Dual-frequency circularly polarized microstrip antenna and design method thereof

Abstract

The invention provides a dual-frequency circularly polarized microstrip antenna and a design method thereof, and relates to the technical field of antennas. The dual-frequency circularly polarized microstrip antenna comprises an antenna plate, the center deviation area of which is provided with a feeding point, and the feeding point is used for connecting the antenna plate with a bottom plate; the first diagonal line of the square antenna plate is provided with a first tuning network loading point, the bottom plate is provided with a first tuning network, the first tuning network loading point is connected with the first tuning network, and the first tuning network is used for adjusting a first intrinsic working mode on the first diagonal line to a first phase of a target resonant frequency; a second diagonal line of the antenna plate is provided with a second tuning network loading point, the bottom plate is provided with a second tuning network, the second tuning network loading point is connected with the second tuning network, and the second tuning network is used for adjusting a second intrinsic working mode on the second diagonal line to a second phase of the target resonant frequency; and the phase difference between the first phase and the second phase is 90 degrees, so that the circularly polarized microstrip antenna can work in different frequency bands.

Description

Technical Field

[0001] The present invention relates to the field of antenna technology, and in particular to a dual-frequency circularly polarized microstrip antenna and a design method thereof. Background Art

[0002] Antennas are the core components for converting electromagnetic waves into electrical signals in wireless communication systems, and their performance directly affects the communication quality and system integration. In practical applications, microstrip antennas are a commonly used type of antenna in wireless communication systems, and are widely used in application scenarios such as array antennas, phased array antennas, and radar antenna array units, especially in satellite communications, navigation terminals, and other application scenarios that require circularly polarized electromagnetic waves.

[0003] Common circularly polarized microstrip antennas generally control the circular polarization direction by means of angle cutting, slot loading, etc. to achieve left-hand or right-hand circular polarization characteristics. However, existing circularly polarized microstrip antennas are mostly designed based on a single resonant mode to ensure that the radiation performance of the antenna and the axial ratio of the radiated electromagnetic waves in a single frequency band meet the circular polarization characteristics. However, there are more and more scenarios in which the transceiver links need to work in different frequency bands. If the existing circularly polarized microstrip antennas are used, two sets of independent antennas need to be configured to cover the transmitting and receiving frequency bands respectively, which will increase the size of the wireless communication terminal. If a single antenna is forced to be reused, the frequency band offset will cause problems such as axial ratio deterioration, affecting the communication reliability of the wireless communication terminal. Summary of the invention

[0004] In view of the problems existing in the prior art, the present invention provides a dual-frequency circularly polarized microstrip antenna and a design method thereof.

[0005] The present invention provides a dual-frequency circularly polarized microstrip antenna, comprising: An antenna board, wherein a feeding point is provided in a central deviation area of ​​the antenna board, and the feeding point is used to connect the antenna board to a bottom plate; The antenna plate is square, a first tuning network loading point is provided on a first diagonal line of the antenna plate, a first tuning network is provided on the bottom plate, the first tuning network loading point is connected to the first tuning network, and the first tuning network is used to adjust the first intrinsic working mode on the first diagonal line to a first phase of a target resonant frequency; A second tuning network loading point is provided on the second diagonal line of the antenna board, and a second tuning network is provided on the bottom plate. The second tuning network loading point is connected to the second tuning network, and the second tuning network is used to adjust the second intrinsic working mode on the second diagonal line to the second phase of the target resonant frequency; wherein the phase difference between the first phase and the second phase is 90 degrees.

[0006] According to a dual-frequency circularly polarized microstrip antenna provided by the present invention, antenna plate cut corners are provided at two corners of the first diagonal line or the second diagonal line; Wherein, the antenna plate cutting angle is used to generate an offset of the resonant frequency; The first tuning network is used to adjust the first intrinsic working mode on the first diagonal line to a first phase of the target resonant frequency in coordination with the offset; The second tuning network is used to adjust the second intrinsic working mode on the second diagonal line to a second phase of the target resonant frequency in coordination with the offset.

[0007] According to a dual-frequency circularly polarized microstrip antenna provided by the present invention, a third tuning network loading point is further provided on the first diagonal line, the third tuning network loading point and the first tuning network loading point are symmetrically distributed on both sides of the center point, the third tuning network loading point is used to load a third tuning network, and the third tuning network is the same as the first tuning network; A fourth tuning network loading point is also provided on the second diagonal line. The fourth tuning network loading point and the second tuning network loading point are symmetrically distributed on both sides of the center point. The fourth tuning network loading point is used to load a fourth tuning network. The fourth tuning network is the same as the second tuning network.

[0008] According to a dual-frequency circularly polarized microstrip antenna provided by the present invention, the tuning network includes a capacitor and an inductor, the capacitor is connected in series with the inductor, the capacitor is connected to a loading point of the tuning network, and the inductor is grounded.

[0009] According to a dual-frequency circularly polarized microstrip antenna provided by the present invention, the tuning network includes: A first tuning circuit, the first tuning circuit comprising a first capacitor and an inductor, the first capacitor and the inductor are connected in series, the inductor is grounded, and the first capacitor is connected to a tuning network loading point; A second tuning circuit, the second tuning circuit comprising a second capacitor, one end of the second capacitor being grounded, and the other end being connected to a loading point of the tuning network; Wherein, the first tuning circuit and the second tuning circuit are connected in parallel.

[0010] According to a dual-frequency circularly polarized microstrip antenna provided by the present invention, the tuning network includes: A first tuning circuit, wherein the first tuning circuit comprises a capacitor and a first inductor, the capacitor and the first inductor are connected in series, the first inductor is grounded, and the capacitor is connected to a loading point of a tuning network; A second tuning circuit, wherein the second tuning circuit comprises a second inductor, one end of the second inductor is grounded, and the other end of the second inductor is connected to a loading point of the tuning network; Wherein, the first tuning circuit and the second tuning circuit are connected in parallel.

[0011] The present invention also provides a dual-frequency circularly polarized microstrip antenna design method, wherein the antenna board of the dual-frequency circularly polarized microstrip antenna is square, a first tuning network loading point is provided on a first diagonal line of the antenna board, and a second tuning network loading point is provided on a second diagonal line, and the method comprises: When the first tuning network loading point and the second tuning network loading point are in an open circuit state, determining a first intrinsic working mode on the first diagonal and a second intrinsic working mode on the second diagonal; determining a target resonant frequency of the dual-frequency circularly polarized microstrip antenna; Determine a first reference distance between a loading point of the first tuning network and a center point, and determine a second reference distance between a loading point of the second tuning network and a center point; Determine a first tuning network that shifts a first intrinsic working mode on the first diagonal line to the target resonant frequency based on a first reference distance, and determine a second tuning network that shifts a second intrinsic working mode on the second diagonal line to the target resonant frequency based on a second reference distance; When the first tuning network meets the preset standard, the first distance between the loading point of the first tuning network and the center point is obtained according to the first reference distance; when the second tuning network meets the preset standard, the second distance between the loading point of the second tuning network and the center point is obtained according to the second reference distance.

