CN110567556A - Frequency modulation continuous wave radar level meter for measuring material level in container - Google Patents
Frequency modulation continuous wave radar level meter for measuring material level in container Download PDFInfo
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- CN110567556A CN110567556A CN201911041080.4A CN201911041080A CN110567556A CN 110567556 A CN110567556 A CN 110567556A CN 201911041080 A CN201911041080 A CN 201911041080A CN 110567556 A CN110567556 A CN 110567556A
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
- G01F23/00—Indicating or measuring liquid level or level of fluent solid material, e.g. indicating in terms of volume or indicating by means of an alarm
- G01F23/22—Indicating or measuring liquid level or level of fluent solid material, e.g. indicating in terms of volume or indicating by means of an alarm by measuring physical variables, other than linear dimensions, pressure or weight, dependent on the level to be measured, e.g. by difference of heat transfer of steam or water
- G01F23/28—Indicating or measuring liquid level or level of fluent solid material, e.g. indicating in terms of volume or indicating by means of an alarm by measuring physical variables, other than linear dimensions, pressure or weight, dependent on the level to be measured, e.g. by difference of heat transfer of steam or water by measuring the variations of parameters of electromagnetic or acoustic waves applied directly to the liquid or fluent solid material
- G01F23/284—Electromagnetic waves
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Abstract
The application relates to a frequency modulation continuous wave radar level gauge for measuring material level in a container, belonging to the technical field of radar level gauges. The application includes: the local oscillation module is used for generating local oscillation signals; the transmitting access is used for receiving the local oscillation signal generated by the local oscillation module and forming electromagnetic waves so as to transmit the electromagnetic waves to a target object; the receiving path is used for receiving the electromagnetic wave reflected by the target object and forming a reflected signal; and the frequency mixer is used for receiving the local oscillation signal generated by the local oscillation module and the reflected signal formed by the receiving path, and mixing to form a mixed frequency signal for determining the distance of the material level. Through the method and the device, the problem of a near-end measurement blind area of the frequency modulation continuous wave radar level meter is solved, and the measurement reliability of the frequency modulation continuous wave radar level meter is improved.
Description
Technical Field
The application belongs to the technical field of radar level meters, and particularly relates to a frequency modulation continuous wave radar level meter for measuring material levels in a container.
Background
a frequency modulated continuous wave radar level gauge is one type of radar level gauge, as shown in FIG. 1, FIG. 1 is a schematic view of a typical structure of a related art frequency modulated continuous wave radar level gauge.
In fig. 1, a processing module 1 is a device responsible for data processing, and the processing module 1 controls a local oscillator module 3 to output a local oscillator signal with a frequency change, which generally changes linearly with time, i.e., with chirp, through a frequency control module 2. The local oscillator signal may be divided into one path to be provided to the frequency control module 2 for frequency control, and if the frequency control is open-loop control, the feedback signal may not be provided.
the local oscillation module 3 divides one path of local oscillation signal into a circulator 4 to be used as a transmitting signal of the frequency modulation continuous wave radar level meter, and divides the other path of local oscillation signal to be input into a frequency mixer 5. In fig. 1, a microwave path 100 (hereinafter, referred to as a transmitting-receiving common microwave path 100) is commonly used for signal transmission and reception of the fm continuous wave radar level gauge, and radio frequency connectors (100a, 100b), a radio frequency cable 100c, a feed source 100d, a waveguide 100e and an antenna 100f in the transmitting-receiving common microwave path 100 are all shared for transmitting and receiving, and isolation of signal transmission and reception is achieved through a circulator 4. As shown in fig. 2, fig. 2 is a schematic diagram of an exemplary structure of a circulator 4 in the related art, when a port a is used as an input, a port B is an output terminal, and a port C is an isolation terminal; while port C is the output and port a is the isolated port when port B is the input. For the current frequency-modulated continuous wave radar level gauge with a microwave path 100 shared by transmitting and receiving, a port a is connected to the local oscillator module 3, a port B is connected to the microwave path 100 shared by transmitting and receiving, and a port C is connected to the mixer 5. The local oscillation module 3 transmits the local oscillation signal to the frequency mixer 5 through the port a of the frequency mixer 5, transmits the local oscillation signal to the transmitting and receiving shared microwave path 100 through the port B of the frequency mixer 5, transmits the electromagnetic wave to the target object through the transmitting and receiving shared microwave path 100, receives the electromagnetic wave reflected by the target object through the transmitting and receiving shared microwave path 100, forms a reflected signal, and transmits the reflected signal to the frequency mixer 5. The mixer 5 mixes the local oscillation signal with the received reflection signal to obtain a mixed signal, which is a frequency difference signal between the local oscillation signal and the reflection signal. The mixer 5 transmits the mixing 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 acquires the mixing signal from the a/D conversion module 7 and processes the signal, thereby obtaining the material level distance.
for a frequency modulated continuous wave radar level gauge as shown in fig. 1, in practical use, on one hand, due to the disadvantage of the circulator 4 in terms of signal isolation, it is reflected in that: the local oscillation signal of the local oscillation module 3 is input from the port A of the circulator 4 as a transmission signal, most of the signal is output from the port B, and a small part of the signal is leaked from the port C and is leaked into the frequency mixer 5; on the other hand, when the transmission signal output from the port B is transmitted through the transmitting and receiving shared microwave path 100, because impedance matching of each connection point in the transmitting and receiving shared microwave path 100 cannot be perfect, for example, connection structures such as a radio frequency cable, a feed source, a waveguide, an antenna, and the like cannot be perfectly matched, a part of the transmission signal transmitted through the transmitting and receiving shared microwave path 100 is directly reflected back, and enters the circulator 4 from the port B of the circulator 4.
the above-mentioned few local oscillator signals leaked from the port C due to the insufficient isolation capability of the circulator 4 and the part of transmission signals directly reflected back in the transmitting and receiving shared microwave path 100 are all regarded as reflection signals after entering the circulator 4, and then are transmitted to the mixer 5 for frequency mixing processing, so that a strong interference echo is formed at the near end of the frequency modulated continuous wave radar level gauge, and further the frequency modulated continuous wave radar level gauge has a measurement blind area at the near end. As shown in fig. 3 and 4, fig. 3 is a schematic diagram of one measurement result of the frequency modulated continuous wave radar level gauge, fig. 4 is a schematic diagram of another measurement result of the frequency modulated continuous wave radar level gauge, and in fig. 3 and 4, a local oscillator signal at I is a local oscillator signal at least partially leaked out from a port C due to insufficient isolation capability of a circulator 4, and a part of a transmission signal directly reflected back in a transmitting-receiving shared microwave path 100 to form a near-end interference wave; and II, the target reflected wave. FIG. 3 illustrates a situation where a target object is far away from an FM continuous wave radar level gauge, in which a near-end interference wave and a reflected wave of the target object can be effectively distinguished, and when the target object is near the FM continuous wave radar level gauge, as shown in FIG. 4, the reflected wave of the target object cannot be effectively identified due to the interference of the near-end interference wave, so that a near-end measurement blind zone is formed, and the near-end measurement of the FM continuous wave radar level gauge is unreliable.
disclosure of Invention
to overcome at least some of the problems of the related art, the present application provides a frequency modulated continuous wave radar level gauge for measuring a level of a material in a container, which helps to solve the problem of a near-end measurement blind zone of the frequency modulated continuous wave radar level gauge, thereby improving the measurement reliability of the frequency modulated continuous wave radar level gauge.
