RU2569581C2 - Microwave single-channel radio interferometer with waveguide probing path - Google Patents

Abstract

FIELD: radio engineering, communication.

SUBSTANCE: invention relates to radio electronic engineering in the microwave range and can be used to measure parameters of high-speed processes of movement of different material objects, impact-wave and detonation fronts, and plasma. A microwave single-channel radio interferometer with a waveguide probing path, made on a dielectric waveguide with a dielectric radiator at the end, includes a transmitting-receiving device with two microwave outputs of receiving and transmitting channels, respectively, and a directional coupler for receiving a signal reflected from an analysed object. The microwave output of the transmitting channel of the transmitting-receiving device is connected to a waveguide probing path, and the microwave output of the receiving channel of the transmitting-receiving device is connected to a dielectric waveguide which, on the end portion, forms said directional coupler on a distributed coupling with the dielectric waveguide of the waveguide probing path.

EFFECT: obtaining limiting decoupling of the receiving and transmitting channels of the transmitting-receiving device of a reflecting-type microwave radio interferometer to increase sensitivity and the dynamic range of measurements of the radio interferometer, reducing background noise level, which increases accuracy of measuring movement of objects.

2 dwg

Description

The invention relates to electronic equipment in the microwave range and can be used to measure the parameters of fast-moving processes of motion of various material objects, shock-wave and detonation fronts, plasma.

For these purposes, microwave reflective-type microwave radio interferometers (RIs) are widely used with one emitter at the RI output for sensing an object and receiving a reflected signal [1].

Known single-channel microwave radiation sources contain a transmit-receive device (PPU) with a transmitting channel and a receiving channel, made according to the direct detection scheme or according to a superheterodyne circuit.

PUF provides the generation of probe radiation, reception and conversion of a signal reflected from a moving object under investigation into periodic voltages, which are supplied to the registration system from the device outputs.

The radio interferometer has one microwave output of the transmitting channel, loaded onto the wave guide probing path to irradiate the object of research and receive the reflected signal.

The received signal is branched into the receiver channel of the PPU by a directional coupler or a double T-bridge at the output of the transmitting channel [1; 2; 3].

The disadvantage of such radio interferometers having a combined transmitting and receiving microwave output of the PPU is the limited isolation of the receiving channel from the transmitting one, which leads to a limitation of the receiver sensitivity and dynamic measurement range, phase noise due to spurious re-reflections at the output of the transmitting channel.

In addition, the location of the object of study in hard-to-reach places or in the diagnosis of fast-moving processes requires spatial separation of the foam and the object of research by several tens of meters and their connection with a flexible waveguide probing path.

For this purpose, depending on the wavelength range used, a cable-guiding probing path in the form of a coaxial cable [4] or in the form of a dielectric waveguide [5] can be used.

The implementation of PUFs with separate microwave outputs of the transmitting and receiving channels, characteristic of the RI of the pass-through type [1], requires the presence of a wave guide probing path with an emitter for irradiating the object of study and a second path with an emitter for receiving the reflected signal. This option is unacceptable for reflective radiation sources, since the implemented bistatic sounding mode is incorrect at small distances from the emitters to the object of study.

Closest to the proposed invention is a microwave single-channel radio interferometer selected for the prototype, containing a directional coupler for receiving a signal reflected from the object of study in the transmitting channel to the microwave transmitting and receiving output of the PPU and an extended cable wave guide path connected to the specified transmitting and receiving output of the transmitting channel object of study [4].

The disadvantages of this interferometer, as well as analogs, are the limited isolation of the receiver from the transmitting channel and phase noise, limiting the accuracy of the measurements due to the mismatch of the impedance at the output of the transmitting channel PPU.

The technical result of the proposed invention is the possibility of obtaining the maximum isolation of the receiving and transmitting channels of the PUF of the microwave radiation reflective type to increase the sensitivity and dynamic measurement range of the radio interferometer, reduce phase noise, which ultimately increases the accuracy of measuring the movement of objects.