[0012] According to a dual-frequency circularly polarized microstrip antenna design method provided by the present invention, the first tuning network that shifts the first intrinsic working mode on the first diagonal line to the target resonant frequency is determined based on a first reference distance, and the second tuning network that shifts the second intrinsic working mode on the second diagonal line to the target resonant frequency is determined based on a second reference distance, including: Determine a circular polarization axis ratio, and obtain an offset of a target resonant frequency of the dual-frequency circularly polarized microstrip antenna according to the circular polarization axis ratio; Determine a first phase of the target resonant frequency shifted in a first direction based on the offset, and determine a second phase of the target resonant frequency shifted in a second direction based on the offset; wherein a phase difference between the first phase and the second phase is 90 degrees; A first tuning network is determined based on a first reference distance to shift a first eigenworking mode on the first diagonal line to a first phase of a first target resonant frequency, and a second tuning network is determined based on a second reference distance to shift a second eigenworking mode on the second diagonal line to a second phase of a second target resonant frequency.

[0013] According to a dual-frequency circularly polarized microstrip antenna design method provided by the present invention, antenna plate cut corners are provided at two corners of the first diagonal line or the second diagonal line; The method of determining a first tuning network that shifts a first intrinsic working mode on the first diagonal line to the target resonant frequency based on a first reference distance, and determining a second tuning network that shifts a second intrinsic working mode on the second diagonal line to the target resonant frequency based on a second reference distance, comprises: Determine the offset and offset direction of the target resonant frequency of the dual-frequency circularly polarized microstrip antenna generated by the antenna plate cutting angle; Determine a first phase of the target resonant frequency shifted in a first direction based on the offset, and determine a second phase of the target resonant frequency shifted in a second direction based on the offset; wherein a phase difference between the first phase and the second phase is 90 degrees; A first tuning network is determined based on a first reference distance to shift a first eigenworking mode on the first diagonal line to a first phase of a first target resonant frequency, and a second tuning network is determined based on a second reference distance to shift a second eigenworking mode on the second diagonal line to a second phase of a second target resonant frequency.

[0014] According to a dual-frequency circularly polarized microstrip antenna design method provided by the present invention, the target resonant frequency includes a high frequency and a low frequency; The method comprises: determining a first tuning network that shifts a first intrinsic working mode on the first diagonal line to the target resonant frequency based on a first reference distance, and determining a second tuning network that shifts a second intrinsic working mode on the second diagonal line to the target resonant frequency based on a second reference distance, comprising: Determine, based on the first reference distance, a first tuning network that shifts the first intrinsic working mode on the first diagonal line to the high frequency in the first working frequency band and shifts the first intrinsic working mode on the first diagonal line to the low frequency in the second working frequency band; A second tuning network is determined based on the second reference distance to shift the second intrinsic working mode on the second diagonal line to the high frequency in the first working frequency band and to shift the second intrinsic working mode on the second diagonal line to the low frequency in the second working frequency band.

[0015] The dual-frequency circularly polarized microstrip antenna and the design method thereof provided by the present invention connect the antenna board to the base plate through the feeding point of the center deviation area of ​​the square antenna board, connect to the first tuning network on the base plate through the first tuning network loading point on the first diagonal, and connect to the second tuning network on the base plate through the second tuning network loading point on the second diagonal. The first tuning network can adjust the first intrinsic working mode on the first diagonal to the first phase of the target resonant frequency, and the second tuning network can adjust the second intrinsic working mode on the second diagonal to the second phase of the target resonant frequency, so that the circularly polarized microstrip antenna can work in different frequency bands through the first tuning network connected to the first tuning network loading point on the first diagonal and the second tuning network connected to the second tuning network loading point on the second diagonal. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0017] Figure 1 This is one of the structural schematic diagrams of the dual-frequency circularly polarized microstrip antenna provided by the present invention.

[0018] Figure 2 This is the second structural schematic diagram of the dual-frequency circularly polarized microstrip antenna provided by the present invention.

[0019] Figure 3 This is the third structural schematic diagram of the dual-frequency circularly polarized microstrip antenna provided by the present invention.

[0020] Figure 4 This is the fourth structural schematic diagram of the dual-frequency circularly polarized microstrip antenna provided by the present invention.

[0021] Figure 5 This is one of the structural schematic diagrams of the first tuning network of the dual-frequency circularly polarized microstrip antenna provided by the present invention.

[0022] Figure 6 This is the fifth structural schematic diagram of the dual-frequency circularly polarized microstrip antenna provided by the present invention.

[0023] Figure 7 This is the second structural schematic diagram of the first tuning network of the dual-frequency circularly polarized microstrip antenna provided by the present invention.

[0024] Figure 8 This is the third structural schematic diagram of the first tuning network of the dual-frequency circularly polarized microstrip antenna provided by the present invention.

[0025] Fig. 9 It is one of the Smith schematic diagrams of the tuning network of the dual-frequency circularly polarized microstrip antenna provided by the present invention.

[0026] Fig.10 This is the second Smith schematic diagram of the tuning network of the dual-frequency circularly polarized microstrip antenna provided by the present invention. Fig.11 This is the third Smith schematic diagram of the tuning network of the dual-frequency circularly polarized microstrip antenna provided by the present invention.

[0027] Fig.12 This is one of the antenna resonant frequency schematic diagrams of the dual-frequency circularly polarized microstrip antenna provided by the present invention.

[0028] Fig.13 This is one of the axial ratio schematic diagrams of the dual-frequency circularly polarized microstrip antenna provided by the present invention.

[0029] Fig.14 This is the sixth structural schematic diagram of the dual-frequency circularly polarized microstrip antenna provided by the present invention.

[0030] Fig.15 This is the second schematic diagram of the antenna resonant frequency of the dual-frequency circularly polarized microstrip antenna provided by the present invention.

[0031] Fig.16 This is the second schematic diagram of the axial ratio of the dual-frequency circularly polarized microstrip antenna provided by the present invention.