In order to achieve the purpose, the following technical scheme is adopted in the application:
the present application provides a frequency modulated continuous wave radar level gauge for measuring a level of a material in a container, comprising:
The local oscillation module is used for generating local oscillation signals;
the transmitting access is used for receiving the local oscillation signal generated by the local oscillation module and forming electromagnetic waves so as to transmit the electromagnetic waves to a target object;
the receiving path is used for receiving the electromagnetic wave reflected by the target object and forming a reflected signal;
And the frequency mixer is used for receiving the local oscillation signal generated by the local oscillation module and the reflection signal formed by the receiving channel and mixing to form a mixing frequency signal for determining the distance of the material level.
further, the air conditioner is provided with a fan,
the transmission path is arranged in a vertical direction, has a certain space span in the electromagnetic wave transmission direction from top to bottom, and comprises:
The transmitting feed source is used for receiving the local oscillation signal generated by the local oscillation module and converting the local oscillation signal into electromagnetic wave;
the transmitting antenna is used for transmitting the electromagnetic wave generated by the transmitting feed source to the target object;
The transmitting antenna has a span in an electromagnetic wave transmitting direction;
The receiving path is arranged in a vertical direction, has a certain spatial span in a bottom-up electromagnetic wave receiving direction, and includes:
The receiving antenna is used for receiving the electromagnetic wave reflected by the target object;
The receiving antenna has a span in an electromagnetic wave transmitting direction;
And the receiving feed source is used for converting the electromagnetic wave received by the receiving antenna into the reflected signal and transmitting the reflected signal to the mixer.
Further, the air conditioner is provided with a fan,
The transmission path further includes:
The transmitting waveguide is used for transmitting the electromagnetic wave generated by the transmitting feed source to the transmitting antenna;
The receive path further comprises:
And the receiving waveguide is used for transmitting the electromagnetic waves received by the receiving antenna to the receiving feed source.
Further, the air conditioner is provided with a fan,
the transmitting feed source is directly or indirectly connected with the local oscillator module, and the receiving feed source is directly or indirectly connected with the frequency mixer.
Further, the air conditioner is provided with a fan,
The local oscillator module and the transmitting feed source transmit signals through a first radio frequency cable, and the mixer and the receiving feed source transmit signals through a second radio frequency cable;
The first radio frequency cable and the local oscillator module, the first radio frequency cable and the transmitting feed source, the second radio frequency cable and the frequency mixer, and the second radio frequency cable and the receiving feed source are connected through radio frequency connectors.
Further, the air conditioner is provided with a fan,
If the transmitting path comprises the transmitting feed and the transmitting antenna but does not comprise the transmitting waveguide, and the receiving path comprises the receiving feed and the receiving antenna but does not comprise the receiving waveguide, the transmitting feed and the receiving feed are both formed on the same circuit board, and the transmitting feed is positioned in the transmitting antenna and the receiving feed is positioned in the receiving antenna; or,
if the transmitting path comprises the transmitting feed, the transmitting waveguide and the transmitting antenna and the receiving path comprises the receiving feed, the receiving waveguide and the receiving antenna, the transmitting feed and the receiving feed are both formed on the circuit board, the transmitting feed is positioned in the transmitting waveguide and the receiving feed is positioned in the receiving waveguide.
Further, the air conditioner is provided with a fan,
If the transmitting path comprises the transmitting feed source and the transmitting antenna but does not comprise the transmitting waveguide, and the receiving path comprises the receiving feed source and the receiving antenna but does not comprise the receiving waveguide, forming the transmitting feed source by utilizing a part of a first microstrip line formed on the circuit board extending into the transmitting antenna, wherein the first microstrip line is directly connected with the local oscillator module; the part of a second microstrip line formed on the circuit board extending into the receiving antenna is used for forming the receiving feed source, wherein the second microstrip line is directly connected with the mixer; or,
if the transmitting path comprises the transmitting feed source, the transmitting waveguide and the transmitting antenna, and the receiving path comprises the receiving feed source, the receiving waveguide and the receiving antenna, the transmitting feed source is formed by the part of the first microstrip line extending into the transmitting waveguide; and a part extending into the receiving waveguide by using the second microstrip line forms the receiving feed source.
Further, the air conditioner is provided with a fan,
If the transmitting path comprises the transmitting feed source and the transmitting antenna but does not comprise the transmitting waveguide, and the receiving path comprises the receiving feed source and the receiving antenna but does not comprise the receiving waveguide, forming the transmitting feed source by utilizing a first microstrip antenna formed on the circuit board, wherein the first microstrip antenna is positioned in the transmitting antenna, and the first microstrip antenna is directly connected with the local oscillation module; and forming the receiving feed source by using a second microstrip antenna formed on the circuit board, wherein the second microstrip antenna is positioned in the receiving antenna, and the second microstrip antenna is directly connected with the mixer; or,
if the transmitting path comprises the transmitting feed source, the transmitting waveguide and the transmitting antenna, and the receiving path comprises the receiving feed source, the receiving waveguide and the receiving antenna, the transmitting feed source is formed by using the first microstrip antenna, wherein the first microstrip antenna is positioned in the transmitting waveguide, and the first microstrip antenna is directly connected with the local oscillation module; and forming the receiving feed source by using the second microstrip antenna, wherein the second microstrip antenna is positioned in the receiving waveguide, and the second microstrip antenna is directly connected with the mixer.
further, the air conditioner is provided with a fan,
the transmitting antenna and the receiving antenna are of independent structures, and the transmitting antenna and the receiving antenna are attached in parallel or are arranged close to each other.
further, the air conditioner is provided with a fan,
the transmitting antenna and the receiving antenna are formed by separating an antenna clapboard formed by the single antenna along the axis direction.
Further, the air conditioner is provided with a fan,
The transmitting waveguide and the receiving waveguide are of independent structures, and the transmitting waveguide and the receiving waveguide are arranged in a side-by-side attached mode or are arranged close to each other.
further, the air conditioner is provided with a fan,
the transmitting waveguide and the receiving waveguide are formed by separating a waveguide partition plate formed by the single waveguide along the axial direction.
further, the air conditioner is provided with a fan,
The frequency modulated continuous wave radar level gauge further comprises:
A guard mechanism for preventing foreign objects from entering the launch path and the receive path.
further, the air conditioner is provided with a fan,
the guard mechanism includes: an antenna shield formed at free end antenna ports of both the transmitting antenna and the receiving antenna.
Further, the air conditioner is provided with a fan,
the guard mechanism includes: and the plugging heads are respectively formed in the transmitting waveguide and the receiving waveguide or respectively formed in the transmitting antenna or the receiving antenna.
