RU2510035C1 - Device to measure total resistance and noise parameters of microwave dipole - Google Patents

Abstract

FIELD: electricity.

SUBSTANCE: device to measure total resistance and noise parameters of a microwave dipole, comprising a meter of frequency characteristics and an integrated circuit within a central transmission line, a section of a transmission line connected to the central transmission line, electric switches - semiconductor instruments, controlled by DC voltages, the meter of frequency characteristics is connected with one end of the central transmission line, its other end - to the measured dipole. Where the meter of frequency characteristics is a meter of spectral density of noise capacity, the integrated circuit is made in the form of a monolithic integrated circuit on a semiconductor substrate, at the same time the section of the transmission line is made equal to one eighth of the wave length in the transmission line, electric switches are field transistors with Schottky barrier and at least in the form of one pair, at the same time in each specified pair the source of one field transistor with Schottky barrier is connected with the central line of transmission at the distance of one eighth of wavelength in the transmission line from the point of connection of the measured dipole and between its pairs, its drain with one end of the transmission line section, the other end of which is connected with the drain of the other field transistor with Schottky barrier, its drain is grounded, DC control voltages are supplied to gates of every field transistor with Schottky barrier from the appropriate source of DC control voltage.

EFFECT: expansion of working frequency band, increased accuracy of measurement by reduced error of measurement and simplified device with preservation of automation capability.

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Description

The invention relates to measuring equipment, namely, devices for measuring the impedance and noise parameters of a two-terminal microwave, and can be used in microwave electronic equipment.

Effective design of microwave electronic products is based on knowledge of the dependence on the frequency of the impedance of the two-terminal microwave, which is determined experimentally with subsequent mathematical processing of the measurement data.

A device is known for measuring the impedance of a two-terminal network, comprising a microwave signal generator and a coaxial circuit containing a measuring transmission line connected between the microwave generator and the measured two-terminal network. At a frequency f, using a measuring transmission line, two characteristics are measured: the module Г (f) and the phase Ф (f) of the reflection coefficient, and the total (complex) resistance of the two-terminal network Z (f), equal to the sum of the active R (f) and reactive jX (f ) components calculated according to well-known mathematical formulas [1].

This device is different:

increased error, due to the need to measure two frequency characteristics: module Г (f) and phase Ф (f), each of which is measured with a certain error, respectively, the resulting error is multiplied,

the complexity of the automation of the measurement process due to the use of a coaxial measuring transmission line.

A device for measuring the impedance of a two-terminal network is provided, comprising a microwave signal generator, transmitting coefficient module and reflection coefficient module, and an integrated circuit consisting of a central transmission line, a segment of a transmission line connected to the central conductor using electrical keys, pin diodes, and the second segment of the transmission line, galvanically connected to the transmission line, while the measured two-terminal is included at the end of the second segment of the transmission line [2].

At a frequency f in the working frequency band, the values of the reflection coefficient modulus G (f) and the transmission coefficient modulus T (f) are measured, and then the value Z (f) is calculated using mathematical formulas.

At the same time, the segment of the transmission line included in the integrated circuit using an electric key (pin diode) ensures unambiguity in determining the sign of the reactive component of the impedance X (f).

Compared with the previous one, this device provides the ability to automate the measurement process and is relatively easy.

The disadvantage of this device, as well as the previous one, is the increased error also due to the need to measure two frequency characteristics: the reflection coefficient module G (f) and the transmission coefficient module T (f), for which two types of meters are used: a reflection coefficient module measurer and gear ratio module meter.

In addition, the presence in this device of a significant heterogeneity, namely a T-shaped connection of the central transmission line and the second segment of the transmission line, also leads to an increase in the measurement error of the impedance of the two-terminal on microwave.

A device for determining the impedance of a two-terminal on a microwave, containing a microwave signal generator, a meter of the coefficient of reflection coefficient and an integrated circuit consisting of a Central conductor (central transmission line), a segment of a transmission line connected to the Central conductor using a pin diode, and a second segment transmission lines of length l, while the meter of the coefficient of reflection coefficient and the generator of the microwave signal are located at one end of the central conductor.

This device, in order to significantly simplify the measurement process, additionally contains a second pin diode, with the help of which the second line segment is connected to the central conductor in a place separated from the first segment, and the measured two-terminal device is connected at the end opposite from the microwave signal generator [3] - prototype .

This device in comparison with the previous analogue provides a reduction in the measurement error of the impedance of a two-terminal on microwave due to the exception:

a) one of the meters - meter module transmission coefficient,

b) a T-shaped connection of the Central transmission line and the second segment of the transmission line.

The disadvantage of this device is:

firstly, low measurement accuracy due to use:

a) a meter of the coefficient of reflection coefficient having a relatively low accuracy of measuring the frequency response,

b) as electrical keys, as in the previous analogue, of concentrated semiconductor devices - pin diodes,

secondly, a narrow working frequency band due to the presence of resonant frequencies due to the presence of the distance between the segments of the transmission lines,

thirdly, the complexity of the device due to the use of pin diodes, the control voltage of which is supplied through the power filters.

