Small circularly polarized three-antenna applied to angle measurement

Abstract

The invention discloses a small circularly polarized three-antenna applied to angle measurement, which comprises three dielectric substrates, two metal layers and three patch antennas on the uppermost layer, and is characterized in that the patch antennas are connected to the bottom metal layer through copper columns, and the patch antennas radiate received signals; three circular grooves are dug in the metal layer of the bottom layer, so that the situation that signals cannot be transmitted to the antenna of the upper layer due to current short circuit during feeding is prevented. According to the invention, the patch antenna with a small size forms good circular polarization performance, the three antennas can radiate circular polarization electromagnetic waves in different polarization directions, and the specific angle of a signal source in the vertical direction can be calculated according to the phase difference.

Description

Technical Field

[0001] The present invention belongs to the technical field of antennas, and particularly relates to a small circularly polarized three-antenna applied to angle measurement. Background Art

[0002] With the rapid development of wireless communication systems such as cellular networks, wireless local area networks, satellite communications, and the Internet of Things, the communication methods, information access channels, and ways of interacting with the surrounding environment in modern society have undergone a complete revolution. This revolution has made wireless communication systems gradually become an indispensable part of human daily life, and antennas, as devices that can effectively convert electrical signals and electromagnetic waves, are crucial components in wireless communication systems. Antennas have also evolved from the initial linear antennas to the current digital and intelligent 5G antennas. Among them, there are a wide variety of antennas, and antennas can be divided into different categories according to different classification criteria. For example, according to the trajectory formed by the end of the electric field vector changing with time, they can be divided into: circularly polarized antennas, linearly polarized antennas, and elliptically polarized antennas; according to their different application structural forms, they can be divided into: microstrip antennas, dielectric resonator antennas, substrate integrated waveguide (SIW) antennas, and helical antennas, etc.

[0003] Circularly polarized antennas have unique advantages compared with other types of polarized antennas. Linearly polarized antennas have the problem of polarization mismatch. Linearly polarized antennas have higher requirements for the polarization direction of the receiving antenna. Only when the polarization direction of the receiving antenna is the same as that of the transmitting antenna can the strongest signal be received. Secondly, the anti-interference ability of linearly polarized antennas is weak, and linearly polarized signals are easily affected by multipath effects and atmospheric refraction, resulting in signal fading. The circularly polarized wave radiated by a circularly polarized antenna is an equal-amplitude rotating field, which can be decomposed into two equal-amplitude orthogonal linearly polarized waves with a phase difference of 90°; secondly, when the circularly polarized wave encounters an obstacle during transmission, its reflected wave has its rotation direction reversed, and the reflected signal will not be received by the receiving antenna, avoiding clutter and multipath interference and ensuring the accuracy of signal transmission; then, because the electric field vector of the circularly polarized wave is the same in all directions, the mutual interference during signal propagation is small, avoiding the problem of polarization mismatch and ensuring the transmission efficiency of the signal; in addition, both linearly polarized waves and circularly polarized waves will exhibit the Faraday polarization deflection phenomenon, but circularly polarized antennas are not sensitive to the polarization deflection direction, so they can overcome the distortion loss caused by the Faraday polarization rotation of electromagnetic waves by the ionosphere. As a form of realizing circular polarization performance, microstrip antennas can be directly printed on a thin substrate. Therefore, microstrip antennas have the characteristics of compact structure, light weight, and low profile, and can be easily integrated with microelectronic devices and circuits, reducing the complexity of the system. Therefore, the use of microstrip structures to achieve circular polarization performance has always attracted the attention of researchers.

[0004] In recent years, increasingly stringent communication requirements have made circularly polarized microstrip antennas need to possess various high performances. For example, in satellite communication systems, in order to increase the channel capacity and reduce the influence of multipath interference, broadband dual-circularly polarized microstrip antennas with high isolation characteristics are applied; in radio frequency communication systems, if circularly polarized microstrip filter antennas with high gain characteristics are adopted, not only can a longer communication distance be provided, but also problems such as multipath loss, insensitivity to the orientation of devices, and interference can be solved. Summary of the Invention

[0005] Aiming at the deficiencies of the prior art, the present invention proposes a small circularly polarized three-antenna applied to angle measurement.

