A polarized antenna and millimeter wave radar thereof

Abstract

The embodiment of the application discloses a polarized antenna and a millimeter wave radar thereof, which comprises a substrate configured as a reference ground; a rectangular microstrip line arranged on the surface of the substrate; a first feeding microstrip line and a second feeding microstrip line connected at one end to any two adjacent sides of the four sides of the rectangular microstrip line; and a first loading microstrip line and a second loading microstrip line arranged on the remaining two adjacent sides of the four sides. In the above manner, the embodiment of the application can balance the current through the T-shaped loading microstrip, increase the isolation to more than 30 dB, reduce the system size, simplify the system design, save the cost, and also have good matching from the antenna to the chip port.

Description

TECHNICAL FIELD

[0001] The embodiments of the present application relate to the field of antenna polarization, and in particular to a polarization antenna and a millimeter wave radar thereof. BACKGROUND

[0002] Today, when smart phones are widely used, the market needs a large number of polarization antennas, so a large amount of manpower and material resources are invested in this field to develop antennas with specified beam width, good cross-polarization discrimination rate and good matching with wide frequency band and feed cable, and the antennas are easy to manufacture.

[0003] The same-aperture cross-polarization antenna generally includes two feed ports, and the antenna transmits and receives spatial electromagnetic waves with polarization directions perpendicular to each other. Although a high isolation can be achieved between the feed ports with perpendicular polarization, it is very difficult to achieve a port isolation greater than 30 dB in the millimeter wave band. For a system, a high transmit-receive port isolation is conducive to reducing electromagnetic leakage from transmission to reception, preventing system saturation and improving dynamic range. The existing same-aperture cross-polarization antenna schemes that can achieve high port isolation are as follows:

[0004] 1. A traditional direct feed (side feed, back feed) scheme, two 90-degree directional feed ports respectively provide mutually perpendicular polarization excitation;

[0005] 2. A multi-layer coupled feed structure or a complex compensation structure, which adjusts the compensation structure to offset the crosstalk between the ports;

[0006] 3. A differential polarization feed scheme, the differential structure helps to suppress non-ideal modes, increase the orthogonality of polarization modes, and improve the port isolation.

[0007] On the other hand, a T-shaped microstrip loading structure can be used for loading of a patch antenna, which does not require a via structure. However, unlike the present application, it is generally used to achieve single-port multi-frequency point and multi-mode resonance through this loading effect, and has not been used for the design of same-aperture cross-polarization patch antennas. SUMMARY

[0008] The technical problem solved by the embodiments of the present application is to provide a polarization antenna and a millimeter wave radar thereof, which can simultaneously achieve same-aperture dual-port cross-polarization excitation, high port isolation, and simple antenna characteristics of single-layer single-end structure.

[0009] To solve the above technical problems, one technical scheme adopted by the embodiments of the present application is to provide a polarization antenna, comprising: a substrate configured as a reference ground; a rectangular microstrip line arranged on a surface of the substrate; a first feed microstrip line and a second feed microstrip line connected at any two adjacent sides of four sides of the rectangular microstrip line; and a first loading microstrip line and a second loading microstrip line arranged on the remaining two adjacent sides of the four sides.

[0010] In some embodiments, the microstrip line is a rectangular microstrip line with mounting notches arranged on four sides.

[0011] In some embodiments, the mounting notches are arranged at middle positions of the four sides, and the mounting notches are concave rectangles.

[0012] In some embodiments, the length and width of the first feeding microstrip line are equal to the length and width of the second feeding microstrip line respectively; the first feeding microstrip line and the second feeding microstrip line are arranged in the mounting notches of the corresponding sides of the rectangular microstrip line, the width of the mounting notch is greater than the width of the first feeding microstrip line, and the length of the first feeding microstrip line is greater than the length of the mounting notch.

[0013] In some embodiments, the first loading microstrip line is composed of a first vertical microstrip line and a first parallel microstrip line, the first vertical microstrip line is connected to the midpoint of the width direction of the first parallel microstrip line, and the length and width of the first parallel microstrip line are greater than the length and width of the first vertical microstrip line respectively; the second loading microstrip line is composed of a second vertical microstrip line and a second parallel microstrip line, the second vertical microstrip line is connected to the midpoint of the width direction of the second parallel microstrip line, and the length and width of the second parallel microstrip line are greater than the length and width of the second vertical microstrip line respectively; the length of the first vertical microstrip line is greater than the length of the first feeding microstrip line, and the width of the first vertical microstrip line is equal to the width of the first feeding microstrip line.