The technical result of the claimed device for measuring the impedance and noise parameters of a two-terminal on a microwave is to expand the working frequency band, increase the measurement accuracy by reducing the measurement error and simplify the device while maintaining automation capabilities.

The specified technical result is achieved in a device for measuring the impedance and noise parameters of a two-terminal microwave, containing a frequency response meter and an integrated circuit consisting of a central transmission line, a segment of a transmission line connected to a central transmission line, electrical keys - semiconductor devices controlled by constant voltage, the frequency response meter is connected to one end of the central transmission line, its other end to the measured two-terminal network, asno invention wherein

- as a meter of frequency characteristics using a meter of spectral density of noise power,

- the integrated circuit is made in the form of a monolithic integrated circuit on a semiconductor substrate, while the length of the transmission line is made equal to one eighth of the wavelength in the transmission line,

- as electric keys, field-effect transistors with a Schottky barrier are used and functionally in at least one pair,

wherein

in each pair mentioned, the source of one Schottky field-effect transistor is connected to the central transmission line at a distance of one eighth of the wavelength in the transmission line from the junction of the measured two-terminal network and between the pairs, its drain with one end of the transmission line segment, the other end of which is connected to the drain another field-effect transistor with a Schottky barrier, its source is grounded, constant control voltages are applied to the gates of each field-effect transistor with a Schottky barrier from a corresponding source of constant th control voltage.

Disclosure of the invention

The set of essential features of the claimed device for measuring the impedance and noise parameters of a two-terminal microwave, including another connection of the elements of the device, will provide, namely:

the use as a meter of the frequency characteristics of a spectral density meter of noise power will provide:

firstly, the simplification of both the device and the measurement process and, as a result, improving the measurement accuracy by reducing the measurement error due to the use of:

a) the properties of a two-terminal microwave to generate its own noise signal and thereby the possibility of excluding a noise generator from the device,

b) only one meter of frequency characteristics - a spectral noise power spectral density meter, which is used as a standard microwave measuring receiver (type P5-9, P5-16, etc.).

The implementation of the integrated circuit in the form of a monolithic integrated circuit on a semiconductor substrate, which is significantly smaller than the integrated circuit, as well as the execution of a segment of the transmission line equal to one eighth of the wavelength in the transmission line will provide an extension of the working frequency band.

Moreover, the latter (the execution of a segment of the transmission line equal to one eighth of the wavelength in the transmission line) will provide an increase in the interval between resonant frequencies and, as a result, in addition to the aforementioned decrease in the measurement error and, consequently, increase the measurement accuracy.

Using field-effect transistors with a Schottky barrier as electrical keys will provide:

a) an increase in the number of possible state variants of a monolithic integrated circuit, and

b) the possibility of applying statistical methods for processing measurement results and, as a result, in addition to the above-mentioned increase in measurement accuracy.

Moreover, the number of possible state variants of a monolithic integrated circuit increases with the number of each pair of field-effect transistors with a Schottky barrier.

The invention is illustrated by drawings.

Figure 1 shows the topology of the claimed device for measuring the impedance and noise parameters of a two-terminal microwave, where

- a meter of frequency characteristics - 1, in the form of a spectral density meter of noise power,

- monolithic integrated circuit - 2 consisting of:

central transmission line - 3,

segment of the transmission line - 4,

electrical keys - two field-effect transistors with a Schottky barrier - 5, 6, respectively,

- measured bipolar - 7,

- two sources of constant control voltage - 8, 9, respectively.

Figure 2 is given its equivalent circuit.

Figure 3 shows the measured dependence on the frequency of the spectral density of noise power (SPMSh) of the measured two-terminal with a monolithic integrated circuit in the working frequency band from 1 GHz to 18 GHz.

Figure 4 shows the calculated dependences on the frequency of the active and reactive components of the impedance and the spectral density of the noise power (noise parameters) of the measured two-terminal microwave.

Concrete example

The claimed device for measuring the impedance and noise parameters of a two-terminal microwave oven contains:

frequency response meter 1 in the form of a noise power spectral density meter, type P5-9,

a monolithic integrated circuit 2, made on a gallium arsenide substrate, comprising: a central transmission line 3 of a width of 0.08 mm, a segment of a transmission line 4 of the same width and a length of 1 mm, which corresponds to one eighth wavelength in a line transmission, electric keys - two field-effect transistors with a Schottky barrier 5, 6, respectively,

measured two-terminal 7 - avalanche-span diode (LPD),

two sources of constant control voltage 8, 9, respectively, type HP 4142.

