WO2021082030A1

WO2021082030A1 - Frequency-modulated continuous-wave radar level meter for measuring material level in container

Info

Publication number: WO2021082030A1
Application number: PCT/CN2019/115539
Authority: WO
Inventors: 呼秀山; 夏阳
Original assignee: 北京锐达仪表有限公司
Priority date: 2019-10-30
Filing date: 2019-11-05
Publication date: 2021-05-06

Abstract

A frequency-modulated continuous-wave radar level meter for measuring a material level in a container, belonging to the technical field of radar level meters. Said radar level meter comprises: a local oscillation module (3), configured to generate a local oscillation signal; a transmission path (200), configured to receive the local oscillation signal generated by the local oscillation module (3) and form an electromagnetic wave so as to transmit same to a target object; a reception path (300), configured to receive the electromagnetic wave reflected back by the target object and form a reflection signal; a frequency mixer (5), configured to receive the local oscillation signal generated by the local oscillation module (3), receive the reflection signal formed by the reception path (300), and perform frequency mixing to form a frequency mixing signal for determining a material level distance. This invention helps solve the problem of a near-end measurement blind zone of a frequency-modulated continuous-wave radar level meter, thereby improving the measurement reliability of the frequency-modulated continuous-wave radar level meter.

Description

A FM continuous wave radar level meter for measuring the level of materials in a container

Technical field

The application belongs to the technical field of radar level gauges, and specifically relates to a frequency modulated continuous wave radar level gauge for measuring the material level in a container.

Background technique

The frequency modulated continuous wave radar level gauge is a kind of radar level gauge, as shown in Figure 1, which is a schematic diagram of a typical structure of the frequency modulated continuous wave radar level gauge in related technologies.

In Figure 1, the processing module 1 is a device responsible for data processing. The processing module 1 controls the local oscillator module 3 through the frequency control module 2 to output a local oscillator signal with a frequency change. This frequency change generally changes linearly with time. That is chirp. The local oscillator signal can be divided into one way for the frequency control module 2 as a feedback signal for frequency control. If the frequency control is an open-loop control, there is no need for this feedback signal.

The local oscillator module 3 splits the local oscillator signal into one channel to the circulator 4 as the transmission signal of the FM continuous wave radar level gauge, and splits one channel into the mixer 5. In Figure 1, the signal transmission and reception of the FM continuous wave radar level gauge share a microwave path 100 (the following is represented by the microwave path 100 shared by transmission and reception), and the radio frequency connector in the shared microwave path 100 ( 100a, 100b), the radio frequency cable 100c, the feed source 100d, the waveguide 100e, and the antenna 100f are all shared for transmission and reception, and the circulator 4 is used to complete the isolation of signal transmission and reception. As shown in Figure 2, Figure 2 is a schematic diagram of a typical structure of the circulator 4 in the related art. When port A is used as input, port B is the output terminal, and port C is the isolated terminal; and when port B is used as input , Port C is the output terminal, and Port A is the isolation terminal. For the current FM continuous wave radar level gauge with the microwave path 100 shared by transmission and reception, port A is connected to the local oscillator module 3, port B is connected to the microwave path 100 shared by transmission and reception, and port C is connected to the mixer 5. The local oscillator module 3 transmits the local oscillator signal from the mixer 5 port A to the mixer 5 through the mixer 5 port B to the transmission and reception shared microwave path 100, and transmits to the target through the transmission and reception shared microwave path 100 The electromagnetic wave is emitted, and then the electromagnetic wave reflected by the target object is received through the microwave path 100 shared by the transmitting and receiving, and the reflected signal is formed and transmitted to the mixer 5. The mixer 5 mixes the local oscillator signal with the received reflected signal to obtain a mixed signal. This mixed signal is the frequency difference signal between the local oscillator signal and the reflected signal. The mixer 5 transmits the mixed signal to the intermediate frequency amplifier 6 to amplify the signal. The intermediate frequency amplifier 6 outputs the amplified signal to the A/D conversion module 7, and the processing module 1 collects the mixed frequency from the A/D conversion module 7. Signal, and then process this signal to get the level distance.

For the FM continuous wave radar level gauge shown in Figure 1, in actual use, on the one hand, due to the lack of signal isolation in the circulator 4, it is embodied as: the local oscillator signal of the local oscillator module 3 is used as the transmitted signal from the ring Port A of the device 4 is input, most of the signal is output from port B, a small part of it leaks out from port C, and leaks into mixer 5. On the other hand, the transmit signal output from port B is transmitting and receiving a common microwave During transmission in the channel 100, the impedance matching of each connection point in the microwave channel 100 shared by the transmitter and receiver cannot be perfect. For example, the connection structure of radio frequency cables, feeds, waveguides, and antennas cannot achieve perfect matching. Part of the transmitted signal transmitted in the microwave path 100 shared by the transmission and reception is directly reflected back, and then enters the circulator 4 from the port B of the circulator 4.

The above-mentioned small part of the local oscillator signal leaked from port C due to the insufficient isolation capability of the circulator 4, and the part of the transmitted signal directly reflected back in the microwave path 100 shared by the transmission and reception, after entering the circulator 4, will be treated as As a reflected signal, it is sent to the mixer 5 for mixing processing. This will form a strong interference echo at the near end of the FM continuous wave radar level meter, which will cause the FM continuous wave radar level meter to be in There is a measurement dead zone at the near end. As shown in Figure 3 and Figure 4, Figure 3 is a schematic diagram of a measurement result of the FM continuous wave radar level meter, and Figure 4 is another schematic diagram of the measurement result of the FM continuous wave radar level meter. In Figures 3 and 4, I It is the near-end interference wave formed by a small part of the local oscillator signal leaked from port C due to the insufficient isolation capability of the circulator 4, and the part of the transmitted signal that is directly reflected back in the shared microwave path 100 for transmission and reception; II Where is the reflected wave from the target. Figure 3 shows the situation where the target is far away from the FM continuous wave radar level meter. In this case, the near-end interference wave and the target reflected wave can be effectively distinguished, and when the target is away from the FM continuous wave radar object When the level meter is close, as shown in Figure 4, the reflected wave of the target object cannot be effectively identified due to the interference of the near-end interference wave, resulting in a near-end measurement blind zone, resulting in unreliable near-end measurement of the FM continuous wave radar level meter .

Summary of the invention

In order to at least overcome the problems in the related technology to a certain extent, this application provides a FM continuous wave radar level gauge for measuring the material level in a container, which is helpful for solving the near-end measurement of the FM continuous wave radar level gauge. The problem of the blind zone further improves the measurement reliability of the FM continuous wave radar level gauge.

