Microstrip-to-waveguide device and radar level gauge

Abstract

An embodiment of the present application provides a microstrip-to-waveguide device and a radar level gauge. When designing the microstrip-to-waveguide device, two antenna units can be arranged in the waveguide cavity of the waveguide structure. Two microstrip transmission lines for feeding the two antenna units can extend into the waveguide cavity through different microstrip ports arranged on the waveguide cavity and feed the antenna units connected thereto respectively, so that the two microstrip transmission lines can be isolated, and the isolation degree of the signals transmitted by the two antenna units can be improved. Further, a resonant probe can also be arranged in the waveguide cavity, and the isolation degree of the signals transmitted by the two antenna units can be improved through the resonant characteristics of the resonant probe. Through the above structural design, there is no need to introduce components such as a power divider or a hybrid ring into the circuit, making the structure of the entire microstrip-to-waveguide device simpler and having better isolation degree, which is suitable for devices such as radar level gauges that require a smaller volume of the RF module.

Description

Technical Field

[0001] The present application relates to the field of radio frequency technology, and more particularly, to a microstrip-to-waveguide device and a radar level gauge. Background Art

[0002] For products such as radar level gauges, due to limited radio frequency space, in related technologies, when designing the antenna of a radar level gauge, a common transceiver antenna solution is generally adopted, that is, the same antenna is used to transmit or receive signals to reduce the volume occupied by the antenna. Since the transceiver shares the same antenna, in order to avoid mutual interference between the transmitted and received signals, a power divider or a hybrid ring is usually additionally provided to achieve transceiver isolation. Due to the need to additionally increase a power divider or a hybrid ring, the overall structure will become more complex, port matching will be more difficult, the processing accuracy requirements will be high, and the lengthening of the structure will lead to an increase in signal power loss, and thus the final isolation degree fails to reach the expected effect. Therefore, it is necessary to provide a solution for realizing transceiver signal isolation to make the overall structure simpler and the isolation degree better. Summary of the Invention

[0003] In view of this, the present application provides a microstrip-to-waveguide device and a radar level gauge.

[0004] According to a first aspect of the present application, a microstrip-to-waveguide device is provided. The microstrip-to-waveguide device includes a dielectric substrate, a waveguide structure, a microstrip antenna, and a resonant probe. The waveguide structure, the microstrip antenna, and the resonant probe are all disposed on the dielectric substrate;

[0005] The waveguide structure includes a waveguide cavity, and a first microstrip port and a second microstrip port disposed on the waveguide cavity;

[0006] The microstrip antenna includes a first antenna unit, a second antenna unit, a first microstrip transmission line, and a second microstrip transmission line. The first antenna unit and the second antenna unit are located inside the waveguide cavity. The first microstrip transmission line extends into the waveguide cavity through the first microstrip port and is connected to the first antenna unit to feed the first antenna unit, and the second microstrip transmission line extends into the waveguide cavity through the second microstrip port and is connected to the second antenna unit to feed the second antenna unit;

[0007] The resonant probe is located inside the waveguide cavity and on the symmetry axis of the first microstrip transmission line and the second microstrip transmission line.

[0008] According to a second aspect of the present application, a radar level gauge is provided. The radar level gauge includes the microstrip-to-waveguide device mentioned in the first aspect above.

[0009] Applying the solution provided by the present application, when designing a microstrip-to-waveguide device, two antenna units can be arranged in the waveguide cavity of the waveguide structure to realize signal transmission and reception. At the same time, in order to avoid interference between the signals transmitted by the two antenna units, two microstrip ports can be arranged on the waveguide cavity. The two microstrip transmission lines for feeding the two antenna units can extend into the waveguide cavity through different microstrip ports and feed the antenna units connected thereto. Since the two microstrip transmission lines extend into the waveguide cavity through different microstrip ports, the two microstrip transmission lines can be isolated, and to a certain extent, the isolation degree of the signals transmitted by the two antenna units can be improved. Further, a resonant probe can also be arranged in the waveguide cavity, and the isolation degree of the signals transmitted by the two antenna units can be improved through the resonant characteristics of the resonant probe. Through the above structural design, it is not necessary to introduce components such as a power divider or a hybrid ring into the circuit. Since no redundant components are introduced, the structure of the entire microstrip-to-waveguide device is simpler and shorter, and the isolation degree is better, which is suitable for devices such as radar level gauges that require a smaller volume of the antenna module.

