A small-size dipole antenna and microwave module

Abstract

The utility model relates to the field of antenna discloses a small size dipole antenna and microwave module. It includes the substrate, interval is equipped with the main antenna and the auxiliary antenna on the substrate, the same side of main antenna and auxiliary antenna all is equipped with a polygonal antenna, the polygonal antenna forms polygonal reflection surface. The utility model polygonal reflection surface can make the reflection wave and the radiation wave superposition enhancement, and the radiation energy is concentrated to the front and produces the directivity gain, adjusts the radiation direction of antenna, and the polygonal reflection surface extends with certain angle and guarantees when the excitation signal deviates from the antenna resonant frequency, the in -phase condition of reflection wave and radiation wave will not deteriorate rapidly, so that the antenna can maintain the lower input reflection loss in the wide frequency band, and the stability is good, and the production cost and material cost are reduced, and it is applicable to the narrow space of lamps and lanterns.

Description

Technical Field

[0001] This utility model relates to the field of antenna technology, and more specifically, to a small-sized dipole antenna and microwave module. Background Technology

[0002] Lighting radar sensors are widely used because they can automatically turn off lights when no one is present. During installation, the sensor needs to be installed inside the light fixture, which can create shadows. Therefore, the size of the radar sensor antenna is critical, and it's desirable to minimize its size. Currently, two common types of radar antennas are planar antennas and pin-type monostage antennas. Planar antennas offer advantages such as long radar range and good stability; however, they are relatively large. Pin-type monostage antennas are smaller in size; however, they have a large backlobes, resulting in poor radiation stability and weak anti-interference capabilities. When the light fixture has a metal casing, the radar module may experience self-excitation interference due to the electromagnetic shielding environment, causing abnormal sensing signals, because the entire antenna base is inside the fixture. Additionally, the radiation pattern of a pin-type antenna resembles an apple, with a concave detection dead zone in the center, similar to the apple core, creating a sensing blind spot directly below the light fixture.

[0003] In related technologies, dipole antennas have been developed to address the issues of center detection dead zone and interference self-oscillation. Specifically, a pair of dipole antennas, each consisting of two coaxial straight conductors, are fed in the middle to form a symmetrical structure. When the operating frequency matches the antenna length (e.g., a half-wavelength antenna), the current distribution on the conductors exhibits a standing wave pattern. Since the dipole is formed by the resonance of the two antennas, it does not rely on a reference ground plane. This avoids the abnormalities caused by metal interference on the ground plane in monopole antennas. The second dipole antenna is omnidirectional. When the standing wave wavelength matches the operating wavelength of the electromagnetic wave, this resonant characteristic allows the antenna to efficiently convert electromagnetic energy, providing uniform radiation and reception capabilities across 360 degrees in the horizontal plane, thus solving the problem of center detection dead zone in monopole antennas.

[0004] However, existing dipole antennas are limited by their overall size, resulting in lower antenna gain and a smaller detection radius for the radar sensor. Furthermore, existing radar modules composed of dipole antennas all employ analog mixer circuits. These modules, due to the limitations of component precision, exhibit poor range consistency in radar sensing. Additionally, radar modules using analog mixer circuits require a shielding cover at the bottom to block radiated interference, increasing their overall size. Utility Model Content

[0005] To address at least one of the aforementioned problems, this invention first provides a small-sized dipole antenna, comprising a substrate, a main antenna and a secondary antenna spaced apart on the substrate, wherein a polygonal antenna is provided on the same side of both the main antenna and the secondary antenna, and the polygonal antenna forms a polygonal reflective surface.

[0006] Optionally, the main antenna includes a first main folded dipole arm, a second main folded dipole arm, a third main folded dipole arm, and a fourth main folded dipole arm. The first main folded dipole arm extends away from the sub-antenna. One end of the second main folded dipole arm is connected to the end of the first main folded dipole arm away from the sub-antenna, and the other end extends towards the polygonal antenna and is connected to the third main folded dipole arm. The other end of the third main folded dipole arm extends towards the sub-antenna and is connected to the fourth main folded dipole arm. The other end of the fourth main folded dipole arm extends towards the polygonal antenna.

[0007] Optionally, the secondary antenna includes a first folded dipole arm, a second folded dipole arm, a third folded dipole arm, and a fourth folded dipole arm. The first folded dipole arm extends away from the main antenna. One end of the second folded dipole arm is connected to the end of the first folded dipole arm away from the main antenna, and the other end extends towards the polygonal antenna and is connected to the third folded dipole arm. The other end of the third folded dipole arm extends towards the main antenna and is connected to the fourth folded dipole arm. The other end of the fourth folded dipole arm extends towards the polygonal antenna.