To achieve the above objectives, this application adopts the following technical solutions:

This application provides a FM continuous wave radar level gauge for measuring the level of materials in a container, including:

The local oscillator module is used to generate the local oscillator signal;

The transmitting path is used to receive the local oscillator signal generated by the local oscillator module and form an electromagnetic wave to emit to the target;

The receiving path is used to receive the electromagnetic waves reflected by the target and form a reflected signal;

The mixer is used to receive the local oscillator signal generated by the local oscillator module and the reflected signal formed by the receiving path, and mix to form a mixing signal for determining the level distance.

further,

The emission path is arranged in a vertical direction, has a certain spatial span in the electromagnetic wave emission direction from top to bottom, and includes:

The transmitting feed source is used to receive the local oscillator signal generated by the local oscillator module and transform it into an electromagnetic wave;

A transmitting antenna for transmitting electromagnetic waves generated by the transmitting feed source to the target;

The transmitting antenna has a span in the electromagnetic wave transmitting direction;

The receiving path is arranged in a vertical direction, has a certain spatial span in the electromagnetic wave receiving direction from bottom to top, and includes:

A receiving antenna for receiving electromagnetic waves reflected by the target;

The receiving antenna has a span in the electromagnetic wave emission direction;

The receiving feed is used to convert the electromagnetic wave received by the receiving antenna into the reflected signal, and send it to the mixer.

further,

The emission path further includes:

A transmitting waveguide for transmitting electromagnetic waves generated by the transmitting feed source to the transmitting antenna;

The receiving path further includes:

The receiving waveguide is used to transmit the electromagnetic wave received by the receiving antenna to the receiving feed.

further,

The transmitting feed source is directly or indirectly connected to the local oscillator module, and the receiving feed source is directly or indirectly connected to the mixer.

further,

Transmitting signals between the local oscillator module and the transmitting feed through a first radio frequency cable, and transmitting signals between the mixer and the receiving feed through a second radio frequency cable;

Wherein, between the first radio frequency cable and the local oscillator module, between the first radio frequency cable and the transmit feed, between the second radio frequency cable and the mixer, And the connection between the second radio frequency cable and the receiving feed source is through a radio frequency connector.

further,

If the transmit path includes the transmit feed and the transmit antenna, but does not include the transmit waveguide, and the receive path includes the receive feed and the receive antenna, but does not include the receive waveguide, Then the transmitting feed source and the receiving feed source are both formed on the same circuit board, and the transmitting feed source is located in the transmitting antenna, and the receiving feed source is located in the receiving antenna; or,

If the transmit path includes the transmit feed, the transmit waveguide, and the transmit antenna, and the receive path includes the receive feed, the receive waveguide, and the receive antenna, the transmit feed , The receiving feed sources are all formed on the circuit board, and the transmitting feed source is located in the transmitting waveguide, and the receiving feed source is located in the receiving waveguide.

further,

If the transmit path includes the transmit feed and the transmit antenna, but does not include the transmit waveguide, and the receive path includes the receive feed and the receive antenna, but does not include the receive waveguide, Forming the transmitting feed source by using the part of the first microstrip line formed on the circuit board extending into the transmitting antenna, wherein the first microstrip line is directly connected to the local oscillator module; and The receiving feed is formed by using a portion of a second microstrip line formed on the circuit board extending into the receiving antenna, wherein the second microstrip line is directly connected to the mixer; or,

If the transmit path includes the transmit feed, the transmit waveguide, and the transmit antenna, and the receive path includes the receive feed, the receive waveguide, and the receive antenna, use the first The part of the microstrip line extending into the transmitting waveguide forms the transmitting feed; and the part of the second microstrip line extending into the receiving waveguide forms the receiving feed.

further,

If the transmit path includes the transmit feed and the transmit antenna, but does not include the transmit waveguide, and the receive path includes the receive feed and the receive antenna, but does not include the receive waveguide, The transmitting feed is formed by using a first microstrip antenna formed on the circuit board, wherein the first microstrip antenna is located in the transmitting antenna, and the first microstrip antenna is The vibration module is directly connected; and the receiving feed is formed by using a second microstrip antenna formed on the circuit board, wherein the second microstrip antenna is located in the receiving antenna, and the second microstrip antenna The line is directly connected to the mixer; or,

If the transmit path includes the transmit feed, the transmit waveguide, and the transmit antenna, and the receive path includes the receive feed, the receive waveguide, and the receive antenna, use the first A microstrip antenna forms the transmit feed, wherein the first microstrip antenna is located in the transmit waveguide, and the first microstrip antenna is directly connected to the local oscillator module; and the second microstrip antenna is used A band antenna forms the receiving feed, wherein the second microstrip antenna is located in the receiving waveguide, and the second microstrip line is directly connected to the mixer.

further,

The transmitting antenna and the receiving antenna are of independent structures, and the transmitting antenna and the receiving antenna are arranged in parallel and close to each other, or arranged close to each other.

further,

The transmitting antenna and the receiving antenna are formed separately by an antenna partition formed by a single antenna along the axial direction.

further,

The transmitting waveguide and the receiving waveguide are independent structures, and the transmitting waveguide and the receiving waveguide are arranged side by side and attached to each other, or arranged close to each other.

further,

The transmitting waveguide and the receiving waveguide are formed separately by a waveguide partition formed in the axial direction of a single waveguide.

further,

The FM continuous wave radar level gauge further includes:

A protection mechanism is used to prevent foreign objects from entering the transmitting path and the receiving path.

further,

The protection mechanism includes an antenna protection cover formed at the free end antenna openings of both the transmitting antenna and the receiving antenna.

further,

The protection mechanism includes: a plugging head, respectively formed in the transmitting waveguide and the receiving waveguide, or respectively formed in the transmitting antenna or the receiving antenna.

further,

The bottom of the antenna shield is a planar structure, or an outer convex structure, or an inner concave structure.

further,

If the transmitting antenna and the receiving antenna are of independent structures, the transmitting antenna and the receiving antenna are each close to the side of each other, and are connected to or close to the antenna shield.

further,

If the transmitting antenna and the receiving antenna are formed separately by an antenna partition formed by a single antenna along the axial direction, the antenna partition is connected to or close to the antenna shield.

further,

Both the transmitting antenna and the receiving antenna face the sides of the antenna shield and are attached to the antenna shield.

further,

Both the transmitting antenna and the receiving antenna each face the side surface of the antenna shield, and a fixing mechanism for fixing the fixed antenna shield is formed.

further,

The internal space formed by the radome, the transmitting antenna and the receiving antenna is filled with an anti-deformation material capable of allowing microwaves to penetrate.

further,

The transmitting antenna and the receiving antenna are both horn antennas or lens antennas.

further,

The FM continuous wave radar level gauge further includes:

A frequency control module connected to the local oscillator module;

An intermediate frequency amplifier, connected to the mixer;

An A/D conversion module, connected to the intermediate frequency module;

The processing module is respectively connected with the A/D conversion module and the frequency control module.

further,

The FM continuous wave radar level gauge further includes:

The display module is connected with the processing module.

further,

The FM continuous wave radar level gauge further includes:

A communication module, connected to the processing module; and/or,

The interface module is connected with the processing module.

further,

The transmitting feed source and the receiving feed source are linearly polarized feed sources.

further,

The transmitting feed source and the receiving feed source are circularly polarized feed sources, and the polarization directions of the two are opposite, wherein one is a left-handed polarization direction, and the other is a right-handed polarization direction.

further,

The transmitting waveguide and the receiving waveguide are cylindrical structures with a semicircular cross section, and the plane side surfaces of the transmitting waveguide and the receiving waveguide are close to or close to each other to form a cylindrical outer contour.

further,

The transmitting antenna and the receiving antenna are conical structures with a semicircular cross section, and the plane side surfaces of the transmitting antenna and the receiving antenna are close to or close to each other to form a conical outer contour.

