A wide-beam dipole antenna and microwave induction module

Abstract

This application discloses a wide-beam dipole antenna and a microwave sensing module, including a wide-beam dipole antenna and a PCB motherboard. The PCB motherboard has a slot for the feed point to pass through, and the feed points of the main and secondary antennas on the PCB motherboard are respectively soldered to the feed points of the main and secondary antennas of the wide-beam dipole antenna. The wide-beam dipole antenna is vertically mounted on the top layer of the PCB motherboard, and the bottom layer of the PCB motherboard integrates radio frequency (RF) circuitry, including a filter circuit, an oscillation circuit, and a mixer circuit. This application's technical solution improves product consistency and facilitates mass production.

Description

Technical Field

[0001] This application relates to the field of microwave sensing technology, and in particular to a wide-beam dipole antenna and a microwave sensing module. Background Technology

[0002] The sensitivity of the microwave sensing module is also closely related to the speed of human movement. When a person moves slowly, the microwave sensing module generates a low-frequency signal, while when the person moves quickly, it generates a high-frequency signal. The same thing happens when a person approaches or moves away from the microwave sensing module: the frequency generated by moving diagonally towards or away from the microwave sensing module is lower than the frequency generated by moving in a straight line, because the speed of approaching or moving away from the detector at an angle is slower. For two targets moving at the same speed, moving in a straight line generates a high-frequency signal, while moving diagonally generates a low-frequency signal.

[0003] Existing 5.8G microwave sensing modules typically use monopole antennas. This approach is widely used because the antenna is small enough to fit inside the lighting fixture without dark areas. However, the antenna's star-shaped radiation pattern and maximum vertical installation height of 4 meters have always been a weakness of this antenna module. The linewidth and thickness of the microstrip line directly affect the module's performance, and it is difficult to control consistency during mass production.

[0004] Therefore, existing technologies have shortcomings and need to be improved. Summary of the Invention

[0005] This application proposes a wide-beam dipole antenna and a microwave sensing module to improve product consistency and facilitate mass production.

[0006] This application provides a wide-beam dipole antenna, comprising: a substrate, a main antenna and a secondary antenna symmetrically distributed on both sides of the substrate, wherein the main antenna and the secondary antenna respectively include a feed point, a symmetrical balun, an impedance matching balun, a first folded dipole arm, a second folded dipole arm, a parasitic segment of the first dipole arm, and a parasitic segment of the second dipole arm connected in sequence; the feed point, the symmetrical balun, the impedance matching balun, the first folded dipole arm and the second folded dipole arm are connected end to end in sequence, one end of the parasitic segment of the first dipole arm is connected to the middle part of the second folded dipole arm, and the tail end of the parasitic segment of the first dipole arm is connected to the head end of the parasitic segment of the second dipole arm;

[0007] The feed point, symmetrical balun, and impedance matching balun are arranged sequentially along the first direction. The feed point protrudes to the outside of the substrate, and the width of the symmetrical balun gradually decreases along the first direction. The first folded oscillator arm is arranged perpendicular to the impedance matching balun along the second direction. The second folded oscillator arm is arranged perpendicular to the first folded oscillator arm along the opposite direction of the first direction. The parasitic branch of the first oscillator arm is arranged perpendicular to the second folded oscillator arm along the opposite direction of the second direction. The parasitic branch of the second oscillator arm is arranged perpendicular to the first oscillator arm parasitic branch along the opposite direction of the first direction.

[0008] In some embodiments, the substrate is configured as an FR4 double-sided board, the dielectric constant of the substrate is set to 2 to 4.6, the length of the substrate is set to 8 to 20 mm, the width of the substrate is set to 10 to 25 mm, and the thickness of the substrate is set to 0.4 to 1.2 mm.

[0009] In some embodiments, the feed point protrudes 1-3 mm beyond the substrate, and the welding portion of the feed point has a semi-circular groove.

[0010] In some embodiments, the symmetrical baron includes square portions and isosceles triangular portions arranged along a first direction, wherein the side length of the square portions is set to 4.5-6 mm, the base side length of the isosceles triangular portions is set to 4.5-6 mm, and the leg length of the isosceles triangular portions is set to 3.5-4 mm.

[0011] In some embodiments, the impedance matching balun has a linewidth of 0.4 mm and a line length of 7.5 mm; the first folded oscillator arm has a linewidth of 1.3 mm and a line length of 6.3 mm; the second folded oscillator arm has a linewidth of 1.3 mm and a line length of 8.6 mm; the first oscillator arm parasitic segment has a linewidth of 0.5 mm and a line length of 2.6 mm; and the second oscillator arm parasitic segment has a linewidth of 0.5 mm and a line length of 2 mm.

