RU2715406C1 - Input linear module of broadband receiving microwave device with extended dynamic range - Google Patents

Abstract

FIELD: physics.

SUBSTANCE: invention relates to input linear modules (ILM) of microwave frequency receiving devices. For this purpose, the UHF broadband microwave receiving device with an extended dynamic range comprises a power and control board and a microwave portion comprising 1x2 microwave switch, to input of which input microwave signal is supplied, first amplifying cascade, which input is connected to second output of microwave switch 1x2, microwave switch 2x1, first input of which is connected to output of first amplifier stage, wherein first output of microwave switch 1x2 is directly connected to second input of microwave switch 2x1, and output of microwave switch 2x1 is connected to input of second amplifier stage by means of controlled microwave attenuator, wherein the input of the controlled microwave attenuator is connected to the output of microwave switch 2x1, and the output of the controlled microwave attenuator is connected to the input of the second amplification stage.

EFFECT: technical result is development of ILM of broadband microwave receiving device with extended dynamic range, having possibility of smooth adjustment of signal attenuation in wide frequency range.

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Description

The invention relates to electronics, in particular to the input linear modules of the receiving devices of the microwave range.

The main trend in the development of radio electronics in recent years is the increase in the number and expansion of the range of radio communications, active radar, radio navigation and other emitting devices. As a result, interest in adequate means of passive radar is increasing. The use of technical means of passive radar in real conditions occurs, as a rule, in a complex jamming environment. The equipment should fulfill its main function under the influence of high-intensity interference, that is, receive useful signals of small amplitude against the background of powerful interfering signals. The required noise immunity is achieved by expanding the instantaneous dynamic range (DD) of the input signals. The DD of the passive radar receiver is determined, inter alia, by the parameters of the broadband microwave receivers and input linear paths.

The input linear module (VLM) is an input protected broadband low-noise microwave amplifier with an adjustable gain. The parameters of this amplifier to a large extent determine both the lower boundary of the DD - the sensitivity of the microwave receiver, and its upper boundary. The modern microwave base allows you to implement fairly high characteristics of such amplifiers in the operating frequency band, noise figure, gain, linearity of the amplitude characteristic and other parameters. At the same time, there is a search for technical solutions that would allow for the production of VLM with extended DD.

A known method of expanding the dynamic range in radio systems (RF patent No. 2614345, IPC Н03В 1/00, published March 24, 2017, authors: Ryabov I.V., Klyuzhev E.S., Dedov A.N., Garifullina A.V. ), consisting in the fact that N blocks of operational amplifiers are introduced, having different amplification factors and connected in parallel, as well as a set of K1.N keys that connect the corresponding operational amplifier; the dynamic range extender also has a second group consisting of N blocks of operational amplifiers that are connected in parallel using K2.N keys; when transmitting a signal, the first group of operational amplifiers works, and when receiving / processing a signal, the second group of operational amplifiers.

This method describes a well-known multi-stage amplifier circuit in which the principle of switchable individual amplification stages is applied to expand the DD. The disadvantages of devices that implement the proposed method is a large step of the stages of attenuation of the signal and their limited number, determined by the number of stages. A further increase in the number of stages leads to an unjustified complication of the design of the amplifier, which naturally leads to a decrease in the reliability of its operation, as well as to an increase in the dimensions of the device as a whole.

The known design of the low-noise amplifier (LNA) of the X-band using an input switch to operate in large and small signal modes ("Extending the dynamic range of the low-noise amplifier of the X-band", A. A. Conduktorov, A. I. Kirpichenkov, Electronics. Series 3: Microelectronics, 2015, No. 4 (160), pp. 35-38, UDC 621.396.621), selected as a prototype. The device has two modes of operation: low noise and large signal mode. In low-noise mode, the signal supplied to the input is amplified by the first amplification stage, and then passes through the switch to the second amplification stage. In the large signal mode, the signal received at the input is reflected from the switch, entering the bypass channel through the circulator, and then passes through the switch to the second amplifier stage. The valve is included in the circuit as a coordinated load in the arm of the circulator; in the large signal mode, the valve is also a matching element in the input circuit of the transistor. To control the level of input power at the output, a power detector can be installed. With an alternative design of a low-noise amplifier, the main difference of the circuit is that the input signal is switched using the MIS switch.

The disadvantage of the proposed design of the low-noise amplifier, selected as a prototype of the invention, is that the use of circulators in the circuit of the amplifier in question significantly reduces its bandwidth. It should also be noted that this device has too limited a range of gain control, due to the presence of only a switchable stage in the absence of additional adjustment tools. The above disadvantages significantly reduce the possibility of widespread use of the prototype.

