RU2357355C1 - Microwave oscillator - Google Patents

Abstract

FIELD: electrical engineering.

SUBSTANCE: present invention relates to electrical engineering, to electronics and transistor based microwave oscillators. The microwave oscillator has active and frequency and power controlling elements, each of which is made from a Schottky-barrier field-effect transistor on a common source circuit. One end of the oscillating system is connected to the gate of the Schottky-barrier field-effect transistor of the active element, and the other is connected to drain of the Schottky-barrier field-effect transistor of the element controlling the frequency. The active element is connected to the corresponding sources through power supply filters. The above mentioned is made in form of an integrated circuit on one side of an insulating substrate. On the other side of the insulating substrate there is a metallic film with thickness 5-10 mcm, in which a longitudinal axially symmetrical aperture is made, short circuited on one end. The conductor of the oscillating system, connected to the gate of the Schottky-barrier field-effect transistor of the active element, is perpendicular to the longitudinal axially symmetrical aperture. The source and drain of the Schottky-barrier field-effect transistor of the element controlling power are connected to the metallic film through plated-through holes in the insulating substrate on both sides of the longitudinal axially symmetrical aperture at a distance of a quarter-wavelength, from the short circuited end of the longitudinal axially symmetrical aperture and from the above mentioned conductor of the oscillating system.

EFFECT: wider range of frequency tuning with increase in output power of microwaves and, consequently, increase in efficiency.

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Description

The invention relates to electronic equipment, namely to microwave generators on a transistor with electrical frequency tuning.

In communication systems and radar stations, microwave generators are widely used, in which the frequency is controlled by voltage.

In some cases, optimization of both the frequency tuning range and the microwave power output value is required.

A known design of a microwave generator on a transistor with electric frequency adjustment, containing a field-effect transistor with a Schottky barrier, made of a semiconductor material - gallium arsenide, an oscillating system connected to it and a semiconductor device controlled by voltage, while the field-effect transistor with a Schottky barrier is connected according to the scheme with a common source, one end of the oscillating system is connected to the gate of the field-effect transistor with a Schottky barrier, and the other to a voltage-controlled semiconductor device, as which serves as a varactor diode [1].

The use of a varactor diode as a voltage-controlled semiconductor device is based on the dependence of the capacitance of the varactor diode on the voltage applied to it.

The use of a field-effect transistor with a Schottky barrier made of gallium arsenide in the design of the generator provides a sufficiently high upper limit of the frequency tuning range of the microwave generator.

However, this microwave generator is inherent in:

- the difficulty in achieving a wider range of tuning the frequency of the microwave generator from the control voltage, which is due to the varactor diode having an uncontrolled voltage-voltage characteristic;

- the impossibility of creating a monolithic structure, since a field-effect transistor with a Schottky barrier and a varactor diode are performed separately, due to their physical, constructive and technological differences.

A microwave generator is also known on a transistor with electric frequency tuning, in which both the active and frequency controlling elements are made on a field-effect transistor with a Schottky barrier, connected according to the scheme with a common source, the active element is connected to the corresponding sources through power filters - prototype [2].

The generator contains an oscillating system, one end of which is connected to the gate of the field-effect transistor with a Schottky barrier of the active element, and the other to the drain of the field-effect transistor with a Schottky barrier, which controls the frequency of the element to which a constant voltage of positive polarity is applied, and a control voltage is applied to its gate and DC voltage of negative polarity equal to (0.6-0.8) Uots, where Uots is the cutoff voltage of the field effect transistor with a Schottky barrier, which controls the frequency of the element.

Thus, the capacitance of a field-effect transistor with a Schottky barrier, which controls the frequency of the element, depends on two voltages - on the drain - a constant voltage of positive polarity and a gate - the sum of a constant voltage of negative polarity and a control voltage, in contrast to a varactor diode, the capacitance of which, as was said above, depends on only one control voltage.

The presence of a more complex functional dependence of the capacitance of a field-effect transistor with a Schottky barrier, which controls the frequency of the element on the voltages, than the varactor diode allows, to determine the optimal combination of these voltages, which provides a wider range of tuning of the frequency of the microwave generator from the control voltage.

However, the further expansion of the frequency tuning range of the generator is hindered by the fact that with its increase the microwave output power decreases, which is especially observed and takes place at the borders of this frequency tuning range.

In turn, a decrease in the microwave output power leads to a proportional decrease in the efficiency of the microwave generator.

The technical result of the proposed invention is to expand the range of frequency tuning while increasing the output power of the microwave and, accordingly, increasing the efficiency.