This application adopts the above technical solutions and has at least the following beneficial effects:

The FM continuous wave radar level meter provided in this application eliminates the microwave path shared by the circulator and transmitter and receiver, and adopts independent transmission and reception paths to solve the problem of the near-end measurement blind zone of the FM continuous wave radar level meter. Problems, and then improve the measurement reliability of the FM continuous wave radar level gauge.

It should be understood that the above general description and the following detailed description are only exemplary and explanatory, and cannot limit the application.

Description of the drawings

In order to more clearly describe the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings that need to be used in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only These are some embodiments of the present application. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative work.

Figure 1 is a schematic diagram of a typical structure of a FM continuous wave radar level gauge in related technologies;

Figure 2 is a schematic diagram of a typical structure of a circulator in the related art;

Figure 3 is a schematic diagram of a measurement result of a FM continuous wave radar level gauge;

Figure 4 is a schematic diagram of another measurement result of the FM continuous wave radar level gauge;

Figure 5 is a schematic structural diagram of a FM continuous wave radar level gauge provided by an embodiment of the application;

6 is a schematic structural diagram of a FM continuous wave radar level gauge provided by another embodiment of the application;

Fig. 7 is a schematic structural diagram of a FM continuous wave radar level gauge provided by another embodiment of the application;

FIG. 8 is a schematic structural diagram of a FM continuous wave radar level gauge provided by another embodiment of the application;

Fig. 9 is a schematic diagram of a specific structure at A in Fig. 8;

FIG. 10 is a schematic structural diagram of a FM continuous wave radar level gauge provided by another embodiment of the application;

FIG. 11 is a schematic diagram of a specific structure at B in FIG. 10.

Detailed ways

In order to make the purpose, technical solution and advantages of this application clearer, the technical solution of this application will be described in detail below. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in this application, all other implementations obtained by a person of ordinary skill in the art without creative work shall fall within the scope of protection of this application.

This application provides a FM continuous wave radar level gauge for measuring the level of materials in a container. The top of the container has an opening or a microwave-permeable window structure. Please refer to Figures 5 to 7. Wave radar level gauge, including:

The local oscillator module 3 is used to generate a local oscillator signal;

The transmitting path 200 is used to receive the local oscillator signal generated by the local oscillator module 3 and form an electromagnetic wave to emit to the target;

The receiving path 300 is used to receive the electromagnetic waves reflected by the target and form a reflected signal;

The mixer 5 is configured to receive the local oscillator signal generated by the local oscillator module 3 and the reflected signal formed by the receiving channel 300, and mix to form a mixing signal for determining the level distance.

Specifically, in the above-mentioned embodiment scheme, relative to the FM continuous wave radar level meter in the related technology (such as the FM continuous wave radar level meter shown in FIG. 1), the FM continuous wave radar level meter provided in this application ( As shown in Figures 5 to 7), by abandoning the circulator 4 and the microwave channel 100 shared by the transmitter and receiver, and set up separate transmission channels 200 and receiving channels 300, on the one hand, it can solve the problem of insufficient isolation of the circulator resulting in part of the transmitted signal. Leakage is a problem that is treated as a reflected signal and then sent to the mixer for mixing processing; on the other hand, the transmission and reception channels are independent of each other, and the transmission and reception of the signal are independent of each other. The transmission path 200 is only used for transmission. Used, not used for receiving; the receiving path 300 is only used for receiving, not for transmitting, so that there is no situation that the transmitted signal is directly coupled to the receiving path 300, and even the connection points in the transmitting path 200 will cause signal reflection , The signal reflected in the transmission path 200 can not be received, so that the part of the transmitted signal directly reflected in the microwave path shared by the transmission and reception can be solved. After entering the circulator, it will be treated as a reflected signal and then sent to the mixer. 5 The problem of mixing processing. Therefore, the solution of the embodiment of the present application can effectively solve the above two problems, and further can solve the problem of the near-end measurement blind zone of the FM continuous wave radar level gauge, thereby improving the measurement reliability of the FM continuous wave radar level gauge.

In one embodiment, the transmitting path 200 includes:

The emission path 200 is arranged in a vertical direction, and has a certain spatial span in the electromagnetic wave emission direction from top to bottom (as shown in FIG. 8 and FIG. 10), and includes: (as shown in FIG. 5)

The transmitting feed source 200a is used to receive the local oscillator signal generated by the local oscillator module 3 and transform it into an electromagnetic wave;

The transmitting antenna 200b is used to transmit the electromagnetic wave generated by the transmitting feed source 200a to the target;

The transmitting antenna 200b has a span in the electromagnetic wave transmitting direction;

The receiving path 300 is arranged in a vertical direction, and has a certain spatial span in the electromagnetic wave receiving direction from bottom to top (as shown in FIG. 8 and FIG. 10), and includes: (as shown in FIG. 5)

The receiving antenna 300a is used to receive the electromagnetic waves reflected by the target;

The receiving antenna 300a has a span in the electromagnetic wave emission direction;

The receiving feed 300b is used to convert the electromagnetic wave received by the receiving antenna 300a into the reflected signal, and send it to the mixer.

Specifically, the transmitting feed source 200a is connected to the local oscillator module 3, and the receiving feed source 300b is connected to the mixer 5. It can be seen that the mixer 5 is only connected to the receiving feed source 300b, but not to the transmitting feed source 200a, so there are only 5 mixers. The reflected signal formed by the receiving feed 300b will be received.

The transmitting antenna 200b and the receiving antenna 300a may be horn antennas or lens antennas. For horn antennas, the cross section may be semicircular, rectangular, or other irregular shapes.

For the two feed sources of the transmitting feed source 200a and the receiving feed source 300b, the structures of the two feed sources may be the same, and the specific feed source structure may be a feed structure of a coaxial to waveguide.