[0006] The technical solution adopted by the present invention to solve the problems of the prior art is: a small circularly polarized three-antenna applied to angle measurement includes three layers of dielectric substrates, two layers of metal layers, and three patch antennas on the top layer. The patch antennas are connected to the bottom metal layer using copper columns, and the patch antennas are used to radiate the received signals; three circular slots are dug in the metal layer at the bottom to prevent current short-circuit during feeding and cause the signal to not be transmitted to the upper-layer antennas. At the same time, transmission lines and signal processing chips are also distributed on the metal layer at the bottom. The transmission lines are used to transmit the electromagnetic wave signals received by the antennas, and the signal processing chips process and calculate the phase difference of the signals received by the left and right antennas.

[0007] A further improvement scheme is: the overall stacked layers of the antenna are, from bottom to top in sequence, the bottom metal layer, the first layer of dielectric substrate, the second layer of metal layer, the second layer of dielectric substrate, the third layer of dielectric substrate, and three patch antennas.

[0008] A further improvement scheme is: the three patch antennas are linearly and evenly distributed on the third layer of dielectric substrate and are parallel to the edge of the third layer of dielectric substrate; the shape of each patch antenna is: obtained by cutting off the upper left and lower right corners of a rectangle with a length of one wavelength at 8 GHz and a width of 0.9 wavelength. The cut-off corners are isosceles triangles with side lengths of one-sixth to one-fourth of the wavelength at 8 GHz. The three patch antennas are completely the same in size and shape.

[0009] A further improvement scheme is: an antenna feeding point is included on the central axis of each patch antenna. The antenna feeding points in the left and right patch antennas are both at a distance of one-fifth of the vertical side length from the upper horizontal side of the patch antenna; the antenna feeding point of the middle patch antenna is at a distance of four-fifths of the vertical side length from the upper horizontal side of the patch antenna.

[0010] The three circular slots on the bottom metal layer are all directly below the antenna feeding points.

[0011] A further improvement solution is as follows: The thicknesses of the three-layer dielectric substrate are different. The second-layer dielectric substrate is the thickest, followed by the first-layer dielectric substrate, and finally the third-layer dielectric substrate. The dielectric constants of the three-layer dielectric substrate are all 4.2. The thicknesses of the third-layer dielectric substrate, the second-layer dielectric substrate, and the first-layer dielectric substrate are 0.1316 mm, 1.13 mm, and 0.1112 mm respectively, the lengths are all 36 mm, and the widths are all 10 mm.

[0012] The materials of the two metal layers are both copper, and the thickness is 0.036 mm.

[0013] A further improvement solution is as follows: The feeding method of the small circularly polarized three-element antenna is that a copper column penetrates through the three-layer dielectric substrate, is input from the circular groove in the bottom metal layer, and is transmitted to the top patch antenna through the copper column. The diameter of the copper column is smaller than the diameter of the circular groove to prevent short circuit during feeding.

[0014] Compared with the prior art, the present invention has the following beneficial effects:

[0015] 1. The structure of the present invention is simple, fabricated by printed circuit technology, convenient for large-scale production, easy to assemble, convenient to use, and easy to popularize.

[0016] 2. The patch antenna of the present invention is printed on a dielectric substrate with a smaller width, and can be applied to handheld devices such as remote controls that have high requirements for antenna size.

[0017] 3. The present invention arranges 3 patch antennas horizontally. Compared with other circularly polarized array antennas, each antenna in this array has good impedance matching and circular polarization performance.

[0018] 4. The present invention cuts off a right triangle at the upper left corner and the lower right corner of the 3 patch antennas respectively, and the length and width of the antenna are not equal, which can enable the smaller-sized patch antenna to form good circular polarization performance.