[0008] Optionally, the polygonal reflective surface is a right-angled trapezoidal reflective surface.

[0009] Optionally, the substrate is provided with an impedance matching balun, which includes a symmetrical balun and an impedance matching line connected to each other. The symmetrical balun is located on the side of the main antenna and the sub-antenna close to the polygonal reflector, and the symmetrical balun is located between the two polygonal reflectors; the impedance matching line is located between the main antenna and the sub-antenna.

[0010] Optionally, the symmetrical balun includes interconnected rectangular segments and isosceles triangular segments.

[0011] Optionally, a PCB board is provided on the side of the polygonal antenna away from the main antenna, and a radar chip is provided on the PCB board.

[0012] Optionally, the PCB board is provided with an antenna soldering slot, and both sides of the antenna soldering slot are provided with connecting pads, and the two connecting pads are respectively soldered to the main antenna and the sub-antenna.

[0013] Optionally, the PCB board is provided with a transmitting and receiving circuit, an antenna impedance matching circuit, and a filtering circuit.

[0014] Compared with the prior art, the beneficial technical effects of this utility model are as follows:

[0015] 1. By adding a polygonal antenna on the same side of the main antenna and the secondary antenna, the polygonal antenna forms a polygonal reflector. The polygonal reflector can enhance the superposition of reflected and radiated waves, concentrate the radiated energy forward to generate directional gain, and adjust the radiation direction of the antenna. The polygonal reflector extends at a certain angle to ensure that when the excitation signal deviates from the antenna resonant frequency, the in-phase condition of the reflected and radiated waves will not deteriorate rapidly, so that the antenna can maintain a low input reflection loss in a wider frequency band and expand the radar detection radius.

[0016] 2. Compared with traditional analog mixer circuits, the radar chip is integrated on the PCB board to form a radar module. Since the chip integrates the phase-locked loop function, it can lock a fixed frequency. Therefore, it has high consistency and good stability in mass production. The microwave module designed with radar chip does not require a shielding cover, which is convenient for production and reduces production and material costs.

[0017] 3. Both the main antenna and the secondary antenna are bent to form multiple folded dipole arms, which can improve impedance through parallel current paths and voltage superposition effects, while maintaining radiation performance. This balances impedance matching, bandwidth and mechanical stability within the effective space.

[0018] 4. Impedance matching baluns achieve broadband matching in a compact size through a combination of rectangular and isosceles triangular segments (non-standard rectangles or circles). The balun is directly integrated onto the substrate and connected to the PCB board slot via pads, eliminating the need for RF connectors and making it suitable for lighting fixtures in confined spaces.

[0019] In addition, this utility model provides a microwave module, including the small-sized dipole antenna as described above.

[0020] Compared with the prior art, the microwave module of this utility model has the same advantages as the small-size dipole antenna mentioned above, which will not be repeated here. Attached Figure Description

[0021] Figure 1 This is a planar structural diagram of the substrate, main antenna, secondary antenna, and PCB board in an embodiment of this utility model;

[0022] Figure 2 This is a planar structural diagram of the substrate, main antenna, and sub-antenna in an embodiment of this utility model;

[0023] Figure 3This is a circuit diagram of the PCB board in an embodiment of this utility model.

[0024] Explanation of reference numerals in the attached diagram: 1. Substrate; 11. Polygonal reflector; 12. Symmetrical balun; 13. Impedance matching line; 2. Main antenna; 21. First main folded dipole arm; 22. Second main folded dipole arm; 23. Third main folded dipole arm; 24. Fourth main folded dipole arm; 3. Sub-antenna; 31. First sub-sub-folded dipole arm; 32. Second sub-sub-folded dipole arm; 33. Third sub-sub-folded dipole arm; 34. Fourth sub-sub-folded dipole arm; 4. PCB board. Detailed Implementation

[0025] To make the above-mentioned objectives, features and advantages of this utility model more apparent and understandable, the following description is provided in conjunction with the appendix. Figure 1-3 This application will be described in further detail.

[0026] The accompanying drawings of this utility model embodiment provide a coordinate system XY, where the positive direction of the X-axis represents the right, the negative direction of the X-axis represents the left, the positive direction of the Y-axis represents the top, and the negative direction of the Y-axis represents the bottom.