Further, the air conditioner is provided with a fan,
the bottom of the antenna protective cover is of a plane structure, or a convex structure, or a concave structure.
Further, the air conditioner is provided with a fan,
If the transmitting antenna and the receiving antenna are of independent structures, the transmitting antenna and the receiving antenna are close to one side of the other side respectively and are connected or close to the antenna protective cover.
further, the air conditioner is provided with a fan,
If the transmitting antenna and the receiving antenna are formed by separating the single antenna along the axis direction through the antenna partition plate, the antenna partition plate is connected or close to the antenna protective cover.
further, the air conditioner is provided with a fan,
The transmitting antenna and the receiving antenna are respectively faced to the side face of the antenna protective cover and attached to the antenna protective cover.
further, the air conditioner is provided with a fan,
Both the transmitting antenna and the receiving antenna face the side face of the antenna shield, and a fixing mechanism for fixing the antenna shield is formed.
further, the air conditioner is provided with a fan,
The inner space formed by the antenna housing, the transmitting antenna and the receiving antenna is filled with an anti-deformation material which can be penetrated by microwaves.
Further, the air conditioner is provided with a fan,
The transmitting antenna and the receiving antenna are both horn antennas or lens antennas.
Further, the air conditioner is provided with a fan,
The frequency modulated continuous wave radar level gauge further comprises:
The frequency control module is connected with the local oscillation module;
an intermediate frequency amplifier connected to the mixer;
The A/D conversion module is connected with the intermediate frequency module;
And the processing module is respectively connected with the A/D conversion module and the frequency control module.
Further, the air conditioner is provided with a fan,
The frequency modulated continuous wave radar level gauge further comprises:
And the display module is connected with the processing module.
further, the air conditioner is provided with a fan,
the frequency modulated continuous wave radar level gauge further comprises:
The communication module is connected with the processing module; and/or the presence of a gas in the gas,
and the interface module is connected with the processing module.
further, the air conditioner is provided with a fan,
The transmit feed and the receive feed are linearly polarized feeds.
Further, the air conditioner is provided with a fan,
The transmitting feed source and the receiving feed source are circularly polarized feed sources, and the polarization directions of the transmitting feed source and the receiving feed source are opposite, wherein one is a left-hand polarization direction, and the other is a right-hand polarization direction.
Further, the air conditioner is provided with a fan,
The transmitting waveguide and the receiving waveguide are cylindrical structures with semicircular cross sections, and the planar side surfaces of the transmitting waveguide and the receiving waveguide are close to or attached to each other to form a cylindrical outer contour.
further, the air conditioner is provided with a fan,
The transmitting antenna and the receiving antenna are in a conical structure with a semicircular cross section, and the plane side surfaces of the transmitting antenna and the receiving antenna are close to or attached to each other to form a conical outer contour.
this application adopts above technical scheme, possesses following beneficial effect at least:
the application provides a frequency modulation continuous wave radar level meter, through giving up circulator and the shared microwave passageway of sending and receiving, adopt to set up independent transmission route and receiving route separately, realize solving the problem of frequency modulation continuous wave radar level meter near-end measurement blind area, and then promote frequency modulation continuous wave radar level meter's measurement reliability.
it is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the application.
Drawings
In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present application, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.
FIG. 1 is a schematic diagram of an exemplary configuration of a frequency modulated continuous wave radar level gauge of the related art;
FIG. 2 is a schematic view showing an exemplary structure of a circulator in the related art;
FIG. 3 is a schematic illustration of a measurement of a frequency modulated continuous wave radar level gauge;
FIG. 4 is a schematic illustration of another measurement of a frequency modulated continuous wave radar level gauge;
FIG. 5 is a schematic view of a frequency modulated continuous wave radar level gauge according to an embodiment of the present application;
FIG. 6 is a schematic structural diagram of a frequency modulated continuous wave radar level gauge according to another embodiment of the present application;
FIG. 7 is a schematic structural diagram of a frequency modulated continuous wave radar level gauge according to another embodiment of the present application;
FIG. 8 is a schematic view of a frequency modulated continuous wave radar level gauge according to another embodiment of the present application;
FIG. 9 is a schematic diagram of the specific structure at A in FIG. 8;
FIG. 10 is a schematic view of a frequency modulated continuous wave radar level gauge according to another embodiment of the present application;
fig. 11 is a schematic diagram of a specific structure at B in fig. 10.
Detailed Description
In order to make the objects, technical solutions and advantages of the present application more apparent, the technical solutions of the present application will be described in detail below. It is to be understood that the embodiments described are only a few embodiments of the present application and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the examples given herein without making any creative effort, shall fall within the protection scope of the present application.
The present application provides a frequency modulated continuous wave radar level gauge for measuring a level of a material in a container, said container having an open-celled or microwave-transparent window structure in a top portion thereof, please refer to fig. 5 to 7, the frequency modulated continuous wave radar level gauge comprising:
The local oscillation module 3 is used for generating local oscillation signals;
The transmitting path 200 is configured to receive the local oscillation signal generated by the local oscillation module 3, and form an electromagnetic wave to transmit the electromagnetic wave to a target object;
a receiving path 300 for receiving the electromagnetic wave reflected by the target object and forming a reflected signal;
and a mixer 5, configured to receive the local oscillator signal generated by the local oscillator module 3 and the reflected signal formed by the receiving path 300, and mix the received signals to form a mixed signal for determining the distance between the filling levels.
Specifically, in the above-mentioned embodiment, compared to the related art frequency-modulated continuous wave radar level gauge (such as the frequency-modulated continuous wave radar level gauge shown in fig. 1), the frequency-modulated continuous wave radar level gauge (such as those shown in fig. 5 to 7) provided in the present application eliminates the circulator 4 and the common microwave path 100 for transmitting and receiving, and adopts the arrangement of the separate transmitting path 200 and receiving path 300, so as to solve the problem that a part of the transmitted signal leaks due to insufficient isolation capability of the circulator, is regarded as the reflected signal, and is then transmitted to the mixer for frequency mixing processing; on the other hand, the independent transmitting path and receiving path realize the mutual independence of the transmission and reception of the signals, and the transmitting path 200 is only used for the transmitting function and is not used for the receiving function; the receiving path 300 is used for receiving only and not for transmitting, so that the condition that the transmitting signal is directly coupled to the receiving path 300 does not exist, and even if signal reflection occurs at each connection point in the transmitting path 200, the signal reflected back in the transmitting path 200 cannot be received, thereby solving the problem that part of the transmitting signal directly reflected back in the transmitting and receiving shared microwave path is taken as a reflected signal after entering the circulator and then is transmitted to the mixer 5 for mixing processing. Therefore, the problems in the two aspects can be effectively solved, the problem of a near-end measurement blind zone of the frequency modulation continuous wave radar level meter can be solved, and the measurement reliability of the frequency modulation continuous wave radar level meter is improved.
in one embodiment, the transmit path 200 includes:
the transmission path 200 is vertically arranged, has a certain space span in the electromagnetic wave transmission direction from top to bottom (as shown in fig. 8 and 10), and includes: (as shown in FIG. 5)
The transmitting feed source 200a is used for receiving the local oscillation signal generated by the local oscillation module 3 and converting the local oscillation signal into electromagnetic wave;
The transmitting antenna 200b is used for transmitting the electromagnetic wave generated by the transmitting feed source 200a to the target object;
the transmitting antenna 200b has a span in an electromagnetic wave transmitting direction;
The receiving path 300 is vertically arranged, has a certain spatial span in a bottom-up electromagnetic wave receiving direction (as shown in fig. 8 and 10), and includes: (as shown in FIG. 5)
a receiving antenna 300a for receiving the electromagnetic wave reflected by the target;
The receiving antenna 300a has a span in an electromagnetic wave transmitting direction;
And a receiving feed source 300b, configured to convert the electromagnetic wave received by the receiving antenna 300a into the reflected signal, and transmit the reflected signal to the mixer.