[0019] 5. The three antennas in the present invention can radiate circularly polarized electromagnetic waves in different polarization directions. The left and right antennas radiate circularly polarized electromagnetic waves in the same direction, while the middle antenna radiates circularly polarized electromagnetic waves in the opposite direction. The distances from the signal source to the left and right antennas are not equal, so there is a phase difference between the signals received by the two antennas. According to the magnitude of the phase difference, the specific angle of the signal source in the horizontal direction can be calculated; similarly, there will also be a phase difference between the signals received by the left and middle antennas in the patch antenna due to the different distances from the signal source to the two antennas. According to the magnitude of the phase difference, the specific angle of the signal source in the vertical direction can be calculated. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 is the overall structural schematic diagram of the embodiment of the present invention;

[0021] Figure 2 It is a schematic diagram of the patch antenna structure of an embodiment of the present invention;

[0022] Figure 3 It is a schematic diagram of the structure of the second metal layer of the present invention;

[0023] Figure 4 It is a schematic diagram of the structure of the bottom metal layer of the present invention (the transmission line and the signal processing chip are not shown);

[0024] Figure 5 It is a simulation result diagram of the return loss of the 8GHz small circularly polarized three - antenna system of an embodiment of the present invention;

[0025] Figure 6 It is a simulation result diagram of the axial ratio of the 8GHz small circularly polarized three - antenna system of an embodiment of the present invention;

[0026] Figure 7 It is the radiation pattern of the left antenna of an embodiment of the present invention on the YOZ plane at 8GHz;

[0027] Figure 8 It is the radiation pattern of the middle antenna of an embodiment of the present invention on the YOZ plane at 8GHz;

[0028] Figure 9 It is the radiation pattern of the right antenna of an embodiment of the present invention on the YOZ plane at 8GHz. Detailed implementation manners

[0029] The following will describe in detail the specific implementation manners of the present invention with reference to the accompanying drawings.

[0030] Please refer to Figures 1 to 9 As shown, a small circularly polarized three - antenna for angle measurement sequentially includes a patch antenna 1, a dielectric substrate 2, a dielectric substrate 3, a metal layer 4, a dielectric substrate 5, and a metal layer 6.

[0031] Specifically, the patch antenna 1 is a rectangle with unequal length and width, and a right - angled triangle 9 is cut off at each of the diagonal corners. Three circular grooves 10 and circular grooves 11 are respectively dug out from the metal layer 4 and the metal layer 6, and the current flows into the antenna feeding point 8 through the copper column 7.

[0032] In this embodiment, as Figure 2 shown, the patch antenna 1 includes a feeding point 8 and the cut - off isosceles right - angled triangle 9. Among them, changing the position of the feeding point 8 will affect the return loss performance of the antenna, and changing the size of the cut - off isosceles right - angled triangle 9 will affect the circular polarization performance of the antenna. Further, adjusting the position of the feeding point 8 reduces the return loss of the antenna at 8GHz to below - 10dB, and changing the size of the isosceles triangle reduces the axial ratio to 3dB at 8GHz to meet the actual requirements.

[0033] The left and right antennas in the patch antenna 1 receive signals, and the signals are transmitted to the metal layer 6 through the copper posts. When the angle of the signal source deviates from the 0° direction, the distances from the signal source to the left and right antennas are not equal, and a phase difference is generated in the signals received by the two antennas. The specific angle of the signal source in the horizontal direction can be calculated based on the magnitude of the phase difference. Similarly, the signals received by the left and middle antennas in the patch antenna 1 will also generate a phase difference due to the different distances from the signal source to the two antennas, and the specific angle of the signal source in the vertical direction can be calculated based on the magnitude of the phase difference.

[0034] The copper post 7 in the small circularly polarized three - antenna applied to angle measurement penetrates through the patch antenna 1, the dielectric substrate 2, the dielectric substrate 3, the metal layer 4, the dielectric substrate 5, and the metal layer 6. Circular grooves 10 and 11 with radii larger than that of the copper post 7 are respectively opened in the metal layer 4 and the metal layer 6, aiming to prevent short - circuit when there is current passing through the copper post, as Figure 2 、 Figure 3 、 Figure 4 shown.