[0014] In some embodiments, the length and width of the first vertical microstrip line are equal to the length and width of the second vertical microstrip line respectively, and the length and width of the first parallel microstrip line are equal to the length and width of the second parallel microstrip line respectively.

[0015] In some embodiments, the other end of the first feeding microstrip line is connected to a microstrip transmission line to match the feeding port to a preset resistance value.

[0016] In some embodiments, the substrate is a rectangle with a preset length and a preset width, and the preset length and the preset width are greater than the length and the width of the rectangular microstrip line respectively.

[0017] In some embodiments, the microstrip transmission line is a quarter wavelength microstrip transmission line to match the feeding port to 50 ohms.

[0018] To solve the above technical problems, another technical solution adopted by the embodiment of the present application is to provide a millimeter wave radar, which comprises the polarization antenna according to any one of claims 1-9.

[0019] The embodiment of the present application has the advantages that, compared with the prior art, the embodiment of the present application can increase the isolation to more than 30 dB by loading the microstrip balanced current in T shape, secondly, the embodiment of the present application only uses a single layer pattern without holes, so as to improve the processing precision and save the cost, and can be realized by using the PCB process, finally, the embodiment of the present application adopts single-port side feeding, which is helpful for integration with a millimeter wave radio frequency chip, reduces the system size, simplifies the system design, and also has good matching from the antenna to the chip port. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 is a top view of a polarization antenna provided by the embodiment of the present application, showing the structure of the polarization antenna;

[0021] Figure 2 is a top view of another polarization antenna provided by the embodiment of the present application, showing the structure of the polarization antenna;

[0022] Figure 3 is a top view and a side view of another polarization antenna provided by the embodiment of the present application, showing the size of the polarization antenna;

[0023] Fig. 4(a) shows the deflection direction of the current when the feeding port is excited without using the loaded microstrip line;

[0024] Fig. 4(b) shows the deflection direction of the current when the feeding port is excited using the loaded microstrip line;

[0025] Figure 5 is a simulation diagram of another polarization antenna provided by the embodiment of the present application, showing the two-port S parameters of the polarization antenna;

[0026] Figure 6 is a simulation diagram of single-port excitation of the polarization antenna provided by the embodiment of the present application, showing the actual gain of the polarization antenna;

[0027] Figure 7 is a simulation diagram of another polarization antenna provided by the embodiment of the present application, showing the two-port S parameters under the error caused by the length and width of the radio frequency line. DETAILED DESCRIPTION

[0028] For the purpose of facilitating the understanding of the present application, the present application will be described in more detail below in conjunction with the accompanying drawings and specific embodiments. It should be noted that when an element is described as "fixed to" another element, it can be directly on the other element or one or more intervening elements can be present therebetween. When an element is described as "connected to" another element, it can be directly connected to the other element or one or more intervening elements can be present therebetween. The terms "upper", "lower", "inner", "outer", "bottom", and the like as used in the present specification indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are merely for the purpose of facilitating the description of the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application. In addition, the terms "first", "second", "third", and the like are only for the purpose of description and cannot be understood as indicating or implying relative importance.

[0029] Unless otherwise defined, all technical and scientific terms used in the present specification have the same meaning as commonly understood by one of ordinary skill in the art to which the present application belongs. The terms used in the present specification are merely for the purpose of describing specific embodiments of the present application and are not intended to limit the present application. The term "and / or" used in the present specification includes any and all combinations of one or more of the related listed items.

[0030] In addition, the technical features involved in the different embodiments of the present application described below can be combined with each other as long as there is no conflict between them.

[0031] According to some embodiments of the present application, for example Figure 1 As shown in FIG. 1 or 2, the polarized antenna is a patch antenna in structure. It should be noted that the patch antenna is a pie-shaped directional antenna composed of two metal plates stacked together, the upper patch is excited by the signal source, and the lower has a larger metal reference ground plane, and the two metals are filled with dielectric.

[0032] According to some embodiments of the present application, for example Figure 1 As shown in FIG. 1 or 2, the polarized antenna can include a substrate 20 and a rectangular microstrip line 10 arranged on the surface of the substrate 20.