The technical result is achieved by the fact that in a microwave single-channel radio interferometer with a wave guide sounding path, including a transmit-receive device consisting of a receive channel and a transmit channel, a directional coupler for receiving a signal reflected from the object under study and a wave guide sounding path made on a dielectric waveguide for sensing object of research and reception of the reflected signal, the transceiver has two microwave outputs, one of which is is the output of the transmitting channel to which the waveguiding sounding path is connected with a dielectric emitter at the end, the other is the microwave output of the receiving channel to which a dielectric waveguide of at least one meter length is connected, which in a final section forms a directional directional waveguide of the waveguide sounding path a coupler for receiving a signal reflected from the object under study.

Figure 1 shows a microwave single-channel radio interferometer with a waveguide sounding path. The PUF of the radio interferometer is represented by a block diagram without detailing the circuit solution.

Figure 2 shows a microwave single-channel radio interferometer with a waveguide sounding path. PPU is executed according to the superheterodyne scheme.

Figure 1 shows a microwave single-channel radio interferometer with a waveguide sounding path. PPU 1 of the radio interferometer, which can be performed according to the direct detection circuit or according to the superheterodyne circuit, contains a transmitting channel 2 with a microwave output 3 and a receiving channel 4 with a microwave output 5. Between the channels of the PPU 2 and 4, an internal communication link for transmitting the reference signal is realized. To the microwave output 3 of the transmitting channel 2 is connected waveguide probing path 6, made on a dielectric waveguide (DW) with a dielectric emitter 7 at the end for sensing the object of study and receiving the reflected signal. To the microwave output 5 of the receiving channel 4 is connected a dielectric waveguide 8 with a length of at least 1 m and forming a directional coupler 9 in a distributed section with a distributed connection with the dielectric waveguide of the waveguide sounding path 6.

Figure 2 shows an example implementation of a microwave single-channel radio interferometer, PPU which is made according to the superheterodyne scheme.

PUF 1 of the radio interferometer contains a crystal oscillator 10 common to the transmitting and receiving channels, coupled to synthesizers of the reference frequencies 11 and 12 of the transmitter and local oscillator, respectively. Synthesizers 11 and 12 are connected to the blocks of the transmitter 13 and the local oscillator 14, made according to the scheme of high multiplication.

The reference channel of the radio interferometer contains a mixer 15 connected to the transmitter unit 13 by a power divider 16 and to the local oscillator unit 14 by a power divider 17. The output of the reference mixer 15 through a divider 18 is connected to quadrature phase detectors 19 and 20.

To the microwave output 3 of the transmitting channel of the PPU, containing the transmitter unit 13 and the power divider 16, a waveguide probing path 6 connected to a dielectric waveguide with a dielectric emitter 7 at the end is connected.

A dielectric waveguide 8 of at least one meter in length is connected to a mixer 21 of the receiver channel of the PPU containing a local oscillator unit 14 and a power divider 17 through a microwave output 5, which in the final section forms a directional coupler 9 for receiving reflected from the test channel in distributed communication with the waveguide probing path 6 signal object. At the same time, the local oscillator unit 14 is connected to the mixer 21 through a power divider 17, the output of the mixer 21 of the receiver channel of the PPU through the divider 22 is connected to quadrature phase detectors 19 and 20.

A microwave single-channel radio interferometer with a waveguide sounding path works as follows.

In the transmitting channel 2 of the transceiver 1 of the radio interferometer (Fig. 1), a highly stable continuous signal is generated, which from the microwave output 3 enters an extended probing waveguide path 6, made on the Far East with the emitter 7 at the end to probe the object of study and receive the reflected signal. At the same time, part of the generated signal from the transmitting channel 2 enters the receiving channel 4 as a coherent reference signal.

Due to the acceptable linear losses in the DW (2 dB / m in the 3 mm range), the length of the probing waveguide path 6 can be up to 10 m in almost the entire microwave range, up to submillimeter waves. With this length and due to the flexibility of the probing path on the DW, it is possible to irradiate and receive the reflected signal by the dielectric emitter 7 from the objects of study in hard-to-reach places.

The dielectric emitter 7 is made of the same dielectric as the DW of the wave guide probing path 6 to ensure coordination, and the shape of the emitter 7 is selected from the conditions for the formation of the beam nature of the radiation.

