Hybrid polarized antenna and communication device

Abstract

The application provides a hybrid polarized antenna and a communication device, the hybrid polarized antenna comprising a PCB board and six branches arranged on the PCB board, a feeding point being arranged at the center of the top layer of the PCB board, the feeding point being connected to the radio frequency port of the antenna through an impedance matching circuit, a reference ground plane being further arranged on the top layer of the PCB board, each branch comprising a straight line trace on the top layer of the PCB board and an oblique line trace on the bottom layer of the PCB board, and being connected to form a continuous spiral zigzag structure, and a tuning device being connected in series in the middle of the spiral zigzag of each branch; the six branches comprising two feeding branches and four ground branches, the first ends of the feeding branches being connected to the feeding point in common, and the ends being suspended; the first ends of the four ground branches being connected to the reference ground plane in common, and the ends being suspended. Through the zigzag line trace design of the six branches, the application realizes the multi-band and circular polarization characteristics of the antenna, and improves the flexibility of the antenna debugging.

Description

Technical Field

[0001] This application relates to the field of wireless communication technology, and in particular to a hybrid polarization antenna and communication device. Background Technology

[0002] In the field of wireless communication, antennas are key components for transmitting and receiving electromagnetic waves in space, and their performance directly affects communication quality. Based on their polarization, antennas can be classified into three types: linear polarization, circular polarization, and elliptical polarization. Circularly polarized antennas are widely used in satellite communication because they effectively reduce the impact of interference signals such as reflections, thereby improving communication quality. For example... Figure 1 The image shows a commonly used traditional circularly polarized microstrip antenna, consisting of a bottom base plate and an upper square antenna plate, both made of metal. The feed point is located slightly below the center of the antenna plate. Two corners along one diagonal of the antenna plate are beveled to achieve circular polarization. The choice of bevel angle depends on whether the radiated electromagnetic wave requires left-hand or right-hand circular polarization. However, while this traditional circularly polarized microstrip antenna has a relatively simple structure, it suffers from large size and difficulties in subsequent debugging. Summary of the Invention

[0003] In view of this, this application proposes a hybrid polarization antenna and communication device, which realizes multi-band and circular polarization characteristics of the antenna through a six-segment zigzag routing design, thereby improving the flexibility of antenna tuning.

[0004] In a first aspect, this application provides a hybrid polarization antenna, including a PCB board and six branches disposed on the PCB board. A feed point is disposed at the center of the top layer of the PCB board, and the feed point is connected to the radio frequency port of the antenna through an impedance matching circuit. A reference ground plane is also disposed on the top layer of the PCB board. Each branch includes a straight trace located on the top layer of the PCB board and a diagonal trace located on the bottom layer of the PCB board, and they are connected to form a continuous spiral zigzag structure through vias at both ends of the traces. A tuning device is connected in series in the middle of the spiral zigzag of each branch.

[0005] The six branches include two power supply branches and four ground branches, with two ground branches distributed on both sides of each power supply branch. The beginning ends of the two power supply branches are connected to the power supply point, and their ends are suspended. The beginning ends of the four ground branches are connected to the reference ground plane, and their ends are suspended.

[0006] After the two feed stubs are energized, an alternating electromagnetic field is generated around them, which excites their corresponding two ground stubs, forming different antenna operating states to achieve circular polarization radiation in multiple frequency bands.

[0007] From the above, the application provides a mixed polarized antenna, in which six branches composed of two feeding branches and four ground branches are arranged on a double-sided PCB, each branch adopts a unique spiral broken line structure and is connected with a tuning device in series, the first end of each feeding branch is connected with a feeding point and the tail end is suspended, the first end of each ground branch is connected with a reference ground plane and the tail end is suspended, the unique asymmetric suspended-ground structure enables each feeding branch to excite its corresponding two ground branches and form different antenna operating states, and circularly polarized radiation is realized, which helps to improve the radiation performance and circular polarization characteristics of the antenna, and the tuning device in the middle of each branch can be used to adjust the resonant frequency, so that the antenna supports multiple frequency bands.