The specified technical result is achieved by the proposed microwave generator, containing the active and frequency-controlling elements, which are each made on a field-effect transistor with a Schottky barrier according to a common source circuit, an oscillating system, one end of which is connected to the gate of a field-effect transistor with a Schottky barrier of the active element, and the other with the drain of a field-effect transistor with a Schottky barrier, which controls the frequency of the element, the active element is connected to the corresponding sources through power filters, while The components and their connections are made in the form of an integrated circuit on an insulating substrate, into which an additional power control element is introduced, also made on a field-effect transistor with a Schottky barrier and as part of the integrated circuit, the integrated circuit is made on one side of the insulating substrate, and on the other the side is made of a metal film with a thickness of 5-10 μm, in which a longitudinal axisymmetric gap is made, short-circuited at one end, a conductor of the oscillatory system connected to the gate a transistor with a Schottky barrier of the active element, located perpendicular to the longitudinal axisymmetric gap, the source and drain of the field transistor with a Schottky barrier, which controls the power of the element, are connected to the metal film through metallized through holes made in an insulating substrate on both sides of the longitudinal axisymmetric gap equal to a quarter of the wavelength, both from the short-closed end of the longitudinal axisymmetric gap, and from the said conductor of the oscillatory system We, and the gate of the FET with Schottky barrier controlling the power element is fed a control voltage.

The microwave generator can be made both in hybrid and in integral integral design.

The microwave generator can be placed both in the housing and in the waveguide.

Disclosure of the essence of the proposed invention.

Introduction to the microwave generator of the power control element in the form of a field-effect transistor with a Schottky barrier in conjunction with the presence in the design of a longitudinal axisymmetric slit short-circuited at one end, and in conjunction with the proposed connection of both the active element and the power control element, and in conjunction with other features of the proposed claims allows matching the output signal of the microwave generator with a load with a low reflection coefficient, and thereby implement a more effective efficient power take-off and, therefore, to increase the microwave output power and, accordingly, the efficiency factor.

A longitudinal axisymmetric gap in the microwave generator, short-circuited at one end and its proposed connection with the power control element through metallized through holes made in an insulating substrate on both sides of the longitudinal axisymmetric gap, each equal to a quarter of the wavelength, as from a short-closed end longitudinal axisymmetric gap, and from the aforementioned conductor of the oscillatory system, performs at least two functions:

firstly, it makes it possible to include a microwave that controls the power of the element into the microwave generator and allows you to vary the microwave power output over a wide range and thereby make the optimal choice of both the frequency tuning range and the microwave power output value.

When applying to the gate of a field-effect transistor with a Schottky barrier the power control element, the control voltage Up, equal to zero, the said transistor opens, a current flows through it, which is equivalent to a short circuit of the longitudinal axisymmetric gap at a distance equal to a quarter of the wavelength from the conductor of the oscillatory system.

When a field-effect transistor with a Schottky barrier is applied to the gate, which controls the power of the element, the control voltage Up, equal to the cut-off voltage Uots, the mentioned transistor closes, the current does not flow through it, which is equivalent to a short circuit of the longitudinal axisymmetric gap at a distance equal to half the wavelength from the vibrational conductor system.

Thus, changing the control voltage Up from zero to the cut-off voltage Uot, the short circuit of the longitudinal axisymmetric slit is moved within a quarter to half of the wavelength, which allows us to determine the optimal value of the control voltage Up at which the output signal of the microwave generator is matched with a low load reflection coefficient;

Secondly, it serves to output the energy of microwave oscillations.

The implementation of a metal film on the other side of the insulating substrate as indicated in the claims is necessary for the implementation of a longitudinal axisymmetric gap.

The thickness of the metal film is limited on the one hand, less than 5 microns, the need to preserve its integrity, and on the other, more than 10 microns, impractical from the point of view of saving metal, such as gold, which is known due to its high electrical and thermal conductivity, and adhesive strength , and not high chemical activity is widely used as a metal film.

The performance of the power-controlling element as active and frequency-controlling elements in the form of field-effect transistors with a Schottky barrier provides the possibility of their execution in a monolithic integral design.

Thus, the proposed microwave generator will provide:

firstly, the possibility of carrying out simultaneously with the electrical frequency adjustment and electrical power adjustment;

secondly, and most importantly, it will allow optimizing both the frequency tuning range and the microwave output power value, while expanding the frequency tuning range while increasing the microwave output power.

The invention is illustrated by drawings.

Figure 1 is a General view of the proposed microwave generator, where

- the active element in the form of a field effect transistor with a Schottky barrier - 1,

- frequency-controlling element in the form of a field-effect transistor with a Schottky barrier - 2,

- oscillatory system - 3,

- power filters - 4,

- integrated circuit - 5,

- insulating substrate - 6,

- power control element in the form of a field effect transistor with a Schottky barrier - 7,

- metal film - 8,

- longitudinal axisymmetric gap - 9,

- conductor of the oscillatory system - 10,

- through metallized holes - 11.

Figure 2 shows the equivalent circuit of the microwave generator.

Figure 3 shows the dependence of the frequency f and the output power P of the microwave generator on the control voltage Uf at an optimal control voltage Up equal to -1.2 V.

Example 1

A variant of a microwave generator in a monolithic integral design is considered.

The insulating substrate in the form of a gallium arsenide crystal is made with a thickness of 100 μm.

Field-effect transistors with a Schottky barrier of the active and frequency and power control elements are made the same, while the length and width of the gate are 0.3 μm and 300 μm, respectively.