The transmitting feed source and the receiving feed source may be linearly polarized feed sources, or the transmitting feed source and the receiving feed source are circularly polarized feed sources, and the polarization directions of the two are opposite, where one One is the left-handed polarization direction, and the other is the right-handed polarization direction. The feed source is located on the microwave circuit or fixed on the microwave circuit board, and the corresponding antenna is aligned with the feed source in the vertical direction below the feed source.

For the transmitting antenna 200b and the receiving antenna 300a, they can be formed by metal casting, or they can be formed by casting a plastic into an integral structure, and then coated with conductive material on the surface.

As shown in FIG. 6, FIG. 8 and FIG. 10, the transmitting path 200 further includes:

The transmitting waveguide 200c is used to transmit the electromagnetic waves generated by the transmitting feed source 200a to the transmitting antenna 200b;

The receiving path 300 further includes:

The receiving waveguide 300c is used to transmit the electromagnetic waves received by the receiving antenna 300a to the receiving feed 300b.

Specifically, the transmitting antenna 200b transmits the radar waves generated by the transmitting feed 200a through the transmitting waveguide 200c, and transmits the received radar waves to the receiving feed 300b through the receiving antenna 300a through the receiving waveguide 300c. In practical applications, The axes of the transmitting waveguide 200c and the transmitting antenna 200b are collinear, and the axes of the receiving waveguide 300c and the receiving antenna 300a are collinear.

For the transmitting waveguide 200c and the receiving waveguide 300c, they can be formed by metal casting, or they can be formed by plastic casting into an integral structure, and then coated with conductive material on the surface.

In one embodiment, the transmitting feed source 200a is directly or indirectly connected to the local oscillator module 3, and the receiving feed source 300b is directly or indirectly connected to the mixer 5.

For the indirect connection, as shown in FIG. 7, in a specific embodiment, a signal is transmitted between the local oscillator module 3 and the transmitting feed source 200a through a first radio frequency cable 200d, and the mixer 5 The signal is transmitted between the receiving feed source 300b and the second radio frequency cable 300d;

Wherein, between the first radio frequency cable 200d and the local oscillator module 3, between the first radio frequency cable 200d and the transmitting feed source 200a, the second radio frequency cable 300d and the hybrid Between the frequency converters 5, and between the second radio frequency cable 300d and the receiving feed source 300b, they are all connected by radio frequency connectors (200e, 200f, 300e, 300f,).

Specifically, as shown in FIG. 7, the transmitting feed source 200a and the local oscillator module 3 are indirectly connected through a first radio frequency cable 200d, and the receiving feed source 300b and the mixer 5 are indirectly connected through a second radio frequency cable 300d. , Both the transmitting feed 200a and the receiving feed 300b transmit signals through radio frequency cables, and the extension of the FM continuous wave radar level gauge in the length direction can be realized through the radio frequency cables.

For the case of direct connection, as shown in Figure 8 to Figure 10, in actual applications, the local oscillator module 3 and the mixer 5 are shaped on a circuit board, and the microstrip line directly connected to the local oscillator module 3 can be used to form the transmitter. The feed source 200a and the microstrip line directly connected to the mixer 5 can be used to form the receiving feed source 300b. It is also possible to form a microstrip antenna for transmission on the circuit board, and connect it directly to the local oscillator module 3. The microstrip antenna for transmission forms the transmitting feed 200a, and a microstrip antenna is formed on the circuit board. The receiving microstrip antenna is directly connected to the mixer 5, and the receiving microstrip antenna forms the receiving feed 300b. For the microstrip antenna used as the feed source, it can be a microstrip array antenna formed by multiple array elements, or a microstrip antenna formed by a single array element. The direct connection between the transmitting feed source 200a and the local oscillator module 3 and the direct connection between the receiving feed source 300b and the mixer 5 help to reduce the problem of impedance mismatch caused by the connection point.

Around the above-mentioned transmitting feed source 200a is directly connected to the local oscillator module 3, and the receiving feed source 300b is directly connected to the mixer 5, this application will also give a further extended embodiment for description below. .

In an embodiment, if the transmitting path 200 includes the transmitting feed 200a and the transmitting antenna 200b, but does not include the transmitting waveguide 200c, and the receiving path 300 includes the receiving feed 300b and the transmitting antenna 200b. If the receiving antenna 300a does not include the receiving waveguide 300c, the transmitting feed source 200a and the receiving feed source 300b are both formed on the same circuit board 11, and the transmitting feed source 200a is located on the transmitting antenna 200b , And the receiving feed 300b is located in the receiving antenna 300a; or,

As shown in FIGS. 8 to 10, if the transmitting path 200 includes the transmitting feed 200a, the transmitting waveguide 200c, and the transmitting antenna 200b, and the receiving path 300 includes the receiving feed 300b, The receiving waveguide 300c and the receiving antenna 300a, the transmitting feed source 200a and the receiving feed source 300b are both formed on the circuit board 11, and the transmitting feed source 200a is located in the transmitting waveguide 200c, And the receiving feed 300b is located in the receiving waveguide 300c.

Specifically, the above-mentioned transmitting path 200 includes the transmitting feed 200a and the transmitting antenna 200b, but does not include the transmitting waveguide 200c, and the receiving path 300 includes the receiving feed 300b and the receiving antenna. 300a, but not including the receiving waveguide 300c, is to directly transmit the radar waves generated by the transmitting feed 200a through the transmitting antenna 200b, and directly transmit the received radar waves to the receiving feed 300b through the receiving antenna 300a In practical applications, the above situation needs to be satisfied: the transmitting port from the transmitting feed 200a to the transmitting antenna 200b has a spatial span in the transmitting direction, and the receiving port from the receiving feed 300b to the patch antenna also needs to have space in the receiving direction. The above-mentioned spatial span can be realized by the transmitting antenna 200b and the receiving antenna 300a themselves. For example, a horn antenna can be used to realize this spatial span.

Further, as shown in FIGS. 8 and 9, if the transmitting path 200 includes the transmitting feed 200a and the transmitting antenna 200b, but not including the transmitting waveguide 200c, and the receiving path 300 includes the The receiving feed 300b and the receiving antenna 300a, but not including the receiving waveguide 300c, use the portion of the first microstrip line formed on the circuit board 11 extending into the transmitting antenna 200b to form the transmitting antenna. The feed source 200a, wherein the first microstrip line is directly connected to the local oscillator module 3; and is formed by using the portion of the second microstrip line formed on the circuit board 11 extending into the receiving antenna 300a The receiving feed 300b, wherein the second microstrip line is directly connected to the mixer 5; or,

If the transmit path 200 includes the transmit feed 200a, the transmit waveguide 200c, and the transmit antenna 200b, and the receive path 300 includes the receive feed 300b, the receive waveguide 300c, and the receive antenna 300a, the part of the first microstrip line extending into the transmitting waveguide 200c is used to form the transmitting feed source 200a; and the part of the second microstrip line extending into the receiving waveguide 300c is used to form the transmitting feed source 200a. The receiving feed 300b.