[0008] Optionally, the impedance matching circuit comprises at least one parallel tuning branch and at least one series tuning branch.

[0009] The parallel tuning branch comprises a first inductor and a first capacitor connected in parallel between the signal path and the reference ground, respectively.

[0010] The series tuning branch comprises a second inductor and a second capacitor connected in series on the signal path.

[0011] From the above, the combination of parallel and series tuning branches (L-type, Π-type, etc.) can more finely adjust the input impedance of the antenna, so that it better matches the standard impedance (such as 50Ω) within the working frequency band, thereby minimizing signal reflection loss and improving energy transmission efficiency.

[0012] Optionally, the tuning device is an inductor, a capacitor, or a combination circuit of an inductor and a capacitor.

[0013] From the above, the tuning device can be an inductor, a capacitor, or a combination thereof, and by replacing or adjusting these devices, the resonant frequency and coupling strength of each branch can be independently and accurately fine-tuned, providing a physical basis for subsequent implementation of multi-frequency, circular polarization, and other functions.

[0014] Optionally, the two feeding branches are a first feeding branch and a second feeding branch, and the four ground branches are a first ground branch, a second ground branch, a third ground branch, and a fourth ground branch.

[0015] The first ground branch and the third ground branch are a pair of ground branches symmetrically distributed on both sides of the first feeding branch and jointly form a first antenna operating state.

[0016] The second ground branch and the fourth ground branch are a pair of ground branches symmetrically distributed on both sides of the second feeding branch and jointly form a second antenna operating state.

[0017] From the above, the four ground branches are clearly divided into two pairs, and each pair corresponds to a pair of feeding branches arranged symmetrically. This symmetrical layout in space is conducive to exciting electric field components with equal amplitude and a certain angle in space, thereby providing an ideal structure for generating high-quality circularly polarized waves. Moreover, the symmetrical structure can also help to achieve symmetry in the antenna radiation pattern and avoid directional distortion. At the same time, the grouping mode provides a clear physical basis for independent regulation of dual-band or dual-mode operation.

[0018] Optionally, when the lengths of a pair of ground branches are the same and the parameters of the tuning devices connected in series are configured to have a preset difference, the pair of ground branches and the corresponding feeding branches together generate two resonant modes with a preset phase difference at a target frequency band, thereby enabling the antenna to exhibit circularly polarized radiation characteristics at the target frequency band.

[0019] From the above, by setting the parameters of a pair of symmetric ground branches to a "preset difference", the two resonant modes generated by the coupling of the pair of branches and the feeding branches can be artificially split slightly (one slightly higher and one slightly lower). At the center frequency, these two modes naturally form the required phase difference at a certain angle, thereby reliably converting the antenna from linear polarization to circular polarization operation.

[0020] Optionally, the positive and negative relationship of the preset difference is used to control the handedness of the circularly polarized radiation characteristics. Specifically:

[0021] When the tuning device parameter value of the first ground branch is greater than that of the third ground branch paired with it, the antenna exhibits a first circular polarization characteristic in the corresponding target frequency band.

[0022] When the tuning device parameter value of the first ground branch is less than that of the third ground branch, the antenna exhibits a second circular polarization characteristic in the corresponding target frequency band, which is opposite to the first circular polarization characteristic.

[0023] From the above, by setting the positive and negative relationship of the preset difference to directly determine the circular polarization direction (left-handed LHCP or right-handed RHCP), it means that only by simply exchanging the parameter sizes of the tuning devices on a pair of ground branches, the circular polarization direction of the antenna can be reversed. This enables the same antenna platform to adapt to different polarization requirements of communication systems, greatly improving the versatility and application range of the antenna.