[0027] In a first aspect, this utility model embodiment provides a small-sized dipole antenna, referring to... Figure 1 The small-sized dipole antenna includes a substrate 1, a main antenna 2, a secondary antenna 3, and a PCB board 4. The main antenna 2 and the secondary antenna 3 are located on the same side of the substrate 1, symmetrically spaced along the left-right direction of the substrate 1. Both the main antenna 2 and the secondary antenna 3 are fixedly connected to the substrate 1 by soldering. Below each of the main antenna 2 and the secondary antenna 3 is a polygonal antenna, fixedly connected to the substrate 1. Each polygonal antenna forms a polygonal reflector 11. The polygonal reflector 11 enables the superposition and enhancement of reflected and radiated waves, concentrating radiated energy forward to generate directional gain and adjusting the antenna's radiation direction. The polygonal reflector 11 extends at a certain angle to ensure that when the excitation signal deviates from the antenna's resonant frequency, the in-phase condition of the reflected and radiated waves does not rapidly deteriorate, allowing the antenna to maintain low input reflection loss over a wide frequency band and expand the radar detection radius. The PCB board 4 is located below the substrate 1 (i.e., on the side of the polygonal antenna away from the main antenna 2) and is electrically connected to the substrate 1.

[0028] Referring to the coordinate system XY in the accompanying drawings of this embodiment, let the X direction be the length direction of substrate 1; and the Y direction be the height direction of substrate 1. The length of substrate 1 is 10-15 mm; the height is 12-20 mm; and the thickness is 0.4-1 mm. In this embodiment, the preferred length of substrate 1 is 13.5 mm; the height is 16 mm; and the thickness is 0.6 mm. The substrate 1 can be made of any one of ceramic substrate, FR4 substrate, PI substrate, RO4003 substrate, or Rogers substrate. In this embodiment, the preferred substrate 1 is FR4 substrate, and the dielectric constant of substrate 1 is 2.2–4.6.

[0029] Reference Figure 1 and Figure 2 The main antenna 2 includes a first main folded dipole arm 21, a second main folded dipole arm 22, a third main folded dipole arm 23, and a fourth main folded dipole arm 24. The first main folded dipole arm 21 extends away from the sub-antenna 3. One end of the second main folded dipole arm 22 is connected to the end of the first main folded dipole arm 21 away from the sub-antenna 3, and the other end extends towards the polygonal antenna and connects to the third main folded dipole arm 23. The other end of the third main folded dipole arm 23 extends towards the sub-antenna 3 and connects to the fourth main folded dipole arm 24. The other end of the fourth main folded dipole arm 24 extends towards the polygonal antenna. The main antenna 2 is bent to form multiple folded dipole arms, which can improve impedance through parallel current paths and voltage superposition effects while maintaining unchanged radiation performance, thus balancing impedance matching, bandwidth, and mechanical stability within the effective space.

[0030] The widths of the first main folding vibrating arm 21, the second main folding vibrating arm 22, the third main folding vibrating arm 23, and the fourth main folding vibrating arm 24 are all 1.3 mm. The extension direction of each main folding vibrating arm is assumed to be its own length direction. The length of the first main folding vibrating arm 21 is 6.3 mm; the length of the second main folding vibrating arm 22 is 5.3 mm; the length of the third main folding vibrating arm 23 is 2.6 mm; and the length of the fourth main folding vibrating arm 24 is 1.15 mm.

[0031] Reference Figure 1 and Figure 2The secondary antenna 3 includes a first folded dipole arm 31, a second folded dipole arm 32, a third folded dipole arm 33, and a fourth folded dipole arm 34. The first folded dipole arm 31 extends away from the main antenna 2. One end of the second folded dipole arm 32 is connected to the end of the first folded dipole arm 31 away from the main antenna 2, and the other end extends towards the polygonal antenna and connects to the third folded dipole arm 33. The other end of the third folded dipole arm 33 extends towards the main antenna 2 and connects to the fourth folded dipole arm 34. The other end of the fourth folded dipole arm 34 extends towards the polygonal antenna. The effect of bending the secondary antenna 3 to form multiple folded dipole arms is the same as that of the main antenna 2, and will not be repeated here.

[0032] The widths of the first folding oscillator arm 31, the second folding oscillator arm 32, the third folding oscillator arm 33, and the fourth folding oscillator arm 34 are all 1.3 mm. The extension direction of each folding oscillator arm is assumed to be its own length direction. The length of the first folding oscillator arm 31 is 6.3 mm; the length of the second folding oscillator arm 32 is 5.3 mm; the length of the third folding oscillator arm 33 is 2.6 mm; and the length of the fourth folding oscillator arm 34 is 1.15 mm.

