Antenna array for microwave moisture meter and microwave moisture meter

Abstract

The invention provides an antenna array for a microwave moisture meter and the microwave moisture meter. The antenna array for the microwave moisture meter comprises a power division network and two sets of radiation array units, the power division network is arranged on a first dielectric substrate, and the two sets of radiation array units are symmetrically arranged at the two ends of the first dielectric substrate; the radiation array unit comprises a plurality of unit antennas, each unit antenna comprises a feed structure, a plurality of rectangular slot lines, an index gradual change slot formed by two index gradual change slot lines and a resonant ring formed at the top end of the index gradual change slot, and the plurality of rectangular slot lines are arranged on two sides of a radiation surface of the index gradual change slot lines. And the lengths of the rectangular slot lines arranged on the same side of the radiating surface are sequentially reduced along the direction from the top end of the exponential gradual change slot to the opening of the exponential gradual change slot. According to the antenna array for the microwave moisture meter, the gain can be increased, the beam width can be reduced, and the bandwidth can be increased.

Description

Technical Field

[0001] The invention relates to the technical field of microwave moisture detection, and in particular to an antenna array for a microwave moisture meter and a microwave moisture meter. Background Art

[0002] In industrial and agricultural production, there are strict requirements for the moisture content of some materials (medium) during storage, transportation and use. Materials that do not meet the moisture content may cause the corresponding product functions and performance to fail, or cause the production efficiency to fail to meet the requirements. Therefore, microwave moisture detection is widely used in production and processing to control the moisture content of production materials and ensure that the moisture content of materials is within the design requirements. The existing scheme generally uses a microwave moisture meter for microwave moisture detection. When the microwave moisture meter detects the moisture content of fine aggregates such as sand and gravel, this material will have a large attenuation of the microwave signal. The microwave moisture meter is installed above the fine aggregate conveyor belt. The conveyor belt is relatively narrow, and the microwave moisture meter needs to have a narrower beam width. In addition, since the conveyor belt is moving, the microwave moisture meter needs to be able to reduce the Doppler effect caused by the movement. The existing microwave moisture meter has a small antenna gain, a large beam width, and a small bandwidth, which cannot meet the above needs well. Summary of the invention

[0003] The object of the present invention is to provide an antenna array for a microwave moisture meter and a microwave moisture meter to solve the technical problems of small antenna gain, large beam width and small bandwidth of the microwave moisture meter in the prior art.

[0004] The technical solution of the present invention is as follows: an antenna array for a microwave moisture meter is provided, comprising a power division network and two groups of radiation array units, wherein the power division network is arranged on a first dielectric substrate, and the two groups of radiation array units are symmetrically arranged at two ends of the first dielectric substrate;

[0005] The radiation array unit includes a plurality of unit antennas, each of which includes a feeding structure, a plurality of rectangular slot lines, an exponentially tapered slot formed by two exponentially tapered slot lines, and a resonant ring formed at the top of the exponentially tapered slot. The plurality of rectangular slot lines are arranged on both sides of a radiation surface of the exponentially tapered slot line, and the length of the rectangular slot lines arranged on the same side of the radiation surface decreases successively along a direction from the top of the exponentially tapered slot to the opening of the exponentially tapered slot.

[0006] Furthermore, the two groups of radiation array units are respectively arranged on a second dielectric substrate and a third dielectric substrate, and the second dielectric substrate and the third dielectric substrate are parallel to each other and perpendicular to the first dielectric substrate.

[0007] Furthermore, corresponding rectangular slot lines of any two adjacent unit antennas among the plurality of unit antennas are connected.

[0008] Furthermore, the width of the rectangular groove line is 2 mm, the number of rectangular groove lines arranged on both sides of the radiation surface is equal and one-to-one corresponding, the distance between any two adjacent rectangular groove lines arranged on the same side of the radiation surface is 5.5 mm, the maximum length of the rectangular groove lines arranged on the same side of the radiation surface is 23 mm, and the length of the rectangular groove lines arranged on the same side of the radiation surface decreases successively with a gradient of 1 mm along the direction from the top of the exponential gradient groove to the opening of the exponential gradient groove.

[0009] Furthermore, the length of the unit antenna is 130 mm, and the width of the unit antenna is 70.26 mm.

[0010] Furthermore, the diameter of the resonant ring is 19 mm.

[0011] Furthermore, the feeding structure includes a fan-shaped microstrip stub and a microstrip feed line, the fan-shaped surface radius of the fan-shaped microstrip stub is 10 mm, and the maximum width of the microstrip feed line is 1.9 mm.