[0024] Optionally, the four ground branches are configured to have at least two different resonant frequencies, enabling the antenna to achieve a mixed polarization operation mode at at least two different frequency bands. At least one frequency band is a circular polarization operation mode, and the remaining frequency bands are linear polarization operation modes.

[0025] From the above, by configuring four ground branches to different resonant frequencies, the antenna can work in multiple frequency bands, and each frequency band can independently select the polarization mode (for example, frequency band A is right circular polarization, and frequency band B is linear polarization). This enables a single antenna to simultaneously meet the needs of multiple different communication modules (such as GPS circular polarization reception and Wi-Fi linear polarization transmission) inside a complex wireless device, achieving extreme integration and design flexibility.

[0026] Optionally, the tuning device is a switch-type tuning circuit, which is composed of a third inductor and a switch device in series, and then connected in parallel with a fourth inductor, the switch device is controlled by a controller, and the equivalent inductance value of the ground branch is adjusted by switching the on-off state of the switch device, so that the antenna switches between multiple frequency bands.

[0027] From the above, by using a controlled switch-type tuning circuit to replace the fixed tuning device, the equivalent inductance of each branch can be switched in real time through an electrical signal, thereby adjusting the resonant frequency of each branch, so that the antenna is upgraded from fixed multi-frequency to reconfigurable multi-frequency. By controlling all switches, the antenna can select to work in up to eight preset frequency bands, or combine these frequency points to form an extremely wide bandwidth, dynamically adapting to different communication standards or frequency band requirements.

[0028] Optionally, the adjustment of the equivalent inductance value of the ground branch by switching the on-off state of the switch device specifically includes:

[0029] When the switch device is turned on, the third inductor and the fourth inductor are connected in parallel to form a first equivalent inductance value;

[0030] When the switch device is turned off, only the fourth inductor is connected to the circuit to form a second equivalent inductance value;

[0031] By switching the state of the switch device, the switching of the ground branch between two resonant frequencies is realized.

[0032] From the above, by switching the state of the switch device, the switching of the ground branch between two resonant frequencies is realized.

[0033] In a second aspect, the application provides a communication device comprising the above-mentioned hybrid polarization antenna.

[0034] These and other aspects of the application will become more fully understood from the following description of (several) embodiments. BRIEF DESCRIPTION OF DRAWINGS

[0035] Figure 1A top view of a structure of a commonly used traditional circularly polarized microstrip antenna;

[0036] Figure 2 A top view of a structure of a hybrid polarized antenna provided in an embodiment of the present application;

[0037] Figure 3a A schematic diagram of straight-line traces on a top layer of a PCB in an embodiment of the present application;

[0038] Figure 3b A schematic diagram of diagonal traces on a bottom layer of a PCB in an embodiment of the present application;

[0039] Figure 4 A circuit diagram of a first hybrid polarized antenna provided in an embodiment of the present application;

[0040] Figure 5 A circuit diagram of a second hybrid polarized antenna provided in an embodiment of the present application;

[0041] Figures 6a-6c A schematic diagram of results of a simulation experiment provided in an embodiment of the present application;

[0042] Figure 7 A schematic diagram of results of another simulation experiment provided in an embodiment of the present application.

[0043] It should be understood that in the above structural schematic diagrams, the sizes and shapes of the blocks are only for reference and should not constitute an exclusive interpretation of the embodiments of the present application. The relative positions and inclusion relationships between the blocks presented by the structural schematic diagrams are only used to schematically represent the structural correlations between the blocks, and are not intended to limit the physical connection manner of the embodiments of the present application. DETAILED DESCRIPTION

[0044] The technical solutions provided by the present application will be further described below in conjunction with the drawings and embodiments. It should be understood that the system structures and service scenarios provided in the embodiments of the present application are mainly used to illustrate possible implementation manners of the technical solutions of the present application, and should not be interpreted as the only limitation of the technical solutions of the present application. Those skilled in the art can know that the technical solutions provided by the present application are also applicable to similar technical problems as the system structure evolves and new service scenarios appear.