Specifically, the transmitting feed source 200a is connected to the local oscillation module 3, and the receiving feed source 300b is connected to the mixer 5, and thus, the mixer 5 is only connected to the receiving feed source 300b, and is not connected to the transmitting feed source 200a, and thus, the mixer 5 only receives the reflected signal formed by the receiving feed source 300 b.
for the transmitting antenna 200b and the receiving antenna 300a, there may be a horn antenna or a lens antenna, and for the horn antenna, the cross section may be a semicircle, a rectangle, or other irregular shape.
for the two feeds, the transmission feed 200a and the reception feed 300b, the structures of the two feeds may be the same, and the specific feed structure may be a coaxial waveguide feed structure.
the transmitting feed source and the receiving feed source can be linear polarization feed sources, or the transmitting feed source and the receiving feed source are circular polarization feed sources, and the polarization directions of the transmitting feed source and the receiving feed source are opposite, wherein one is a left-hand polarization direction, and the other is a right-hand polarization direction. The feed source is positioned on the microwave circuit board or fixed on the microwave circuit board, and the corresponding antenna is aligned to the feed source in the vertical direction below the feed source.
the transmitting antenna 200b and the receiving antenna 300a may be formed by metal casting or plastic casting as an integral structure, and then coated with a conductive material.
as shown in fig. 6, 8 and 10, the transmission path 200 further includes:
A transmitting waveguide 200c for transmitting the electromagnetic wave generated by the transmitting feed source 200a to the transmitting antenna 200 b;
The receiving path 300 further includes:
a receiving waveguide 300c for transmitting the electromagnetic wave received by the receiving antenna 300a to the receiving feed 300 b.
specifically, the transmitting antenna 200b transmits the radar wave generated by the transmitting feed 200a through the transmitting waveguide 200c, and transmits the received radar wave to the receiving feed 300b through the receiving antenna 300a through the receiving waveguide 300c, in practical application, 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.
the transmission waveguide 200c and the reception waveguide 300c may be formed by metal casting or plastic casting as an integral structure, and then coated with a conductive material.
In one embodiment, the transmission feed 200a is directly or indirectly connected to the local oscillation module 3, and the reception feed 300b is directly or indirectly connected to the mixer 5.
for the indirect connection situation, as shown in fig. 7, in a specific embodiment, the local oscillator module 3 and the transmission feed source 200a transmit signals through a first radio frequency cable 200d, and the mixer 5 and the reception feed source 300b transmit signals through a second radio frequency cable 300 d;
The first rf cable 200d and the local oscillator module 3, the first rf cable 200d and the transmitting feed source 200a, the second rf cable 300d and the mixer 5, and the second rf cable 300d and the receiving feed source 300b are connected by rf connectors (200e, 200f, 300e, 300 f).
Specifically, as shown in fig. 7, the transmitting feed source 200a is indirectly connected to the local oscillation module 3 through a first radio frequency cable 200d, the receiving feed source 300b is indirectly connected to the mixer 5 through a second radio frequency cable 300d, the transmitting feed source 200a and the receiving feed source 300b both transmit signals through radio frequency cables, and the extension of the frequency modulation 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 fig. 8 to 10, in practical application, the local oscillation module 3 and the mixer 5 are formed on one circuit board, and the transmission feed source 200a may be formed by a microstrip line directly connected to the local oscillation module 3, and the reception feed source 300b may be formed by a microstrip line directly connected to the mixer 5. Alternatively, a microstrip antenna for transmitting may be formed on the circuit board and directly connected to the local oscillation module 3, where the microstrip antenna for transmitting forms the transmitting feed 200a, and a microstrip antenna for receiving may be formed on the circuit board and directly connected to the mixer 5, where the microstrip antenna for receiving forms the receiving feed 300 b. The microstrip antenna used as the feed source can be a microstrip array antenna formed by a plurality of array elements or a microstrip antenna formed by a single array element. The direct connection between the transmission feed source 200a and the local oscillator module 3 and the direct connection between the reception feed source 300b and the mixer 5 help to reduce the impedance mismatch problem caused by the connection point.
further extended embodiments are described below in the present application, where the transmission feed source 200a is directly connected to the local oscillation module 3, and the reception feed source 300b is directly connected to the mixer 5.
In one embodiment, if the transmission path 200 includes the transmission feed 200a and the transmission antenna 200b but does not include the transmission waveguide 200c, and the reception path 300 includes the reception feed 300b and the reception antenna 300a but does not include the reception waveguide 300c, the transmission feed 200a, the reception feed 300b are both formed on the same circuit board 11, and the transmission feed 200a is located in the transmission antenna 200b, and the reception feed 300b is located in the reception antenna 300 a; or,
as shown in fig. 8 to 10, if the transmission path 200 includes the transmission feed 200a, the transmission waveguide 200c, and the transmission antenna 200b, and the reception path 300 includes the reception feed 300b, the reception waveguide 300c, and the reception antenna 300a, the transmission feed 200a, the reception feed 300b are both formed on the circuit board 11, and the transmission feed 200a is located in the transmission waveguide 200c, and the reception feed 300b is located in the reception waveguide 300 c.
Specifically, for the case that the transmission path 200 includes the transmission feed 200a and the transmission antenna 200b but does not include the transmission waveguide 200c, and the reception path 300 includes the reception feed 300b and the reception antenna 300a but does not include the reception waveguide 300c, the radar wave generated by the transmission feed 200a is directly transmitted by the transmission antenna 200b, and the radar wave received by the transmission feed is directly transmitted to the reception feed 300b by the reception antenna 300a, in practical applications, the following conditions are required to be satisfied: the transmission ports from the transmission feed 200a to the transmission antenna 200b have a spatial span in the transmission direction, and the reception ports from the reception feed 300b to the patch antenna also need to have a spatial span in the reception direction, which can be realized by the transmission antenna 200b and the reception antenna 300a themselves, for example, a horn antenna can be used to realize the spatial span.