[0033] Wherein, the "rectangular microstrip line" refers to a microstrip line composed of a rectangle without the need to set complex structures such as slots or vias. The specific size design can be determined according to the actual needs.

[0034] It should be noted that based on the design idea and implementation principle disclosed in the present application, adjustments, replacements or combinations made to the structure of the antenna system described in the specific embodiments of the present application according to the actual needs are within the scope of the present application.

[0035] The antenna structure design idea and specific implementation principle of the present application are described in detail below with reference to the attached drawings of the present application specification, taking a polarized antenna with a working frequency coverage range of 24GHz-24.25GHz and a wavelength of 12mm as an example. Based on the same design idea, one or more embodiments in the present application specification can be adjusted, replaced or combined according to different actual application scenarios by those skilled in the art to obtain other more different antenna systems without being limited to the polarized antenna described in the present application specification, for example, changing the working frequency of the polarized antenna.

[0036] According to some embodiments of the present application, please refer to Figure 1 , Figure 1 A top view of a polarized antenna provided for an embodiment of the present application shows the structure of the polarized antenna, which includes a rectangular microstrip line 10, a first feeding microstrip line 11, a second feeding microstrip line 12, a first loaded microstrip line 13, a second loaded microstrip line 14, and a substrate 20 for carrying all the above microstrip lines.

[0037] Among them, in order to connect the first feeding microstrip line 11, the second feeding microstrip line 12, the first loaded microstrip line 13 and the second loaded microstrip line 14 to the rectangular microstrip line 10, an installation notch is arranged on the corresponding side of the four side edges of the rectangular microstrip line 10, and the installation notch is located at the middle position of the corresponding side, and the four installation notches are all concave rectangles with equal length and width.

[0038] The first feeding microstrip line 11 is arranged in the installation notch corresponding to any side edge of the rectangular microstrip line, and the first feeding microstrip line 11 is arranged exactly at the middle position of the length direction of the installation notch to form a single-polarized side-fed single-layer patch antenna; on the basis of the single-polarized side-fed single-layer patch antenna, the second feeding microstrip line 12 is arranged in the installation notch of the side edge adjacent to the side edge corresponding to the first feeding microstrip line 11, and the second feeding microstrip line 12 is arranged exactly at the middle position of the length direction of the installation notch. At this time, the first feeding microstrip line 11 and the second feeding microstrip line 12 are perpendicular to each other, and two mutually perpendicular polarization excitation directions can be obtained. However, the worst isolation between the two ports is only 17dB, which cannot meet the requirement of high port isolation. The first feeding microstrip line 11 and the second feeding microstrip line 12 serve as feeding ports.

[0039] It should be noted that the length and width of the first feeding microstrip line 11 are equal to the length and width of the second feeding microstrip line 12 respectively; the width of the installation notch is greater than the width of the first feeding microstrip line 11 and the width of the second feeding microstrip line 12, and the length of the first feeding microstrip line 11 and the length of the second feeding microstrip line 12 are greater than the length of the installation notch.

[0040] The first loading microstrip line 13 and the second loading microstrip line 14 are arranged on the other two adjacent sides of the rectangular microstrip line 10. The first loading microstrip line 13 is arranged in the mounting notch corresponding to either of the other two adjacent sides of the rectangular microstrip line 10, and is arranged at the middle position in the width direction of the mounting notch. The second loading microstrip line 14 is arranged in the mounting notch corresponding to the other of the other two adjacent sides of the rectangular microstrip line 10, and is arranged at the middle position in the width direction of the mounting notch.

[0041] In some embodiments, the first loading microstrip line 13 is a T-shaped loading microstrip line, which is composed of a first vertical microstrip line and a first parallel microstrip line. The first vertical microstrip line is connected to the middle position in the width direction of the first parallel microstrip line. The length and width of the first parallel microstrip line are greater than those of the first vertical microstrip line. The length of the first vertical microstrip line is greater than that of the first feeding microstrip line 11, and the width of the first vertical microstrip line is equal to that of the first feeding microstrip line 11.

[0042] In some embodiments, the second loading microstrip line 14 is a T-shaped loading microstrip line, which is composed of a second vertical microstrip line and a second parallel microstrip line. The second vertical microstrip line is connected to the middle position in the width direction of the second parallel microstrip line. The length and width of the second parallel microstrip line are greater than those of the second vertical microstrip line. The length of the second vertical microstrip line is greater than that of the second feeding microstrip line 12, and the width of the second vertical microstrip line is equal to that of the second feeding microstrip line 12.