[0045] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the present application belongs. If there is an inconsistency, the meaning indicated in the specification or derived from the content described in the specification shall prevail. In addition, the terms used herein are only for the purpose of describing the embodiments of the present application and are not intended to limit the present application.

[0046] The technical solutions provided by the present application will be further described below in conjunction with the drawings and embodiments. It should be understood that the system structures and service scenarios provided in the embodiments of the present application are mainly used to illustrate possible implementation manners of the technical solutions of the present application, and should not be interpreted as the only limitation of the technical solutions of the present application. Those skilled in the art can know that the technical solutions provided by the present application are also applicable to similar technical problems as the system structure evolves and new service scenarios appear.

[0047] The embodiment of the present application provides a hybrid polarization antenna, and specifically realizes an innovative antenna physical structure and a tuning mode. The antenna utilizes a double-sided printed circuit board (PCB) technology, designs six spiral meander branches in a central symmetric distribution, and realizes flexible configuration and reconstruction of an antenna operating frequency, a bandwidth, a polarization mode (linear polarization / circular polarization) and a circular polarization rotation direction by connecting tunable passive devices or switchable circuit networks in series in each branch. The scheme effectively solves the problems of a large size, difficult debugging and single function of a traditional circular polarization antenna.

[0048] As shown in Figures 2-3b , the hybrid polarization antenna provided by the embodiment of the present application is constructed based on a dielectric substrate (namely a PCB board). A feeding point and a reference ground plane are arranged on the top layer of the PCB board. The feeding point is located on the top layer of the PCB board, and the reference ground plane is located near the feeding point. Six groups of radial linear traces (as shown in Figure 3a ) are etched on the top layer of the PCB board, and six groups of corresponding oblique traces (as shown in Figure 3b ) are etched on the bottom layer of the PCB board. Each group of top layer traces and corresponding bottom layer traces are electrically connected through metal vias at both ends, and together form a continuous spiral meander structure with a spatial spiral sense. Each spiral meander structure is a branch, and a tuning device is connected in series in the middle of the spiral meander structure of each branch.

[0049] Of the six branches, two located directly above (for example, in the direction shown in Figure 2 ) are defined as a feeding branch 1 and a feeding branch 2, and the remaining four branches are uniformly distributed around the two feeding branches and are defined as a ground branch 1, a ground branch 2, a ground branch 3 and a ground branch 4. The ground branch 1 and the ground branch 3 are symmetrically distributed on both sides of the feeding branch 1, and the trace width and the interval are the same. The three-branch structure constitutes a first operating state of the antenna. The ground branch 2 and the ground branch 4 are symmetrically distributed on both sides of the feeding branch 2, and the trace width and the interval are the same. The three-branch structure constitutes a second operating state of the antenna. Through the symmetric layout, a hardware physical basis for realizing good circular polarization characteristics is provided.

[0050] In some embodiments, in order to realize a multi-frequency design, the trace width and the interval of the antenna operating state of the two groups of three-branch structures can also be different, that is, the total trace length of one group of three-branch structures is slightly shorter, which is suitable for an antenna operating state of a high frequency, and the total trace length of the other group of three-branch structures is slightly longer, which is suitable for an antenna operating state of a low frequency, so as to ensure good antenna performance.

[0051] The first ends of the two feeding branches (i.e. the starting points of the spiral meander structure, close to the center of the PCB) are connected to a feeding point at the center of the top layer of the PCB, which is connected to an external RF port through an impedance matching circuit, for matching the input impedance of the antenna to the standard impedance (usually 50Ω) of the system. The last ends of the two feeding branches (i.e. the ending points of the spiral meander structure) are suspended. The first ends of the four ground branches are connected to the reference ground plane, and the last ends of the four ground branches are suspended.

