SU1737361A1 - Device for measuring parameters of signal reflected from input of microwave component - Google Patents

Abstract

The invention relates to microwave measurement technology and can be used to monitor antenna parameters during transmitter operation. The purpose of the invention is to increase the sensitivity. The device contains a microstrip measuring line with sensors, the substrate of which is made of electrical material, a microwave generator connected to the input of the measuring line, each of the sensors contains an optically coupled collimating lens system, the input of which is the sensor input, a phase cell and a photodetector, the output of which is a sensor output, and the input of each sensor is optically coupled to the laser via a light divider, the measuring line is made in three sections, the first and second sections of the line are Electro-optic material with a linear electro-optic effect, and a third section is quadratic, each section being a phase cell of a corresponding sensor number, the cross section of the section perpendicular to the optical axis of the sensor, and the electrical lengths of the sections at the microwave signal frequency are respectively 90, 180 and more than 360 el. grad., a polarizer is inserted into each of the sensors between the collimating lens system and the phase cell, and a light analyzer between the photodetector and the phase cell, and the polarization planes of the light analyzer and polarizer are mutually perpendicular, the output of the first sensor through the amplifier is connected to the first the inputs of the first adder and the first voltage divider, the output of the second sensor through the amplifier is connected with the second inputs of the first adder and the first voltage divider, the output of the first adder is connected to the inverting input The output of the third sensor is connected to the second input of the second adder, the second input of the second voltage divider is connected to the output of the second adder, the phase indicator is connected to the output of the first voltage divider, the output of the second voltage divider voltages - reflectance modulus indicator. 2 Il. (L С vi с XI 00 о

Description

This invention relates to microwave measurement technology and can be used to monitor antenna parameters in

the transmitter operation, as well as for measuring the modulus and phase of the reflection coefficient and the standing wave ratio in the path.

The purpose of the invention is to increase the sensitivity.

FIG. 1 shows a block diagram of a device for measuring parameters of a signal reflected from an input of a microwave element; in fig. 2 shows an example of construction of a measuring line.

The device contains a coherent light source 1, a light divider 2, the first, second and third sensors 3-5, measuring line 6, microwave generator 7, the microwave element 8 under study, amplifiers 9-11, first and second dividers 12, 13 , the first and second adders 14, 15, the phase indicator 16 and the reflectance modulus indicator 17. Each sensor includes a collimating lens system 18, the input of which is the sensor input, a polarizer 19, a phase cell 20, an analyzer 21, and a photo detector 22.

The microwave generator 7 through the measuring line 6, along which sensors 3-5 are located, is connected to the input of the element under study 8. The source of coherent light 1 through the light divider 2 is optically connected to the input of each of the sensors 3-5. In each sensor, a system of collimating lenses 18 is optically coupled to a photodetector 22, an analyzer 21, a phase cell 20, and a polarizer 19. The outputs of the sensors 3.4 are connected electrically through the amplifiers 10 and 11 to the first adder 14 and the first divider 12. The output of the third sensor 5 through amplifier 9 is connected to the second adder 15, the second input of which is connected to the output of the first adder 14. The outputs of the adders 14, 15 are connected to the inputs of the second divider 12, and the outputs of the dividers 12 and 13 are connected respectively to the phase indicators 16 and 17 reflection coefficient modules.

The light divider 2 is designed to divide the light beam into three beams of equal intensity. A system consisting of a polarizer 19, a phase cell 20 and an analyzer 21 serves to produce at the output of the photodetector 22 a signal proportional to the effective voltage across the electrodes of the phase cell 20. The purpose of the other elements of the device is clear from FIG. one.

A device for measuring the parameters of the signal reflected from the input of the microwave element works as follows. After switching on the microwave generator 7, due to the partial reflection from the microwave element 8 under study, in the sections of the measuring line 6, the mode of the shifted waves is established. The coherent light beam generated by laser 1 in light divider 2 is divided into three beams of equal intensity, which are fed to the optical inputs of each sensor. After passing through the system of collimating lenses 18 and the polarizer 19, the linearly polarized light beam enters the phase cell 20, which is the first section of the measuring line 6, the light of which propagates in a direction parallel to the direction of propagation of the microwave wave.