[0010] It should be understood that the above general description and the following detailed description are only exemplary and explanatory, and cannot limit this specification. Brief Description of the Drawings

[0011] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the following drawings are only some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0012] Figure 1 It is a side view of a microstrip-to-waveguide device according to an embodiment of the present application.

[0013] Figure 2 It is a top view of a microstrip-to-waveguide device according to an embodiment of the present application.

[0014] Figure 3 It is a schematic diagram of two antenna units of a microstrip-to-waveguide device according to an embodiment of the present application.

[0015] Figure 4 It is a cross-sectional view of a microstrip-to-waveguide device according to an embodiment of the present application.

[0016] Figure 5 It is a side view of a microstrip-to-waveguide device according to an embodiment of the present application. Detailed Description of the Embodiments

[0017] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present application without creative efforts shall fall within the protection scope of the present application.

[0018] For products such as radar level gauges, due to limited RF space, their antennas generally adopt a transceiver-sharing antenna solution, using the same antenna to transmit or receive signals to reduce the volume occupied by the antenna. Since the transceiver shares the antenna, in order to avoid mutual interference between the transmitted and received signals, a power divider or hybrid ring is usually additionally provided to achieve transceiver isolation. Since a power divider or hybrid ring needs to be added additionally, the overall structure will become more complex. In addition, the power divider or hybrid ring usually requires precise port matching to ensure signal transmission efficiency and reduce reflection loss. However, it is very difficult to achieve perfect matching during the design and manufacturing process, making port matching more difficult, with high processing accuracy requirements. And because more components such as power dividers or hybrid rings need to be added to the circuit, the overall circuit structure will be lengthened, resulting in increased signal power loss, and further resulting in the final isolation not reaching the expected effect.

[0019] A microstrip-to-waveguide device is a conversion device used to connect a microstrip transmission line and a waveguide, and its main function is to convert the signal transmission of the microstrip transmission line into waveguide transmission, or vice versa. A microstrip transmission line is a planar transmission line structure, usually composed of a metal conductor strip on an insulating substrate and a bottom metal ground layer. Parameters such as the width and shape of the conductor strip of the microstrip line and the dielectric constant of the substrate can be adjusted to meet the requirements of specific applications. Microstrip transmission lines are commonly used in the design of radio frequency (RF) and microwave circuits, such as microstrip antennas, power dividers, filters, couplers, etc. A waveguide is a closed metal structure used to transmit high-frequency signals. The transmission characteristics of the waveguide are different from those of the microstrip line, so appropriate conversion is required. The microstrip-to-waveguide device provides an efficient way to achieve signal conversion between two different types of transmission lines.

[0020] In the scenario of signal transmission and reception using a microstrip antenna, in order to achieve good isolation between the transmitted and received signals and not make the overall circuit structure too complex, the structure of the microstrip-to-waveguide device can be improved to achieve signal isolation. Based on this, the embodiments of the present application provide a microstrip-to-waveguide device. Two antenna units can be arranged in the waveguide cavity of the waveguide structure. The two antenna units can be used to achieve signal transmission and reception. At the same time, in order to avoid interference between the transmitted signal and the received signal and improve the transmission and reception isolation, two microstrip ports can be arranged on the waveguide cavity. The two microstrip transmission lines for feeding the two antenna units can extend into the waveguide cavity through different microstrip ports and feed the antenna units connected to them respectively. Since the two microstrip transmission lines extend into the waveguide cavity through different microstrip ports, the two microstrip transmission lines can be isolated, and to a certain extent, the isolation of the transmitted and received signals can be improved. Further, a resonant probe can be arranged in the waveguide cavity. By arranging the resonant probe on the symmetry axis, the symmetry of the electromagnetic field distribution can be ensured, thereby reducing the mutual interference between the antenna units and improving the isolation of the transmitted and received signals.