As shown in Figs. 8 and 9, specifically, in the above-mentioned related embodiments, the feed is formed by a microstrip line. In practical applications, the microstrip line extending into the waveguide can be made into a needle shape as the feed. The transmitting waveguide 200c and the receiving waveguide 300c are directly fixed on the circuit board 11, and then the sides of the transmitting waveguide 200c and the receiving waveguide 300c have openings, and the first microstrip line connected to the local oscillator module 3 extends into the transmitting waveguide 200c. In the transmitting feed source 200a, the transmitting signal generated by the local oscillator module 3 enters the transmitting waveguide 200c through the first microstrip line for transmission in and out. The portion of the second microstrip line connected to the microwave receiving signal input end of the mixer 5 extending into the receiving waveguide 300c constitutes the receiving feed 300b.

Regarding the case where the transmitting path 200 does not include the transmitting waveguide 200c, and the receiving path 300 does not include the receiving waveguide 300c, and the transmitting antenna 200b and the receiving antenna 300a are directly fixed on the circuit board 11, the transmitting antenna 200b and the receiving antenna 300a can be horn antennas. The related implementation can refer to the above-mentioned implementation in which the transmitting waveguide 200c and the receiving waveguide 300c have openings on the sides and introducing the microstrip line.

Further, as shown in FIGS. 10 and 11, if the transmitting path 200 includes the transmitting feed 200a and the transmitting antenna 200b, but does not include the transmitting waveguide 200c, and the receiving path 300 includes the The receiving feed 300b and the receiving antenna 300a, but not including the receiving waveguide 300c, the transmitting feed 200a is formed by using the first microstrip antenna formed on the circuit board 11, wherein the first A microstrip antenna is located in the transmitting antenna 200b, and the first microstrip antenna is directly connected to the local oscillator module 3; and a second microstrip antenna formed on the circuit board 11 is used to form the receiving feed The source 300b, wherein the second microstrip antenna is located in the receiving antenna 300a, and the second microstrip line is directly connected to the mixer 5; or,

If the transmit path 200 includes the transmit feed 200a, the transmit waveguide 200c, and the transmit antenna 200b, and the receive path 300 includes the receive feed 300b, the receive waveguide 300c, and the receive antenna 300a, the first microstrip antenna is used to form the transmitting feed source 200a, wherein the first microstrip antenna is located in the transmitting waveguide 200c, and the first microstrip antenna and the local oscillator module 3 direct connection; and using the second microstrip antenna to form the receiving feed 300b, wherein the second microstrip antenna is located in the receiving waveguide 300c, and the second microstrip line and the mixed The frequency converter 5 is directly connected.

Specifically, FIG. 10 shows a situation in which the transmitting path 200 includes a transmitting waveguide 200c and the receiving path 300 includes a receiving waveguide 300c in the above-mentioned related embodiment, and the transmitting waveguide 200c and the receiving waveguide 300c are directly fixed on the circuit board 11. Regarding the case where the transmitting path 200 does not include the transmitting waveguide 200c, and the receiving path 300 does not include the receiving waveguide 300c, and the transmitting antenna 200b and the receiving antenna 300a are directly fixed on the circuit board 11, the transmitting antenna 200b and the receiving antenna 300a can be horn antennas. For related implementations, reference may be made to the application of microstrip antennas respectively provided in the transmitting waveguide 200c and the receiving waveguide 300c shown in FIG. 10.

As shown in FIG. 11, the microstrip antenna used as the feed source can be a microstrip array antenna formed by multiple array elements, or a microstrip antenna formed by a single array element.

For the formation of the transmitting antenna 200b and the receiving antenna 300a, the present application provides the following related embodiments for description.

In one embodiment, the transmitting antenna 200b and the receiving antenna 300a are of independent structures, and the transmitting antenna 200b and the receiving antenna 300a are arranged side by side or close to each other.

Specifically, the transmitting antenna 200b and the receiving antenna 300a are independent structures, and one may be a mirror image of the other. In specific applications, two horns with a semicircular cross section can be combined into a horn structure with a circular appearance. For example, the transmitting antenna and the receiving antenna are conical structures with a semicircular cross section. And the plane side surfaces of the transmitting antenna and the receiving antenna are close to or close to each other to form a conical outer contour. The situation shown in Figures 8 and 10 can be formed by the parallel arrangement of the transmitting antenna 200b and the receiving antenna 300a. The arrangement of the two can be implemented by welding, bundling, bonding, buckling, mortise and tenon, etc. .

In another embodiment, the transmitting antenna 200b and the receiving antenna 300a are formed separately by an antenna partition formed by a single antenna along the axial direction.

Specifically, the transmitting antenna 200b and the receiving antenna 300a are two modules of a single antenna, which are formed by being separated by an antenna partition. Taking a horn antenna as an example, the situation shown in Figs. 8 and 10 can also be inserted in the middle of a horn antenna. A conductive partition separates the transmitting antenna 200b and the receiving antenna 300a.

For the formation of the transmitting waveguide 200c and the receiving waveguide 300c, this application provides the following related embodiments for description.

In one embodiment, the transmitting waveguide 200c and the receiving waveguide 300c are independent structures, and the transmitting waveguide 200c and the receiving waveguide 300c are arranged side by side or close to each other.

Specifically, the transmitting waveguide 200c and the receiving waveguide 300c are independent structures, and one may be a mirror image of the other. In specific applications, two waveguides with a semicircular or semi-elliptical cross section can be combined into a waveguide with a circular or elliptical appearance. For example, the transmitting waveguide and the receiving waveguide are semicircular in cross section. The cylindrical structure of the transmitting waveguide and the plane side surface of the receiving waveguide are close to or close to each other to form a cylindrical outer contour. The situation shown in FIGS. 8 and 10 can be formed by attaching the transmitting waveguide 200c and the receiving waveguide 300c side by side. For the attaching arrangement of the two, it can be realized by welding, bundling, bonding, buckle, mortise and so on. .

In specific applications, when the transmitting antenna 200b and the receiving antenna 300a are attached to form an integral antenna with a circular cross-section, and when the transmitting waveguide 200c and the receiving waveguide 300c are attached to form an integral waveguide with a circular cross-section, the circle Both the integral antenna of the circular structure and the integral waveguide of the circular structure may be collinear in axis.

The transmitting waveguide 200c and the receiving waveguide 300c may be waveguides with gradually increasing diameters.

In another embodiment, the transmitting waveguide 200c and the receiving waveguide 300c are formed separately by a waveguide partition formed in the axial direction of a single waveguide.