Further, as shown in fig. 8 and 9, if the transmission path 200 includes the transmission feed 200a and the transmission antenna 200b but does not include the transmission waveguide 200c, and the reception path 300 includes the reception feed 300b and the reception antenna 300a but does not include the reception waveguide 300c, the transmission feed 200a is formed by using a portion of a first microstrip line formed on the circuit board 11 extending into the transmission antenna 200b, wherein the first microstrip line is directly connected to the local oscillation module 3; and the receiving feed source 300b is formed by a part of a second microstrip line formed on the circuit board 11 extending into the receiving antenna 300a, wherein the second microstrip line is directly connected with the mixer 5; or,
if the transmission path 200 includes the transmission feed 200a, the transmission waveguide 200c, and the transmission antenna 200b, and the reception path 300 includes the reception feed 300b, the reception waveguide 300c, and the reception antenna 300a, the transmission feed 200a is formed by a portion of the first microstrip line extending into the transmission waveguide 200 c; and the receiving feed source 300b is formed by a portion of the second microstrip line extending into the receiving waveguide 300 c.
As shown in fig. 8 and 9, in particular, in the related embodiment, the feed source is formed by a microstrip line, and in practical application, the microstrip line extending into the waveguide may be formed into a pin shape to serve as the feed source. The transmitting waveguide 200c and the receiving waveguide 300c are directly fixed on the circuit board 11, then the side surfaces of the transmitting waveguide 200c and the receiving waveguide 300c are both provided with openings, a part of a first microstrip line connected with the local oscillator module 3 extending into the transmitting waveguide 200c forms a transmitting feed source 200a, and a transmitting signal generated by the local oscillator module 3 enters the transmitting waveguide 200c through the first microstrip line for in-and-out transmission. A portion of the second microstrip line connected to the microwave reception signal input end of the mixer 5 extending into the reception waveguide 300c constitutes a reception feed 300 b.
for the case where the transmission path 200 does not include the transmission waveguide 200c, and the reception path 300 does not include the reception waveguide 300c, and the transmission antenna 200b and the reception antenna 300a are directly fixed on the circuit board 11, the transmission antenna 200b and the reception antenna 300a may employ a horn antenna, and the related implementation may refer to an embodiment in which the transmission waveguide 200c and the reception waveguide 300c have openings on the sides thereof, and microstrip lines are introduced.
further, as shown in fig. 10 and 11, if the transmission path 200 includes the transmission feed 200a and the transmission antenna 200b but does not include the transmission waveguide 200c, and the reception path 300 includes the reception feed 300b and the reception antenna 300a but does not include the reception waveguide 300c, the transmission feed 200a is formed by using a first microstrip antenna formed on the circuit board 11, wherein the first microstrip antenna is located in the transmission antenna 200b and is directly connected to the local oscillation module 3; and forming the receiving feed 300b by using a second microstrip antenna formed on the circuit board 11, wherein the second microstrip antenna is located in the receiving antenna 300a and is directly connected with the mixer 5; or,
If the transmission path 200 includes the transmission feed 200a, the transmission waveguide 200c and the transmission antenna 200b, and the reception path 300 includes the reception feed 300b, the reception waveguide 300c and the reception antenna 300a, the transmission feed 200a is formed by using the first microstrip antenna, wherein the first microstrip antenna is located in the transmission waveguide 200c, and the first microstrip antenna is directly connected to the local oscillation module 3; and forming the receiving feed 300b by using the second microstrip antenna, wherein the second microstrip antenna is located in the receiving waveguide 300c, and the second microstrip antenna is directly connected to the mixer 5.
specifically, fig. 10 shows a case where the transmission path 200 includes the transmission waveguide 200c and the reception path 300 includes the reception waveguide 300c in the above-described related embodiment, and the transmission waveguide 200c and the reception waveguide 300c are directly fixed on the circuit board 11. For the above case where the transmission path 200 does not include the transmission waveguide 200c, and the reception path 300 does not include the reception waveguide 300c, and the transmission antenna 200b and the reception antenna 300a are directly fixed on the circuit board 11, the transmission antenna 200b and the reception antenna 300a may employ a horn antenna, and the related implementation thereof may refer to the application in which microstrip antennas are respectively provided in the transmission waveguide 200c and the reception waveguide 300c shown in fig. 10.
As shown in fig. 11, the microstrip antenna may be a microstrip array antenna formed by a plurality of array elements or a microstrip antenna formed by a single array element.
Regarding the formation of the transmitting antenna 200b and the receiving antenna 300a, the following related embodiments are given in the present application for explanation.
In one embodiment, the transmitting antenna 200b and the receiving antenna 300a are independent structures, and the transmitting antenna 200b and the receiving antenna 300a are attached to each other in parallel or are disposed 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 a specific application, a horn structure with a circular appearance can be combined by two horns with semicircular cross sections, for example, the transmitting antenna and the receiving antenna are conical structures with semicircular cross sections, and the planar side surfaces of the transmitting antenna and the receiving antenna are close to or attached to each other to form a conical outer contour. Fig. 8 and 10 show a case where the transmitting antenna 200b and the receiving antenna 300a are attached to each other in parallel, and the attachment of the transmitting antenna 200b and the receiving antenna 300a may be performed by welding, bundling, bonding, fastening, mortise and tenon connection, or the like.
in another embodiment, the transmitting antenna 200b and the receiving antenna 300a are separated by an antenna partition formed by a single antenna in the axial direction.
Specifically, the transmitting antenna 200b and the receiving antenna 300a are two modules of a single antenna, and are separated by an antenna partition plate, taking a horn antenna as an example, fig. 8 and 10 show that the transmitting antenna 200b and the receiving antenna 300a may also be separated by a conductive partition plate inserted between the horn antennas.
For the formation of the transmitting waveguide 200c and the receiving waveguide 300c, the following related embodiments are given in the present application for explanation.
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 attached to each other in parallel or are disposed 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 a specific application, a waveguide with a circular or elliptical appearance can be synthesized by two waveguides with a semicircular or semi-elliptical cross section, for example, the transmitting waveguide and the receiving waveguide are cylindrical structures with semicircular cross sections, and the planar side surfaces of the transmitting waveguide and the receiving waveguide are close to or attached to each other to form a cylindrical outer contour. Fig. 8 and 10 show a case where the transmitting waveguide 200c and the receiving waveguide 300c are attached in parallel, and the attachment of the two may be performed by welding, bundling, bonding, fastening, mortise and tenon joint, or the like.
in a particular application, where transmit antenna 200b and receive antenna 300a are mated to form a unitary antenna having a circular cross-section, and where transmit waveguide 200c and receive waveguide 300c are mated to form a unitary waveguide also having a circular cross-section, both the unitary antenna of circular structure and the unitary waveguide of circular structure may be co-axial.
The transmitting waveguide 200c and the receiving waveguide 300c may be waveguides having gradually increasing calibers.
in another embodiment, the transmitting waveguide 200c and the receiving waveguide 300c are formed separately by a waveguide partition formed by a single waveguide in the axial direction.