[0043] The length and width of the first vertical microstrip line are equal to those of the second vertical microstrip line, and the length and width of the first parallel microstrip line are equal to those of the second parallel microstrip line.

[0044] The first loading microstrip line 13 and the second loading microstrip line 14 are arranged opposite to the first feeding microstrip line 11 and the second feeding microstrip line 12, respectively. The loading effect of the first loading microstrip line 13 and the second loading microstrip line 14 balances the antenna excitation current, so that the polarization isolation is improved to more than 30 dB.

[0045] The substrate 20 is rectangular in a top view, and has a preset length and a preset width, which are greater than the length and the width of the rectangular microstrip line 10 respectively. It should be noted that the substrate 20 includes two layers, a bottom layer is a metal plate with a preset metal height, and an intermediate layer is a sheet-shaped dielectric with a preset dielectric height, which is greater than the preset metal height. The length and the width of the metal plate and the sheet-shaped dielectric are the preset length and the preset width. The rectangular microstrip line 10, the first feeding microstrip line 11, the second feeding microstrip line 12, the first loading microstrip line 13 and the second loading microstrip line 14 are arranged on the sheet-shaped dielectric as the intermediate layer.

[0046] Compared with the prior art, the embodiment of the present application can improve the isolation to more than 30 dB by loading a T-shaped microstrip balance current; secondly, the present application only uses a single layer pattern without holes, so it is beneficial to improve the processing precision and save costs, and can be realized by using a PCB process; finally, the present application adopts a single-port side feeding, which is helpful for integration with a millimeter wave radio frequency chip, reduces the system size, and simplifies the system design.

[0047] Based on the above-mentioned polarized antenna, the embodiment of the present application further provides another polarized antenna, Figure 2 The top view of another polarized antenna shows its structure, which includes a rectangular microstrip line 10, a first feeding microstrip line 11, a second feeding microstrip line 12, a first loading microstrip line 13, a second loading microstrip line 14, a first microstrip transmission line 15, a first microstrip transmission line 16 and a substrate 20 for carrying all the above-mentioned microstrip lines.

[0048] Among them, in order to connect the first feeding microstrip line 11, the second feeding microstrip line 12, the first loading microstrip line 13 and the second loading microstrip line 14 to the rectangular microstrip line 10, an installation notch is arranged on each of the four side edges of the rectangular microstrip line 10, and the installation notch is located at the middle position of the corresponding side edge, and the four installation notches are all concave rectangles with equal length and width.

[0049] The first feeding microstrip line 11 is arranged in the installation notch corresponding to any side edge of the rectangular microstrip line, and the first feeding microstrip line 11 is arranged at the middle position of the length direction of the installation notch, so as to form a single-polarized side feeding single-layer patch antenna; on the basis of the single-polarized side feeding single-layer patch antenna, the second feeding microstrip line 12 is arranged in the installation notch of the side edge adjacent to the side edge corresponding to the first feeding microstrip line 11, and the second feeding microstrip line 12 is arranged at the middle position of the length direction of the installation notch. At this time, the first feeding microstrip line 11 and the second feeding microstrip line 12 are perpendicular to each other, and two mutually perpendicular polarization excitation directions can be obtained. However, the worst isolation between the two ports is only 17 dB, which cannot meet the requirement of high port isolation. The first feeding microstrip line 11 and the second feeding microstrip line 12 serve as feeding ports.

[0050] It should be noted that the length and width of the first feeding microstrip line 11 are equal to the length and width of the second feeding microstrip line 12 respectively; the width of the mounting gap is greater than the width of the first feeding microstrip line 11 and the width of the second feeding microstrip line 12, and the length of the first feeding microstrip line 11 and the length of the second feeding microstrip line 12 are greater than the length of the mounting gap.

[0051] The first loading microstrip line 13 and the second loading microstrip line 14 are arranged on the remaining two adjacent sides of the four sides of the rectangular microstrip line 10. The first loading microstrip line 13 is arranged in the mounting gap corresponding to any one of the remaining two adjacent sides of the rectangular microstrip line 10, and the first loading microstrip line 13 is arranged at the middle position in the width direction of the mounting gap; the second loading microstrip line 14 is arranged in the mounting gap corresponding to the other one of the remaining two adjacent sides of the rectangular microstrip line 10, and the second loading microstrip line 14 is arranged at the middle position in the width direction of the mounting gap.

