RU2321106C1 - Microwave phase shifter - Google Patents

Abstract

FIELD: electrical engineering; microwave phase shifters built around semiconductor devices.

SUBSTANCE: proposed microwave phase shifter has two transmission lines of similar wave impedance ,one of them being designed for microwave signal input and other one, for its output; two Schottky-barrier field-effect transistors; inductance coils of same rating; and capacitors of either different or same rating. Source of first Schottky-barrier field-effect transistor is connected to transmission line at input and to one of first inductance coil leads; drain is connected through first capacitor to transmission line at output and to one of second inductance coil leads. Drain of second Schottky-barrier field-effect transistor is connected to other leads of both inductance coils and to one of leads of second capacitor; source and other lead of second capacitor are grounded. Gates of Schottky-barrier field-effect transistors are interconnected and connected to one DC control voltage supply.

EFFECT: reduced irregularity of phase variation in operating frequency band, reduced reflection factor module and direct loss; simplified design and reduced mass of microwave phase shifter.

2 cl, 5 dwg

Description

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

Microwave phase shifters characterize:

- the magnitude of the phase change of the microwave signal, the value of which is set;

- the magnitude of the non-uniformity of the phase change in the working frequency band, which should be as small as possible;

- direct losses Ap, the value of which should be as small as possible;

- the magnitude of the reflection coefficient modulus, which should be as small as possible;

- the presence of the number of sources of constant control voltage, which should be as small as possible;

- the value of the constant control voltage.

Microwave phase shifters based on semiconductor devices are widely used in microwave technology.

Especially multi-bit microwave phase shifters with discrete phase change, which are a cascade connection of several at least two discharges, containing in each discharge, including inductance and capacitance.

Connecting and disconnecting capacitors and inductances in each discharge is carried out by electronic switches, which are used as semiconductor diodes and transistors. This allows you to get the required combination of discrete changes in the phase of the microwave phase shifter.

Known multi-bit microwave phase shifter, containing in each discharge a connection of inductors and capacitors. As electronic keys, semiconductor pin diodes are used, to which constant control voltages are applied. Semiconductor pin diodes switch the connection of inductors and capacitors in the form of a high-pass filter to their connection in the form of a low-pass filter [1].

The disadvantage of this multi-bit phase shifter is the presence in each discharge of two sources of constant control voltage, which complicates the design and increases the overall dimensions of the microwave phase shifter.

In addition, since pin diodes are bipolar devices, it is necessary to use power filters to decouple the circuit for direct current and microwave signal, which also complicates the design and increases the weight and size characteristics of the microwave phase shifter.

A multi-bit microwave phase shifter is known, which also contains a connection of inductors and capacitors in each discharge. Semiconductor transistors - field effect transistors with a Schottky barrier, are used as electronic keys in this microwave phase shifter. The microwave phase shifter contains two transmission lines with the same wave impedances, one for the input of the microwave signal, the other for output, two field-effect transistors with a Schottky barrier, inductance and capacitance, while one of the source and drain electrodes of both field-effect transistors with a Schottky barrier is connected to transmission lines at the input and output, and the valves are fed with constant control voltages [2] - prototype.

Compared to the analogue, this microwave phase shifter eliminates the need for power filters, since field-effect transistors with a Schottky barrier are three-pole devices and, therefore, have internal isolation of the circuit for direct current and microwave signal.

However, the presence in this microwave phase shifter, as in the analogue, of two sources of constant control voltage complicates the design and increases the overall dimensions of the microwave phase shifter.

Moreover, this microwave phase shifter does not allow the optimal selection of the parameters of the microwave phase shifter elements and thereby ensure its high characteristics, for example, reducing uneven phase changes in the working frequency band, reducing the magnitude of the reflection coefficient and the magnitude of direct losses.

The technical result of the invention is to reduce the unevenness of phase changes in the working frequency band, reduce the magnitude of the reflection coefficient and the magnitude of direct losses while simplifying the design and reducing the overall dimensions of the microwave phase shifter.