The oscillation system 3 in this case is a segment of a thin conductor with a given value of inductance, a plane-parallel capacitor with a given value of capacitance and a conductor of the oscillatory system 10.

On one side of the insulating substrate 6, as mentioned above in the form of a gallium arsenide crystal, a topology of a monolithic integrated circuit 5 is made, containing an active element 1, control elements with a frequency of 2 and a power of 7, an oscillatory system 3 with a conductor of an oscillatory system 10, and power filters 4 s using traditional methods of thin-film technology.

In this case, the conductor of the oscillatory system 10, connected to the gate of the field-effect transistor with a Schottky barrier of the active element 1, is perpendicular to the longitudinal axisymmetric gap 9.

On the other side of the insulating substrate 6, a metal film 8 is made of a thickness equal to 7 μm by vacuum deposition of gold, in which a longitudinal axisymmetric gap 9 is made with a width of 50 μm, short-circuited at one end, and the other end serves as an output of microwave energy.

In the insulating substrate 6 on both sides of the longitudinal axisymmetric slit 9, there are through gold-plated holes 11, each at a distance equal to a quarter of the wavelength, both from the short-closed end of the longitudinal axisymmetric slit 9 and from the said conductor of the oscillating system 10, for example, for frequency 33 GHz, equal to 1 mm.

Example 2-3.

Analogously to example 1, microwave generators were made, but with metal film thicknesses of 5 and 10 μm, respectively.

On the manufactured samples of the microwave generator, the dependences of the frequency f and the output power P of the microwave generator on the control voltage Uf were taken, which is reflected in figure 3.

The operation of the device.

Consider the option of the proposed microwave generator with a central frequency of the operating range equal to, for example, 33 GHz.

A voltage Uc of 5 V is applied to the drain of a field-effect transistor with a Schottky barrier of the active element 1, connected according to the circuit with a common source

A voltage of U ₃ equal to 1 V is applied to its shutter.

By changing the control voltage Uf at the gate of a field-effect transistor with a Schottky barrier, which controls the element frequency from 0 to the cutoff voltage Uots, an oscillation frequency f equal to 33 GHz 6 is obtained, and the output power P is equal to 50 mW.

Further, by changing the control voltage Up at the gate of a field-effect transistor with a Schottky barrier, which controls the power of the element, an output power P of 70 mW is obtained, while the oscillation frequency f changes and becomes equal to 26 GHz.

By changing the control voltage Uf at the gate of a field-effect transistor with a Schottky barrier, which controls the element frequency from 0 to the cutoff voltage Uots, a change in the oscillation frequency f in the operating frequency range from 26 GHz to 40 GHz and a change in the output power P from 60 mW to 70 mW are obtained.

As indicated above, all this is reflected in figure 3.

Thus, the proposed microwave generator in comparison with the prototype will allow:

- expand the frequency tuning range by about twenty percent;

- while increasing the output power of the microwave, and, accordingly, the efficiency of approximately two times.

In addition, the design of the proposed microwave generator provides:

- its implementation both in hybrid and in integral integral design;

- and its use both in the case and in the waveguide.

Information sources

1. Gassanov L.G., Lipatov A.A., Markov V.V. "Solid-state microwave devices in communications technology." - M .: Radio and communications, 1988, p. 193.

2. RF patent №2277293, IPC Н03В 7/14, priority 05.10.2004 - prototype.

Claims (3)

1. A microwave generator containing active and frequency-controlling elements that are each made on a field-effect transistor with a Schottky barrier according to a common source circuit, an oscillating system, one end of which is connected to the gate of a field-effect transistor with a Schottky barrier of the active element, and the other to a field drain a Schottky barrier transistor controlling the frequency of the element, the active element is connected to the appropriate sources through power filters, while the above elements and their connections are made in the form of an integrated circuit and an insulating substrate, characterized in that the power control element is additionally introduced into the generator, also made on a field-effect transistor with a Schottky barrier and as part of the integrated circuit, the integrated circuit is made on one side of the insulating substrate, and a metal film is made on its other side equal to 5-10 microns, in which a longitudinal axisymmetric gap is made, short-circuited at one end, a conductor of the oscillatory system connected to the gate of a field-effect transistor with a Schott barrier and the active element, located perpendicular to the longitudinal axisymmetric gap, the source and drain of the field-effect transistor with a Schottky barrier, which controls the power of the element, are connected to the metal film through metallized through holes made in an insulating substrate on both sides of the longitudinal axisymmetric gap, each equal to a quarter of the length waves, both from the short-closed end of the longitudinal axisymmetric gap, and from the aforementioned conductor of the oscillatory system, and to the gate of the field-effect transistor Schottky barrier power control element, the control voltage is supplied. 2. The microwave generator according to claim 1, characterized in that the microwave generator can be performed both in hybrid and in integral integral design. 3. The microwave generator according to claim 1, characterized in that the microwave generator can be placed both in the housing and in the waveguide.

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