RU2367066C1 - Microwave phase changer - Google Patents

Abstract

FIELD: physics; conductors.

SUBSTANCE: invention relates to electronic engineering and more specifically to microwave phase changers on semiconductor devices. A microwave phase changer is proposed, which has two transmission lines with the same characteristic impedance, one meant for microwave signal input, and the other for output, a Schottky-barrier field-effect transistor, two bipolar reactive elements with different or same value. The drain of the Schottky-barrier field-effect transistor is connected to one end of one of the bipolar reactive elements, and the other end to the transmission line at the output. The source of the Schottky-barrier field-effect transistor is earthed, and direct control voltage is applied across its gate. The microwave phase changer additionally contains two transmission line sections, the first with length equal to or less than half the wavelength, and the second, with length equal to quarter wavelength. The said wavelength corresponds to the medium frequency of the operating frequency band.

EFFECT: wider operation frequency band, reduced direct losses, simplification of design and weight and size characteristics of the microwave phase changer.

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Description

The invention relates to electronic equipment, namely to microwave phase shifters on semiconductor devices.

In the microwave technique, various types of microwave phase shifters are widely used: phase manipulators with 180 ° phase change, with a controlled phase angle, multi-bit with discrete phase change, which are a cascade connection of at least two discharges, and switching elements in each discharge carry out electronic keys, which are used as semiconductor devices.

One of the main characteristics of the microwave phase shifter along with the magnitude of the phase change of the microwave signal is the width of the working frequency band.

Known broadband phase shifter at 180 ° A.A. Mikhoparkina, based on a three-circuit parametric converter on diodes with low-frequency pumping [1].

One of the disadvantages of this phase shifter is the restriction on the magnitude of the phase change, which is only 180 °.

Known broadband phase shifter with a controlled phase angle, containing a broadband differential quadrature filter, two proportional links with an adjustable transmission coefficient and an adder. In this case, one of the outputs of the quadrature filter is connected to the input of the first, and the other to the input of the second, providing a corresponding change in the amplitude of the quadrature components of the signal, proportional to the links whose outputs are connected to the inputs of the adder [2].

One of the disadvantages of this phase shifter is the design complexity due to the presence in it, first of all, of two quadrature bridges on PiN diodes.

Known strip phase shifter containing a strip conductor made in the shape of a meander and enclosed between two dielectric boards, on the outer sides of which are wide strips galvanically connected by jumpers, the first pair of switching diodes connected at the input and output ends between the meander and one of the wide strips, a second pair of diodes connected at the input and output ends of one of the wide strips and a screen, a fifth diode and an absorption resistor connected in series, including nye between meander and a wide strips at a distance of a quarter of a parasitic resonance of short wavelength from one end of the meander, the nominal resistance of the absorbing resistor is equal to half the wave resistance feeders [3].

This phase shifter in comparison with the previous ones allows you to get an arbitrary value of the phase difference of the signal and somewhat expand the working frequency band due to the use of strip conductors.

One of the disadvantages of this phase shifter is its high direct losses due to the presence of absorbing resistors in it.

Moreover, this microwave phase shifter, like the previous ones, has significant limitations on broadband due to the presence of several diodes and several conductors, which create resonant circuits with diode capacitances, and also because of the relatively low coefficient of overlap in the diode capacitance.

In addition, since diodes are bipolar semiconductor devices, it is necessary to use power filters to decouple them by microwave and constant control voltage, which complicates the design and increases the overall dimensions.

Known microwave phase shifter, in which, in particular, in order to simplify the design and reduce weight and size characteristics, three-pole semiconductor devices are used. This microwave phase shifter contains two transmission lines with the same wave impedances, one for inputting a microwave signal, the other for output, two field effect transistors with a Schottky barrier, inductors of the same magnitude and capacitance of either different or the same magnitude. In this case, the source of the first field-effect transistor with a Schottky barrier is connected to the transmission line at the input and to one of the ends of the first inductance, and the drain through the first capacitance is connected to the transmission line at the output and to one of the ends of the second inductance, the drain of the second field-effect transistor to the Schottky barrier is connected with the other ends of both inductances and with one of the ends of the second capacitance, and the source and the other end of the second capacitance are grounded, the gates of field-effect transistors with a Schottky barrier are interconnected and connected to one source of constant voltage ulation voltage [4 - prototype].