[0032] Fig.17 It is a flow chart of the dual-frequency circularly polarized microstrip antenna design method provided by the present invention.

[0033] Reference numerals: 1: antenna board; 2: feeding point; 3: first tuning network loading point; 4: second tuning network loading point; 5: bottom plate; 6: antenna board cut corner; 7: third tuning network loading point; 8: fourth tuning network loading point. DETAILED DESCRIPTION

[0034] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the drawings of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0035] Combine the following Figure 1-Figure 17 The dual-frequency circularly polarized microstrip antenna and the design method thereof of the present invention are described.

[0036] Figure 1 The structure of the dual-frequency circularly polarized microstrip antenna provided by the present invention is shown in FIG. Figure 1 ,like Figure 1 As shown, the dual-frequency circularly polarized microstrip antenna comprises: An antenna board 1, wherein a feeding point 2 is provided in a central deviation area of ​​the antenna board 1, and the feeding point 2 is used to connect the antenna board 1 to a bottom plate 5; The antenna board 1 is square, a first tuning network loading point 3 is provided on a first diagonal line of the antenna board 1, a first tuning network is provided on the bottom plate 5, the first tuning network loading point 3 is connected to the first tuning network, and the first tuning network is used to adjust the first intrinsic working mode on the first diagonal line to a first phase of a target resonant frequency; A second tuning network loading point 4 is provided on the second diagonal line of the antenna board 1, and a second tuning network is provided on the base plate 5. The second tuning network loading point 4 is connected to the second tuning network, and the second tuning network is used to adjust the second intrinsic working mode on the second diagonal line to the second phase of the target resonant frequency; wherein the phase difference between the first phase and the second phase is 90 degrees.

[0037] The base plate 5 and the antenna plate 1 may be made of metal. The center deviation area refers to the area near the center point of the antenna plate 1. The specific range of the center deviation area of ​​the feeding point 2 can be set according to the actual impedance of the antenna in the actual application scenario, and no further limitation is made in this embodiment.

[0038] The feeding point 2 is used for input and output of electromagnetic wave signals. The feeding point 2 can connect the antenna board 1 to the bottom plate 5 through a coaxial probe or a microstrip line. The bottom plate 5 can also be called a ground plate as a reference ground.

[0039] It can be understood that the first and second of the first diagonal line and the second diagonal line are mainly used to distinguish different diagonal lines rather than to limit the order of precedence or the like.

[0040] It can be understood that the target resonant frequency of the dual-frequency circularly polarized microstrip antenna includes a high-frequency resonant frequency and a low-frequency resonant frequency. For example, the resonant frequency of the first eigenmode can be 500 MHz. The first tuning network can adjust the first eigenmode to a first phase of a high-frequency resonant frequency of 700 MHz, and adjust the first eigenmode to a first phase of a low-frequency resonant frequency of 300 MHz, etc. This is not further limited in the present embodiment.

[0041] The adjustment of the second intrinsic working mode by the second tuning network is basically similar to the adjustment of the first intrinsic working mode by the first tuning network. The difference is that the second tuning network adjusts the second intrinsic working mode to the second phase of the target resonant frequency, which will not be repeated in this embodiment.

[0042] Exemplarily, the first tuning network can shift the first intrinsic working mode on the first diagonal line toward the high frequency direction to the first phase of the target resonant frequency, and the second tuning network can shift the second intrinsic working mode on the second diagonal line toward the low frequency direction to the second phase of the target resonant frequency, so as to achieve a phase difference of 90 degrees between the first phase and the second phase, and the working mode on the first diagonal line of the square antenna board is orthogonal to the working mode on the second diagonal line, and the amplitude of the working mode on the first diagonal line is equal to the amplitude of the working mode on the second diagonal line, thereby enabling the circular polarization of the electromagnetic waves radiated by the antenna board.

[0043] The dual-frequency circularly polarized microstrip antenna provided by the present invention connects the antenna plate 1 to the base plate 5 through a feeding point 2 in the center deviation area of ​​the square antenna plate 1, connects to the first tuning network on the base plate 5 through a first tuning network loading point 3 on the first diagonal, and connects to the second tuning network on the base plate 5 through a second tuning network loading point 4 on the second diagonal. The first tuning network can adjust the first intrinsic working mode on the first diagonal to the first phase of the target resonant frequency, and the second tuning network can adjust the second intrinsic working mode on the second diagonal to the second phase of the target resonant frequency, so that the circularly polarized microstrip antenna can work in different frequency bands through the first tuning network connected to the first tuning network loading point 3 on the first diagonal and the second tuning network connected to the second tuning network loading point 4 on the second diagonal.

[0044] In one embodiment, a support plate may be provided between the antenna plate 1 and the bottom plate 5, or multiple support members may be provided for support. In the case where multiple support members are provided, 3 or 4 support columns may be provided, and the specific number of support columns is not further limited in this embodiment. The support column may be a separately provided support column, or a connecting metal column between the tuning network loading point and the corresponding tuning network. In this embodiment, the specific structure of the support column is not further limited.

[0045] like Figure 2 As shown, based on the above embodiment, antenna board cut corners 6 are provided at two corners of the first diagonal line or the second diagonal line; Wherein, the antenna plate cut angle 6 is used to generate an offset of the resonant frequency; The first tuning network is used to adjust the first intrinsic working mode on the first diagonal line to a first phase of the target resonant frequency in coordination with the offset; The second tuning network is used to adjust the second intrinsic working mode on the second diagonal line to a second phase of the target resonant frequency in coordination with the offset.

[0046] by Figure 2Based on the direction shown, for example, the diagonal line between the lower left corner and the upper right corner can be used as the first diagonal line, and the diagonal line between the upper left corner and the lower right corner can be used as the second diagonal line. In this case, the feeding point 2 can be set in the area below the center.

[0047] Whether to set the antenna board corner 6 at the corner of the first diagonal line or the corner of the second diagonal line can be determined according to whether the circular polarization direction of the electromagnetic wave radiated by the antenna is left-hand circular polarization or right-hand circular polarization.

[0048] Exemplarily, when antenna board corner cuts 6 are provided at two corners of the second diagonal, the second tuning network can adjust the second intrinsic working mode on the second diagonal to the target resonant frequency, and the offset of the resonant frequency generated by the antenna board corner cut 6 is matched to shift in the second direction to obtain the second phase of the target resonant frequency. The parameters of the first tuning network can be adjusted based on the offset of the resonant frequency generated by the antenna board corner cut 6, so that the first tuning network can adjust the first intrinsic working mode on the first diagonal to the target resonant frequency, and shift the same offset in the first direction to obtain the first phase of the target resonant frequency. For example, when the antenna board is square, the target resonant frequency is 300MHz, and the antenna board corner cut 6 generates a 3MHz offset in the high frequency direction, then the second tuning network can preliminarily adjust the second intrinsic working mode on the second diagonal to 300MHz, and finally adjust the second intrinsic working mode on the second diagonal to 303MHz with the 3MHz offset, and the first tuning network can adjust the first intrinsic working mode on the first diagonal to 297MHz.