[0052] In some embodiments, the first loading microstrip line 13 is a T-shaped loading microstrip line, which is composed of a first vertical microstrip line and a first parallel microstrip line. The first vertical microstrip line is connected to the midpoint of the first parallel microstrip line in the width direction, and the length and width of the first parallel microstrip line are greater than the length and width of the first vertical microstrip line respectively. The length of the first vertical microstrip line is greater than the length of the first feeding microstrip line 11, and the width of the first vertical microstrip line is equal to the width of the first feeding microstrip line 11.

[0053] In some embodiments, the second loading microstrip line 14 is a T-shaped loading microstrip line, which is composed of a second vertical microstrip line and a second parallel microstrip line. The second vertical microstrip line is connected to the midpoint of the second parallel microstrip line in the width direction, and the length and width of the second parallel microstrip line are greater than the length and width of the second vertical microstrip line respectively. The length of the second vertical microstrip line is greater than the length of the second feeding microstrip line 12, and the width of the second vertical microstrip line is equal to the width of the second feeding microstrip line 12.

[0054] The length and width of the first vertical microstrip line are equal to the length and width of the second vertical microstrip line respectively, and the length and width of the first parallel microstrip line are equal to the length and width of the second parallel microstrip line respectively.

[0055] The first loading microstrip line 13 and the second loading microstrip line 14 are opposite to the first feeding microstrip line 11 and the second feeding microstrip line 12 respectively, and the polarization isolation degree is improved to more than 30 dB through the load effect of the first loading microstrip line 13 and the second loading microstrip line 14 to balance the antenna excitation current.

[0056] The first microstrip transmission line 15 is connected to the other end of the first feeding microstrip line 11, and the second microstrip transmission line 16 is connected to the other end of the second feeding microstrip line 12, so that the first feeding microstrip line 11 and the second feeding microstrip line 12 as the feeding ports are matched to a preset resistance value.

[0057] The length and the width of the first microstrip transmission line 15 are greater than the length and the width of the first feeding microstrip line 11 respectively, and the length and the width of the first microstrip transmission line 15 are equal to the length and the width of the second microstrip transmission line 16 respectively.

[0058] In some embodiments, the first microstrip transmission line 15 and the second microstrip transmission line 16 are both quarter-wavelength microstrip transmission lines, so that the impedance of the first feeding microstrip line 11 and the second feeding microstrip line 12 as the feeding ports is matched to 50 ohms.

[0059] As viewed from the top, the substrate 20 is a rectangle with a preset length and a preset width, and the preset length and the preset width are greater than the length and the width of the rectangular microstrip line 10 respectively. It should be noted that the substrate 20 includes two layers, a bottom layer is a metal plate with a preset metal height, and an intermediate layer is a sheet-shaped dielectric with a preset dielectric height, and the preset dielectric height is greater than the preset metal height. The length and the width of the metal plate and the sheet-shaped dielectric are both the preset length and the preset width. The rectangular microstrip line 10, the first feeding microstrip line 11, the second feeding microstrip line 12, the first loaded microstrip line 13, and the second loaded microstrip line 14 are all arranged on the sheet-shaped dielectric as the intermediate layer.

[0060] Compared with the prior art, the embodiment of the application can improve the isolation to more than 30 dB by loading a T-shaped microstrip balanced current, secondly, the application only uses a single layer pattern without holes, so it is beneficial to improve the processing precision and save costs, and can be realized by using a PCB process, finally, the application adopts a single-port side feeding, which is helpful for integration with a millimeter wave radio frequency chip, reduces the system size, simplifies the system design, and also has good matching from the antenna to the chip port.

[0061] Please refer to Figure 3 , Figure 3 Another top view and side view of a polarized antenna provided for the embodiment of the application, which shows the size of the polarized antenna, in particular:

[0062] As viewed from the top, the substrate 20 is a square with a preset length equal to a preset width, that is, the side length of the substrate is 9.00 mm (marked as Lg in Figure 3 As viewed from the side, the height of the metal plate as the bottom layer of the substrate 20 is 0.035 mm (marked as Tc in Figure 3 ), and the height of the sheet-shaped dielectric as the intermediate layer of the substrate 20 is 0.254 mm (marked as Ts in Figure 3 ).