[0012] Furthermore, the curvature of the exponential gradient groove line is 0.08, the top width of the exponential gradient groove is 1 mm, and the opening width of the exponential gradient groove is 70.26 mm.

[0013] Furthermore, the power division network includes a Wilkinson power division unit, and the Wilkinson power division unit includes 1 input port, 6 output ports and 2 ground ports.

[0014] Another technical solution of the present invention is as follows: a microwave moisture meter is provided, comprising an antenna array for a microwave moisture meter as described in any of the above technical solutions.

[0015] The beneficial effects of the present invention are as follows: by arranging the power division network on the first dielectric substrate, the two groups of the radiation array units are symmetrically arranged at the two ends of the first dielectric substrate; the radiation array unit includes a plurality of unit antennas, each of the unit antennas includes a feeding structure, a plurality of rectangular slot lines, an exponentially tapered slot formed by two exponentially tapered slot lines, and a resonant ring formed at the top of the exponentially tapered slot, the plurality of rectangular slot lines are arranged on both sides of the radiation surface of the exponentially tapered slot line, and the length of the rectangular slot lines arranged on the same side of the radiation surface decreases successively along the direction from the top of the exponentially tapered slot to the opening of the exponentially tapered slot; the gain can be increased, the beam width can be reduced, and the bandwidth can be increased, thereby improving the detection accuracy of the moisture content of materials, especially fine aggregates such as sand and gravel. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1A first structural schematic diagram of an antenna array for a microwave moisture meter provided in an embodiment of the present invention;

[0017] Figure 2 A schematic diagram of the structure of a group of radiation array units provided by an embodiment of the present invention;

[0018] Figure 3 A schematic diagram of the structure of a unit antenna provided by an embodiment of the present invention;

[0019] Figure 4 A second structural schematic diagram of an antenna array for a microwave moisture meter provided in an embodiment of the present invention;

[0020] Figure 5 A schematic diagram of the structure of a power division network provided in an embodiment of the present invention;

[0021] Figure 6 The horizontal electric field pattern of the antenna array for a microwave moisture meter provided by an embodiment of the present invention at 1 GHz;

[0022] Figure 7 The vertical electric field pattern of the antenna array for a microwave moisture meter provided by an embodiment of the present invention at 1 GHz;

[0023] Figure 8 The horizontal electric field pattern of the antenna array for a microwave moisture meter provided in an embodiment of the present invention at 2 GHz;

[0024] Fig. 9 The vertical electric field pattern of the antenna array for a microwave moisture meter provided by an embodiment of the present invention at 2 GHz;

[0025] Fig.10 The horizontal electric field pattern of the antenna array for a microwave moisture meter provided by an embodiment of the present invention at 3 GHz;

[0026] Fig.11 The vertical electric field pattern of the antenna array for a microwave moisture meter provided by an embodiment of the present invention at 3 GHz;

[0027] Fig.12 The horizontal electric field pattern of the antenna array for a microwave moisture meter provided by an embodiment of the present invention at 4 GHz;

[0028] Fig.13 The vertical electric field pattern of the antenna array for a microwave moisture meter provided in an embodiment of the present invention at 4 GHz;

[0029] Fig.14 The horizontal electric field pattern of the antenna array for a microwave moisture meter provided by an embodiment of the present invention at 5 GHz;

[0030] Fig.15 The vertical electric field pattern of the antenna array for a microwave moisture meter provided in an embodiment of the present invention at 5 GHz.

[0031] Figure numerals: 10-power division network; 11-first dielectric substrate; 12-Wilkinson power division unit; 20-radiation array unit; 21-second dielectric substrate; 22-third dielectric substrate; 23-unit antenna; 24-feeding structure; 241-microstrip feed line; 242-fan-shaped microstrip stub; 25-rectangular slot line; 26-exponential gradient slot; 27-resonance ring. DETAILED DESCRIPTION

[0032] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0033] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present invention. The appearance of the phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0034] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the terms used in this way can be interchangeable under appropriate circumstances, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein.

[0035] In the description of the embodiments of the present application, "multiple" refers to two or more than two, and other quantifiers are similar and should be understood. The preferred embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention. In addition, the embodiments of the present application and the features therein may be combined with each other if there is no conflict.