[0021] In the embodiments of the present application, two antenna units are used to achieve signal transmission and reception. In order to improve the isolation of the signals transmitted by the two antenna units, a dual-microstrip-port design of the waveguide cavity can be adopted to achieve dual-path feeding to improve the transmission and reception isolation. At the same time, the resonant probe can be further used to improve the isolation of the transmitted and received signals. Through the above structural design, it is not necessary to introduce components such as a power divider or a hybrid ring into the circuit. Since no redundant components are introduced, the structure of the entire microstrip-to-waveguide device is simpler and shorter, and the isolation is better, which is suitable for devices such as radar level gauges that require a smaller volume of the antenna module.

[0022] The following combines Figure 1 and Figure 2 to introduce the microstrip-to-waveguide device provided by the embodiments of the present application. Among them, Figure 1 is a side view of the microstrip-to-waveguide device, Figure 2 is a top view of the microstrip-to-waveguide device. As shown in Figure 1 and Figure 2 , the microstrip-to-waveguide device includes a dielectric substrate 11, a waveguide structure 12, a microstrip antenna 13, and a resonant probe 14. Among them, the waveguide structure 12, the microstrip antenna 13, and the resonant probe 14 are all arranged on the dielectric substrate 11.

[0023] Among them, a grounding layer is provided at the bottom of the dielectric substrate 11, and the dielectric substrate 11 can adopt a high-frequency substrate.

[0024] The waveguide structure 12 includes a waveguide cavity 121, and a first microstrip port 122 and a second microstrip port 123 disposed on the waveguide cavity 121. The shape of the waveguide cavity 121 can be flexibly designed based on actual requirements. For example, it can be designed as a circle or a rectangle. The first microstrip port 122 and the second microstrip port 123 can be two openings provided at different positions of the waveguide cavity 121 to extend a microstrip transmission line into the waveguide cavity 121. In some embodiments, the first microstrip port 122 and the second microstrip port 123 are arranged at 90 degrees.

[0025] The microstrip antenna 13 includes a first antenna unit 131, a second antenna unit 132, a first microstrip transmission line 133, and a second microstrip transmission line 134. Among them, the first antenna unit 131 and the second antenna unit 132 are disposed on the dielectric substrate 11 and are located inside the waveguide cavity 121. The first antenna unit 131 can be used to transmit signals and / or receive signals, and the second antenna unit 132 is also used to transmit signals and / or receive signals. For example, when the first antenna unit 131 is used to transmit signals, the second antenna unit 132 can be used to receive signals. When the first antenna unit 131 is used to receive signals, the second antenna unit is used to transmit signals. Or the first antenna unit 131 and the second antenna unit 132 can be used as an antenna, and this antenna can switch between transmission and reception modes. When switched to the transmitting antenna mode, both antenna units are used to transmit signals. When switched to the receiving antenna mode, both antenna units are used to receive signals. The first antenna unit 131 and the second antenna unit 132 can adopt coupled antennas to couple the signals transmitted by the microstrip transmission line into the waveguide cavity 121.

[0026] In some embodiments, the first antenna unit 131 and the second antenna unit 132 can adopt probe antennas. Since the probe antenna has a simple structure, the overall structure and volume of the entire device can be simplified.

[0027] Among them, the first microstrip transmission line 133 extends into the waveguide cavity 121 through the first microstrip port 122 and is connected to the first antenna unit 131 to feed the first antenna unit 131. The second microstrip transmission line 134 extends into the waveguide cavity 121 through the second microstrip port 123 and is connected to the second antenna unit 132 to feed the second antenna unit 132.