[0052] During operation, the RF signal directly excites the two feeding branches through the impedance matching circuit and the feeding point, so that the two feeding branches generate alternating current and electromagnetic field respectively. The electromagnetic field excites the current on the two adjacent ground branches through near-field coupling mechanism, so as to form effective radiation. The feeding branch 1, the ground branch 1 and the ground branch 3 symmetrically distributed on both sides of the feeding branch 1 form an antenna operating mode (referred to as mode A), and the feeding branch 2, the ground branch 2 and the ground branch 4 symmetrically distributed on both sides of the feeding branch 2 form another antenna operating mode (referred to as mode B). Since the physical length and the line spacing of the two groups of three-branch structures can be independently designed, the mode A and the mode B can resonate at different frequencies, so as to realize dual-frequency operation.

[0053] In order to realize good signal transmission, the impedance matching circuit is preferably designed in the embodiments of the present application. As shown in Figure 4 the matching circuit can be specifically implemented as a two-stage tuning network.

[0054] Firstly, a parallel tuning branch is arranged close to the feeding point, which is composed of an inductor L1 connected in parallel to the ground and a capacitor C1 connected in parallel to the ground. The parallel structure is mainly used for coarse adjustment of the input impedance of the antenna. Secondly, a series tuning branch is connected in series on the signal path after the parallel branch, which is composed of a series inductor L2 and a series capacitor C2. The series structure is mainly used for fine adjustment of the input resistance part and further compensation of the impedance. By reasonably selecting the values of L1, C1, L2 and C2, the impedance from the Port1 port (i.e. the RF port) to the antenna can be close to the standard impedance 50Ω in the target operating frequency band, so as to maximize the power transmission efficiency and improve the antenna VSWR and return loss performance.

[0055] In some embodiments, the series tuning branch of the impedance matching circuit is further provided with an inductor L3 connected in parallel to the ground at the rear end, which is used to work with the two-stage matching network at the front end to "finally compensate" the impedance after the transformation of the previous two stages. By carefully selecting the value of L3, an additional parallel inductance and capacitance can be provided at a specific frequency, which can accurately cancel the small capacitive reactance that may be left at the antenna port at the frequency, or be used to fine-tune the real part value of the input resistance, so that the return loss is deeper and wider in the target frequency band.

[0056] In some embodiments, the tuning devices in each branch can be selected as inductors, capacitors, or a combination of inductors and capacitors. For example... Figure 4 As shown, the tuning device can be an inductor, where L02 is the tuning device for feed stub 1, L03 is the tuning device for feed stub 2, and L04, L05, L06, and L07 correspond to the tuning devices for feed stubs 1, 2, 3, and 4, respectively. Port1 is connected to the antenna feed point through an impedance matching circuit. In practical use, the length and spacing of the broken lines are designed first based on the target antenna operating frequency and the required antenna size. The broken line spacing mainly affects the overall length of the antenna broken line trace. The lower the target antenna operating frequency, the longer the broken line trace needs to be. Therefore, the smaller the spacing, the more bends the trace can make, and the longer the trace. The closer the resonant frequency of the antenna trace is to the target frequency, the more it can be adjusted to the target operating frequency by supplementing it with a tuning device connected in series in the middle. However, the smaller the spacing, the longer the trace, and the denser the trace, the worse the antenna radiation effect. The supplement value of the tuning device can be smaller, and the device loss performance is lower. Conversely, the larger the spacing of the trace, the shorter the trace, and the better the radiation performance of the trace. However, a larger tuning device is required, and the device loss is greater. In actual use, the approximate antenna spacing is determined by comparing the best antenna radiation effect after different spacings and device supplementation. The length of the trace is determined by the size of the antenna board. Try to fill the board as much as possible to make the trace area larger, and the antenna radiation effect will be better.