In the proposed single-channel reflector-type radio interferometer, in contrast to the prototype, the reflected signal is branched into the receiving channel 4 of the control unit 1 not in the control unit, but in a directional coupler 9 made on the distributed connection of the dielectric waveguides of the waveguide sounding path 6 and the dielectric waveguide 8 connected to the microwave the output 5 of the receiving channel 4 PPU 1 radio interferometer.

Due to the high directivity of this type of couplers (more than 30 dB) and a dielectric waveguide length of at least one meter, almost complete isolation (more than 80 dB) of the radio interferometer received from the transmitting channel of the PPU is ensured, noise level is reduced by minimizing spurious re-reflections at the output of the PPU.

A microwave single-channel radio interferometer with a wave guide probing path, the PUF of which is made according to the superheterodyne circuit, operates as follows (Fig. 2).

The thermostabilized quartz oscillator 10 with a frequency of 100 MHz synchronizes the synthesizers 11 and 12, made at the frequencies of the decimeter range (5 ÷ 8 GHz). The signals from the synthesizers are fed to the blocks of the transmitter 13 and the local oscillator 14, made according to the scheme of high multiplication. Due to the possibility of choosing a multiplication factor from 10 to 30, it is possible to implement a radio interferometer up to the frequencies of the submillimeter range.

Part of the signals from the blocks of the transmitter 13 and the local oscillator 14 through the power dividers 16 and 17 are fed to the mixer 15, forming at its output a signal of the reference intermediate frequency, which through the divider 18 is fed to the phase detectors 19 and 20. At the same time, the signal of the local oscillator 14 after the divider 17 is fed to mixer of the receiving channel 21. From the output of the mixer of the receiving channel 21, an information signal is fed to the divider 22 and then to the phase detectors 19 and 20, the quadrature signals from which are fed to the registration system.

The signal from the transmitter unit 13 through a power divider 16 enters the wave guide probing path 6, made on a dielectric waveguide. Due to acceptable linear losses, the length of the probing tract can be up to 10 m. With such a length and flexibility of the probing tract, it is possible to irradiate the objects of research in hard-to-reach places.

The wave-guiding sounding path 6 ends with a dielectric emitter 7, which probes the object of study and receives the reflected signal.

An experimental verification of the layout of the millimeter-wave radio interferometer was carried out according to the superheterodyne circuit.

When measuring the displacements of the test object (metal plate) in the range from 10 to 100 mm with a duration of the motion process of ~ 20 μs, the accuracy of measuring displacements was ± 0.05 mm. In similar measurements using a radio interferometer with one transceiver output, the measurement accuracy is almost an order of magnitude worse (± 0.4 mm).

Literature

1. Koch B. Radio-electronic methods for the study of fast processes / In the book. Physics of fast processes. Translation Ed. Zlatina N.A., Moscow: MIR, 1971, v. 1.

2. Porshnev S.V. Radar measurement methods for experimental ballistics / Ekaterinburg: Ur O RAS, 1999, - 211 p.

3. Zarko V.E., Vdovin D.V., Perov V.V. Methodological problems of measuring the burning rate of solid fuels using microwave radiation / Combustion and Explosion Physics, 2000, vol. 36, No. 1, pp. 68-78.

4. McCall, Bondzhanni, Miranda. A microwave interferometer for recording shock and detonation waves and the movement of matter / Instruments for Scientific Research, 1985, No. 8, pp. 117-124.

5. Patent RU 2116047 C1, Khramtsov P.A., Fedorov V.A., Method and device for assessing the state of human posture.

Claims (1)

A microwave single-channel radio interferometer with a waveguide sounding path, including a transmitting and receiving device, consisting of a receiving channel and a transmitting channel, a directional coupler for receiving a signal reflected from the object being studied and a waveguide sounding path made on a dielectric waveguide, characterized in that the transmitting and transmitting device has two microwave outputs, one of which is the output of the transmitting channel, to which a wave guide sounding path with ktricheskim emitter at the end, the other is a microwave output of the reception channel connected to the dielectric waveguide length of at least one meter, in which the end portion forms a distributed coupling with the dielectric waveguide probe volnoveduyuschego tract directional coupler for receiving a reflected signal from the test object.

Images