[0063] From the top view, the rectangular microstrip line 10 is a square with a side length of 3.10 mm (in...). Figure 3 (marked as Lp); the length of the mounting notches on the four sides of the rectangular microstrip line 10 is 0.50 mm (in Figure 3 The mounting notches, marked as Df, located on the four sides of the rectangular microstrip line 10, are 0.60 mm wide. Figure 3 The diagram shows that the distance between the first feed microstrip line 11 and the side of the mounting notch is Gf = 0.20 mm. It is known that the first feed microstrip line 11 is positioned at the midpoint of the width direction of the mounting notch; combining this with the width of the first feed microstrip line 11, the width of the mounting notch can be obtained. The length of the first feed microstrip line 11 is 1.20 mm. Figure 3 (marked as Lf), the length of the first feed microstrip line 11 is 0.20 mm (in Figure 3 (marked as Wf); the length of the first vertical microstrip line constituting the first feed microstrip line 11 is 1.43 mm (in Figure 3 (marked as Ls1), the width of the first vertical microstrip line is 0.20 mm (in Figure 3 (marked as Ws1); the length of the first parallel microstrip line constituting the first feed microstrip line 11 is 0.30 mm (in Figure 3 (marked as Ls2), the width of the first vertical microstrip line is 3.30 mm (in Figure 3 (marked as Ws2); the length of the first microstrip transmission line 15 is 1.60 mm (in Figure 3 (marked as Lt), the width of the first microstrip transmission line 15 is 1.02 mm (in Figure 3 (marked as Wt).

[0064] From the side view, the heights of the rectangular microstrip line 10, the first feed microstrip line 11, the second feed microstrip line 12, the first loading microstrip line 13, the second loading microstrip line 14, the first microstrip transmission line 15, and the first microstrip transmission line 16 are all 0.035 mm (in...). Figure 5 (marked as Tc).

[0065] Referring to Figure 4, the beneficial effects of the polarized antenna described in this embodiment of the invention can be intuitively demonstrated. Figure 4(a) shows the current bias direction when the feed port is excited without using a loaded microstrip line (Jsurf_gnd represents the current bias direction). Without using a T-type loaded microstrip line, due to the asymmetry of the cross-polarized feed structure, when one port of a microstrip antenna with two feed ports is excited, the current will be biased towards the other loaded port, causing the antenna excitation mode to deviate from the TM10 mode, thereby generating large crosstalk and deteriorating the isolation.

[0066] Figure 4(b) shows the deflection direction of the current (Jsurf_gnd represents the deflection direction of the current) when the microstrip line is loaded when the feed port is excited, and it can be seen that when one port is excited, the current direction returns to the parallel x-axis direction, the two-mode port orthogonality is good, and the isolation is obviously improved, and the antenna radiation is normal.

[0067] Simulation experiments are performed on the above-mentioned another polarization antenna covering the 24GHz-24.25GHz frequency band, Figure 5 The two-port S parameters of the polarization antenna are shown. It can be seen from Figure 6 that after the T-shaped microstrip is loaded, the isolation (|S21|) in the 24GHz-24.25GHz frequency band is improved from 17dB to 35dB, and the matching (S11) is kept below -10dB, which can indicate that the polarization antenna meets the application requirements.

[0068] When one feed port is excited and the other feed port is connected to a matching load, the simulation results of the single-port directional diagram can be obtained, as shown in Figure 6 . Figure 7 The actual gain of the polarization antenna is shown, and it can be seen that the highest co-polarization gain of the single port is 5.2dBi, the E-plane co-polarization pattern is wider than the H-plane, and there is no obvious recess, which meets the normal antenna TM10 radiation mode; the worst co-polarization-cross-polarization gain suppression ratio at each angle is greater than 25dB, so it can be explained that the polarization orthogonality of the polarization antenna is good.