[0012] This application embodiment also provides a microwave induction module, including a wide-beam dipole antenna as described in any one of claims 1 to 5, and a PCB motherboard for mounting the wide-beam dipole antenna; the PCB motherboard has a slot for the feed point to pass through, and the feed points of the main antenna and the secondary antenna of the PCB motherboard are respectively soldered to the feed points of the main antenna and the secondary antenna of the wide-beam dipole antenna; the wide-beam dipole antenna is vertically mounted on the top layer of the PCB motherboard, and the bottom layer of the PCB motherboard integrates radio frequency circuitry, including a filter circuit, an oscillation circuit, and a mixer circuit.

[0013] In some embodiments, the filter circuit includes capacitor Cp1, capacitor Cp2, microstrip line TrL1, microstrip line TrL2, and resistor Re1; one end of capacitor Cp1 is connected to the 5V positive terminal of a DC power supply, one end of microstrip line TrL1 is connected to capacitor Cp1, and the other end is connected to capacitor Cp2, and one end of microstrip line TrL2 is connected to capacitor Cp2, and the other end is connected to resistor Re1.

[0014] In some embodiments, the oscillation circuit includes resistors Re2 and Re3, capacitors Cp3, Cp4, Cp5, Cp6, and Cp7, a microstrip line TrL3, a microstrip line TrL4, and a high-frequency transistor Q1. The other end of resistor Re1 is connected to resistors Re2, Cp4, Cp5, and the microstrip line TrL3; the other end of resistor Re2 is connected to capacitors Cp3 and Re3; the other ends of capacitors Cp4 and Cp5 are grounded; the other end of the microstrip line TrL3 is connected to capacitor Cp6 and the collector of the high-frequency transistor Q1; the other end of capacitor Cp3 is grounded; the other end of resistor Re3 is connected to capacitor Cp7 and the base of the high-frequency transistor Q1; the other end of capacitor Cp7 is connected to the microstrip line TrL4; and the emitter of the high-frequency transistor Q1 is grounded.

[0015] In some embodiments, the mixer circuit includes a capacitor Cp8, microstrip lines TrL5, TrL6, TrL7, TrL8, and a mixer transistor Ze1; one end of the capacitor Cp8 is connected to the emitter of the high-frequency transistor Q1, and the other end is connected to microstrip lines TrL5 and TrL6; the other end of microstrip line TrL5 is connected to pin 1 (IF signal output) of the mixer transistor Ze1; the other end of microstrip line TrL6 is connected to microstrip lines TrL7 and TrL8; the other end of microstrip line TrL7 is connected to pin 2 of the mixer transistor Ze1; and pin 3 of the mixer transistor Ze1 is connected to ground.

[0016] The feed point of the main antenna is connected to the microstrip line TrL8, and the feed point of the secondary antenna is grounded.

[0017] In some embodiments, the PCB motherboard is configured as an FR4 double-sided board, the dielectric constant of the PCB motherboard is set to 2.2 to 4.6, and the thickness of the PCB motherboard is set to 0.4 to 1 mm.

[0018] Compared with the prior art, the beneficial effects of this application are: by designing a printed dipole radiating arm into a specific L-shape, the antenna impedance bandwidth is effectively broadened; and by using a parasitic magnetic dipole, the antenna beamwidth is broadened, increasing the gain at low elevation angles, thereby enabling the detection range to cover a greater distance; the antenna can be fabricated using a conventional FR4 dielectric substrate, and the human motion sensing RF circuit consists of a DC filter circuit, a high-frequency oscillation circuit, and a double-balanced mixer detector circuit. This circuit can adapt to high and low temperatures to meet system requirements, and makes the human motion sensing module highly stable, small in size, simple to process, and widely applicable. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0020] Figure 1 This is a front view of the wide-beam dipole antenna of this application;

[0021] Figure 2 This is a schematic diagram of the overall structure of the microwave induction module of this application;

[0022] Figure 3 This is a schematic diagram of the installation structure of the wide-beam dipole antenna and the PCB motherboard in this application;

[0023] Figure 4 This is the schematic diagram of the radio frequency circuit of this application;

[0024] Figure 5 This is a diagram showing the antenna return loss of this application;

[0025] Figure 6 This is the three-dimensional gain pattern of the antenna in this application;

[0026] The realization of the purpose, functional features and advantages of this application will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0027] The technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments.

[0028] Unless otherwise defined, all technical and scientific terms used in this application have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used in this application's specification is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.