[0036] Figure 1 1 is a schematic diagram of the first structure of the antenna array for a microwave moisture meter according to an embodiment of the present invention. It should be noted that if substantially the same results are achieved, the antenna array for a microwave moisture meter according to the present invention is not necessarily Figure 1 The structure sequence shown is limited. Figure 1As shown, the antenna array for a microwave moisture meter includes a power division network 10 and two groups of radiation array units 20, wherein the power division network 10 is arranged on a first dielectric substrate 11, and the two groups of radiation array units 20 are symmetrically arranged at two ends of the first dielectric substrate 11;

[0037] The radiation array unit 20 includes a plurality of unit antennas 23, each of the unit antennas 23 includes a feeding structure 24, a plurality of rectangular slot lines 25, an exponentially tapered slot 26 formed by two exponentially tapered slot lines, and a resonant ring formed at the top of the exponentially tapered slot 26, the plurality of rectangular slot lines 25 are arranged on both sides of the radiation surface of the exponentially tapered slot line, and the length of the rectangular slot lines 25 arranged on the same side of the radiation surface decreases successively along the direction from the top of the exponentially tapered slot 26 to the opening of the exponentially tapered slot 26.

[0038] In the embodiment of the present invention, the power division network 10 is arranged on the first dielectric substrate 11, and the two groups of the radiation array units 20 are symmetrically arranged at the two ends of the first dielectric substrate 11; the radiation array unit 20 includes a plurality of unit antennas 23, each of the unit antennas 23 includes a feeding structure 24, a plurality of rectangular slot lines 25, an exponentially tapered slot 26 formed by two exponentially tapered slot lines, and a resonant ring formed at the top of the exponentially tapered slot 26, the plurality of rectangular slot lines 25 are arranged on both sides of the radiation surface of the exponentially tapered slot line, and the length of the rectangular slot lines 25 arranged on the same side of the radiation surface decreases successively along the direction from the top of the exponentially tapered slot 26 to the opening of the exponentially tapered slot 26; the gain can be increased, the beam width can be reduced, and the bandwidth can be increased, thereby improving the detection accuracy of the moisture content of materials, especially fine aggregates such as sand and gravel.

[0039] In a specific embodiment, the above-mentioned unit antenna 23 can be a double-sided printed antenna on a dielectric substrate (Vivaldi antenna), the front side of which includes a metal radiation patch composed of an exponential gradient slot line, an equal-width rectangular slot line 25 and a circular resonant cavity (resonant ring), and the back side includes a feeding structure 24.

[0040] In some embodiments, the two groups of radiation array units 20 are respectively disposed on a second dielectric substrate 21 and a third dielectric substrate 22 , and the second dielectric substrate 21 and the third dielectric substrate 22 are parallel to each other and perpendicular to the first dielectric substrate 11 .

[0041] In a specific embodiment, the first dielectric substrate 11, the second dielectric substrate 21 and the third dielectric substrate 22 are all two-layer PCBs (Printed Circuit Boards), which are made of FR-4 grade materials and have a thickness of 1.6 mm.

[0042] In a specific embodiment, according to product requirements, the radiation array unit 20 of the antenna array that can be used for a microwave moisture meter may include three unit antennas 23, that is, forming a 2*3 antenna array, and the spacing between any two adjacent unit antennas 23 in each radiation array unit 20 can be 60 mm, and the spacing between two groups of radiation array units 20 can be 60 mm.

[0043] In some embodiments, corresponding rectangular slot lines 25 of any two adjacent unit antennas 23 among the plurality of unit antennas 23 are connected.

[0044] In the embodiment of the present invention, by connecting the corresponding rectangular slot lines 25 of any two adjacent unit antennas 23 among the multiple unit antennas 23, the gain of the unit antenna 23 can be increased, thereby improving the detection accuracy of the moisture content of materials, especially fine aggregates such as sand and gravel.

[0045] In a specific embodiment, a schematic diagram of the structure of a group of radiation array units is shown as follows: Figure 2 As shown by Figure 1 and Figure 2 It can be known that the corresponding rectangular slot lines 25 of any two adjacent unit antennas 23 among the plurality of unit antennas 23 are connected.

[0046] In some embodiments, the width of the rectangular groove line 25 is 2 mm, the number of the rectangular groove lines 25 arranged on both sides of the radiation surface is equal and one-to-one corresponding, the distance between any two adjacent rectangular groove lines 25 arranged on the same side of the radiation surface is 5.5 mm, the maximum length of the rectangular groove lines 25 arranged on the same side of the radiation surface is 23 mm, and the length of the rectangular groove lines 25 arranged on the same side of the radiation surface decreases gradually with a gradient of 1 mm along the direction from the top of the exponential gradient groove 26 to the opening of the exponential gradient groove 26.

[0047] In a specific embodiment, Figure 1 , Figure 2 As shown, the number of rectangular slot lines 25 arranged on the same side of the radiation surface is 7, and the number of rectangular slot lines 25 arranged on both sides of the radiation surface is equal and corresponds one to one.