The presence of bipolar reactive elements in this microwave phase shifter in the form of capacitors and inductances of the same or different size, connected either according to the scheme of a non-resonant low-pass filter or according to the scheme of a non-resonant high-pass filter depending on the switching of field-effect transistors with a Schottky barrier, made it possible to slightly expand the working band frequencies and reduce direct losses.

In addition, the need to use power filters is eliminated, since field-effect transistors with a Schottky barrier are three-pole semiconductor devices and, therefore, have internal isolation by microwave and constant control voltage, and thus simplified the design and reduced the overall dimensions of the microwave phase shifter.

However, the presence in this phase shifter of microwave external reactive elements in the form of inductance, which, together with the internal reactive elements in the form of a capacitance of two field-effect transistors with a Schottky barrier, form resonant circuits, which does not significantly increase the width of the working frequency band.

The technical result of the invention is the expansion of the working frequency band, reducing direct losses, simplifying the design and reducing the weight and size characteristics of the microwave phase shifter.

The specified technical result is achieved by the proposed microwave phase shifter, containing two transmission lines with the same wave impedances, one for the input of the microwave signal, the other for the output, the field effect transistor with a Schottky barrier, two bipolar reactive elements of either different or the same size, while the field drain a Schottky barrier transistor is connected to one of the ends of one of the bipolar reactive elements, and its other end is connected to the output transmission line, the source of the field-effect transistor with a Schottky barrier is grounded, and a constant control voltage is applied to its gate, into which two segments of the transmission line are additionally introduced, the first of which is equal to half the wavelength and less, and the second is equal to one fourth of the wavelength, while one end of the first segment of the transmission line is connected to the line transmission at the input and with one of the ends of the first bipolar reactive element, and its second end with one of the ends of the second bipolar reactive element and with the transmission line at the output, one end of the second segment of the transmission line is connected to another the end of the first bipolar reactive element, and its second end - with the other end of the second bipolar reactive element, while the drain of the field-effect transistor with a Schottky barrier is connected to either one or the other end of the second segment of the transmission line, while the specified wavelength corresponds to the average frequency working frequency band.

In the microwave phase shifter, the first and second reactive elements are made in the form of capacitance or inductance.

In the microwave phase shifter, the values of the reactive elements in the form of capacitance or inductance are selected based on the required phase shift of the microwave signal in accordance with the formulas:

C1 = (1 + sin Ф) / (Z0 π f0 cos Ф),

C2 = cos Ф / [(1 + sin Ф) Z0 π f0],

L1 = (1 + sin Ф) Z0 / (4 π f0 cos Ф),

L2 = Z0 cos Ф / [4 π f0 (1 + sin Ф)], where

C1 and C2 - tanks respectively of the first and second reactive elements in the form of tanks,

L1 and L2 - inductance, respectively, of the first and second reactive elements in the form of inductance,

Z0 - wave impedance of the transmission line at the input,

f0 is the central band of the working frequency range,

Ф - the required value of the phase shift.

The set of features of the proposed microwave phase shifter, namely:

the introduction of an additional first segment of the transmission line with a length equal to a quarter of the wavelength, and its proposed connection ensure the inclusion of either one first or one second bipolar reactive element, and thereby ensures the implementation of the required phase difference of the signal, that is, the implementation of the physical nature of the microwave phase shifter.

The introduction of an additional second segment of the transmission line with a length equal to half the wavelength or less, and its proposed connection ensure the inclusion of only one bipolar reactive element at the input or output of the microwave phase shifter with this segment of the transmission line and thereby exclude the possibility of narrow-band resonant circuits and, therefore, provide significant expansion of the working frequency band.