The specified technical result is achieved by the fact that in the known microwave phase shifter containing two transmission lines with the same wave impedances, one is for the input of the microwave signal, the other is for the output, two field effect transistors with the Schottky barrier, the inductance of the same magnitude and capacitance is either different, or the same size. 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 connected to the other ends of both inductances and to one of the ends of the second capacitance, and the source and the other end of the second capacitance are grounded, and the gates of field-effect transistors with a Schottky barrier are interconnected and connected to one constant source control voltage.

The values of inductances and capacitances are selected based on the required phase shift of the microwave signal.

The proposed connection of the elements of the microwave phase shifter, namely 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 second field effect transistor with a Schottky barrier is connected to the other ends of both inductances and to one of the ends of the second capacitance, and the source and the other end of the second capacitance are grounded in combination with the other indicated essential features and it provides the possibility of realizing the optimum values of the parameters of the microwave phase shifter element and thereby will reduce the unevenness of the phase change in the operating frequency band to reduce the magnitude of the reflection coefficient of the module and the amount of direct loss.

The proposed connection of the elements of the microwave phase shifter made it possible to halve the number of inductances, since they can realize both a low-pass filter and a high-pass filter depending on the constant control voltage.

The connection of the first field-effect transistor with a Schottky barrier with the first capacitance, and the second with the second capacitance will reduce in the first case, and in the second increase the total capacitance and thereby improve the characteristics of the low-pass filter and high-pass filter, namely, to reduce the unevenness of the phase change in the working frequency band, reduce the magnitude of the reflection coefficient modulus and the magnitude of direct losses in the implementation of the optimal values of the parameters of the elements of the microwave phase shifter

The interconnection of the gates of both field-effect transistors with a Schottky barrier and their connection with a single source of constant control voltage will reduce the weight and size characteristics of the microwave phase shifter, which is especially important when performing the phase shifter as part of integral microwave integrated circuits.

In addition, as mentioned above, the proposed connection of the elements of the microwave phase shifter allowed to halve the number of inductances and thereby simplify the design and further reduce the overall dimensions of the microwave phase shifter.

As can be seen from the above, the proposed combination of essential features will ensure the above technical result.

The invention is illustrated by drawings.

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

- two transmission lines: one for inputting a microwave signal - 1, the other for output - 2,

- two field effect transistors with a Schottky barrier - 3 and 4, respectively,

- inductance - 5 and 6, respectively,

- capacities - 7 and 8, respectively,

- source of constant control voltage - 9.

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

Figure 3 shows the dependence of the magnitude of the phase change of the signal from the frequency of the microwave signal,

Figure 4 shows the dependence of the magnitude of the reflection coefficient modulus on the frequency of the microwave signal.

Figure 5 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 both field effect transistors with a Schottky barrier were supplied with a constant control voltage equal to zero, and curves 2 to the cutoff voltage Uotc.

An example of a specific implementation 1.

The microwave phase shifter is made in integral integral design on a semiconductor substrate of gallium arsenide with a thickness of 0.1 mm, using classical thin-film technology.

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

Field-effect transistors with a Schottky barrier 3 and 4, respectively, have a cut-off voltage Uot. Of -2.5 V.

Inductances 5 and 6 are made identical in the form of rectangular spirals from a metal conductor made by sputtering gold with a thickness of 4 μm and a width of 20 μm.

Capacities 7 and 8 are made in the form of plane-parallel capacitors with a dielectric layer of silicon oxide with a thickness of 5 μm.

With the required phase shift of 90 degrees, the inductances 5 and 6 are 10 nH, the capacitances 7 and 8 are 1 pF - the same value.

In this case, the source of the first field-effect transistor with a Schottky barrier 3 is connected to the transmission line at the input 1 and to one of the ends of the first inductance 5, and the drain through the first capacitance 7 is connected to the transmission line at the output 2 and to one of the ends of the second inductance 6. Stoke the second field-effect transistor with a Schottky barrier 4 is connected to the other ends of both inductors 5 and 6 and to one of the ends of the second capacitor 8, and the source and the other end of the second capacitor 8 are grounded. The gates of both field-effect transistors with a Schottky barrier 3 and 4 are interconnected and connected to one source of constant control voltage 9.

Example 2

The microwave phase shifter is made analogously to example 1, but the inductances are 7.5 nH, and capacitances 7 and 8 are made of different sizes 1 and 1.5 pF, respectively.

This corresponds to the required phase shift of 180 degrees.