[0049] The first tuning network can also adjust the first intrinsic working mode on the first diagonal and the second tuning network can adjust the second intrinsic working mode on the second diagonal to the same resonant frequency. For example, when the antenna plate is square, the target resonant frequency is 300MHz, and the antenna plate cut angle 6 produces a 6MHz offset in the high frequency direction, then the second tuning network can adjust the second intrinsic working mode on the second diagonal to 297MHz, and the second intrinsic working mode on the second diagonal is adjusted to 303MHz with the offset, and the first tuning network can adjust the first intrinsic working mode on the first diagonal to 297MHz.

[0050] In this way, the second tuning network adjusts the second intrinsic working mode on the second diagonal to 303MHz, which is higher than the target resonant frequency of 300MHz, and the phase is ahead of the target resonant frequency of 300MHz; the first tuning network adjusts the first intrinsic working mode on the first diagonal to 297MHz, which is lower than the target resonant frequency of 300MHz, and the phase lags behind the target resonant frequency of 300MHz, so that the phase difference between the working mode on the first diagonal and the working mode on the second diagonal can be 90 degrees. As mentioned above, when the antenna plate is square, the working mode on the first diagonal is orthogonal to the working mode on the second diagonal, and the amplitude of the working mode on the first diagonal is equal to the amplitude of the working mode on the second diagonal. Therefore, when the phase difference between the working mode on the first diagonal and the working mode on the second diagonal is 90 degrees, the electromagnetic waves radiated by the microstrip antenna can be circularly polarized.

[0051] It can be understood that the offset given in this embodiment is for illustration only, and the specific offset for achieving a phase difference of 90 degrees between the working mode on the first diagonal line and the working mode on the second diagonal line can be set according to actual working conditions, and no further limitation is made in this embodiment.

[0052] In the present embodiment, on the basis of the structural form of the antenna board 1 with circular polarization formed by antenna board cut corners 6 at the two diagonal corners, a first tuning network is added to tune the first intrinsic working mode, and a second tuning network is added to tune the second intrinsic working mode. The dual tuning networks are combined to independently control the resonant frequencies and phase relationships of the two antenna modes, so as to realize dual-band circularly polarized radiation on a single antenna board 1 and increase the compactness of the dual-band circularly polarized microstrip antenna.

[0053] like Figure 3 and Figure 4 As shown, based on any of the above embodiments, a third tuning network loading point 7 is further provided on the first diagonal line, and the third tuning network loading point 7 and the first tuning network loading point 3 are symmetrically distributed on both sides of the center point, and the third tuning network loading point 7 is used to load a third tuning network, and the third tuning network is the same as the first tuning network; A fourth tuning network loading point 8 is also provided on the second diagonal line. The fourth tuning network loading point 8 and the second tuning network loading point 4 are symmetrically distributed on both sides of the center point. The fourth tuning network loading point 8 is used to load a fourth tuning network, and the fourth tuning network is the same as the second tuning network.

[0054] The adjustment of the third intrinsic working mode by the third tuning network and the adjustment of the fourth intrinsic working mode by the fourth tuning network are basically similar to the adjustment of the first intrinsic working mode by the first tuning network. The difference is that the fourth tuning network adjusts the fourth intrinsic working mode to the second phase of the target resonant frequency, which will not be repeated in this embodiment.

[0055] It can be understood that the third tuning network also adjusts the third eigenmode to the first phase of the target resonant frequency.

[0056] In this embodiment, by adding a symmetrically distributed third tuning network loading point 7 on the first diagonal line, adding a symmetrically distributed fourth tuning network loading point 8 on the second diagonal line, and setting the third tuning network to be the same as the first tuning network, and setting the fourth tuning network to be the same as the second tuning network, the single-point tuning network is expanded to a distributed tuning network, and the impedance that the tuning network needs to bear is distributed to the two tuning networks, the risk of a single tuning network approaching the limit operating condition can be reduced.

[0057] In addition, the superposition effect between distributed tuning networks can achieve finer equivalent parameter steps. For example, when the adjustment step of a single tuning network is 0.5pF (picofarad), the superposition effect between two symmetrical distributed tuning networks can compress the adjustment step to 0.25pF, reducing the adjustment difficulty of each tuning network.

[0058] Moreover, the complementary characteristics of the symmetrical distributed tuning network can suppress the interference of a single tuning network on parameter accuracy and reduce the frequency control error of the dual-frequency circularly polarized antenna.

[0059] It is understandable that the first tuning network loaded at the first tuning network loading point 3 on the first diagonal line and the third tuning network loaded at the third tuning network loading point 7 are the same, or only one tuning network loading point is reserved to load the corresponding tuning network, which can simplify the design of the antenna board 1. The setting of the tuning network loading point and its tuning network on the first diagonal line is similar, and will not be repeated in this embodiment.

[0060] Based on any of the above embodiments, the tuning network includes a capacitor and an inductor, the capacitor is connected in series with the inductor, the capacitor is connected to a loading point of the tuning network, and the inductor is grounded.

[0061] In this embodiment, the first tuning network, the second tuning network, the third tuning network and the fourth tuning network are substantially the same, except that the values ​​of specific components are slightly different on the basis of fine-tuning. Figure 5 As shown, in the first tuning network, the capacitor is connected to the first tuning network loading point. It can be understood that in the second tuning network, the capacitor is connected to the second tuning network loading point, and in the third tuning network, the capacitor is connected to the third tuning network loading point.

[0062] like Figure 6As shown, a first tuning network loading point and a third tuning network loading point are symmetrically distributed on the first diagonal line, a second tuning network loading point and a fourth tuning network loading point are symmetrically distributed on the second diagonal line, and each tuning network loading point is loaded with a corresponding tuning network as an example for explanation.

[0063] It can be understood that the feeding point transmits or receives electromagnetic wave signals mainly through the first working mode on the first diagonal and the second working mode on the second diagonal, the first tuning network loaded at the first tuning network loading point and the third tuning network loaded at the third tuning network loading point adjust the first intrinsic working mode on the first diagonal, and the second tuning network loaded at the second tuning network loading point and the fourth tuning network loaded at the fourth tuning network loading point adjust the second intrinsic working mode on the second diagonal.