The connection of a field-effect transistor with a Schottky barrier with a second bipolar reactive element will directly allow the implementation of a microwave phase shifter without resonant circuits and thereby increase the working frequency band and reduce the amount of direct microwave losses.

The presence in the microwave phase shifter of only one field-effect transistor with a Schottky barrier will simplify its design and reduce weight and size characteristics, which is especially important when designing a phase shifter as part of a monolithic-integrated microwave circuit.

Moreover, the proposed connection of the elements of the microwave phase shifter will halve the number of bipolar reactive elements such as capacitance and inductance, and thereby, in addition to the above, simplify the design and reduce the overall dimensions of the microwave phase shifter.

So, the set of essential features of the proposed microwave phase shifter, in comparison with the prototype and especially with other analogs, will ensure the expansion of the working frequency band, reduction of direct losses, simplification of design and reduction of weight and size characteristics.

The invention is illustrated by drawings.

Figure 1 gives the topology of the proposed microwave phase shifter, where

- two transmission lines, one for input of the microwave signal - 1, the other for output - 2,

- field effect transistor with a Schottky barrier - 3,

- two bipolar reactive elements, the first - 4, the second - 5,

- two segments of the transmission line, the first - 6, the second - 7,

- source of constant control voltage - 8.

Figure 2 shows the equivalent circuit of the microwave phase shifter.

Figure 3 shows the dependence of the phase value of the signal f on the frequency of the microwave signal.

Figure 4 shows the dependence of the direct losses Ap on the frequency of the microwave signal.

In this case, curves 1 of the indicated dependences were measured when a field-effect transistor with a Schottky barrier is supplied with a constant control voltage equal to zero, and curves 2 equal to the cutoff voltage Uots.

An example of a specific implementation of the proposed microwave phase shifter.

The microwave phase shifter is made in a monolithic-integral version on a semiconductor substrate of gallium arsenide with a thickness of 0.1 mm using the classic thin-film technology.

Two transmission lines, one for inputting a microwave signal 1, the other for output 2, are made with the same wave impedances equal to 50 Ohms, which corresponds to a wire width of 0.08 mm.

A field-effect transistor with a Schottky barrier 3 is made with a gate length and width of 0.4 μm and 300 μm, respectively, with the same drain and source lengths equal to each 20 μm, has a cut-off voltage Uot. Of -2.5 V.

Both bipolar reactive elements, the first 4 and second 5, are each made in the form of a capacitance of the same value equal to 1 pF, for example, in the form of plane-parallel capacitors with plate sizes of 100 × 100 μm with a dielectric layer of silicon oxide 5 μm thick.

This corresponds to the required phase shift of the signal, equal to 45 degrees.

The second segment of the microstrip transmission line 7 is made of a width of 0.08 μm and a length of 1.5 mm

Moreover, one end of the first segment of the transmission line 6 is connected to the transmission line at the input 1 and to one of the ends of the first bipolar reactive element 4, and its second end to one of the ends of the second bipolar reactive element 5 and to the transmission line at the output 2. One the end of the second segment of the transmission line 7 is connected to the other end of the first bipolar reactive element 4, and its second end to the other end of the second bipolar reactive element 5 and to the drain of the field effect transistor with a Schottky barrier 3, the source of which is grounded, and gate control voltage fed to the constant.

Example 2

The microwave phase shifter is made analogously to example 1, but both bipolar reactive elements 4 and 5 are each made in the form of an inductance of the same magnitude equal to 2.5 nH.

This corresponds to a required phase shift of 45 degrees.

The proposed microwave phase shifter operates as follows.

When applying to the gate of a field-effect transistor with a Schottky barrier 3 a control voltage of 0 V from a source of constant control voltage 8, the field-effect transistor with a Schottky barrier becomes open.

As a result of this, a field-effect transistor with a Schottky barrier has a low resistance, Z Open. Since its source is grounded, and the drain is connected to the end of the second bipolar reactive element 5, this reactive element is connected to the ground through a low resistance Z open.