The technical result of the invention is the development of an input linear module (VLM) of a microwave broadband receiver with an extended dynamic range, with the ability to smoothly adjust signal attenuation in a wide frequency range.

The technical result is achieved by the fact that the proposed VLM broadband microwave receiver with an extended dynamic range, built on the basis of a model that combines the functions of a “variable amplifier” and “adjustable attenuator”.

An input linear module of a broadband microwave receiver with an extended dynamic range is proposed, containing a power and control board located in the case, and a microwave part including a 1 × 2 microwave switch, to the input of which a microwave input signal is supplied, the first amplifier stage, the input of which is connected to the second the output of the microwave switch 1 × 2, the microwave switch 2 × 1, the first input of which is connected to the output of the first amplifier stage and the second amplifier stage, the input of which is connected to the output of the microwave switch 2 × 1, characterized by m, that the first output of the 1 × 2 microwave switch is directly connected to the second input of the 2 × 1 microwave switch, and the output of the 2 × 1 microwave switch is connected to the input of the second amplifier stage via a controlled microwave attenuator, while the input of the controlled microwave attenuator is connected to the output of the microwave switch 2 × 1, and the output of the controlled microwave attenuator is connected to the input of the second amplifier stage.

In the proposed input linear module of a broadband microwave receiver with an extended dynamic range, a bandpass filter and a power limiter can be additionally included, while the input of a 1 × 2 microwave switch is connected to the output of the bandpass filter, and the input of the bandpass filter is connected to the output power limiter.

In the proposed input linear module of a broadband microwave receiver with an extended dynamic range, a 2 × 1 microwave switch can be included to connect a control signal, while the input of a 1 × 2 microwave switch is connected to the second output of a 2x1 microwave switch for connecting a control signal.

The proposed input linear module of a broadband microwave receiver with an extended dynamic range includes both a switchable amplification stage and a controlled microwave attenuator with an amplifier.

Traditionally, in circuitry, if it is necessary to build amplifiers with an extended dynamic range, designs are implemented that include the installation of an adjustable attenuator at the input of the amplifier, or the construction of multi-stage amplification devices with the ability to connect / disconnect individual stages. However, circuits with an adjustable attenuator at the input only simultaneously increase the values of both boundaries, but do not lead to an increase in the instantaneous value of DD. In addition, such an attenuator has its own losses, which reduces the sensitivity of the device. The disadvantage of circuits with switchable cascades is the large step of the signal attenuation stages and their limited number, determined by the number of cascades.

In the present invention, it was possible to achieve the expansion of instant DD, while maintaining a small gain adjustment step. The proposed input linear module of a microwave broadband receiver with an extended dynamic range can provide both a small attenuation adjustment step and a DD extension. Since when the first amplifier stage is connected, it sets the upper limit of the dynamic range from a certain attenuation value, then obtaining the maximum attenuation depth with a small step implies the following algorithm. With the first amplifier stage turned on, the attenuation is set by the controlled microwave attenuator up to the maximum level. When this value is reached, the first amplifier stage is turned off and then attenuation is introduced by the controlled microwave attenuator from the initial to maximum attenuation.

Thus, the proposed input linear module of a microwave broadband receiver with an extended dynamic range operates in two modes:

- the first amplifier stage is connected and amplifies the input signal;

- the first amplifier stage is disabled, the input signal is bypassed.

The main criterion that determines the effectiveness of the proposed combined input circuit module of a broadband microwave receiver with an extended dynamic range is to obtain the maximum integrated dynamic range (DD _int ) in the entire attenuation range of the controlled microwave attenuator and in all modes:

DD (a) is the function of DD from the effective value of attenuation of the transmission coefficient.

A is the maximum total attenuation when adjusting the gear ratio.

In the present invention, when attenuation is introduced by a controlled microwave attenuator in the mode when the first amplifier stage is connected, an increase in the dynamic range is observed, while its limiting value is limited by the gain of the first amplifier stage and its linearity.

In the second mode, when the first amplifier stage is turned off, the dynamic range does not increment, since the circuit degenerates into a “variable attenuator”. But, it is important to note that the combined scheme allows you to have a small step of attenuation in the implementation of both the first and second modes. This circumstance is extremely important for use in the composition of the destination equipment.

The criterion DD _{int is in} good agreement with the tactics and logic of the operation of the equipment in the presence of interference. When overloaded, the input signal is attenuated to the desired level, despite the loss of sensitivity. In the present invention, when the input signal is weakened, the sensitivity deteriorates insignificantly, due to which the dynamic range is expanded and, in turn, the technical characteristics of the destination equipment are increased.