[0035] As Figure 5 shown, in this embodiment, the return losses of the three antennas in the antenna system are all lower than - 10 dB at 8 GHz. Refer to Figure 6 shown, in this embodiment, the axial ratios of the left and right antennas in the antenna system are lower than 3 dB at 8 GHz, and the axial ratio of the middle antenna is lower than 7 dB. Refer to Figure 7 shown, in this embodiment, the maximum gain of the left antenna in the YOZ plane pattern at 8 GHz is 1.3 dB. Refer to Figure 8 shown, in this embodiment, the maximum gain of the right antenna in the YOZ plane pattern at 8 GHz is 1.8 dB. Refer to Figure 9 shown, in this embodiment, the maximum gain of the middle antenna in the YOZ plane pattern at 8 GHz is 1.0 dB.

[0036] From the above simulation results, it can be seen that the small circularly polarized three - antenna proposed by the present invention has good return loss and circular polarization performance at the operating frequency of 8 GHz, and the gains of the three antennas at 8 GHz are all greater than 1 dB. At the same time, the left and right antennas radiate circularly polarized electromagnetic waves in the same direction, while the middle antenna radiates circularly polarized electromagnetic waves in the opposite direction. The biggest innovation of this array is that it can achieve and ensure excellent circular polarization characteristics in the case of a small width, and uses the method of unit rotation to realize angle measurement in the vertical direction. The invention can meet the small - size requirements of antennas for handheld remote control devices, and can accurately measure the specific angles of the signal source relative to the signal source in the horizontal and vertical directions.

[0037] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and changes. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A small circularly polarized three-antenna for angle measurement, characterized in that: include: A three-layer dielectric substrate, two metal layers and three patch antennas on the top layer, wherein the patch antenna (1) is connected to the bottom metal layer (6) using a copper column (10), and the patch antenna (1) radiates the received signal; three circular grooves (11) are dug out of the bottom metal layer.

2. A small circularly polarized three-antenna for angle measurement according to claim 1, characterized in that: The small circularly polarized three-antenna overall stack comprises, from bottom to top, a bottom metal layer (6), a first dielectric substrate (5), a second metal layer (4), a second dielectric substrate (3), a third dielectric substrate (2), and three patch antennas (1).

3. A small circularly polarized three-antenna for angle measurement according to claim 2, characterized in that: The three patch antennas (1) are evenly distributed in a straight line on the third dielectric substrate (2) and are parallel to the edge of the third dielectric substrate (2); The shape of each patch antenna (1) is: a rectangle with a length of one wavelength at 8 GHz and a width of 0.9 wavelengths, obtained by cutting off the upper left and lower right corners, the cut corners being an isosceles triangle with a side length of one sixth to one quarter of a wavelength at 8 GHz, and the three patch antennas (1) are exactly the same in size and shape.

4. The small circularly polarized three-antenna for angle measurement according to claim 3, characterized in that: Each patch antenna (1) has an antenna feeding point (8) on its central axis; the antenna feeding points (8) in the left and right patch antennas (1) are each located one-fifth of the vertical length of the horizontal side of the patch antenna; and the antenna feeding point (8) in the middle patch antenna is located four-fifths of the vertical length of the horizontal side of the patch antenna.

5. A small circularly polarized three-antenna for angle measurement according to claim 4, characterized in that: The three circular grooves (11) on the bottom metal layer (6) are all located directly below the antenna feeding point (8).

6. A small circularly polarized three-antenna for angle measurement according to claim 5, characterized in that: The three dielectric substrates have different thicknesses, the second dielectric substrate (3) being the thickest, followed by the first dielectric substrate (5), and finally the third dielectric substrate (2). The dielectric constants of the three dielectric substrates are all 4.

2. The thicknesses of the third dielectric substrate, the second dielectric substrate, and the first dielectric substrate are 0.1316 mm, 1.13 mm, and 0.1112 mm, respectively. The lengths are all 36 mm, and the widths are all 10 mm. The two metal layers are both made of copper and have a thickness of 0.036 mm.

7. A small circularly polarized three-antenna for angle measurement according to claim 6, characterized in that: The feeding method of the small circularly polarized three antennas is that a copper column (10) penetrates through a three-layer dielectric substrate, is input from a circular groove (11) in a bottom metal layer (6), and is transmitted to the patch antenna on the top layer through the copper column (10), wherein the diameter of the copper column is smaller than the diameter of the circular groove.

Images