[0029] This embodiment presents a wide-beam dipole antenna, referencing... Figure 1 The antenna includes a substrate, a main antenna and a secondary antenna symmetrically distributed on both sides of the substrate. The main antenna and the secondary antenna each include a feed point 022, a symmetrical balun 023, an impedance matching balun 025, a first folded dipole 026, a second folded dipole arm 027, a first dipole arm parasitic segment 028, and a second dipole arm parasitic segment 029 connected in sequence. The feed point 022, the symmetrical balun 023, the impedance matching balun 025, the first folded dipole 026, and the second folded dipole arm 027 are connected end to end in sequence. One end of the first dipole arm parasitic segment 028 is connected to the middle of the second folded dipole arm 027, and the tail end of the first dipole arm parasitic segment 028 is connected to the head end of the second dipole arm parasitic segment 029.

[0030] The feed point 022, the symmetrical balun 023, and the impedance matching balun 025 are arranged sequentially along the first direction. The feed point 022 protrudes to the outside of the substrate, and the width of the symmetrical balun 023 gradually decreases along the first direction. The first folded oscillator 026 is arranged perpendicular to the impedance matching balun 025 along the second direction. The second folded oscillator arm 027 is arranged perpendicular to the first folded oscillator 026 along the opposite direction of the first direction. The parasitic branch 028 of the first oscillator arm is arranged perpendicular to the second folded oscillator arm 027 along the opposite direction of the second direction. The parasitic branch 029 of the second oscillator arm is arranged perpendicular to the first oscillator arm parasitic branch 028 along the opposite direction of the first direction.

[0031] Furthermore, the substrate is configured as an FR4 double-sided board, the dielectric constant of the substrate is set to 2 to 4.6, the length of the substrate is set to 8 to 20 mm, the width of the substrate is set to 10 to 25 mm, and the thickness of the substrate is set to 0.4 to 1.2 mm.

[0032] Furthermore, the feed point 022 protrudes 1-3 mm beyond the outer side of the substrate, and the welding portion of the feed point 022 has a semi-circular groove.

[0033] Furthermore, the symmetrical balun 023 includes a square portion and an isosceles triangular portion arranged along a first direction. The side length of the square portion is set to 4.5-6 mm, the base side length of the isosceles triangular portion is set to 4.5-6 mm, and the leg length of the isosceles triangular portion is set to 3.5-4 mm.

[0034] Furthermore, the impedance matching balun 025 has a linewidth of 0.4 mm and a line length of 7.5 mm; the first folded oscillator 026 has a linewidth of 1.3 mm and a line length of 6.3 mm; the second folded oscillator arm 027 has a linewidth of 1.3 mm and a line length of 8.6 mm; the first oscillator arm parasitic support 028 has a linewidth of 0.5 mm and a line length of 2.6 mm; and the second oscillator arm parasitic support 029 has a linewidth of 0.5 mm and a line length of 2 mm.

[0035] This embodiment presents a microwave induction module, referencing... Figure 2 and Figure 3 The system includes the wide-beam dipole antenna 1 described above, and also includes a PCB motherboard 2 for mounting the wide-beam dipole antenna 1; the PCB motherboard 2 has a slot for the feed point 022 to pass through, the slot size being 2-5mm; the main and secondary antenna feed points 022 of the PCB motherboard 2 are respectively soldered to the feed points 022 of the main antenna and the secondary antenna of the wide-beam dipole antenna 1; the wide-beam dipole antenna 1 is vertically mounted on the top layer of the PCB motherboard 2, and the wide-beam dipole antenna 1 and the PCB motherboard 2 are connected together to form an L-shape; the bottom layer of the PCB motherboard 2 integrates radio frequency circuitry, the radio frequency circuitry including a filter circuit 01, an oscillation circuit 02, and a mixer circuit 03.

[0036] In this embodiment, the feed points 022 of the main antenna and the secondary antenna protrude 1-3mm beyond the outer side of the substrate, and the welding part of the feed point 022 has a semi-circular groove to facilitate soldering to the PCB motherboard 2 via solder pads. The solder pads between the two boards are in contact with each other, and production is carried out manually or by a soldering machine. The PCB motherboard 2 is also provided with a shielding cover 3 and a three-pin header 4. The shielding cover 3 is soldered below the antenna of the PCB motherboard 2 to protect the high-frequency circuit and signal amplification circuit of the baseboard from external temperature and humidity interference, and to shield and absorb signals inside and outside the module. The shielding cover 3 is a concave structure with a length of 14-23mm, a width of 10-20mm, and a height of 2-6mm. The three-pin header 4 is soldered to the motherboard and serves as the power supply port and intermediate frequency signal output port of the module. The three-pin header 4 uses a single row of pins with a spacing of 2.54mm or 2mm, and the pin length is 5-20mm.