[0028] In some embodiments, the first microstrip transmission line 133 and the second microstrip transmission line 134 form a 90-degree angle, so that the above-mentioned first antenna unit 131 and the second antenna unit 132 also form a 90-degree angle, making the polarization directions of the electromagnetic waves generated by the two different and reducing interference.

[0029] The first microstrip transmission line 133 and the second microstrip transmission line 134 can be composed of a metal conductor strip on a layer of insulating substrate and a bottom metal ground layer. Parameters such as the width and shape of the metal conductor strip and the dielectric constant of the substrate can be adjusted to meet the requirements of specific applications. In some embodiments, the first microstrip transmission line 133 and the second microstrip transmission line 134 can be CPW (coplanar waveguide) transmission lines. Of course, other forms of transmission lines can also be used, and the embodiments of the present application do not limit this.

[0030] The resonant probe 14 is disposed on the dielectric substrate 11 and is located within the waveguide cavity 121, and the resonant probe 14 is located on the symmetry axis of the first microstrip transmission line 133 and the second microstrip transmission line 134.

[0031] Among them, the resonant probe 14 is generally designed as a resonant circuit, which exhibits high impedance or low impedance at a specific operating frequency. This circuit has extremely strong selectivity at its resonant frequency. When the frequency of the signal matches the resonant frequency, the signal can pass through or be reflected, while signals of other frequencies will be suppressed or attenuated. Based on the above characteristics of the resonant probe 14, the resonant probe 14 can be used to achieve isolation of the signals transmitted by the two antenna units and avoid interference between them.

[0032] Among them, when the resonant probe 14 is disposed on the symmetry axis of the first microstrip transmission line 133 and the second microstrip transmission line 134, it can ensure the electromagnetic coupling symmetry between the first antenna unit 131 and the second antenna unit 132. The signals transmitted by the two antenna units will propagate in a symmetric manner in the structure, thereby reducing the signal interference or crosstalk phenomenon that may be caused by asymmetric coupling. This helps to improve the signal isolation degree.

[0033] In some embodiments, as Figure 3 shown, both the first antenna unit 131 and the second antenna unit 132 are rectangular patches with chamfers, and the chamfer positions are at the diagonal positions of the two rectangular patches.

[0034] Generally, the radiation characteristics and coupling mode of an antenna are affected by the antenna shape. By chamfering the antenna, the radiation characteristics such as the radiation direction and polarization state of the antenna can be changed, so that the radiation patterns between two antennas are more separated. In addition, the coupling between antennas usually occurs in the overlapping area of their radiation fields. Chamfering can effectively change the receiving and transmitting directions of the antennas, causing the radiation patterns of the two antennas to shift in space, thereby reducing the degree of cross-coupling. When the radiation patterns of the antennas are different and their directions are separated, the energy exchange between them will decrease, thereby improving the isolation between the antennas. Therefore, the first antenna unit 131 and the second antenna unit 132 can be chamfered to change their shapes, and then change their radiation characteristics and coupling mode, so as to achieve the purpose of improving the isolation of the signals between the two. In some embodiments, to ensure the consistency of the transceiver performance, the chamfer position can be the diagonal positions of the two rectangular patches, so that the first antenna unit 131 and the second antenna unit 132 after chamfering still remain symmetric.

[0035] In some embodiments, the chamfer of the rectangular patch can be a 45° chamfer. Among them, the applicant found through experiments that when the chamfer of the rectangular patch is a 45° chamfer, the signals of the two antennas have good isolation.