Since the drain of the field effect transistor with a Schottky barrier is connected to the end of the first bipolar reactive element 4 through the second segment of the transmission line 7 with a length equal to a quarter of the wavelength, then at its end the resistance ZA will be equal to

ZA = Z2 ² / ZOct., Where

ZA is the resistance at the end of the second segment of the transmission line 7 with a length equal to a quarter of the wavelength,

Z2 ² - square wave impedance of the second segment of the transmission line,

Open - resistance of a field effect transistor with a Schottky barrier in the open state.

Resistance ZA will be significantly greater than Z2.

The result is a connection of the first segment of the transmission line 6 and the second bipolar reactive element 5, which is located behind this segment.

Such a connection implements in the microwave phase shifter the phase value of the microwave signal F1.

When applying to the gate of a field-effect transistor with a Schottky barrier 3 a control voltage of -2.5 V from a source of constant control voltage, the field-effect transistor with a Schottky barrier becomes closed.

As a result of this, a field-effect transistor with a Schottky barrier has a small resistance Zcircuit. Since its source is grounded, and the drain is connected to the end of the second bipolar reactive element 5, this reactive element will be connected to the ground through a large resistance Zzakr.

Since the drain of the field effect transistor with a Schottky barrier is connected to the end of the first bipolar reactive element 4 through the second segment of the transmission line 7 with a length equal to a quarter of the wavelength, then at its end the resistance ZB will be equal to

ZB = Z2 ² / Z close, where

ZB is the resistance at the end of the second segment of the transmission line 7 with a length equal to a quarter of the wavelength,

Z2 ² - square wave impedance of the second segment of the transmission line,

Z close - resistance of a field effect transistor with a Schottky barrier in the closed state.

Resistance ZB will be significantly less than Z2.

The result is a connection of the first segment of the transmission line 6 and the first reactive element 4, which is located in front of this segment.

Such a connection implements in the microwave phase shifter the phase value of the microwave signal F2.

So, in the proposed microwave phase shifter, the required magnitude of the phase change of the microwave signal is realized, equal to the difference Ф2 and Ф1, when a negative and zero constant control voltage are applied to the gate of a field-effect transistor with a Schottky barrier, respectively, from one source of constant control voltage.

So, the phase shift of the microwave phase shifter signal is

Ф = Ф2-Ф1.

Consider the case when both bipolar reactive elements 4 and 5 are each made in the form of a tank. If the lengths of the first 6 and second 7 segments of the transmission line are equal to each other and equal to a quarter of the wavelength, then the phases of the microwave signals with an open and closed field-effect transistor with a Schottky barrier are determined from the expressions [5, p. 50-51]

tg (F1) = - (Z1 ² + Z0 ² ) / (2 π f0 C1 Z0 Z1 ² ),

tg (Ф2) = - (Z1 ² + Z0 ² ) / (2 π f0 C2 Z0 Z1 ² ), where

F1 is the phase of the microwave signal with a closed field-effect transistor with a Schottky barrier,

F2 is the phase of the microwave signal with an open field-effect transistor with a Schottky barrier,

Z1 ² - square wave impedance of the first segment of the transmission line.

Insofar as

Ф = Ф2-Ф1,

then from the trigonometric formula for the tangent of the difference of angles we get the expression

tg (Ф) = 2 π f0 (C2-C1) Z0 (Z1 ² + Z0 ² ) Z1 ² / [(Z1 ² + Z0 ² ) ² +

+ (2 π f0 Z0 Z1 ² ) ² C1 C2],

from which, in particular, it follows that the largest value of the phase difference of the signal is achieved with the following equalities:

Z1 = Z0,

C1 = (1 + sin Ф) / (Z0 π f0 cos Ф),

C2 = cos Ф / [(1 + sin Ф) Z0 π f0].

Since capacitances and inductances, the quantities are mutually dual, then, conducting similar calculations, we obtain expressions for inductance, respectively

L1 = (1 + sin Ф) Z0 / (4 π f0 cos Ф),

L2 = Z0 cos Ф / [4 π f0 (1 + sin Ф)].