[0033] In this embodiment, the polygonal antenna is preferably a right trapezoid with the inclined surface of the trapezoid facing upwards, and thus the polygonal reflector 11 is also a right trapezoid. In another embodiment, the polygonal antenna can be a pentagon or a hexagon; in yet another embodiment, the polygonal antenna can be a multi-segment arc.

[0034] Reference Figure 1 and Figure 2 The substrate 1 also includes an impedance matching balun, comprising a symmetrical balun 12 and an impedance matching line 13 connected to each other. The symmetrical balun 12 is located on the side of the main antenna 2 and the sub-antenna 3 closest to the polygonal reflector, and is situated between the two polygonal reflectors 11; the impedance matching line 13 is located between the main antenna 2 and the sub-antenna 3. Let the X direction be the width of the impedance matching line 13; let the Y direction be the length direction of the impedance matching line 13. The width of the impedance matching line 13 is 0.4 mm; its length is 6.6 mm.

[0035] Reference Figure 1 and Figure 2 The symmetrical balun 12 comprises interconnected rectangular segments and isosceles triangular segments, with the isosceles triangular segments positioned above the rectangular segments. Let the X-direction be the length direction of the rectangular segments and the Y-direction be the width direction. Then, the length of the rectangular segments is 4-6 mm, and the width is 3-4 mm. In this embodiment, the preferred length is 5 mm, and the preferred width is 3.5 mm. The base length of the isosceles triangular segments is the same as the length of the rectangular segments, and the leg length of the isosceles triangular segments is 3-4 mm. In this embodiment, the preferred leg length is 3.3 mm.

[0036] The PCB board 4 has a radar chip, which forms a radar module. Since the chip integrates a phase-locked loop function, it can lock a fixed frequency. Therefore, it has high consistency and good stability in mass production. The microwave module designed with radar chip does not require a shield, which is convenient for production and reduces production and material costs.

[0037] Reference Figure 1 and Figure 3 PCB board 4 houses the transmit / receive circuit, antenna impedance matching circuit, and filter circuit. The radar chip U1 and crystal oscillator U5 form the transmit / receive circuit. Capacitors C3 and C7, along with resistor R3, form the antenna impedance matching circuit through a ring-shaped PCD trace, achieving high-efficiency transmission and harmonic suppression. The 5V power supply to the PCB board is externally input and is filtered by C31, C32, and R4 using an RC filter to block external interference.

[0038] The substrate 1 is fixedly connected to the PCB board 4. The PCB board 4 is provided with an antenna soldering groove. Both sides of the antenna soldering groove are provided with connecting pads. The two connecting pads are soldered to the main antenna 2 and the secondary antenna 3 respectively.

[0039] The implementation principle of a small-sized dipole antenna in this application embodiment is as follows: By adding a polygonal antenna on the same side of the main antenna 2 and the secondary antenna 3, the polygonal antenna forms a polygonal reflector 11. The polygonal reflector 11 can enhance the superposition of reflected and radiated waves, concentrate radiated energy forward to generate directional gain, and adjust the radiation direction of the antenna. The polygonal reflector 11 extends at a certain angle to ensure that when the excitation signal deviates from the antenna resonant frequency, the in-phase condition of the reflected and radiated waves will not deteriorate rapidly, so that the antenna can maintain low input reflection loss over a wide frequency band. Compared with traditional analog mixer circuits, the PCB board 4 integrates a radar chip to form a radar module. Since the chip integrates a phase-locked loop function, it can lock a fixed frequency, thus achieving high consistency and good stability in mass production. The microwave module designed with the radar chip does not require a shielding cover, which is convenient for production, reduces production and material costs, and is suitable for the confined space of lighting fixtures.

[0040] Secondly, another embodiment of the present invention provides a microwave module including the small-sized dipole antenna described in the first aspect above.

[0041] Similarly, the components included in the "components," "mechanisms," and "devices" of this disclosure can also be flexibly combined. They can be modularly produced according to actual needs and assembled as an independent module; or they can be assembled separately to form a module in this device. The division of the above-mentioned components in this disclosure is only one embodiment for ease of reading and is not intended to limit the scope of protection of this disclosure. Any technical solution that includes the above-mentioned components and has the same function should be understood as an equivalent technical solution of this disclosure.

[0042] In the description of this disclosure, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this disclosure and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this disclosure.

[0043] Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined with "first," "second," etc., may explicitly or implicitly include at least one of that feature. In the description of this disclosure, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0044] In this disclosure, unless otherwise expressly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise expressly limited. Those skilled in the art can understand the specific meaning of the above terms in this disclosure according to the specific circumstances.