[0036] In some embodiments, the first antenna unit 131 and the second antenna unit 132 can adopt the same antenna unit, that is, their shapes, materials, etc. are the same. In this case, the first antenna unit 131 and the second antenna unit 132 can be symmetrically arranged. Among them, the symmetry axis of the first antenna unit 131 and the second antenna unit 132 coincides with the symmetry axis of the first microstrip transmission line 133 and the second microstrip transmission line 134, that is, this symmetry axis is the bisector of the included angle formed by the first microstrip transmission line 133 and the second microstrip transmission line 134.

[0037] Of course, in some embodiments, the first antenna unit 131 and the second antenna unit 132 can also adopt antennas with different shapes, that is, they can be asymmetric.

[0038] In some embodiments, as shown in FIG. 3, the first microstrip transmission line 133 and the second microstrip transmission line 134 form a 90° angle, and the first antenna unit 131 and the second antenna unit 132 connected to the first microstrip transmission line 133 and the second microstrip transmission line 134 are also arranged at a 90° angle. When the first antenna unit 131 and the second antenna unit 132 are arranged at a 90° angle, the polarization directions of the electromagnetic waves generated by the two are different (for example, the polarization direction of the first antenna unit 131 is the horizontal direction, and the polarization direction of the second antenna unit 132 is the vertical direction), that is, the electromagnetic waves generated by the two will oscillate in different directions, so that the electric field distribution between the two antenna units is different. At the same time, cross-coupling, phase interference and signal overlap can also be reduced, thereby reducing the mutual interference between the signals transmitted by the two antenna units.

[0039] In some embodiments, the position of the resonant probe 14 on the axis of symmetry can be determined based on the impedance to be matched by the first antenna unit 131 and the second antenna unit 132, and / or the isolation between the first antenna unit 131 and the second antenna unit 132.

[0040] Antenna impedance matching refers to adjusting the impedance between the antenna unit and the microstrip transmission line so that the signal can be transmitted from the microstrip transmission line to the antenna unit, or from the antenna unit to the transmission line, to the greatest extent, without reflection and energy loss. The purpose of impedance matching is to ensure the effective transmission of the signal and reduce the reflection loss, thereby improving the efficiency and performance of the communication system. When the microstrip transmission line is connected to the antenna unit, in order to reduce the signal loss, the characteristic impedance of the microstrip transmission line (such as 50Ω, 75Ω) needs to match the input impedance of the antenna unit. If the impedances of the two are equal, the signal can be transmitted from the microstrip transmission line to the antenna unit, or from the antenna unit to the signal transmission line without loss. Otherwise, signal reflection will occur, and the reflected signal will be superimposed on the incident signal to form a reflected wave, which will reduce the transmission efficiency and may cause signal distortion. Since the position of the resonant probe 14 on the axis of symmetry affects the electric field distribution, radiation pattern, etc. of the antenna unit, and thus affects the input impedance of the antenna unit, in some embodiments, the position of the resonant probe 14 on the above axis of symmetry can be dynamically adjusted based on the impedance required by the first antenna unit 131 and the second antenna unit 132 in different scenarios, so as to ensure the impedance matching of the above two antenna units and the microstrip transmission line and reduce the signal loss.

[0041] In some embodiments, the position of the resonant probe 14 on the above-mentioned axis of symmetry can also be determined based on the isolation between the first antenna unit 131 and the second antenna unit 132. For example, when the resonant probe 14 is located at different positions on the above-mentioned axis of symmetry, the isolation between the first antenna unit 131 and the second antenna unit 132 can be determined, and the resonant probe 14 can be set at the position where the isolation is the largest.

[0042] In some embodiments, the resonant probe 14 is grounded.