On the samples of the proposed microwave phase shifter, the values of the phase change of the signal and the magnitude of direct losses from the frequency of the microwave signal were measured.

The results are presented in figure 3 and 4.

Figure 3 shows that the phase of the signal in the microwave phase shifter in the working frequency band changes from -25 degrees to -35 degrees with a constant control voltage equal to 0 V, and changes from -70 degrees to -80 degrees with a constant control voltage equal to -2.5 V.

The magnitude of the phase change of the microwave signal is 45 degrees in the working frequency band from 7 GHz to 15 GHz, which in absolute units is 2 times the width of the working frequency band of the prototype.

Exceeding the width of the working strip in relative units is 1.8 times.

Figure 4 shows that the direct losses in the microwave phase shifter at a frequency of 10 GHz are -0.7 dB at a constant control voltage of 0 V, and -1 dB at a constant control voltage of -2.5 V, which is 0.2 dB lower than that of the prototype.

Thus, the proposed microwave phase shifter allows, in comparison with the prototype:

firstly, to double the operating frequency band,

secondly, to reduce the direct loss by 0.2 dB,

thirdly, to simplify the design and reduce weight and size characteristics.

Information sources

1. RF patent No. 2031493, IPC Н01Р 1/18, priority 06.11.74, publ. 03/20/95.

2. RF patent No. 23033326, IPC Н03Н 11/16, priority 03/28/05, publ. 09/10/06.

3. RF patent №2141151, IPC Н01Р 1/185, priority 10/21/98, publ. 11/10/99.

4. RF patent №2321106, IPC Н01Р 1/185, priority 21.08.06, publ. 03/27/08.

5. Feldstein A.L., Yavich L.R. Microwave four-terminal and eight-terminal synthesis. M .: Communication. 1971.

Claims (3)

1. Microwave phase shifter containing two transmission lines with the same wave impedances, one for input of the microwave signal, the other for output, a field effect transistor with a Schottky barrier, two bipolar reactive elements of either different or the same size, while the drain of the field effect transistor with a barrier Schottky is connected to one end of one of the bipolar reactive elements, and the other end is connected to the output transmission line, the source of the field effect transistor with a Schottky barrier is grounded, and a constant control voltage is applied to its gate tension, characterized in that two segments of the transmission line are additionally introduced into the microwave phase shifter, the first length equal to half the wavelength and less, and the second length equal to a quarter of the wavelength, with one end of the first segment of the transmission line connected to the transmission line at the input and with one of the ends of the first bipolar reactive element, and its second end with one of the ends of the second bipolar reactive element and with a transmission line at the output, one end of the second segment of the transmission line is connected to the other end of the first bipolar a reactive element, and its second end - with the other end of the second bipolar reactive element, while the drain of the field effect transistor with a Schottky barrier is also connected to either one or the other end of the second segment of the transmission line, while the specified wavelength corresponds to the average frequency of the working band frequencies. 2. The microwave phase shifter according to claim 1, characterized in that the first and second reactive elements are made in the form of capacitance or inductance. 3. The microwave phase shifter according to claim 1 or 2, characterized in that the values of the reactive elements in the form of capacitance or inductance are selected based on the required phase shift of the microwave signal in accordance with the formulas:
C1 = (1 + sin Ф) / (Z0 π f0 cos Ф),
C2 = cos Ф / [(1 + sin Ф) Z0 π f0],
L1 = (1 + sin Ф) Z0 / (4 π f0 cos Ф),
L2 = Z0 cos Ф / [4 π f0 (1 + sin Ф)], where
C1 and C2 - tanks, respectively, of the first and second reactive elements in the form of tanks,
L1 and L2 - inductance, respectively, of the first and second reactive elements in the form of inductance,
Z0 - wave impedance of the transmission line at the input,
f0 is the central band of the working frequency range,
Ф - the required value of the phase shift.

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