Since the dielectric substrates of sections 20 of the measuring line 6 are made of crystals having an electro-optical effect, after they pass as a result of interaction with the microwave signal, the eccentricity of the polarization ellipse in them will depend on the effective voltage along the crystal.

The analyzer 21 selects one of the orthogonal components of the polarization of the light, so that the signal at the output of the photodetectors 22 in the sensors 3, 4 will be proportional to ieff.

The electric length of the first section D $ 1 l / 2, therefore the signal from the output of the first sensor 3 will be proportional

r lyoPcOsV

Ui Ur

where p is the modulus and phase of the reflection coefficient (QD), respectively. The electric length of the second section is D0 l, so the signal from the output of the second sensor 4 will be proportional to

U2 U

2 161л12 п

sin

L U R

where Dm is the voltage amplitude in the measuring line section 6.

In the third sensor 5, the measuring section is made on a dielectric substrate having a quadratic electro-optical effect. In this case, the maximum possible value of

ieff and, (1 + I2)

and the signal from the output of the third sensor 5 will be equal to

u3 4g U, (1 - u2)

Amplifiers 11, 10 and 9 have coefficients

OSS

gain 1.4, and, respectively. On

Jt

The output of the first divider 12 generates a signal proportional to the square of the tangent of the phase angle of the reflection coefficient, which is fed to the indicator 16 of the phase of the reflectance, the scale of which is graduated in proportion to the square root of the tangent of the phase and

It displays the phase angle of the reflection coefficient p.

At the output of the first adder 14 od / signals is equal to Us Ui + 4U2, and

the signal at the output of the second adder 15 with one inverting input will be equal to

U

l 256 u3

-1H -4U2.

 l4Ah

These signals are fed to the inputs of the second divider 13, the signal from the output of which is equal to the square of the reflection coefficient module.

The signal from the output of the second divider 13 is supplied to the indicator 17, on which the value of the modulus of the reflection coefficient of the signal from the measured microwave element is displayed.

The consistent direction of propagation of the microwave signal in the sections of the measuring microstrip line and light rays in the dielectric of the measuring line many times in comparison with the prototype increases the length of the interaction of the light beam and the microwave signal in the crystal with an electro-optical effect. This leads to an increase in sensitivity, because even at low microwave power, the eccentricity of the ellipse of polarization of light due to the interaction of light with the signal when passing sections of the measuring line will be noticeable and the signal at the output of the sensors will be significant.

Claims (1)

Invention Formula A device for measuring parameters of a signal reflected from an input of a microwave element, containing a microstrip measuring line, equipped with sensors, the substrate of which is made of an electro-optical material, a microwave generator connected to the input of the measuring line, each of sensors containing optically coupled collimating lenses , the input of which is the input of the sensor, the phase cell formed by the electrodes and the dielectric of the measuring line located along the optical axis of the sensor, a polarizer and a photodetector whose output is the output of the sensor, and the input of each sensor is optically coupled to a laser through a light divider By the fact that, in order to increase the sensitivity, amplifiers, the number of which is equal to the number of sensors, two adders and two voltage dividers, a phase indicator and a reflectance modulus indicator, the output of the first the sensor through the corresponding amplifier is connected with the first inputs of the first adder and the first voltage divider, the output of the second sensor through the amplifier is connected with the second inputs of the first adder and the first voltage divider, the output of the first adder is connected to the inverting input of the second adder the output of the third sensor is connected through the amplifier to the second input of the second adder, the second input of the second voltage divider is connected to the output of the second adder, to the output of the first divider the voltage indicator is connected to the phase, and the output of the second voltage divider - the indicator of the reflection coefficient module, a second polarizer, the polarization plane of which is perpendicular to the polarization plane of the first polarizer, the cross section of the phase cell of the sensor is perpendicular to its optical axis, electrical lengths of the phase cells are entered into each of the sensors between the collimating lens system and the phase cell. first, second and third sensors at a frequency The microwave signals are respectively 90, 180 and more than 360 e. grad., and the dielectric phase cells of the first and second sensors has a linear electro-optical effect, and the third quadratic. nineteen t CsfD # -0f ////) y ///// sfa 20ot generator B P nineteen I sbetf light 2 ,20 J nineteen ///// sfa