[0069] At the same time, in order to verify the feasibility of the PCB process of the polarization antenna on 24GHz, the key size parameters are scanned, and the simulation diagrams of the another polarization antenna under different parameters are obtained, as shown in ​ , the two-port S parameters of the polarization antenna under the error caused by the length and width of the radio frequency line are shown. Specifically, according to the current advanced PCB manufacturing process, the control of the length and width of the radio frequency line can be ensured within ±1mil, so the scanning range of the error is near the optimal value ±1mil. It can be seen that the length Df of the mounting gap has the greatest influence on the frequency deviation, causing a maximum frequency deviation of ±125MHz, which makes the worst isolation in the frequency band drop to about 32dB, but the isolation still meets the requirements. Therefore, it can be proved that the polarization antenna is feasible on the PCB process on 24GHz.

[0070] Based on the antenna system provided in the above embodiment, the embodiment of the present application further provides a millimeter wave radar. The millimeter wave radar applies the polarization antenna, can obtain good port matching on the basis of simple structure design, and can obtain high isolation under the premise of meeting the needs of miniaturized design.

[0071] Such dual polarization can well meet the needs of existing millimeter wave radars in practical scene applications, effectively reduce process errors and meet the needs of miniaturization, and has good application prospect.

[0072] Finally, it should be noted that: the above examples are only used to illustrate the technical solutions of the present application, but not to limit them; under the idea of the present application, the technical features in the above examples or different embodiments can also be combined, the steps can be implemented in any order, and there are many other changes of different aspects of the present application as described above, which are not provided in details for simplicity; although the present application has been described in detail with reference to the foregoing examples, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing examples, or make equivalent replacement for part of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A polarized antenna, characterized in that, include: A substrate, the substrate being configured as a reference ground; A rectangular microstrip line is disposed on the surface of the substrate. The microstrip line is a rectangular microstrip line with mounting notches on all four sides. The mounting notches are respectively disposed at the middle position of the four sides and are concave rectangles. A first feed microstrip line and a second feed microstrip line are connected at one end to any two adjacent sides of the four sides of the rectangular microstrip line; the first feed microstrip line and the second feed microstrip line are both disposed in the mounting notches on the corresponding sides of the rectangular microstrip line, the width of the mounting notch is greater than the width of the first feed microstrip line, and the length of the first feed microstrip line is greater than the length of the mounting notch; A first loading microstrip line and a second loading microstrip line are provided on the other two adjacent sides of the four sides; the first loading microstrip line and the second loading microstrip line are respectively provided in the mounting notches on the corresponding sides of the rectangular microstrip line; The first loading microstrip line is a T-shaped loading microstrip line, which is composed of a first vertical microstrip line and a first parallel microstrip line. The first vertical microstrip line is perpendicularly connected to the midpoint of the width direction of the first parallel microstrip line. The length and width of the first parallel microstrip line are greater than the length and width of the first vertical microstrip line, respectively. The length of the first vertical microstrip line is greater than the length of the first feeding microstrip line, and the width of the first vertical microstrip line is equal to the width of the first feeding microstrip line. The second loading microstrip line is a T-shaped loading microstrip line, which is composed of a second vertical microstrip line and a second parallel microstrip line. The second vertical microstrip line is perpendicularly connected to the midpoint of the width direction of the second parallel microstrip line. The length and width of the second parallel microstrip line are greater than the length and width of the second vertical microstrip line, respectively. The length of the second vertical microstrip line is greater than the length of the second feeding microstrip line, and the width of the second vertical microstrip line is equal to the width of the second feeding microstrip line.

2. The antenna according to claim 1, characterized in that, The length and width of the first feed microstrip line are equal to the length and width of the second feed microstrip line, respectively.

3. The antenna according to claim 1, characterized in that, The length and width of the first vertical microstrip line are equal to the length and width of the second vertical microstrip line, respectively. The length and width of the first parallel microstrip line are equal to the length and width of the second parallel microstrip line, respectively.

4. The antenna according to any one of claims 1-3, characterized in that, The other end of the first feed microstrip line is connected to a microstrip transmission line so that the feed port is matched to a preset resistance value.

5. The antenna according to claim 4, characterized in that, The substrate is a rectangle with a preset length and a preset width, wherein the preset length and the preset width are respectively greater than the length and width of the rectangular microstrip line.

6. The antenna according to claim 4, characterized in that, The microstrip transmission line is a quarter-wavelength microstrip transmission line to match the feed port to 50 ohms.

7. A millimeter-wave radar, characterized in that, The millimeter-wave radar includes a polarized antenna as described in any one of claims 1-6.

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