Specifically, the transmitting waveguide 200c and the receiving waveguide 300c are two modules of a single waveguide, and fig. 8 and 10 may also show a case where the transmitting waveguide 200c and the receiving waveguide 300c are formed by separating a single waveguide by a waveguide partition.
as shown in fig. 8 and 10, in one embodiment, the frequency modulated continuous wave radar level gauge, further comprises:
A shielding mechanism 12 for preventing foreign objects from entering the transmitting path 200 and the receiving path 300.
In the related art, the shielding mechanism 12 is capable of passing electromagnetic waves, but is capable of preventing foreign objects from entering, and in a specific application, the shielding mechanism 12 is capable of blocking corrosion, steam, dust, or high temperature pressure, etc., according to the specific application of the frequency modulated continuous wave radar level gauge. The guard mechanism 12 of the present application also achieves the basic functions described above.
Further, the air conditioner is provided with a fan,
The guard mechanism 12 includes: an antenna shield (the shield mechanism 12 shown in fig. 8 and 10 is a shield) is formed at the free end antenna ports of both the transmitting antenna 200b and the receiving antenna 300 a.
Specifically, fig. 8 and 10 show a schematic structural diagram of an antenna shield, in a finished product of the fm continuous wave radar level gauge, a transmitting antenna 200b and a receiving antenna 300a are installed, and an antenna port of the transmitting antenna 200b and the receiving antenna 300a, which is used for facing a target object, is a free-end antenna port.
Further, the air conditioner is provided with a fan,
The guard mechanism 12 includes: and plugging heads respectively formed in the transmission waveguide 200c and the reception waveguide 300c, or respectively formed in the transmission antenna 200b or the reception antenna 300 a.
it should be noted that, the antenna of frequency modulation continuous wave radar level meter among the correlation technique is the receiving and dispatching sharing, be the monomer antenna, set up antenna house or jam head and reach the protection purpose, the electromagnetic wave that frequency modulation continuous wave radar level meter was sent out, when meetting antenna house or jam head, must take place the reflection, produce the reflected signal, the reflected signal will increase the interference wave of frequency modulation continuous wave radar level meter near-end, it can be understood, when frequency modulation continuous wave radar level meter installation antenna house among the correlation technique, must increase the measurement blind area of frequency modulation continuous wave radar level meter.
Through the application, the problem that the measurement blind area is increased when the frequency modulation continuous wave radar level meter is provided with the protection mechanism 12 can be effectively solved, and the method is characterized in that: in the application, the transmitting antenna 200b and the receiving antenna 300a are arranged in parallel, the transmitting antenna 200b is only used for transmitting electromagnetic waves, and the receiving antenna 300a is only used for receiving electromagnetic waves, in a specific application, the transmitting antenna 200b and the receiving antenna 300a are both aligned to a target object, the transmitting antenna 200b transmits electromagnetic waves to the target object, when the electromagnetic waves in the transmitting direction meet the part, opposite to the part, on the protection mechanism 12, a transmitting signal is generated, and due to the fact that separation and isolation exist between the transmitting antenna 200b and the receiving antenna 300a, the reflected signal is reflected into the transmitting antenna 200b and cannot be received by the receiving antenna 300a, and therefore the problem that the measurement blind area is increased due to the protection mechanism 12 can be solved.
In summary, by the frequency modulated continuous wave radar level gauge solution of the present application, in comparison with the related art frequency modulated continuous wave radar level gauge (such as the frequency modulated continuous wave radar level gauge shown in FIG. 1), a circulator is eliminated, and the independent transmitting path 200 and receiving path 300 are provided at the same time, the following three problems can be solved:
firstly, the problem that a part of the transmitted signal leaks due to insufficient isolation capability of the circulator, is taken as a reflected signal and then is transmitted to the mixer 5 for mixing processing can be solved.
the second, independent transmitting path 200 and receiving path 300, realize the transmission and receiving of the signal are independent each other, the transmitting path 200 is only used as the transmitting function, not used as receiving; the receiving path 300 is used for receiving only and not for transmitting, so that the condition that the transmitting signal is directly coupled to the receiving path 300 does not exist, and even if signal reflection occurs at each connection point in the transmitting path 200, the signal reflected back in the transmitting path 200 cannot be received, thereby solving the problem that part of the transmitting signal directly reflected back in the transmitting and receiving shared microwave path is taken as a reflected signal after entering the circulator and then is transmitted to the mixer 5 for mixing processing.
Thirdly, the problem of increased measurement blind areas caused by the protection mechanism 12 can be solved.
Therefore, the problems of the three aspects can be effectively solved, the problem of a near-end measurement blind zone of the frequency modulation continuous wave radar level meter can be further solved, and the measurement reliability of the frequency modulation continuous wave radar level meter is improved.
In one embodiment, the bottom of the antenna shield is a planar structure, or a convex structure, or a concave structure.
in practical use, the fm continuous wave radar level gauge is vertically disposed, the radome is also vertically disposed, and the bottom of the antenna shield is a portion facing the free-end antenna ports of the transmitting antenna 200b and the receiving antenna 300 a.
specifically, the bottom of the antenna shield may be an upward concave conical surface or a spherical surface, or a downward convex conical surface or a spherical surface.
regarding the relationship between the radome and the transmitting antenna 200b and the receiving antenna 300a, the following related embodiments are given in the present application for explanation.
In one embodiment, if the transmitting antenna 200b and the receiving antenna 300a are independent structures, the transmitting antenna 200b and the receiving antenna 300a are close to each other and connected or close to the antenna shield.
in another embodiment, if the transmitting antenna 200b and the receiving antenna 300a are separately formed by an antenna partition formed by a single antenna in the axial direction, the antenna partition is connected to or adjacent to the antenna shield.
Specifically, the connection mentioned in the above two embodiments can be realized by bonding, threads, screws, buckles, clamping grooves, bundling and other modes, the antenna protective cover can be supported on the positive pressure occasion, and the antenna protective cover can be tightly pulled when being on the negative pressure occasion, so that the deformation of the antenna cover is prevented.
In one embodiment, both the transmitting antenna 200b and the receiving antenna 300a each face the side of the antenna shield, conforming to the antenna shield.
Specifically, the side surface of the antenna protective cover is attached to the transmitting antenna 200b and the receiving antenna 300a, and in a high-voltage occasion, the transmitting antenna 200b and the receiving antenna 300a can support the antenna protective cover.
Further, both the transmitting antenna 200b and the receiving antenna 300a face the side of the antenna shield, respectively, and a fixing mechanism for fixing the antenna shield is formed.
Specifically, the transmitting antenna 200b and the receiving antenna 300a fix the antenna shield through respective fixing mechanisms, so that the antenna shield can be effectively prevented from being deformed when being in a pressure field.
In one embodiment, an inner space formed by the radome, the transmitting antenna and the receiving antenna is filled with a deformation-resistant material capable of being penetrated by microwaves.
specifically, the anti-deformation material can be plastic, so that an inner space formed by the antenna housing, the transmitting antenna and the receiving antenna is filled, the inner space is solid, and the pressure resistance of the antenna housing is improved.