[0064] Combined impedance of the tuning network It can be expressed by the following formula:

[0065] in, is the operating frequency, is the capacitance of the components in the first tuning network, is the inductance of the component in the first tuning network.

[0066] In this way, when ,Right now The combined impedance of the tuning network is The resonant frequency can be adjusted by fine-tuning the parameters of the components in the tuning network loaded by the first tuning network loading point and the third tuning network loading point. The equivalent impedance of the tuning network at is capacitive. , which can make the first eigenmode on the first diagonal line from the resonant frequency Shift to low frequency to resonant frequency .in, is the offset, Much smaller than , ,and .

[0067] Based on a similar working principle, the resonant frequency can be adjusted by fine-tuning the parameters of the components in the tuning network loaded at the second tuning network loading point and the fourth tuning network loading point. The equivalent impedance of the tuning network at is capacitive. , which can make the second eigenmode on the second diagonal line from the resonant frequency Shift to low frequency to resonant frequency .

[0068] Based on a similar working principle, ,Right now The combined impedance of the tuning network is The resonant frequency is inductive, and the parameters of the components in the tuning network loaded by the first tuning network loading point and the third tuning network loading point fine-tuned as mentioned above can be adjusted. The equivalent impedance of the tuned network at is inductive. , which can make the first eigenmode on the first diagonal line from the resonant frequency Shift to high frequency to resonant frequency .in, is the offset, Much smaller than , ,and .

[0069] The parameters of the components in the tuning network loaded by the aforementioned fine-tuned second tuning network loading point and the fourth tuning network loading point can resonate the frequency The equivalent impedance of the tuned network at is inductive. , which can make the second eigenmode on the second diagonal line from the resonant frequency Shift to high frequency to resonant frequency .

[0070] Among them, when shifting to high frequency or shifting to low frequency, The circular polarization direction of the electromagnetic wave radiated by the antenna can be made left-hand circular polarization. The circular polarization direction of the electromagnetic wave radiated by the antenna can be made right-hand circular polarization.

[0071] Understandably, Figure 6 middle, is the capacitance of the components in the second tuning network, is the inductance of the component in the second tuning network. is the capacitance of the components in the third tuning network, is the inductance of the component in the third tuning network. is the capacitance of the components in the fourth tuning network, is the inductance of the component in the fourth tuning network.

[0072] In this embodiment, a capacitor is connected in series with the inductor, and the capacitor is connected to a tuning network loading point. The tuning network in which the inductor is grounded can be inductive in one working frequency band, so that the resonant frequencies of the first intrinsic working mode and the second intrinsic working mode are biased to high frequency, and can be capacitive in another working frequency band, so that the resonant frequencies of the first intrinsic working mode and the second intrinsic working mode are biased to low frequency, thereby realizing the operation of the microstrip antenna in two frequency bands; the tuning network loaded by the tuning network loading point on the first diagonal line can make the first intrinsic working mode slightly shifted toward the first direction in the working frequency band, and the tuning network loaded by the tuning network loading point on the second diagonal line can make the second intrinsic working mode slightly shifted toward the second direction in the working frequency band, thereby realizing circular polarization of the electromagnetic waves radiated by the microstrip antenna.

[0073] In one embodiment, the tuning network can be adjusted to have lower capacitance in one frequency band, and the intrinsic working mode can be adjusted to a high frequency lower than the original resonant frequency, and higher capacitance in another frequency band, and the intrinsic working mode can be adjusted to a lower low frequency, so as to reduce the size of the antenna. For example, the resonant frequency of the first intrinsic working mode can be 500 MHz. The first tuning network can adjust the first intrinsic working mode to a first phase of a high frequency resonant frequency of 300 MHz, and adjust the first intrinsic working mode to a first phase of a low frequency resonant frequency of 200 MHz.

[0074] This can be achieved by adjusting the frequency of a single capacitor device. The lower the frequency of a single capacitor device, the smaller the capacitive property.

[0075] Similarly, by adjusting the component parameters of the tuning network, the tuning network can present lower inductance in one frequency band, adjust the intrinsic working mode to a low frequency higher than the original resonant frequency, and present higher capacitiveness in another frequency band, adjust the intrinsic working mode to a higher high frequency, so as to improve the antenna performance. For example, the resonant frequency of the first intrinsic working mode can be 500 MHz. The first tuning network can also adjust the first intrinsic working mode to a first phase of a high frequency resonant frequency of 800 MHz, and adjust the first intrinsic working mode to a first phase of a low frequency resonant frequency of 700 MHz.

[0076] This can be achieved by adjusting the frequency of a single inductor device. The higher the frequency of a single inductor device, the greater the inductance.

[0077] It can be understood that the high frequency and the low frequency here both refer to the operating frequency.

[0078] In addition to the aforementioned tuning network in which the capacitor is connected in series with the inductor, the capacitor is connected to the loading point of the tuning network, and the inductor is grounded, at least the following tuning network can be used to achieve the above-mentioned inductive property in one working frequency band and capacitive property in another working frequency band: Based on any of the above embodiments, the tuning network includes: A first tuning circuit, the first tuning circuit comprising a first capacitor and an inductor, the first capacitor and the inductor are connected in series, the inductor is grounded, and the first capacitor is connected to a tuning network loading point; A second tuning circuit, the second tuning circuit comprising a second capacitor, one end of the second capacitor being grounded, and the other end being connected to a loading point of the tuning network; Wherein, the first tuning circuit and the second tuning circuit are connected in parallel.

[0079] In this embodiment, the first tuning network, the second tuning network, the third tuning network and the fourth tuning network are substantially the same, except that the values ​​of specific components are slightly different on the basis of fine-tuning. Figure 7 As shown, in the first tuning network, the first capacitor is connected to the first tuning network loading point. It can be understood that in the second tuning network, the first capacitor is connected to the second tuning network loading point, and in the third tuning network, the first capacitor is connected to the third tuning network loading point.

[0080] Based on any of the above embodiments, the tuning network includes: A first tuning circuit, wherein the first tuning circuit comprises a capacitor and a first inductor, the capacitor and the first inductor are connected in series, the first inductor is grounded, and the capacitor is connected to a loading point of a tuning network; A second tuning circuit, wherein the second tuning circuit comprises a second inductor, one end of the second inductor is grounded, and the other end of the second inductor is connected to a loading point of the tuning network; Wherein, the first tuning circuit and the second tuning circuit are connected in parallel.