Wherein

- the frequency response meter 1 is connected to one end of the central transmission line 3, and its other end to the measured two-terminal network (LPD) 7;

- a segment of the transmission line 4 is connected to the Central transmission line;

- the source of one field-effect transistor with a Schottky barrier 5 is connected to the central transmission line 3, its drain is at one end of a section of transmission line 4, the drain of another field-effect transistor with a Schottky barrier 6 is connected to the other end of segment of transmission line 4, its source is grounded, constant control voltage served on the gates of each field effect transistor with a Schottky barrier 5, 6 from the corresponding source of constant control voltage 8, 9.

The claimed device for measuring the impedance and noise parameters and a two-terminal microwave operating as follows.

In the microwave range, the measured two-terminal 7 generates its own noise signal when power is applied.

The noise power spectral density (SPMSh) is measured by a frequency response meter 1 (spectral noise power spectral density meter, type P5-9).

The measured spectral density of noise power in the absence of self-oscillations in the system is determined by the expression [4]:

$$R_{w\mathrm{to}}=S_0\left(f\right)/{|\; |\; |Z\left(f\right)\times \left(C_{\mathrm{to}}{R}_n+D_{\mathrm{to}}\right)+{\mathrm{BUT}}_{\mathrm{to}}{R}_n+{\mathrm{AT}}_{\mathrm{to}}|\; |\; |}^2\left(\mathrm{one}\right)$$

where f is the operating frequency;

Z (f) = R (f) + j × X (f) - impedance of the measured two-terminal microwave 7;

R _n - load resistance, usually R _n is equal to 50 Ohms;

S ₀ (f) is the spectral density of the noise power is the noise parameter of the microwave 2-terminal proper;

A _k , B _k , C _k , D _k - elements of the transmission matrix of a monolithic integrated circuit 2 containing electric keys - semiconductor devices controlled by constant voltage - field effect transistors with a Schottky barrier 5, 6 from the corresponding sources 8, 9.

At a frequency f, the SPSH is measured for three combinations of the values of the control constant voltage of the parameter (k = 1, 2, 3).

The obtained values of SPMSh are substituted into equations (1) and a system of three equations with unknown R, X and S _{0 is} obtained.

First, S _{0 is} excluded from this system and a system of two equations is solved:

| (R + jX) (C ₁ R ₁ + D ₁ ) + A ₁ R ₁ + B ₁ | = | (R + jX) (C ₂ R _n + D ₂ ) + A ₂ R _n + B ₂ |,

| (R + jX) (C ₁ R ₁ + D ₁ ) + A ₂ R ₁ + B ₁ | = | (R + jX) (C ₃ R _n + D ₃ ) + A ₃ R _n + B ₃ |.

The obtained values of R (f) and X (f) are substituted into equation (1) and S ₀ (f) is determined.

The data of measurements and calculations are presented in figure 3 and 4.

As can be seen from figure 3 and 4, the claimed device extends the operating frequency band from 8 GHz to 16 GHz, reduces the measurement error by 1.5 times and, accordingly, increases the accuracy of measurements by 1.5 times.

Thus, the claimed device for measuring the impedance and noise parameters of a two-terminal microwave, in comparison with the prototype, will provide an extension of the working frequency band by 2 times, increased measurement accuracy by 1.5 times, simplification of the device while maintaining automation capabilities.

Information sources

1. Measurements on the microwave. / Translation Ed. VB Shteynshleyger / M .: Owls. radio. - 1952, - p. 87.

2. RF patent No. 2088946, IPC G01R 27/04, priority July 24, 1992, publ. August 27, 1997

3. RF patent №2210082, IPC G01R 27/04, priority 09.08.2001, published 09.08.03.

4. Balyko A.K., Melnikov A.I., Tager A.S. Method for measuring the impedance and noise characteristics of microwave diodes // Electronic Engineering. Ser. 1, Microwave Electronics. 1979, issue 11, pp. 93-94.

Claims (1)

A device for measuring the impedance and noise parameters of a two-terminal on a microwave, containing a frequency characteristics meter and an integrated circuit consisting of a central transmission line, a segment of a transmission line connected to the central transmission line, electrical keys - semiconductor devices controlled by constant voltage, the frequency characteristics meter is connected to one end of the central transmission line, its other end - with a measured two-terminal network, characterized in that as a frequency meter They use a noise power spectral density density meter, the integrated circuit is made as a monolithic integrated circuit on a semiconductor substrate, while the length of the transmission line is equal to one eighth of the wavelength in the transmission line, field-effect transistors with a Schottky barrier and at least at least in the form of one pair, while in each mentioned pair the source of one field-effect transistor with a Schottky barrier is connected to the central transmission line at a distance of one eighth for there are other waves in the transmission line from the junction of the measured two-terminal network and between the pairs, its drain with one end of a segment of the transmission line, the other end of which is connected to the drain of another field-effect transistor with a Schottky barrier, its source is grounded, constant control voltages are applied to the gates of each field-effect transistor with Schottky barrier from the corresponding source of constant control voltage.

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