[0043] Since radar level gauges often use electromagnetic waves in a relatively high frequency band, generally, the higher the frequency band of the electromagnetic wave signal, the more serious its loss. For the scenario where the signal transmitted by the antenna is a signal in a relatively high frequency band, in the related art, when designing the microstrip-to-waveguide structure 12, the common means is to try to avoid introducing components that will increase the loss of the electromagnetic wave signal. For example, the resonant probe 14. At the same time, considering that grounding the resonant probe 14 usually increases the conduction loss, in the related art, the resonant probe 14 is also avoided from being grounded as much as possible. In the embodiments of the present application, a new approach is taken. By setting the resonant probe 14 on the axis of symmetry of the two antenna units in the waveguide cavity, and the resonant probe 14 adopts a grounded design. Since the resonant probe 14 is placed on the axis of symmetry, the symmetry of the electromagnetic field distribution can be ensured, thereby reducing the mutual interference between the two antenna units. This symmetric design helps to simplify the impedance matching process and improve the matching accuracy. At the same time, by adjusting the position of the resonant probe 14 on the axis of symmetry and the size of the resonant probe 14, the input impedance of the antenna unit can be optimized to make it closer to the required impedance value. That is to say, although this design method increases the conduction loss, it can greatly optimize the impedance matching degree of the antenna unit, thereby greatly reducing the reflection loss, reducing the overall loss, and indirectly improving the isolation between the antenna units.

[0044] Figure 4 is a cross-sectional view of the microstrip-to-waveguide device. In some embodiments, as Figure 4 shown, a waveguide port 124 is further provided on the waveguide cavity 121. The microstrip-to-waveguide device is connected to the waveguide through the waveguide port 124. That is, the waveguide structure 12 can adopt a three-port design, where two ports are microstrip ports for introducing the microstrip transmission line into the waveguide cavity 121, and the other port is a waveguide port for connecting to the waveguide and guiding the transmission of electromagnetic signals.

[0045] In some embodiments, the axes of the three ports of the first microstrip port 122, the second microstrip port 123, and the waveguide port 124 are perpendicular to each other at 90°.

[0046] In some embodiments, the waveguide cavity is a circular waveguide cavity. Of course, the waveguide cavity can also be a rectangular, square or other shaped waveguide cavity, which is not limited in the embodiments of the present application. Among them, when the waveguide cavity is a circular waveguide cavity, the above waveguide can also be a circular waveguide. When the waveguide cavity is a rectangular waveguide cavity, the above waveguide is a rectangular waveguide.

[0047] To further introduce the microstrip-to-waveguide device provided by the embodiments of the present application, the following is explained in conjunction with a specific embodiment.

[0048] The following is combined with Figure 5 to introduce the microstrip-to-waveguide device provided in this embodiment.

[0049] The microstrip-to-waveguide device includes a dielectric substrate 11, a waveguide structure 12, a microstrip antenna 13 and a resonant probe 14. The waveguide structure 12, the microstrip antenna 13 and the resonant probe 14 are all arranged on the dielectric substrate 11. Among them, a ground layer is provided at the bottom of the dielectric substrate 11. The waveguide structure 12 adopts a three-port design, and the three ports are respectively a microstrip port 1 (122 in the figure), a microstrip port 2 (123 in the figure), and a waveguide port (124 in the figure). Among them, the waveguide cavity 121 of the waveguide structure 12 is a circular waveguide, and the three ports are three openings formed in the waveguide cavity at an angle of 90 degrees to each other. The microstrip antenna 13 includes a first antenna unit 131, a second antenna unit 132, a microstrip transmission line 1 (133 in the figure) connected to the first antenna unit 131, and a microstrip transmission line 2 (134 in the figure) connected to the second antenna unit 132. Among them, the first antenna unit 131 and the second antenna unit 132 are located in the waveguide cavity 121. The microstrip transmission line 1 extends into the waveguide cavity 121 through the microstrip port 1 and is connected to the first antenna unit 131 to feed the first antenna unit 131. The microstrip transmission line 2 extends into the waveguide cavity 121 through the microstrip port 2 and is connected to the second antenna unit 132 to feed the second antenna unit 132. Among them, the microstrip transmission line 1 and the microstrip transmission line 2 form a 90° angle. The first antenna unit 131 and the second antenna unit 132 are rectangular patches with a 45-degree chamfer, and the chamfer position is the diagonal position of the two rectangular patches. The first antenna unit 131 and the second antenna unit 132 are symmetrically arranged, and their symmetry axes are the symmetry axes of the microstrip transmission line 1 and the microstrip transmission line 2. In order to make the first antenna unit 131 and the second antenna unit 132 generate electromagnetic waves with different polarization directions and improve the transceiver isolation, the first antenna unit 131 and the second antenna unit 132 are arranged at 90 degrees.