Specifically, the transmitting waveguide 200c and the receiving waveguide 300c are two modules of single waveguides. The situation shown in Figs. 8 and 10 may also be that a single single waveguide is separated by a waveguide partition to form the transmitting waveguide 200c and the receiving waveguide 300c.

As shown in Figures 8 and 10, in one embodiment, the FM continuous wave radar level gauge further includes:

The protection mechanism 12 is used to prevent foreign objects from entering the transmitting path 200 and the receiving path 300.

In the related art, the protective mechanism 12 can allow electromagnetic waves to pass through, but can prevent foreign objects from entering. In specific applications, depending on the specific purpose of the FM continuous wave radar level gauge, the protective mechanism 12 can prevent corrosion, steam, dust, or The role of pressure, high temperature, etc. The protection mechanism 12 of the present application also achieves the above-mentioned basic functions.

further,

The protection mechanism 12 includes an antenna protection cover (the protection mechanism 12 shown in FIG. 8 and FIG. 10 is a protection cover), which is formed at the free end antenna openings of the transmitting antenna 200b and the receiving antenna 300a.

Specifically, Figures 8 and 10 show a schematic structural diagram of the antenna shield. In the finished product of the FM continuous wave radar level gauge, the transmitting antenna 200b and the receiving antenna 300a have been installed, the transmitting antenna 200b and the receiving antenna The antenna port of 300a for facing the target is the free-end antenna port.

further,

The protection mechanism 12 includes a plugging head, which is formed in the transmitting waveguide 200c and the receiving waveguide 300c, or respectively, formed in the transmitting antenna 200b or the receiving antenna 300a.

It should be noted that in the related technology, the antenna of the FM continuous wave radar level gauge is shared by the transceiver. It is a single antenna. The radome or plugging the head is installed to achieve the purpose of protection. The electromagnetic waves emitted by the FM continuous wave radar level gauge are When encountering a radome or a blocked head, reflection will inevitably occur, resulting in a reflected signal, and the reflected signal will increase the interference wave at the near end of the FM continuous wave radar level gauge. It is understandable that the FM continuous wave radar object in the related technology When the radome is installed on the level gauge, the measurement blind area of the FM continuous wave radar level gauge will inevitably increase.

However, this application can effectively solve the problem of increasing the measurement blind area when the protective mechanism 12 is installed for the FM continuous wave radar level gauge. The specific expression is: the transmitting antenna 200b and the receiving antenna 300a of this application are arranged in parallel, and the transmitting antenna 200b is only used for The transmitting electromagnetic wave and the receiving antenna 300a are only used to receive electromagnetic waves. In specific applications, the transmitting antenna 200b and the receiving antenna 300a are both aimed at the target. The transmitting antenna 200b transmits electromagnetic waves to the target. The electromagnetic waves in the transmitting direction encounter the protection mechanism. When the part on the 12 opposite to it, a transmission signal is generated. Because of the separation between the transmitting antenna 200b and the receiving antenna 300a, the reflected signal is reflected into the transmitting antenna 200b and will not be received by the receiving antenna 300a. Solve the problem of increasing measurement blind areas caused by the protection mechanism 12.

In summary, through the FM continuous wave radar level meter solution of the present application, compared with the FM continuous wave radar level meter in related technologies (such as the FM continuous wave radar level meter shown in Figure 1), the circulator is discarded. As well as setting up separate transmission channels 200 and receiving channels 300 at the same time, the following three problems can be solved:

First, it can solve the problem that a part of the transmitted signal leaks due to insufficient isolation of the circulator, which is treated as a reflected signal and then sent to the mixer 5 for mixing processing.

Second, the independent transmission path 200 and the receiving path 300 realize the independence of signal transmission and reception. The transmission path 200 is only used for transmitting function, not for receiving; the receiving path 300 is only used for receiving, not for transmitting. In this way, there is no situation that the transmitted signal is directly coupled to the receiving path 300, and even if each connection point in the transmitting path 200 causes signal reflection, the signal reflected in the transmitting path 200 cannot be received, which can solve the problem of transmission and reception sharing. The part of the transmitted signal that is directly reflected back in the microwave path will be treated as a reflected signal after entering the circulator, and then sent to the mixer 5 for mixing processing.

Third, the problem of increasing measurement blind spots caused by the protection mechanism 12 can be solved.

Therefore, the solution of the embodiment of the present application can effectively solve the above-mentioned three problems, and further can solve the problem of the near-end measurement blind area of the FM continuous wave radar level gauge, thereby improving the measurement reliability of the FM continuous wave radar level gauge.

In an embodiment, the bottom of the antenna shield is a planar structure, or an outer convex structure, or an inner concave structure.

In actual use, the FM continuous wave radar level gauge is placed vertically, and the radome is also placed vertically. The bottom of the antenna shield is the part facing the free end antenna ports of the transmitting antenna 200b and the receiving antenna 300a.

Specifically, the bottom of the antenna shield may be an upwardly concave conical surface or spherical surface, or a downwardly protruding conical surface or spherical surface.

Regarding the relationship between the radome and the transmitting antenna 200b and the receiving antenna 300a, the present application provides the following related embodiments for description.

In one embodiment, if the transmitting antenna 200b and the receiving antenna 300a are of independent structures, the transmitting antenna 200b and the receiving antenna 300a are respectively close to the side of each other and connected to or close to the antenna shield .

In another embodiment, if the transmitting antenna 200b and the receiving antenna 300a are formed separately by an antenna partition formed by a single antenna along the axial direction, the antenna partition is connected to or close to the antenna shield.

Specifically, the connection mentioned in the above two embodiments can be realized by bonding, thread, screw, buckle, card slot, strapping, etc. It can support the antenna shield when it is under positive pressure. When under negative pressure, it acts as a tension for the antenna shield to prevent deformation of the antenna cover.

In one embodiment, the transmitting antenna 200b and the receiving antenna 300a each face the side of the antenna shield, and are attached to the antenna shield.

Specifically, the side of the antenna shield is attached to the transmitting antenna 200b and the receiving antenna 300a. In a high-voltage situation, the transmitting antenna 200b and the receiving antenna 300a can support the antenna shield.

Further, the transmitting antenna 200b and the receiving antenna 300a each face the side of the antenna shield, and a fixing mechanism for fixing the fixed antenna shield is formed.

Specifically, both the transmitting antenna 200b and the receiving antenna 300a are fixed to the antenna shield by their respective fixing mechanisms, which can effectively prevent the antenna shield from deforming when under pressure.

In an embodiment, the internal space formed by the radome, the transmitting antenna and the receiving antenna is filled with an anti-deformation material capable of allowing microwaves to penetrate.

Specifically, the anti-deformation material may be plastic to fill the internal space formed by the radome, the transmitting antenna and the receiving antenna, to make it solid, and to improve the pressure resistance of the radome.