As shown in fig. 5 to 7, in one embodiment, the frequency modulated continuous wave radar level gauge further comprises:
the frequency control module 2 is connected with the local oscillation module 3;
An intermediate frequency amplifier 6 connected to the mixer 5;
the A/D conversion module 7 is connected with the intermediate frequency module;
And the processing module 1 is respectively connected with the A/D conversion module 7 and the frequency control module 2.
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 thereof may refer to a frequency modulated continuous wave radar level gauge in the related art, and in addition, in the background art of the present application, the above-mentioned module components are also described correspondingly, so that reference may also be made, and further details are not described herein.
As shown in fig. 5 to 7, further, the frequency modulated continuous wave radar level gauge further comprises:
And the display module 8 is connected with the processing module 1.
specifically, the display module 8 may display data or curves or text, allowing the user to view the current measurement results, and allowing the user to perform parameter inquiry and setting.
As shown in fig. 5 to 7, further, the frequency modulated continuous wave radar level gauge further comprises:
A communication module 9 connected with the processing module 1; and/or the presence of a gas in the gas,
and the interface module 10 is connected with the processing module 1.
specifically, the external output signal mode may be 4-20mA, HART, FF, profibus, etc. through the communication module and/or the interface module.
It is understood that the same or similar parts in the above embodiments may be mutually referred to, and the same or similar parts in other embodiments may be referred to for the content which is not described in detail in some embodiments.
It should be noted that, in the description of the present application, the terms "first", "second", etc. are used for descriptive purposes only and are not to be construed as indicating or implying relative importance. In addition, in the description of the present application, the meaning of "plurality" means at least two unless otherwise specified.
it will be understood that when an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements may be present. Further, "connected" as used herein may include wirelessly connected. The term "and/or" is used to include any and all combinations of one or more of the associated listed items.
Any process or method descriptions in flow charts or otherwise described herein may be understood as: represents modules, segments or portions of code which include one or more executable instructions for implementing specific logical functions or steps of a process, and the scope of the preferred embodiments of the present application includes other implementations in which functions may be executed out of order from that shown or discussed, including substantially concurrently or in reverse order, depending on the functionality involved, as would be understood by those reasonably skilled in the art of the embodiments of the present application.
It should be understood that portions of the present application may be implemented in hardware, software, firmware, or a combination thereof. In the above embodiments, the various steps or methods may be implemented in software or firmware stored in memory and executed by a suitable instruction execution system. For example, if implemented in hardware, as in another embodiment, any one or combination of the following techniques, which are known in the art, may be used: a discrete logic circuit having a logic gate circuit for implementing a logic function on a data signal, an application specific integrated circuit having an appropriate combinational logic gate circuit, a Programmable Gate Array (PGA), a Field Programmable Gate Array (FPGA), or the like.
it will be understood by those skilled in the art that all or part of the steps carried by the method for implementing the above embodiments may be implemented by hardware related to instructions of a program, which may be stored in a computer readable storage medium, and when the program is executed, the program includes one or a combination of the steps of the method embodiments.
in addition, functional units in the 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 are integrated into one module. The integrated module can be realized in a hardware mode, and can also be realized in a software functional module mode. The integrated module, if implemented in the form of a software functional module and sold or used as a stand-alone product, may also be stored in a computer readable storage medium.
the storage medium mentioned above may be a read-only memory, a magnetic or optical disk, etc.
in the description herein, reference to the description of the term "one embodiment," "some embodiments," "an example," "a specific example," or "some examples," etc., means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the application. In this specification, the schematic representations of the terms used above do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.
although embodiments of the present application have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present application, and that variations, modifications, substitutions and alterations may be made to the above embodiments by those of ordinary skill in the art within the scope of the present application.
Claims (29)
1. A frequency modulated continuous wave radar level gauge for measuring a level of a material in a container, comprising:
The local oscillation module is used for generating local oscillation signals;
The transmitting access is used for receiving the local oscillation signal generated by the local oscillation module and forming electromagnetic waves so as to transmit the electromagnetic waves to a target object;
the receiving path is used for receiving the electromagnetic wave reflected by the target object and forming a reflected signal;
And the frequency mixer is used for receiving the local oscillation signal generated by the local oscillation module and the reflection signal formed by the receiving channel and mixing to form a mixing frequency signal for determining the distance of the material level.
2. frequency modulated continuous wave radar level gauge according to claim 1,
the transmission path is arranged in a vertical direction, has a certain space span in the electromagnetic wave transmission direction from top to bottom, and comprises:
The transmitting feed source is used for receiving the local oscillation signal generated by the local oscillation module and converting the local oscillation signal into electromagnetic wave;
the transmitting antenna is used for transmitting the electromagnetic wave generated by the transmitting feed source to the target object;
the transmitting antenna has a span in an electromagnetic wave transmitting direction;
the receiving path is arranged in a vertical direction, has a certain spatial span in a bottom-up electromagnetic wave receiving direction, and includes:
The receiving antenna is used for receiving the electromagnetic wave reflected by the target object;
the receiving antenna has a span in an electromagnetic wave transmitting direction;
And the receiving feed source is used for converting the electromagnetic wave received by the receiving antenna into the reflected signal and transmitting the reflected signal to the mixer.
3. frequency modulated continuous wave radar level gauge according to claim 2,
the transmission path further includes:
The transmitting waveguide is used for transmitting the electromagnetic wave generated by the transmitting feed source to the transmitting antenna;
the receive path further comprises:
And the receiving waveguide is used for transmitting the electromagnetic waves received by the receiving antenna to the receiving feed source.
4. a frequency modulated continuous wave radar level gauge according to claim 2 or 3,
the transmitting feed source is directly or indirectly connected with the local oscillator module, and the receiving feed source is directly or indirectly connected with the frequency mixer.
5. a frequency modulated continuous wave radar level gauge according to claim 4,
the local oscillator module and the transmitting feed source transmit signals through a first radio frequency cable, and the mixer and the receiving feed source transmit signals through a second radio frequency cable;
the first radio frequency cable and the local oscillator module, the first radio frequency cable and the transmitting feed source, the second radio frequency cable and the frequency mixer, and the second radio frequency cable and the receiving feed source are connected through radio frequency connectors.
6. a frequency modulated continuous wave radar level gauge according to claim 4,
If the transmitting path comprises the transmitting feed and the transmitting antenna but does not comprise the transmitting waveguide, and the receiving path comprises the receiving feed and the receiving antenna but does not comprise the receiving waveguide, the transmitting feed and the receiving feed are both formed on the same circuit board, and the transmitting feed is positioned in the transmitting antenna and the receiving feed is positioned in the receiving antenna; or,
If the transmitting path comprises the transmitting feed, the transmitting waveguide and the transmitting antenna and the receiving path comprises the receiving feed, the receiving waveguide and the receiving antenna, the transmitting feed and the receiving feed are both formed on the circuit board, the transmitting feed is positioned in the transmitting waveguide and the receiving feed is positioned in the receiving waveguide.