[0050] The resonant probe 14 can be disposed on the dielectric substrate 11 by means of vias and soldering, and is located in the waveguide cavity. Moreover, the resonant probe 14 is located on the symmetry axis of the first antenna unit 131 and the second antenna unit 132, and its position on the symmetry axis is determined based on the impedances to be matched by the first antenna unit 131 and the second antenna unit 132, as well as the first antenna unit 131 and the second antenna unit 132. Among them, the resonant probe 14 adopts a grounded design.

[0051] The waveguide port 124 is used to connect to a waveguide so as to guide the transmission of electromagnetic signals by means of the waveguide.

[0052] In the embodiment of the present application, by designing two different microstrip ports in the waveguide cavity, the microstrip transmission line for feeding the first antenna unit 131 and the microstrip transmission line for feeding the second antenna unit 132 can be extended into the waveguide cavity 121, so that the two microstrip transmission lines can be isolated in different channels, thereby reducing the interference between the transmitted and received signals and improving the isolation degree of the transmitted and received signals. At the same time, by arranging the resonant probe 14 in the waveguide cavity, the resonant characteristics of the resonant probe 14 can be utilized to further improve the isolation degree of the transmitted and received signals. In addition, by performing chamfering design on the first antenna unit 131 and the second antenna unit 132, the radiation characteristics, coupling modes, etc. of the two can be changed, thereby further improving the isolation degree between the two. In this embodiment, by combining the three methods of dual-port design, arranging the resonant probe 14, and antenna chamfering, the isolation degree of the transmitted and received signals can be greatly improved, and there is no need to introduce a power divider or a hybrid ring to achieve transmit-receive isolation, which can reduce the complexity and processing difficulty of the entire circuit structure. Therefore, the designed microstrip-to-waveguide device can achieve the advantages of simple structure, low loss, and high isolation degree. Moreover, due to the highly symmetric structure inside the entire waveguide cavity, the consistency of the transmit and receive electrical performances can be ensured.

[0053] In addition, the present application also provides a radar level gauge, which includes the microstrip-to-waveguide device mentioned in any of the above embodiments.

[0054] A radar level gauge is a device used to measure the level (height) of liquid or solid materials. It measures the level by emitting electromagnetic waves (radar waves) and analyzing the reflected signals of the waves. The main functions of the antenna of the radar level gauge are to emit electromagnetic waves and receive the electromagnetic waves (radar waves) reflected by the object. Through the above-mentioned microstrip-to-waveguide device, signal isolation between the transmitting antenna and the receiving antenna in the radar level gauge can be achieved, and the structure is simple and the loss is low.

[0055] Among them, the solutions of the above embodiments can be freely combined to obtain new solutions without conflict. Due to space limitations, they are not listed one by one here.

[0056] Embodiments of this specification may be implemented in the form of a computer program product implemented on one or more storage media (including but not limited to disk memories, CD-ROMs, optical memories, etc.) containing program code. Computer-usable storage media include permanent and non-permanent, removable and non-removable media, and information storage can be implemented by any method or technology. The information may be computer-readable instructions, data structures, program modules, or other data. Examples of computer storage media include but are not limited to: phase change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technologies, compact disc read-only memory (CD-ROM), digital versatile disc (DVD) or other optical storage, magnetic cassette tapes, disk storage or other magnetic storage devices, or any other non-transmission media that can be used to store information accessible by a computing device.