[0081] In this embodiment, the first tuning network, the second tuning network, the third tuning network and the fourth tuning network are substantially the same, except that the values ​​of specific components are slightly different on the basis of fine-tuning. Figure 8 As shown, in the first tuning network, the capacitor is connected to the first tuning network loading point. It can be understood that in the second tuning network, the capacitor is connected to the second tuning network loading point, and in the third tuning network, the capacitor is connected to the third tuning network loading point.

[0082] In one embodiment, for the convenience of analysis, the tuning network may be simulated by software to obtain a Smith diagram showing the capacitance or inductance characteristics of the tuning network at different frequencies. Fig. 9 The corresponding positions of different frequency points on the Smith diagram shown can determine that the tuning network with capacitors connected in series with inductors, capacitors connected to the loading point of the tuning network, and inductors grounded can achieve the target effect; see Fig.10The corresponding positions of different frequency points on the Smith diagram shown in the figure can determine that the first tuning circuit includes a first capacitor and an inductor, the first capacitor and the inductor are connected in series, the inductor is grounded, and the first capacitor is connected to the loading point of the tuning network; the second tuning circuit includes a second capacitor, one end of the second capacitor is grounded, and the other end is connected to the loading point of the tuning network; the tuning network in which the first tuning circuit and the second tuning circuit are connected in parallel achieves the target effect; see Fig.11 The corresponding positions of different frequency points on the Smith diagram can determine that the first tuning circuit includes a capacitor and a first inductor, the capacitor and the first inductor are connected in series, the first inductor is grounded, and the capacitor is connected to the loading point of the tuning network; the second tuning circuit includes a second inductor, one end of the second inductor is grounded, and the other end is connected to the loading point of the tuning network; the tuning network in which the first tuning circuit and the second tuning circuit are connected in parallel achieves the target effect. The frequency point is the resonant frequency.

[0083] The effectiveness of the dual-band circularly polarized microstrip antenna provided in this embodiment can be evaluated by simulation methods.

[0084] For example, a simulation model of a dual-band circularly polarized microstrip antenna without each tuning network loading point can be established using three-dimensional antenna electromagnetic simulation software, and antenna plate cut-off angles are set at two corners of the first diagonal or the second diagonal to determine the eigenmode of the single-band circularly polarized microstrip antenna on the original antenna diagonal. Fig.12 The magnitude and Fig.13 The axial ratio, single-frequency circularly polarized microstrip antenna has an original antenna diagonal resonant frequency of 482MHz.

[0085] See also Fig.14 Then, the three-dimensional antenna electromagnetic simulation software can be used to establish the simulation model of the circularly polarized microstrip antenna in which the first tuning network loading point and the third tuning network loading point are symmetrically distributed on the first diagonal line, and the second tuning network loading point and the fourth tuning network loading point are symmetrically distributed on the second diagonal line, and the corresponding tuning network is loaded after fine-tuning of the components, wherein the capacitance in the first tuning network is 2pF and the inductance is 50nH; the capacitance in the third tuning network is 2pF and the inductance is 50nH; the capacitance in the second tuning network is 1.2pF and the inductance is 110nH; the capacitance in the fourth tuning network is 1.2pF and the inductance is 110nH. Please refer to Fig.15 The magnitude and Fig.16The axial ratio shown in the figure determines that the target resonant frequency of the dual-band circularly polarized microstrip antenna includes two frequency bands, 394MHz and 518MHz, and the dual-band axial ratio is less than 3dB, which meets the requirements of circularly polarized electromagnetic wave characteristics. It can be determined that the dual-band circularly polarized microstrip antenna solution provided in this embodiment can effectively support the simultaneous transmission of dual-band circularly polarized electromagnetic waves in wireless communication systems with different transmitting and receiving frequency bands.

[0086] The coordination network adopts a tuning network in which a capacitor is connected in series with the inductor, the capacitor is connected to a loading point of the tuning network, and the inductor is grounded.

[0087] The dual-frequency circularly polarized microstrip antenna design method provided by the present invention is described below. The dual-frequency circularly polarized microstrip antenna design method described below and the dual-frequency circularly polarized microstrip antenna described above can be referred to each other.

[0088] Fig.17 It is one of the flow diagrams of the dual-frequency circularly polarized microstrip antenna design method provided by the present invention. The antenna board of the dual-frequency circularly polarized microstrip antenna is square, and a first tuning network loading point is provided on the first diagonal line of the antenna board, and a second tuning network loading point is provided on the second diagonal line. Fig.17 As shown, the method includes: Step 1701: when the first tuning network loading point and the second tuning network loading point are in an open circuit state, determine a first intrinsic working mode on a first diagonal line and a second intrinsic working mode on a second diagonal line; determine a target resonant frequency of the dual-frequency circularly polarized microstrip antenna; Step 1702: determining a first reference distance between a loading point and a center point of the first tuning network, and determining a second reference distance between a loading point and a center point of the second tuning network; Step 1703: Determine a first tuning network that shifts a first intrinsic working mode on the first diagonal line to the target resonant frequency based on a first reference distance, and determine a second tuning network that shifts a second intrinsic working mode on the second diagonal line to the target resonant frequency based on a second reference distance; Step 1704: When the first tuning network meets the preset standard, a first distance between the loading point of the first tuning network and the center point is obtained according to the first reference distance; when the second tuning network meets the preset standard, a second distance between the loading point of the second tuning network and the center point is obtained according to the second reference distance.

[0089] The open circuit state means that the tuning network loading point is disconnected from the corresponding tuning network, or the tuning network loading point is not loaded with the corresponding tuning network. The intrinsic working mode refers to the working mode in which the frequency of the antenna when radiating electromagnetic waves is at the resonant frequency determined by its own physical characteristics. The target resonant frequency refers to the resonant frequency of the antenna when radiating electromagnetic waves under the action of the loaded tuning network.

[0090] The reference distance refers to the initial position of the tuning network loading point determined based on the antenna structure. The first reference distance refers to the initial position of the first tuning network loading point, and the second reference distance refers to the initial position of the second tuning network loading point.

[0091] The distance refers to the final position of the tuning network loading point determined based on actual calculations. The first distance refers to the final position of the first tuning network loading point, and the second distance refers to the final position of the second tuning network loading point.

[0092] The tuning network complies with the preset standard. Complying with the preset standard means that the value range of the components of the tuning network is within the set value range, so as to avoid the values ​​of the components of the tuning network being too extreme.