[0037] Furthermore, the PCB motherboard 2 is configured as an FR4 double-sided board, the dielectric constant of the PCB motherboard 2 is set to 2.2 to 4.6, the thickness of the PCB motherboard 2 is set to 0.4 to 1 mm, and gold plating or anti-oxidation process is adopted.

[0038] Further, refer to Figure 4The filter circuit 01 includes capacitors Cp1 and Cp2, microstrip line TrL1 and TrL2, and resistor Re1. One end of capacitor Cp1 is connected to the 5V positive terminal of the DC power supply. One end of microstrip line TrL1 is connected to capacitor Cp1 and the other end is connected to capacitor Cp2. One end of microstrip line TrL2 is connected to capacitor Cp2 and the other end is connected to resistor Re1.

[0039] The oscillation circuit 02 includes resistors Re2 and Re3, capacitors Cp3, Cp4, Cp5, Cp6, and Cp7, a microstrip line TrL3, a microstrip line TrL4, and a high-frequency transistor Q1. The other end of resistor Re1 is connected to resistors Re2, Cp4, Cp5, and the microstrip line TrL3. The other end of resistor Re2 is connected to capacitors Cp3 and Re3. The other ends of capacitors Cp4 and Cp5 are grounded. The other end of microstrip line TrL3 is connected to capacitor Cp6 and the collector of high-frequency transistor Q1. The other end of capacitor Cp3 is grounded. The other end of resistor Re3 is connected to capacitor Cp7 and the base of high-frequency transistor Q1. The other end of capacitor Cp7 is connected to the microstrip line TrL4. The emitter of high-frequency transistor Q1 is grounded.

[0040] The mixer circuit 03 includes a capacitor Cp8, microstrip lines TrL5, TrL6, TrL7, TrL8, and a mixer transistor Ze1. One end of the capacitor Cp8 is connected to the emitter of the high-frequency transistor Q1, and the other end is connected to microstrip lines TrL5 and TrL6. The other end of microstrip line TrL5 is connected to pin 1 (IF signal output) of the mixer transistor Ze1. The other end of microstrip line TrL6 is connected to microstrip lines TrL7 and TrL8. The other end of microstrip line TrL7 is connected to pin 2 of the mixer transistor Ze1. Pin 3 of the mixer transistor Ze1 is connected to ground.

[0041] The feed point 022 of the main antenna is connected to the microstrip line TrL8, and the feed point 022 of the secondary antenna is grounded.

[0042] refer to Figure 5 The figure shows that the antenna resonant frequency is between 5.73 GHz and 5.87 GHz, and the return loss is between -25 dB and -40 dB. The center point M2 of the curve falls on the 5.83 GHz channel, which is -33 dB, representing the optimal resonant characteristic for antenna matching. (Reference) Figure 6 As can be seen in the figure, the wide-beam dipole antenna 1 of this application has a wide and concentrated beam, and the antenna gain is very stable at 4.7dB.

[0043] The above are merely preferred embodiments of this application and do not limit the patent scope of this application. Any equivalent structural or procedural transformations made using the content of this application's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of this application.

Claims

1. A wide-beam dipole antenna, characterized in that, include: The device includes a substrate, a main antenna and a secondary antenna symmetrically distributed on both sides of the substrate. The main antenna and the secondary antenna each include a feed point, a symmetrical balun, an impedance matching balun, a first folded dipole arm, a second folded dipole arm, a parasitic segment of the first dipole arm, and a parasitic segment of the second dipole arm, which are connected in sequence. The feed point, the symmetrical balun, the impedance matching balun, the first folded dipole arm, and the second folded dipole arm are connected end to end in sequence. One end of the parasitic segment of the first dipole arm is connected to the middle part of the second folded dipole arm, and the tail end of the parasitic segment of the first dipole arm is connected to the head end of the parasitic segment of the second dipole arm. The feed point, symmetrical balun, and impedance matching balun are arranged sequentially along the first direction. The feed point protrudes to the outside of the substrate, and the width of the symmetrical balun gradually decreases along the first direction. The first folded oscillator arm is arranged perpendicular to the impedance matching balun along the second direction, and the second folded oscillator arm is arranged perpendicular to the first folded oscillator arm along the opposite direction of the first direction. The parasitic branch of the first oscillator arm is arranged perpendicular to the second folded oscillator arm along the opposite direction of the second direction, and the parasitic branch of the second oscillator arm is arranged perpendicular to the first oscillator arm parasitic branch along the opposite direction of the first direction. The substrate is configured as an FR4 double-sided board, the dielectric constant of the substrate is set to 2~4.6, the length of the substrate is set to 8~20mm, the width of the substrate is set to 10~25mm, and the thickness of the substrate is set to 0.4~1.2mm. The feed point protrudes 1-3 mm beyond the outer side of the substrate, and the welding portion of the feed point has a semi-circular groove.