7. A frequency modulated continuous wave radar level gauge according to claim 6,
If the transmitting path comprises the transmitting feed source and the transmitting antenna but does not comprise the transmitting waveguide, and the receiving path comprises the receiving feed source and the receiving antenna but does not comprise the receiving waveguide, forming the transmitting feed source by utilizing a part of a first microstrip line formed on the circuit board extending into the transmitting antenna, wherein the first microstrip line is directly connected with the local oscillator module; the part of a second microstrip line formed on the circuit board extending into the receiving antenna is used for forming the receiving feed source, wherein the second microstrip line is directly connected with the mixer; or,
if the transmitting path comprises the transmitting feed source, the transmitting waveguide and the transmitting antenna, and the receiving path comprises the receiving feed source, the receiving waveguide and the receiving antenna, the transmitting feed source is formed by the part of the first microstrip line extending into the transmitting waveguide; and a part extending into the receiving waveguide by using the second microstrip line forms the receiving feed source.
8. a frequency modulated continuous wave radar level gauge according to claim 6,
if the transmitting path comprises the transmitting feed source and the transmitting antenna but does not comprise the transmitting waveguide, and the receiving path comprises the receiving feed source and the receiving antenna but does not comprise the receiving waveguide, forming the transmitting feed source by utilizing a first microstrip antenna formed on the circuit board, wherein the first microstrip antenna is positioned in the transmitting antenna, and the first microstrip antenna is directly connected with the local oscillation module; and forming the receiving feed source by using a second microstrip antenna formed on the circuit board, wherein the second microstrip antenna is positioned in the receiving antenna, and the second microstrip antenna is directly connected with the mixer; or,
If the transmitting path comprises the transmitting feed source, the transmitting waveguide and the transmitting antenna, and the receiving path comprises the receiving feed source, the receiving waveguide and the receiving antenna, the transmitting feed source is formed by using the first microstrip antenna, wherein the first microstrip antenna is positioned in the transmitting waveguide, and the first microstrip antenna is directly connected with the local oscillation module; and forming the receiving feed source by using the second microstrip antenna, wherein the second microstrip antenna is positioned in the receiving waveguide, and the second microstrip antenna is directly connected with the mixer.
9. A frequency modulated continuous wave radar level gauge according to claim 2 or claim 3, wherein said transmitting antenna and said receiving antenna are independent structures and said transmitting antenna and said receiving antenna are juxtaposed or are disposed in close proximity to each other.
10. a frequency modulated continuous wave radar level gauge according to claim 2 or 3, wherein said transmitting antenna and said receiving antenna are formed separated by an antenna diaphragm formed by a single antenna in the axial direction.
11. a fm cw radar level gauge as claimed in claim 3, wherein said transmitting waveguide and said receiving waveguide are independent structures, and wherein said transmitting waveguide and said receiving waveguide are juxtaposed or adjacent to each other.
12. a frequency modulated continuous wave radar level gauge according to claim 3, wherein said transmitting waveguide and said receiving waveguide are separated by a waveguide partition formed by a monolithic waveguide in the axial direction.
13. A frequency modulated continuous wave radar level gauge according to claim 3, further comprising:
A guard mechanism for preventing foreign objects from entering the launch path and the receive path.
14. frequency modulated continuous wave radar level gauge according to claim 13,
The guard mechanism includes: an antenna shield formed at free end antenna ports of both the transmitting antenna and the receiving antenna.
15. frequency modulated continuous wave radar level gauge according to claim 13,
The guard mechanism includes: and the plugging heads are respectively formed in the transmitting waveguide and the receiving waveguide or respectively formed in the transmitting antenna or the receiving antenna.
16. A frequency modulated continuous wave radar level gauge according to claim 14, wherein the bottom of said antenna shield is of a planar configuration, or is of a convex configuration, or is of a concave configuration.
17. Frequency modulated continuous wave radar level gauge according to claim 14,
If the transmitting antenna and the receiving antenna are of independent structures, the transmitting antenna and the receiving antenna are close to one side of the other side respectively and are connected or close to the antenna protective cover.
18. Frequency modulated continuous wave radar level gauge according to claim 14,
If the transmitting antenna and the receiving antenna are formed by separating the single antenna along the axis direction through the antenna partition plate, the antenna partition plate is connected or close to the antenna protective cover.
19. a frequency modulated continuous wave radar level gauge according to claim 14, wherein both the transmitting antenna and the receiving antenna each face a side of the antenna shield, abutting the antenna shield.
20. a frequency modulated continuous wave radar level gauge according to claim 14, wherein both said transmitting antenna and said receiving antenna each face a side of said antenna shield, a fixing means being formed for fixing said fixed antenna shield.
21. a frequency modulated continuous wave radar level gauge according to claim 14, wherein an inner space formed by said antenna housing and said transmitting and receiving antennas is filled with a deformation resistant material that is transparent to microwaves.
22. a frequency modulated continuous wave radar level gauge according to claim 2 or 3, wherein said transmitting antenna and said receiving antenna are both horn antennas or lens antennas.
23. The frequency modulated continuous wave radar level gauge according to claim 1, further comprising:
The frequency control module is connected with the local oscillation module;
An intermediate frequency amplifier connected to the mixer;
the A/D conversion module is connected with the intermediate frequency module;
And the processing module is respectively connected with the A/D conversion module and the frequency control module.
24. the frequency modulated continuous wave radar level gauge according to claim 23, further comprising:
And the display module is connected with the processing module.
25. the frequency modulated continuous wave radar level gauge according to claim 23, further comprising:
the communication module is connected with the processing module; and/or the presence of a gas in the gas,
and the interface module is connected with the processing module.
26. A frequency modulated continuous wave radar level gauge according to claim 2 or 3, wherein the transmission feed and the reception feed are linearly polarised feeds.
27. a frequency modulated continuous wave radar level gauge according to claim 2 or claim 3, wherein the transmit feed and the receive feed are circularly polarised feeds with opposite polarisation directions, one being left-hand and the other being right-hand.
28. a fm continuous wave radar level gauge according to claim 11, wherein said transmitting waveguide and said receiving waveguide are cylindrical structures with a semi-circular cross-section, and wherein the planar sides of said transmitting waveguide and said receiving waveguide are close or abutting to each other to form a cylindrical outer contour.
29. a frequency modulated continuous wave radar level gauge according to claim 9, wherein said transmitting antenna and said receiving antenna are cone shaped structures with a semi-circular cross-section, and wherein the planar sides of said transmitting antenna and said receiving antenna are close or abutting each other to form a conical outer contour.
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| CN201911041080.4A CN110567556B (en) | 2019-10-30 | 2019-10-30 | Frequency modulation continuous wave radar level gauge for measuring material level in container |
| PCT/CN2019/115539 WO2021082030A1 (en) | 2019-10-30 | 2019-11-05 | Frequency-modulated continuous-wave radar level meter for measuring material level in container |
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| CN201911041080.4A CN110567556B (en) | 2019-10-30 | 2019-10-30 | Frequency modulation continuous wave radar level gauge for measuring material level in container |
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| CN113375758A (en) * | 2021-07-08 | 2021-09-10 | 北京锐达仪表有限公司 | Radar level meter with variable beam angle |
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