[0093] It is understandable that the setting value range of the components of the tuning network can be set according to actual needs, and no further limitation is made in this embodiment.

[0094] The dual-frequency circularly polarized microstrip antenna design method provided by the present invention is characterized in that a first tuning network loading point is set on a first diagonal line of an antenna board, the first tuning network is loaded through the first tuning network loading point, a second tuning network loading point is set on a second diagonal line of the antenna board, the second tuning network is loaded through the second tuning network loading point, the first tuning network can adjust a first intrinsic working mode on the first diagonal line to a target resonant frequency, and the second tuning network can adjust a second intrinsic working mode on the second diagonal line to a target resonant frequency, thereby enabling the circularly polarized microstrip antenna to operate in different frequency bands through the first tuning network connected to the first tuning network loading point on the first diagonal line and the second tuning network connected to the second tuning network loading point on the second diagonal line while avoiding too extreme values ​​of components of the tuning network.

[0095] Based on any of the foregoing embodiments, the first tuning network that shifts the first intrinsic working mode on the first diagonal line to the target resonant frequency is determined based on the first reference distance, and the second tuning network that shifts the second intrinsic working mode on the second diagonal line to the target resonant frequency is determined based on the second reference distance, including: Determine a circular polarization axis ratio, and obtain an offset of a target resonant frequency of the dual-frequency circularly polarized microstrip antenna according to the circular polarization axis ratio; Determine a first phase of the target resonant frequency shifted in a first direction based on the offset, and determine a second phase of the target resonant frequency shifted in a second direction based on the offset; wherein a phase difference between the first phase and the second phase is 90 degrees; A first tuning network is determined based on a first reference distance to shift a first eigenworking mode on the first diagonal line to a first phase of a first target resonant frequency, and a second tuning network is determined based on a second reference distance to shift a second eigenworking mode on the second diagonal line to a second phase of a second target resonant frequency.

[0096] Based on any of the above embodiments, antenna board cut corners are provided at two corners of the first diagonal line or the second diagonal line; The method of determining a first tuning network that shifts a first intrinsic working mode on the first diagonal line to the target resonant frequency based on a first reference distance, and determining a second tuning network that shifts a second intrinsic working mode on the second diagonal line to the target resonant frequency based on a second reference distance, comprises: Determine the offset and offset direction of the target resonant frequency of the dual-frequency circularly polarized microstrip antenna generated by the antenna plate cutting angle; Determine a first phase of the target resonant frequency shifted in a first direction based on the offset, and determine a second phase of the target resonant frequency shifted in a second direction based on the offset; wherein a phase difference between the first phase and the second phase is 90 degrees; A first tuning network is determined based on a first reference distance to shift a first eigenworking mode on the first diagonal line to a first phase of a first target resonant frequency, and a second tuning network is determined based on a second reference distance to shift a second eigenworking mode on the second diagonal line to a second phase of a second target resonant frequency.

[0097] Based on any of the above embodiments, the target resonant frequency includes a high frequency and a low frequency; The method comprises: determining a first tuning network that shifts a first intrinsic working mode on the first diagonal line to the target resonant frequency based on a first reference distance, and determining a second tuning network that shifts a second intrinsic working mode on the second diagonal line to the target resonant frequency based on a second reference distance, comprising: Determine, based on the first reference distance, a first tuning network that shifts the first intrinsic working mode on the first diagonal line to the high frequency in the first working frequency band and shifts the first intrinsic working mode on the first diagonal line to the low frequency in the second working frequency band; A second tuning network is determined based on the second reference distance to shift the second intrinsic working mode on the second diagonal line to the high frequency in the first working frequency band and to shift the second intrinsic working mode on the second diagonal line to the low frequency in the second working frequency band.

[0098] Based on any of the above embodiments, a third tuning network loading point is further provided on the first diagonal line of the dual-frequency circularly polarized microstrip antenna, and the third tuning network loading point and the first tuning network loading point are symmetrically distributed on both sides of the center point; a fourth tuning network loading point is further provided on the second diagonal line, and the fourth tuning network loading point and the second tuning network loading point are symmetrically distributed on both sides of the center point; Before determining the first intrinsic working mode on the first diagonal and the second intrinsic working mode on the second diagonal, the method further includes: Determining that the third tuning network loading point and the fourth tuning network loading point are in an open circuit state; After determining a first reference distance between the first tuning network loading point and the center point, and determining a second reference distance between the second tuning network loading point and the center point, the method further includes: Determine a third reference distance between the third tuning network loading point and the center point, and a fourth reference distance between the fourth tuning network loading point and the center point; After determining a first tuning network that shifts a first intrinsic working mode on the first diagonal line to the target resonant frequency based on the first reference distance, the method further includes: Determining a third tuning network that shifts the first intrinsic working mode on the first diagonal line to the target resonant frequency based on the third reference distance; After determining a second tuning network that shifts a second intrinsic working mode on the second diagonal line to the target resonant frequency based on the second reference distance, the method further includes: Determining a fourth tuning network that shifts the first intrinsic working mode on the first diagonal line to the target resonant frequency based on the fourth reference distance; When the first tuning network meets the preset standard, after obtaining the first distance between the loading point of the first tuning network and the center point according to the first reference distance, the method further includes: When the third tuning network meets the preset standard, a third distance between the loading point of the third tuning network and the center point is obtained according to the third reference distance; When the second tuning network meets the preset standard, after obtaining the second distance between the loading point of the second tuning network and the center point according to the second reference distance, the method further includes: When the fourth tuning network meets the preset standard, a fourth distance between the loading point of the fourth tuning network and the center point is obtained according to the fourth reference distance.

[0099] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A dual-frequency circularly polarized microstrip antenna, characterized in that: include: An antenna board, wherein a feeding point is provided in a central deviation area of ​​the antenna board, and the feeding point is used to connect the antenna board to a bottom plate; The antenna plate is square, a first tuning network loading point is provided on a first diagonal line of the antenna plate, a first tuning network is provided on the bottom plate, the first tuning network loading point is connected to the first tuning network, and the first tuning network is used to adjust the first intrinsic working mode on the first diagonal line to a first phase of a target resonant frequency; A second tuning network loading point is provided on the second diagonal line of the antenna board, and a second tuning network is provided on the bottom plate. The second tuning network loading point is connected to the second tuning network, and the second tuning network is used to adjust the second intrinsic working mode on the second diagonal line to the second phase of the target resonant frequency; wherein the phase difference between the first phase and the second phase is 90 degrees.