[0057] For the device embodiments, since they basically correspond to the method embodiments, the relevant parts can be referred to the descriptions of the method embodiments. The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed to multiple network units. Some or all of the modules can be selected according to actual needs to achieve the purpose of the solution of this embodiment. A person of ordinary skill in the art can understand and implement it without creative work.

[0058] The user information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to data for analysis, stored data, displayed data, etc.) involved in this application are all information and data authorized by the user or fully authorized by all parties. The collection, use, and processing of relevant data need to comply with the relevant laws, regulations, and standards of relevant countries and regions, and corresponding operation entrances are provided for users to choose to authorize or refuse.

[0059] It should be noted that in this article, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. The term "comprising", "including" or any other variant thereof is intended to cover non-exclusive inclusion, so that a process, method, article or device comprising a series of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article or device. Without further limitation, an element defined by the statement "comprising an..." does not exclude the presence of additional identical elements in the process, method, article or device comprising the said element.

[0060] The methods and devices provided by the embodiments of the present invention have been introduced in detail above. Specific examples are used in this article to elaborate on the principles and implementation manners of the present invention. The description of the above embodiments is only used to help understand the method and its core idea of the present invention; at the same time, for those of ordinary skill in the art, according to the idea of the present invention, there will be changes in the specific implementation manners and application scopes. In summary, the content of this specification should not be construed as a limitation to the present invention.

Claims

1. A microstrip to waveguide device, characterized in that: The microstrip-to-waveguide device comprises a dielectric substrate, a waveguide structure, a microstrip antenna and a resonant probe, wherein the waveguide structure, the microstrip antenna and the resonant probe are all arranged on the dielectric substrate; The waveguide structure includes a waveguide cavity, and a first microstrip port and a second microstrip port arranged on the waveguide cavity; The microstrip antenna comprises a first antenna unit, a second antenna unit, a first microstrip transmission line, and a second microstrip transmission line. The first antenna unit and the second antenna unit are located in the waveguide cavity. The first microstrip transmission line extends into the waveguide cavity through the first microstrip port and is connected to the first antenna unit so as to feed the first antenna unit. The second microstrip transmission line extends into the waveguide cavity through the second microstrip port and is connected to the second antenna unit so as to feed the second antenna unit. The resonant probe is located in the waveguide cavity and on the symmetry axis of the first microstrip transmission line and the second microstrip transmission line.

2. The microstrip-to-waveguide device according to claim 1, characterized in that: The first antenna unit and the second antenna unit are both rectangular patches with cut corners, and the cut corner positions are diagonal positions of the two rectangular patches.

3. The microstrip-to-waveguide device according to claim 2, characterized in that: The cutting angle of the rectangular patch is 45°.

4. The microstrip-to-waveguide device according to claim 1, characterized in that: The first antenna unit and the second antenna unit have the same shape, and the first antenna unit and the second antenna unit are symmetrically arranged.

5. The microstrip-to-waveguide device according to claim 4, characterized in that: The first antenna unit and the second antenna unit are arranged at 90 degrees.

6. The microstrip-to-waveguide device according to claim 1, characterized in that: The position of the resonant probe on the symmetry axis is determined based on one or more of the following: The impedance required to be matched between the first antenna unit and the second antenna unit, and the isolation between the first antenna unit and the second antenna unit.

7. The microstrip-to-waveguide device according to claim 1, characterized in that: The resonant probe is grounded.

8. The microstrip-to-waveguide device according to claim 1, characterized in that: The waveguide cavity is also provided with a waveguide port, and the microstrip-to-waveguide device is connected to the waveguide tube via the waveguide port.

9. The microstrip-to-waveguide device according to claim 1, characterized in that: The waveguide cavity is a circular waveguide cavity.

10. A radar level meter, characterized in that: The radar level meter comprises the microstrip-to-waveguide device according to any one of claims 1-9.

Images