As shown in Figures 5 to 7, in one embodiment, the FM continuous wave radar level gauge further includes:

The frequency control module 2 is connected to the local oscillator module 3;

The intermediate frequency amplifier 6 is connected to the mixer 5;

The A/D conversion module 7 is connected to the intermediate frequency module;

The processing module 1 is connected to the A/D conversion module 7 and the frequency control module 2 respectively.

Specifically, the processing module 1 may adopt a DSP processor, and the frequency control module 2 may adopt a phase-locked loop.

For the above-mentioned frequency control module 2, intermediate frequency amplifier 6, A/D conversion module 7, and processing module 1, the related applications can refer to the FM continuous wave radar level meter in the related technology. In addition, in the background technology of this application, There are corresponding descriptions for each of the above-mentioned module components, so you can also refer to them, and will not be further described here.

As shown in Figs. 5 to 7, further, the FM continuous wave radar level gauge further includes:

The display module 8 is connected to the processing module 1.

Specifically, the display module 8 can display data or curves or text, allow the user to observe the current measurement results, and allow the user to query and set parameters.

The communication module 9 is connected to the processing module 1; and/or,

The interface module 10 is connected to the processing module 1.

Specifically, through the communication module and/or the interface module, the external output signal mode can be 4-20mA, HART, FF, profibus, etc.

It can be understood that the same or similar parts in the foregoing embodiments may be referred to each other, and for the contents not described in detail in some embodiments, reference may be made to the same or similar contents in other embodiments.

It should be noted that in the description of this application, the terms "first", "second", etc. are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance. In addition, in the description of this application, unless otherwise specified, the meaning of "plurality" and "multiple" means at least two.

It should be understood that when we say that a component is "connected" to another component, it can be directly connected to the other component, or the connection between the two can also be realized through an intermediate component. In addition, "connection" as used herein may include wireless connection. The term "and/or" used includes any unit and all combinations of one or more of the associated listed items.

Any process or method description in the flowchart or described in other ways herein can be understood as: a module, segment or part of code that includes one or more executable instructions for implementing specific logical functions or steps of the process , And the scope of the preferred embodiments of the present application includes additional implementations, which may not be in the order shown or discussed, including performing functions in a substantially simultaneous manner or in the reverse order according to the functions involved. This should It is understood by those skilled in the art to which the embodiments of the present application belong.

It should be understood that each part of this application can be implemented by hardware, software, firmware, or a combination thereof. In the above embodiments, multiple steps or methods can be implemented by software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if it is implemented by hardware, as in another embodiment, it can be implemented by any one or a combination of the following technologies known in the art: Discrete logic circuits, application-specific integrated circuits with suitable combinational logic gates, programmable gate arrays (PGA), field programmable gate arrays (FPGA), etc.

A person of ordinary skill in the art can understand that all or part of the steps carried in the method of the foregoing embodiments can be implemented by a program instructing relevant hardware to complete. The program can be stored in a computer-readable storage medium, and the program can be stored in a computer-readable storage medium. When executed, it includes one of the steps of the method embodiment or a combination thereof.

In addition, the functional units in the various embodiments of the present application may be integrated into one processing module 58, or each unit may exist alone physically, or two or more units may be integrated into one module. The above-mentioned integrated modules can be implemented in the form of hardware or software function modules. If the integrated module is implemented in the form of a software function module and sold or used as an independent product, it can also be stored in a computer readable storage medium.

The aforementioned storage medium may be a read-only memory, a magnetic disk or an optical disk, etc.

In the description of this specification, descriptions with reference to the terms "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" etc. mean specific features described in conjunction with the embodiment or example , The structure, materials, or characteristics are included in at least one embodiment or example of the present application. In this specification, the schematic representation of the above-mentioned terms does not necessarily refer to the same embodiment or example. Moreover, the described specific features, structures, materials or characteristics may be combined in any one or more embodiments or examples in a suitable manner.

Although the embodiments of the present application have been shown and described above, it can be understood that the above-mentioned embodiments are exemplary and should not be construed as limiting the present application. A person of ordinary skill in the art can comment on the foregoing within the scope of the present application. The embodiment undergoes changes, modifications, substitutions, and modifications.

Claims

A FM continuous wave radar level gauge for measuring the level of materials in a container is characterized in that it comprises:

The local oscillator module is used to generate the local oscillator signal;

The transmitting path is used to receive the local oscillator signal generated by the local oscillator module and form an electromagnetic wave to emit to the target;

The receiving path is used to receive the electromagnetic waves reflected by the target and form a reflected signal;

The mixer is used to receive the local oscillator signal generated by the local oscillator module and the reflected signal formed by the receiving path, and mix to form a mixing signal for determining the level distance.
The FM continuous wave radar level gauge according to claim 1, characterized in that,

The emission path is arranged in a vertical direction, has a certain spatial span in the electromagnetic wave emission direction from top to bottom, and includes:

The transmitting feed source is used to receive the local oscillator signal generated by the local oscillator module and transform it into an electromagnetic wave;

A transmitting antenna for transmitting electromagnetic waves generated by the transmitting feed source to the target;

The transmitting antenna has a span in the electromagnetic wave transmitting direction;

The receiving path is arranged in a vertical direction, has a certain spatial span in the electromagnetic wave receiving direction from bottom to top, and includes:

A receiving antenna for receiving electromagnetic waves reflected by the target;

The receiving antenna has a span in the electromagnetic wave emission direction;

The receiving feed is used to convert the electromagnetic wave received by the receiving antenna into the reflected signal, and send it to the mixer.
The FM continuous wave radar level gauge according to claim 2, characterized in that,

The emission path further includes:

A transmitting waveguide for transmitting electromagnetic waves generated by the transmitting feed source to the transmitting antenna;

The receiving path further includes:

The receiving waveguide is used to transmit the electromagnetic wave received by the receiving antenna to the receiving feed.
The FM continuous wave radar level gauge according to claim 2 or 3, characterized in that:

The transmitting feed source is directly or indirectly connected to the local oscillator module, and the receiving feed source is directly or indirectly connected to the mixer.
The FM continuous wave radar level gauge according to claim 4, characterized in that,

Transmitting signals between the local oscillator module and the transmitting feed through a first radio frequency cable, and transmitting signals between the mixer and the receiving feed through a second radio frequency cable;

Wherein, between the first radio frequency cable and the local oscillator module, between the first radio frequency cable and the transmit feed, between the second radio frequency cable and the mixer, And the connection between the second radio frequency cable and the receiving feed source is through a radio frequency connector.
The FM continuous wave radar level gauge according to claim 4, characterized in that,

If the transmit path includes the transmit feed and the transmit antenna, but does not include the transmit waveguide, and the receive path includes the receive feed and the receive antenna, but does not include the receive waveguide, Then the transmitting feed source and the receiving feed source are both formed on the same circuit board, and the transmitting feed source is located in the transmitting antenna, and the receiving feed source is located in the receiving antenna; or,