2. The dual-frequency circularly polarized microstrip antenna according to claim 1, characterized in that: Antenna board cut corners are provided at two corners of the first diagonal line or the second diagonal line; Wherein, the antenna plate cutting angle is used to generate an offset of the resonant frequency; The first tuning network is used to adjust the first intrinsic working mode on the first diagonal line to a first phase of the target resonant frequency in coordination with the offset; The second tuning network is used to adjust the second intrinsic working mode on the second diagonal line to a second phase of the target resonant frequency in coordination with the offset.

3. The dual-frequency circularly polarized microstrip antenna according to claim 1 or 2, characterized in that: A third tuning network loading point is also provided on the first diagonal line, and the third tuning network loading point and the first tuning network loading point are symmetrically distributed on both sides of the center point, and the third tuning network loading point is used to load a third tuning network, and the third tuning network is the same as the first tuning network; A fourth tuning network loading point is also provided on the second diagonal line. The fourth tuning network loading point and the second tuning network loading point are symmetrically distributed on both sides of the center point. The fourth tuning network loading point is used to load a fourth tuning network. The fourth tuning network is the same as the second tuning network.

4. The dual-frequency circularly polarized microstrip antenna according to claim 3, characterized in that: The tuning network includes a capacitor and an inductor, the capacitor is connected in series with the inductor, the capacitor is connected to a loading point of the tuning network, and the inductor is grounded.

5. The dual-frequency circularly polarized microstrip antenna according to claim 3, characterized in that: The tuning network consists of: A first tuning circuit, the first tuning circuit comprising a first capacitor and an inductor, the first capacitor and the inductor are connected in series, the inductor is grounded, and the first capacitor is connected to a tuning network loading point; A second tuning circuit, the second tuning circuit comprising a second capacitor, one end of the second capacitor being grounded, and the other end being connected to a loading point of the tuning network; Wherein, the first tuning circuit and the second tuning circuit are connected in parallel.

6. The dual-frequency circularly polarized microstrip antenna according to claim 3, characterized in that: The tuning network consists of: A first tuning circuit, wherein the first tuning circuit comprises a capacitor and a first inductor, the capacitor and the first inductor are connected in series, the first inductor is grounded, and the capacitor is connected to a loading point of a tuning network; A second tuning circuit, wherein the second tuning circuit comprises a second inductor, one end of the second inductor is grounded, and the other end of the second inductor is connected to a loading point of the tuning network; Wherein, the first tuning circuit and the second tuning circuit are connected in parallel.

7. A dual-frequency circularly polarized microstrip antenna design method, characterized in that: The antenna plate of the dual-frequency circularly polarized microstrip antenna is square, a first tuning network loading point is provided on a first diagonal line of the antenna plate, and a second tuning network loading point is provided on a second diagonal line, and the method comprises: When the first tuning network loading point and the second tuning network loading point are in an open circuit state, determining a first intrinsic working mode on the first diagonal and a second intrinsic working mode on the second diagonal; determining a target resonant frequency of the dual-frequency circularly polarized microstrip antenna; Determine a first reference distance between a loading point of the first tuning network and a center point, and determine a second reference distance between a loading point of the second tuning network and a center point; Determine a first tuning network that shifts a first intrinsic working mode on the first diagonal line to the target resonant frequency based on a first reference distance, and determine a second tuning network that shifts a second intrinsic working mode on the second diagonal line to the target resonant frequency based on a second reference distance; When the first tuning network meets the preset standard, the first distance between the loading point of the first tuning network and the center point is obtained according to the first reference distance; when the second tuning network meets the preset standard, the second distance between the loading point of the second tuning network and the center point is obtained according to the second reference distance.

8. The dual-frequency circularly polarized microstrip antenna design method according to claim 7, characterized in that: The method of determining a first tuning network that shifts a first intrinsic working mode on the first diagonal line to the target resonant frequency based on a first reference distance, and determining a second tuning network that shifts a second intrinsic working mode on the second diagonal line to the target resonant frequency based on a second reference distance, comprises: Determine a circular polarization axis ratio, and obtain an offset of a target resonant frequency of the dual-frequency circularly polarized microstrip antenna according to the circular polarization axis ratio; Determine a first phase of the target resonant frequency shifted in a first direction based on the offset, and determine a second phase of the target resonant frequency shifted in a second direction based on the offset; wherein a phase difference between the first phase and the second phase is 90 degrees; A first tuning network is determined based on a first reference distance to shift a first eigenworking mode on the first diagonal line to a first phase of a first target resonant frequency, and a second tuning network is determined based on a second reference distance to shift a second eigenworking mode on the second diagonal line to a second phase of a second target resonant frequency.

9. The dual-frequency circularly polarized microstrip antenna design method according to claim 7, characterized in that: Antenna board cut corners are provided at two corners of the first diagonal line or the second diagonal line; The method of determining a first tuning network that shifts a first intrinsic working mode on the first diagonal line to the target resonant frequency based on a first reference distance, and determining a second tuning network that shifts a second intrinsic working mode on the second diagonal line to the target resonant frequency based on a second reference distance, comprises: Determine the offset and offset direction of the target resonant frequency of the dual-frequency circularly polarized microstrip antenna generated by the antenna plate cutting angle; Determine a first phase of the target resonant frequency shifted in a first direction based on the offset, and determine a second phase of the target resonant frequency shifted in a second direction based on the offset; wherein a phase difference between the first phase and the second phase is 90 degrees; A first tuning network is determined based on a first reference distance to shift a first eigenworking mode on the first diagonal line to a first phase of a first target resonant frequency, and a second tuning network is determined based on a second reference distance to shift a second eigenworking mode on the second diagonal line to a second phase of a second target resonant frequency.

10. The dual-frequency circularly polarized microstrip antenna design method according to any one of claims 7 to 9, characterized in that: The target resonant frequency includes a high frequency and a low frequency; The method comprises: determining a first tuning network that shifts a first intrinsic working mode on the first diagonal line to the target resonant frequency based on a first reference distance, and determining a second tuning network that shifts a second intrinsic working mode on the second diagonal line to the target resonant frequency based on a second reference distance, comprising: Determine, based on the first reference distance, a first tuning network that shifts the first intrinsic working mode on the first diagonal line to the high frequency in the first working frequency band and shifts the first intrinsic working mode on the first diagonal line to the low frequency in the second working frequency band; A second tuning network is determined based on the second reference distance to shift the second intrinsic working mode on the second diagonal line to the high frequency in the first working frequency band and to shift the second intrinsic working mode on the second diagonal line to the low frequency in the second working frequency band.

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