[0048] In some embodiments, the length of the unit antenna 23 is 130 mm, and the width of the unit antenna 23 is 70.26 mm.

[0049] In the embodiment of the present invention, by setting the length of the unit antenna 23 to 130 mm and the width of the unit antenna 23 to 70.26 mm, the gain can be increased, the beam width can be reduced, and the bandwidth can be increased, thereby improving the detection accuracy of the moisture content of materials, especially fine aggregates such as sand and gravel.

[0050] In some embodiments, the diameter of the resonant ring is 19 mm.

[0051] In the embodiment of the present invention, the bandwidth can be increased by setting the diameter of the resonant ring to 19 mm.

[0052] In some embodiments, the feeding structure 24 includes a fan-shaped microstrip stub 242 and a microstrip feed line 241 , the fan-shaped surface radius of the fan-shaped microstrip stub 242 is 10 mm, and the maximum width of the microstrip feed line 241 is 1.9 mm.

[0053] In the embodiment of the present invention, the feeding structure 24 includes a fan-shaped microstrip stub 242 and a microstrip feed line 241 , the fan-shaped surface radius of the fan-shaped microstrip stub 242 is 10 mm, and the maximum width of the microstrip feed line 241 is 1.9 mm, thereby increasing the bandwidth.

[0054] In some embodiments, the curvature of the exponentially gradual groove line is 0.08, the top width of the exponentially gradual groove 26 is 1 mm, and the opening width of the exponentially gradual groove 26 is 70.26 mm.

[0055] In the embodiment of the present invention, the curvature of the exponential gradient groove line is 0.08, the top width of the exponential gradient groove 26 is 1 mm, and the opening width of the exponential gradient groove 26 is 70.26 mm, which can increase the gain, reduce the beam width and increase the bandwidth, thereby improving the detection accuracy of the moisture content of materials, especially fine aggregates such as sand and gravel.

[0056] In a specific embodiment, a schematic diagram of the structure of a unit antenna is shown as follows: Figure 3 As shown, Figure 3 The dimensions of the various parts of the unit antenna 23 are shown in FIG. Figure 3 The dimensions are in millimeters (mm).

[0057] In some embodiments, the power division network 10 includes a Wilkinson power division unit 12, and the Wilkinson power division unit 12 includes 1 input port, 6 output ports and 2 ground ports.

[0058] In a specific embodiment, a second schematic diagram of the antenna array for a microwave moisture meter is shown in FIG. Figure 4 As shown, the schematic diagram of the structure of the power division network 10 is as follows: Figure 5 As shown, Figure 5 In the figure, the first port is the input port, the eighth port and the ninth port are ground ports, the second port, the third port, the fourth port, the fifth port, the sixth port and the seventh port are all output ports, which perform equal power and equal phase output. In order to ensure that the output port has good standing wave capability, the eighth port and the ninth port can both be grounded using resistors (for example, 49.9Ω resistors) to ensure the consistency of the output ports.

[0059] In a specific embodiment, the antenna array for the microwave moisture meter is simulated to obtain the horizontal electric field pattern of the antenna array for the microwave moisture meter at 1 GHz, such as Figure 6 As shown in the figure, the vertical electric field pattern of the antenna array used for the microwave moisture meter at 1 GHz is as follows: Figure 7 As shown in Figure 1, the horizontal electric field pattern of the antenna array used for the microwave moisture meter at 2 GHz is as follows: Figure 8 As shown in the figure, the vertical electric field pattern of the antenna array used for the microwave moisture meter at 2 GHz is as follows: Fig. 9 As shown in the figure, the horizontal electric field pattern of the antenna array used for the microwave moisture meter at 3 GHz is as follows: Fig.10 As shown in the figure, the vertical electric field pattern of the antenna array used for the microwave moisture meter at 3 GHz is as follows: Fig.11 As shown in the figure, the horizontal electric field pattern of the antenna array used for the microwave moisture meter at 4 GHz is as follows: Fig.12 As shown in the figure, the vertical electric field pattern of the antenna array used for the microwave moisture meter at 4 GHz is as follows: Fig.13 As shown in Figure 1, the horizontal electric field pattern of the antenna array used for the microwave moisture meter at 5 GHz is as follows: Fig.14 As shown in the figure, the vertical electric field pattern of the antenna array used for the microwave moisture meter at 5 GHz is as follows: Fig.15 As shown, Figure 6-Figure 15 In the example, the values ​​outside the circle correspond to the unit of angle (direction), and the values ​​inside the circle correspond to the unit of dBi. Figures 6 to 15 It can be seen that the antenna array for a microwave moisture meter provided in the embodiment of the present invention can increase the gain, reduce the beam width and increase the bandwidth, thereby improving the detection accuracy of the moisture content of materials, especially fine aggregates such as sand and gravel.

