the useful signal of the probe from the signal of the radiator and from external interferences that reach the aperture of the antenna under study, modulate the phase of the received auxiliary antenna signal with discrete n before applying it to the input of the probe.

In order to ensure equality of the path length of the beam in the method of scanning the probe over the aperture of the antenna under study, during processing, the change in the path length of the beam is taken into account.

40

45

50

In accordance with the above, after simple transformations, formulas are obtained for determining the amplitude and phase of the signal received by the antenna under study, in the form of

Di | (d-x) 2+ y2 f- z 2

-Yrf

+ h2-2dx A CE7 + Ai2 - 2 AO Ai cos (Oo-Ol);

0 Arctg Ao sin Ф0 -Aisln jgi

AO cos F0 - AI cos F1

-Kl Claims The method of measuring the characteristics of an dark-blue, including the emission of electromagnetic waves by the probe in the direction of the antenna under study, the reception of the radiated signal of the antenna under study, the measurement of its amplitude and phase, and the determination of the characteristics of the antenna according to the results of measurements differing from. what, with a purpose. increase the accuracy, in the direction of the probe emit electromagnetic waves by the emitter, receive it additional antenna installed together with the probe, and modulate on the phase with a 180 ° discrete, then fed to the input of the probe, the emitter and the antenna under study are placed on opposite sides of the probe, and the amplitude A and phase F are determined by the ratios

And 4 | Ao2 + Ai2 -2 JSC Ai cos (Ф0-Ф1):

F arctg

Ap sin (Ф0) - AI sin (Ф1) JSC cos (Ф0) - AI cos (Фт)

-Ku,

where AO, Fo; AI Ft is the amplitude and phase of the signal at the output of the antenna under investigation, respectively, when the phase at the output of the additional antenna is modulated to 0 and 180 °; Z is the path length from the radiator to the antenna under study through the additional antenna and

probe in the unperturbed position of the last; To p where D is the wavelength.

Claims (1)

Claim A method of measuring the characteristics of an antenna, including emitting an electromagnetic wave probe in the direction of the antenna under investigation, receiving the emitted signal from the antenna under investigation, measuring its amplitude and phase and determining the characteristics of the antenna from the measurement results, characterized in that, in order to improve accuracy, electromagnetic waves are emitted in the direction of the probe emitter, take it with an additional antenna installed together with the probe, and modulate in phase with a discrete of 180 °, then fed to the input of the probe, and the emitter and Followed antenna placed on different sides of the probe, and the amplitude A and phase P determined by relations 5 _g —__; ___, A = A (Ao ² + A1 ² - 2 Ao Ai cos (Oo-Oi): f = _Arcm ) .. 7 ^ 1 ^{s, n} №).,. ⁹ Ao COS (Fo) - Ai cos (Φι) - To Lo, where Ao ', Fo: Ai Φι is the amplitude and phase of the signal at the output of the studied antenna, respectively, when the phase at the output of the additional antenna is modulated by 0 and 180 °, 1_o the path length from the emitter to the studied antenna through the additional antenna and 20 probe with an unperturbed position of 9 to ** last; K = where Δ ^ is the wavelength.