If the transmit path includes the transmit feed, the transmit waveguide, and the transmit antenna, and the receive path includes the receive feed, the receive waveguide, and the receive antenna, the transmit feed , The receiving feed sources are all formed on the circuit board, and the transmitting feed source is located in the transmitting waveguide, and the receiving feed source is located in the receiving waveguide.
The FM continuous wave radar level gauge according to claim 6, characterized in that,

If the transmit path includes the transmit feed and the transmit antenna, but does not include the transmit waveguide, and the receive path includes the receive feed and the receive antenna, but does not include the receive waveguide, Forming the transmitting feed source by using the part of the first microstrip line formed on the circuit board extending into the transmitting antenna, wherein the first microstrip line is directly connected to the local oscillator module; and The receiving feed is formed by using a portion of a second microstrip line formed on the circuit board extending into the receiving antenna, wherein the second microstrip line is directly connected to the mixer; or,

If the transmit path includes the transmit feed, the transmit waveguide, and the transmit antenna, and the receive path includes the receive feed, the receive waveguide, and the receive antenna, use the first The part of the microstrip line extending into the transmitting waveguide forms the transmitting feed; and the part of the second microstrip line extending into the receiving waveguide forms the receiving feed.
The FM continuous wave radar level gauge according to claim 6, characterized in that,

If the transmit path includes the transmit feed and the transmit antenna, but does not include the transmit waveguide, and the receive path includes the receive feed and the receive antenna, but does not include the receive waveguide, The transmitting feed is formed by using a first microstrip antenna formed on the circuit board, wherein the first microstrip antenna is located in the transmitting antenna, and the first microstrip antenna is The vibration module is directly connected; and the receiving feed is formed by using a second microstrip antenna formed on the circuit board, wherein the second microstrip antenna is located in the receiving antenna, and the second microstrip antenna The line is directly connected to the mixer; or,

If the transmit path includes the transmit feed, the transmit waveguide, and the transmit antenna, and the receive path includes the receive feed, the receive waveguide, and the receive antenna, use the first A microstrip antenna forms the transmit feed, wherein the first microstrip antenna is located in the transmit waveguide, and the first microstrip antenna is directly connected to the local oscillator module; and the second microstrip antenna is used A band antenna forms the receiving feed, wherein the second microstrip antenna is located in the receiving waveguide, and the second microstrip line is directly connected to the mixer.
The FM continuous wave radar level gauge according to claim 2 or 3, wherein the transmitting antenna and the receiving antenna are of independent structures, and the transmitting antenna and the receiving antenna are arranged in parallel and close to each other, Or, set them close to each other.
The FM continuous wave radar level gauge according to claim 2 or 3, wherein the transmitting antenna and the receiving antenna are separated by an antenna partition formed by a single antenna along the axial direction.
The FM continuous wave radar level gauge according to claim 3, wherein the transmitting waveguide and the receiving waveguide are of independent structures, and the transmitting waveguide and the receiving waveguide are arranged side by side, or, Set close to each other.
The FM continuous wave radar level gauge according to claim 3, wherein the transmitting waveguide and the receiving waveguide are formed separately by a waveguide partition formed in the axial direction of a single waveguide.
The FM continuous wave radar level gauge according to claim 3, wherein the FM continuous wave radar level gauge further comprises:

A protection mechanism is used to prevent foreign objects from entering the transmitting path and the receiving path.
The FM continuous wave radar level gauge according to claim 13, characterized in that,

The protection mechanism includes an antenna protection cover formed at the free end antenna openings of both the transmitting antenna and the receiving antenna.
The FM continuous wave radar level gauge according to claim 13, characterized in that,

The protection mechanism includes: a plugging head, respectively formed in the transmitting waveguide and the receiving waveguide, or respectively formed in the transmitting antenna or the receiving antenna.
The FM continuous wave radar level gauge according to claim 14, wherein the bottom of the antenna shield is a flat structure, or a convex structure, or a concave structure.
The FM continuous wave radar level gauge according to claim 14, characterized in that,

If the transmitting antenna and the receiving antenna are of independent structures, the transmitting antenna and the receiving antenna are each close to the side of each other, and are connected to or close to the antenna shield.
The FM continuous wave radar level gauge according to claim 14, characterized in that,

If the transmitting antenna and the receiving antenna are formed separately by an antenna partition formed by a single antenna along the axial direction, the antenna partition is connected to or close to the antenna shield.
The FM continuous wave radar level gauge according to claim 14, wherein the transmitting antenna and the receiving antenna each face the side of the antenna protective cover, and are attached to the antenna protective cover.
The FM continuous wave radar level gauge according to claim 14, wherein the transmitting antenna and the receiving antenna each face the side of the antenna shield, and a shield for fixing the fixed antenna is formed. The fixing mechanism of the cover.
The FM continuous wave radar level gauge according to claim 14, wherein the internal space formed by the radome, the transmitting antenna and the receiving antenna is filled with an anti-deformation material capable of allowing microwaves to penetrate .
The FM continuous wave radar level gauge according to claim 2 or 3, wherein the transmitting antenna and the receiving antenna are both horn antennas or lens antennas.
The FM continuous wave radar level gauge according to claim 1, wherein the FM continuous wave radar level gauge further comprises:

A frequency control module connected to the local oscillator module;

An intermediate frequency amplifier, connected to the mixer;

An A/D conversion module, connected to the intermediate frequency module;

The processing module is respectively connected with the A/D conversion module and the frequency control module.
The FM continuous wave radar level gauge of claim 23, wherein the FM continuous wave radar level gauge further comprises:

The display module is connected with the processing module.
The FM continuous wave radar level gauge of claim 23, wherein the FM continuous wave radar level gauge further comprises:

A communication module, connected to the processing module; and/or,

The interface module is connected with the processing module.
The FM continuous wave radar level gauge according to claim 2 or 3, wherein the transmitting feed source and the receiving feed source are linear polarization feed sources.
The FM continuous wave radar level gauge according to claim 2 or 3, wherein the transmitting feed source and the receiving feed source are circularly polarized feed sources, and the polarization directions of the two are opposite, wherein one One is the left-handed polarization direction, and the other is the right-handed polarization direction.
The FM continuous wave radar level gauge according to claim 11, wherein the transmitting waveguide and the receiving waveguide are cylindrical structures with a semicircular cross section, and the transmitting waveguide and the receiving waveguide The plane side faces of each are close to or close to each other to form a cylindrical outer contour.
The FM continuous wave radar level gauge according to claim 9, wherein the transmitting antenna and the receiving antenna are conical structures with a semicircular cross section, and the transmitting antenna and the receiving antenna The plane side faces of each are close to or close to each other to form a conical outer contour.