2. The wide-beam dipole antenna as described in claim 1, characterized in that, The symmetrical baron includes square portions and isosceles triangular portions arranged along a first direction. The side length of the square portions is set to 4.5~6mm, the base side length of the isosceles triangular portions is set to 4.5~6mm, and the leg length of the isosceles triangular portions is set to 3.5~4mm.

3. The wide-beam dipole antenna as described in claim 1, characterized in that, The impedance matching balun has a linewidth of 0.4 mm and a line length of 7.5 mm; the first folded oscillator arm has a linewidth of 1.3 mm and a line length of 6.3 mm; the second folded oscillator arm has a linewidth of 1.3 mm and a line length of 8.6 mm; the first oscillator arm parasitic support has a linewidth of 0.5 mm and a line length of 2.6 mm; and the second oscillator arm parasitic support has a linewidth of 0.5 mm and a line length of 2 mm.

4. A microwave induction module, characterized in that, The device includes the wide-beam dipole antenna as described in any one of claims 1 to 3, and further includes a PCB motherboard for mounting the wide-beam dipole antenna; the PCB motherboard has a slot for the feed point to pass through, and the feed points of the main antenna and the secondary antenna of the PCB motherboard are respectively soldered to the feed points of the main antenna and the secondary antenna of the wide-beam dipole antenna; the wide-beam dipole antenna is vertically mounted on the top layer of the PCB motherboard, and the bottom layer of the PCB motherboard integrates radio frequency circuitry, the radio frequency circuitry including a filter circuit, an oscillation circuit, and a mixer circuit.

5. The microwave induction module as described in claim 4, characterized in that, The filter circuit includes capacitors Cp1 and Cp2, microstrip line TrL1 and TrL2, and resistor Re1. One end of capacitor Cp1 is connected to the 5V positive terminal of the DC power supply. One end of microstrip line TrL1 is connected to capacitor Cp1 and the other end is connected to capacitor Cp2. One end of microstrip line TrL2 is connected to capacitor Cp2 and the other end is connected to resistor Re1.

6. The microwave sensing module as described in claim 5, characterized in that, The oscillation circuit includes resistors Re2 and Re3, capacitors Cp3, Cp4, Cp5, Cp6, and Cp7, a microstrip line TrL3, a microstrip line TrL4, and a high-frequency transistor Q1. The other end of resistor Re1 is connected to resistors Re2, Cp4, Cp5, and the microstrip line TrL3. The other end of resistor Re2 is connected to capacitors Cp3 and Re3. The other ends of capacitors Cp4 and Cp5 are grounded. The other end of microstrip line TrL3 is connected to capacitor Cp6 and the collector of high-frequency transistor Q1. The other end of capacitor Cp3 is grounded. The other end of resistor Re3 is connected to capacitor Cp7 and the base of high-frequency transistor Q1. The other end of capacitor Cp7 is connected to the microstrip line TrL4. The emitter of high-frequency transistor Q1 is grounded.

7. The microwave sensing module as described in claim 6, characterized in that, The mixing circuit includes a capacitor Cp8, microstrip lines TrL5, TrL6, TrL7, TrL8, and a mixer transistor Ze1. One end of the capacitor Cp8 is connected to the emitter of the high-frequency transistor Q1, and the other end is connected to microstrip lines TrL5 and TrL6. The other end of microstrip line TrL5 is connected to pin 1 (IF signal output) of the mixer transistor Ze1. The other end of microstrip line TrL6 is connected to microstrip lines TrL7 and TrL8. The other end of microstrip line TrL7 is connected to pin 2 of the mixer transistor Ze1. Pin 3 of the mixer transistor Ze1 is connected to ground. The feed point of the main antenna is connected to the microstrip line TrL8, and the feed point of the secondary antenna is grounded.

8. The microwave sensing module as described in claim 4, characterized in that, The PCB motherboard is configured as an FR4 double-sided board, the dielectric constant of the PCB motherboard is set to 2.2~4.6, and the thickness of the PCB motherboard is set to 0.4~1mm.

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