[0060] The antenna array for a microwave moisture meter provided in an embodiment of the present invention is configured by arranging the power division network 10 on a first dielectric substrate 11, and symmetrically arranging two groups of the radiation array units 20 at two ends of the first dielectric substrate 11; the radiation array units 20 include a plurality of unit antennas 23, each of the unit antennas 23 includes a feeding structure 24, a plurality of rectangular slot lines 25, an exponentially tapered slot 26 formed by two exponentially tapered slot lines, and a resonant ring formed at the top of the exponentially tapered slot 26, the plurality of rectangular slot lines 25 are arranged on both sides of the radiation surface of the exponentially tapered slot line, and the length of the rectangular slot lines 25 arranged on the same side of the radiation surface decreases in sequence from the top of the exponentially tapered slot 26 to the opening direction of the exponentially tapered slot 26; the gain can be increased, the beam width can be reduced, and the bandwidth can be increased, thereby improving the detection accuracy of the moisture content of materials, especially fine aggregates such as sand and gravel.

[0061] An embodiment of the present invention provides a microwave moisture meter, comprising the antenna array for a microwave moisture meter as described in any of the above embodiments.

[0062] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0063] The above embodiments only express the preferred implementation modes of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for those of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. An antenna array for a microwave moisture meter, characterized in that: It comprises a power division network and two groups of radiation array units, wherein the power division network is arranged on a first dielectric substrate, and the two groups of radiation array units are symmetrically arranged at two ends of the first dielectric substrate; The radiation array unit includes a plurality of unit antennas, each of which includes a feeding structure, a plurality of rectangular slot lines, an exponentially tapered slot formed by two exponentially tapered slot lines, and a resonant ring formed at the top of the exponentially tapered slot. The plurality of rectangular slot lines are arranged on both sides of a radiation surface of the exponentially tapered slot line, and the length of the rectangular slot lines arranged on the same side of the radiation surface decreases successively along a direction from the top of the exponentially tapered slot to the opening of the exponentially tapered slot.

2. The antenna array for a microwave moisture meter according to claim 1, characterized in that: The two groups of radiation array units are respectively arranged on a second dielectric substrate and a third dielectric substrate. The second dielectric substrate and the third dielectric substrate are parallel to each other and perpendicular to the first dielectric substrate.

3. The antenna array for a microwave moisture meter according to claim 1, characterized in that: The corresponding rectangular slot lines of any two adjacent unit antennas among the plurality of unit antennas are connected.

4. The antenna array for a microwave moisture meter according to claim 1, characterized in that: The width of the rectangular groove line is 2 mm, the number of rectangular groove lines arranged on both sides of the radiation surface is equal and one-to-one corresponding, the distance between any two adjacent rectangular groove lines arranged on the same side of the radiation surface is 5.5 mm, the maximum length of the rectangular groove lines arranged on the same side of the radiation surface is 23 mm, and the length of the rectangular groove lines arranged on the same side of the radiation surface decreases in sequence with a gradient of 1 mm from the top of the exponential gradient groove to the opening direction of the exponential gradient groove.

5. The antenna array for a microwave moisture meter according to claim 1, characterized in that: The length of the unit antenna is 130 mm, and the width of the unit antenna is 70.26 mm.

6. The antenna array for a microwave moisture meter according to claim 1, characterized in that: The diameter of the resonant ring is 19 mm.

7. The antenna array for a microwave moisture meter according to claim 1, characterized in that: The feeding structure comprises a fan-shaped microstrip stub and a microstrip feed line, the fan-shaped surface radius of the fan-shaped microstrip stub is 10 mm, and the maximum width of the microstrip feed line is 1.9 mm.

8. The antenna array for a microwave moisture meter according to claim 1, characterized in that: The curvature of the exponential gradient groove line is 0.08, the top width of the exponential gradient groove is 1 mm, and the opening width of the exponential gradient groove is 70.26 mm.

9. The antenna array for a microwave moisture meter according to claim 1, characterized in that: The power division network includes a Wilkinson power division unit, and the Wilkinson power division unit includes one input port, six output ports and two ground ports.

10. A microwave moisture meter, characterized in that: The invention comprises an antenna array for a microwave moisture meter as described in any one of claims 1 to 9.

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