A power limiter, which can be located at the input, provides protection for the proposed input linear module of a broadband microwave receiver with an extended dynamic range from the influence of interfering microwave signals with a power of up to 2 W in continuous mode and constant voltage. A bandpass filter suppresses out-of-band signals. Also, the proposed input linear module of a microwave broadband receiver with an extended dynamic range may be able to connect at the control signal input by means of a microwave switch to connect the control signal.

The invention is illustrated by drawings.

In FIG. 1 shows a block diagram of the proposed input linear module of a broadband microwave receiver with an extended dynamic range.

In FIG. 2 shows graphs of experimental measurements of the dynamic range of the proposed input linear module of a microwave broadband receiver with an extended dynamic range depending on the attenuation of the tunable microwave attenuator.

In FIG. 1 shows the following items:

1 - microwave switch 1 × 2;

2 - the first amplifier stage;

3 - 2 × 1 microwave switch

4 - controlled microwave attenuator;

5 - second amplification stage.

In FIG. 2 shows the following items:

6 is a graph of the upper boundary of the dynamic range of the proposed input linear module of a broadband microwave receiver with an extended dynamic range;

7 is a graph of the lower boundary of the dynamic range of the proposed input linear module of a microwave broadband receiver with an extended dynamic range (with an equivalent band equal to 10 GHz);

8 is a graph of a dynamic range of a proposed input linear module of a microwave broadband receiver with an extended dynamic range;

9 is a graph of the dynamic range of a “hypothetical amplifier constructed according to the scheme of“ adjustable attenuator.

The sample shown in FIG. 1 of the proposed input linear module of a broadband microwave receiver with extended dynamic range.

The disconnectable first amplifier stage 2 is a circuit of the LNA and two microwave switches 1 and 3, which enable the inclusion of transmission lines bypassing the first amplifier stage 2. The proposed input linear module of the microwave broadband receiver with the extended dynamic range of the VMF has two operating modes:

- 1st, when the first amplifier stage 2 is involved;

- 2nd, when the first amplifier stage 2 is disabled;

The degree of attenuation of the transmission coefficient of the first amplification stage 2, due to the used elemental base, was about 20 dB.

To fine-tune the gain, a 5-bit microwave attenuator 4 was used with an attenuation step of 1 dB and a maximum attenuation of 31 dB, located in the circuit at the output of the first amplifier stage 2. Directly after the controlled microwave attenuator 4, a power amplifier 5 was installed at the module output, point IP3 output which amounted to 40 dBm.

Measurements were made of the manufactured sample of the proposed input linear module of a broadband microwave receiver with an extended dynamic range. The measurement results are shown in the experimental graphs of FIG. 2. when working in all modes. The graphs are taken by sequentially increasing the attenuation of the controlled microwave attenuator 4 in each of the two operating modes of the module. When switching to the next mode, the controlled microwave attenuator 4 was reset to zero.

The shaded area bounded by lines 8 and 9, corresponding to the increment of DD _int , illustrates the achieved expansion of the dynamic range. The break points of the experimental graphs correspond to the disconnection times of the first amplifier stage 2. With the first amplifier stage 2 turned off, the instantaneous dynamic range of the proposed input linear module of the microwave broadband receiver with the extended dynamic range increases by 12 dB. Obviously, the present invention in dynamic range is superior to "adjustable attenuator" in the entire range of attenuation.

Thus, when implementing the present invention, it was possible to obtain an input linear module of a microwave broadband receiver with an extended dynamic range, having both a wider dynamic range compared to the prototype, and the ability to smoothly adjust the signal transfer coefficient in a wide frequency range.

Claims (3)

1. The input linear module of a broadband microwave receiver with an extended dynamic range, containing a power and control board and a microwave part, which includes a 1x2 microwave switch, to the input of which a microwave input signal is supplied, the first amplifier stage, the input of which is connected to the second microwave output 1x2 switch, 2x1 microwave switch, the first input of which is connected to the output of the first amplifier stage, characterized in that the first output of the 1x2 microwave switch is directly connected to the second input of the microwave switch pa 2x1, and 2x1 switch the microwave output connected to the input of the second amplifier stage by controlled microwave attenuator, the control input of the microwave attenuator connected to the output of the microwave 2x1 switch, and the output managed microwave attenuator connected to the input of the second amplifier stage. 2. The input linear module of the microwave broadband receiver with the extended dynamic range according to claim 1, characterized in that the bandpass filter and power limiter are further included, while the input of the 1x2 microwave switch is connected to the output of the bandpass filter, and the input is a bandpass filter a pass filter is connected to the output of the power limiter. 3. The input linear module of the microwave broadband receiver with the extended dynamic range according to claim 1, characterized in that it also includes a 2x1 microwave switch for connecting a control signal, while the input of a 1x2 microwave switch is connected to the second output of a 2x1 microwave switch for connecting a control signal.

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