[0045] In this disclosure, unless otherwise expressly specified and limited, "above" or "below" the second feature can mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0046] It should be noted that when a component is referred to as "fixed to," "set on," "fixed to," or "mounted on" another component, it can be directly on the other component or there may be an intervening component. When a component is considered to be "connected to another component," it can be directly connected to the other component or there may be an intervening component. Furthermore, when a component is considered to be "fixedly connected" to another component, the connection can be detachable or non-detachable, such as through socketing, snap-fitting, integral molding, welding, etc., which are achievable in conventional technologies and will not be elaborated upon here.

[0047] The technical features of the above embodiments can be combined in any way. For the sake of brevity, 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.

[0048] The above embodiments are merely illustrative of several implementation methods of this disclosure, and their descriptions are relatively specific and detailed. However, they should not be construed as limiting the scope of the utility model patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the inventive concept of this disclosure, and these modifications and improvements all fall within the protection scope of this disclosure.

Claims

1. A small-sized dipole antenna, characterized in that: It includes a substrate (1), a main antenna (2) and a secondary antenna (3) spaced apart on the substrate (1), and a polygonal antenna on the same side of the main antenna (2) and the secondary antenna (3), the polygonal antenna forming a polygonal reflective surface (11).

2. The small-sized dipole antenna according to claim 1, characterized in that: The main antenna (2) includes a first main folded vibrating arm (21), a second main folded vibrating arm (22), a third main folded vibrating arm (23) and a fourth main folded vibrating arm (24), wherein the first main folded vibrating arm (21) extends away from the sub-antenna (3); One end of the second main folding vibrating arm (22) is connected to the end of the first main folding vibrating arm (21) away from the sub-antenna (3), and the other end extends toward the side close to the polygonal antenna and is connected to the third main folding vibrating arm (23); the other end of the third main folding vibrating arm (23) extends toward the sub-antenna (3) and is connected to the fourth main folding vibrating arm (24); The other end of the fourth main folding vibrator arm (24) extends toward the side close to the polygonal antenna.

3. The small-sized dipole antenna according to claim 1, characterized in that: The sub-antenna (3) includes a first sub-folded vibrating arm (31), a second sub-folded vibrating arm (32), a third sub-folded vibrating arm (33), and a fourth sub-folded vibrating arm (34). The first sub-folded vibrating arm (31) extends away from the main antenna (2). One end of the second sub-folded vibrating arm (32) is connected to the end of the first sub-folded vibrating arm (31) away from the main antenna (2), and the other end extends towards the polygonal antenna and is connected to the third sub-folded vibrating arm (33). The other end of the third sub-folded vibrating arm (33) extends towards the main antenna (2) and is connected to the fourth sub-folded vibrating arm (34). The other end of the fourth sub-folded vibrating arm (34) extends towards the polygonal antenna.

4. The small-sized dipole antenna according to claim 1, characterized in that: The polygonal reflective surface (11) is a right-angled trapezoidal reflective surface.

5. The small-sized dipole antenna according to claim 1, characterized in that: The substrate (1) is provided with an impedance matching balun, which includes a symmetrical balun (12) and an impedance matching line (13) connected to each other. The symmetrical balun (12) is located on the side of the main antenna (2) and the sub-antenna (3) close to the polygonal reflector (11), and the symmetrical balun (12) is located between the two polygonal reflectors (11). The impedance matching line (13) is located between the main antenna (2) and the sub-antenna (3).

6. The small-sized dipole antenna according to claim 5, characterized in that: The symmetrical balun (12) comprises interconnected rectangular segments and isosceles triangular segments.

7. The small-sized dipole antenna according to any one of claims 1-6, characterized in that: A PCB board (4) is provided on the side of the polygonal antenna away from the main antenna (2). The substrate (1) is connected to the PCB board (4). A radar chip is provided on the PCB board (4).

8. The small-sized dipole antenna according to claim 7, characterized in that: The PCB board (4) is provided with an antenna soldering groove. Both sides of the antenna soldering groove are provided with connecting pads. The two connecting pads are respectively soldered to the main antenna (2) and the sub-antenna (3).

9. The small-sized dipole antenna according to claim 7, characterized in that: The PCB board (4) is provided with a transmitting and receiving circuit, an antenna impedance matching circuit and a filtering circuit.

10. A microwave module, characterized in that, Including the small-sized dipole antenna as described in any one of claims 1-9.

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