Device operation

When applying to the gates of both field-effect transistors with a Schottky barrier 3 and 4 a constant control voltage of 0 V, from one source of constant control voltage 9 both field-effect transistors with a Schottky barrier become open.

As a result of this, the first field-effect transistor with a Schottky barrier 3 has a low resistance Z Open.

The second field-effect transistor with a Schottky barrier 4 also has a low resistance Z Open, but since its source is grounded, the other ends of the inductors 5 and 6 are connected to ground through a small resistance Z Open.

The result is a U-shaped connection of the first capacitance 7 and two inductors 5 and 6 located on both sides of the specified capacitance 7.

Such a connection in the form of a high-pass filter implements the phase of the microwave signal F1 in the microwave phase shifter.

When both field effect transistors with a Schottky barrier 3 and 4 supply negative gates to the gates, which exceeds the absolute value of the cutoff voltage of the field effect transistor with a Schottky barrier Uot., Both field effect transistors with a Schottky barrier will be closed.

In this case, the first field-effect transistor with a Schottky barrier 3 has a large resistance Zcl., Which is equivalent to an open circuit with the first capacitance 7.

The second field effect transistor with a Schottky barrier 4 also has a large resistance Zzakr. and, therefore, will have little effect on the size of the second capacitance 8, the other end of which is grounded.

The result is a T-shaped connection of the second capacitor 8 and two inductors 5 and 6 located on both sides of the specified capacitance 8.

Such a connection in the form of a low-pass filter implements the phase of the microwave signal Ф2 in the microwave phase shifter.

Thus, in the proposed microwave phase shifter, a predetermined magnitude of the phase change of the microwave signal is realized, which is equal to the difference Ф2 and Ф1 when both field effect transistors with the Schottky barrier are supplied with negative and zero constant control voltage, respectively, from one source of constant control voltage.

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

The results are shown in FIGS. 3-5.

As seen:

from figure 3 the phase of the signal in the microwave phase shifter at a frequency of 10 GHz is -10 degrees with a constant control voltage of 0, and 170 degrees with a constant control voltage of 2.5 V, so the magnitude of the phase change of the microwave signal is 180 degrees. In this case, the uneven change in the phase of the microwave signal is 10 degrees, which is approximately half that of the prototype;

from figure 4 the magnitude of the reflection coefficient modulus in the microwave phase shifter at a frequency of 10 GHz is 0.07 with a constant control voltage of 0, and 0.05 with a constant control voltage of -5 V, which is 1.5 times less than the prototype;

from figure 5 direct losses in the microwave phase shifter at a frequency of 10 GHz are -1 dB with a constant control voltage of 0, and -1.2 dB with a constant control voltage of -2.5 V, which is 0.2 dB lower than the prototype

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

firstly, to improve the characteristics of the microwave phase shifter, namely

- reduce the uneven change in the phase of the microwave signal in the working frequency band by about half,

- reduce the magnitude of the reflection coefficient module by 1.5 times,

- reduce direct loss by 0.2 dB;

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

The indicated advantages of a microwave phase shifter are especially relevant when creating miniature both individual microwave devices and, especially in a monolithic integrated design, and microwave electronic devices for various purposes.

Information sources

1. Gassanov L.G., Lipatov A.A., Markov V.V. Solid-state microwave devices in communication technology. - M., Radio and Communications, 1998, p. 149.

2. Malyshev V.A. Onboard active devices of superhigh frequencies. - Leningrad, Shipbuilding, 1990, p. 256.

Claims (2)

1. A microwave phase shifter containing two transmission lines with the same wave impedances, one for input of the 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, while one of the source and drain electrodes of both field-effect transistors with a Schottky barrier are connected to transmission lines either at the input or at the output, and constant control voltages are applied to the gates, characterized in that the source of the first field-effect transistor with bar The Schottky link 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 with the Schottky barrier is connected to the other ends of both inductances and to one of the ends of the second capacitance, and the source and the other end of the second capacitance are grounded, and the gates of field-effect transistors with a Schottky barrier are interconnected and connected to one source of constant control voltage. 2. The microwave phase shifter according to claim 1, characterized in that the values of the inductances and capacitances are selected based on the required phase shift of the microwave signal.

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