[0057] The following is based on Figure 2 Antenna structure and Figure 4 The circuit structure is used to illustrate how to achieve dual-mode circular polarization in a specific target frequency band:

[0058] According to the above design, the trace design of the target antenna operating frequency f1 and f2 is completed. According to f1 being a high frequency greater than f2 being a low frequency, an antenna operating mode is formed by using the feed branch 1 and the ground branch 1 and the ground branch 3 to complete the f1 frequency band design. This set of traces is relatively short, and the trace spacing is larger. Another antenna operating mode is formed by using the feed branch 2 and the ground branch 2 and the ground branch 4 to complete the f2 frequency band design. This set of traces is relatively long, and the trace spacing is smaller. Then the tuning device in the middle of the branch is adjusted. First, only the feed branch 1 and the ground branch 1 are connected, and the other feed branch 2 and the ground branch 2, 3, 4 are all disconnected. According to the target antenna operating frequency f1, the value of the tuning device L02 in the middle of the feed branch 1 and the value of the tuning device L04 of the ground branch 1 are determined, so that the values of the devices (generally inductance) are close to the inductance value LF1, and the antenna operating frequency is at the target operating frequency f1. Then, according to the antenna target circular polarization characteristic rotation requirement, whether the antenna needs left-handed circular polarization or right-handed circular polarization characteristic, if it is a right-handed circular polarization antenna design, the value of the tuning device L04 of the ground branch 1 is changed to an inductance value slightly greater than LF1 , the value of the tuning device L06 of the ground branch 3 is determined to be a device inductance value slightly smaller than the inductance LF1 , after this design, the first antenna operating state formed by the feed branch 1 and the ground branch 1 and the ground branch 3 forms two antenna resonance modes with similar operating frequencies f1. The antenna resonance mode formed by the feed branch 1 and the ground branch 1 has a working frequency f1-k (k value greater than zero and very small) slightly lower than the target working frequency f1, and the phase lags at f1 frequency. The antenna resonance mode formed by the feed branch 1 and the ground branch 3 has a working frequency f1+k (k value greater than zero and very small) slightly higher than the target working frequency f1, and the phase leads at f1 frequency. And the two resonance modes are rotated by 120 degrees. Thus, the antenna operating frequency formed by the feed branch 1 and the ground branch 1 and the ground branch 3 in the f1 frequency band realizes the right-handed circular polarization antenna design.

[0059] Similarly, disconnect the feed branch 1 and the ground branch 1 and the ground branch 3, reconnect the feed branch 2 and the ground branch 2, and then adjust the values of the tuning device L03 of the feed branch 2 and the tuning device L05 of the ground branch 2 to be close to the inductance value LF2. Adjust the antenna resonance mode operating frequency f2 formed by the feed branch 2 and the ground branch 2. Then, according to the antenna target circular polarization characteristic rotation requirement, whether the antenna needs left-handed circular polarization or right-handed circular polarization characteristic, if it is a right-handed circular polarization antenna design, the value of the tuning device L05 of the ground branch 2 is changed to an inductance value slightly greater than LF2 , the value of the tuning device L07 of the ground branch 4 is determined to be a device inductance value slightly smaller than the inductance LF2 , through this design, the second antenna working state of the feed branch 2 and the ground branch 2 and the ground branch 4 forms two antenna resonance modes with similar working frequencies f2, the antenna resonance mode formed by the feed branch 2 and the ground branch 2 has a working frequency f2-k (k is greater than zero and very small) slightly lower than the target working frequency f2, and the phase lags at the f2 frequency, the antenna resonance mode formed by the feed branch 2 and the ground branch 4 has a working frequency f2+k (k is greater than zero and very small) slightly higher than the target working frequency f2, and the phase leads at the f2 frequency, and the two resonance modes are rotated by 120 degrees, so that the antenna working state of the feed branch 2 and the ground branch 2 and the ground branch 4 in the f2 frequency band is right-hand circularly polarized antenna design.

[0060] Conversely, if the target antenna polarization mode in the f1 frequency band is left-hand circularly polarized antenna characteristics, only the tuning devices of the ground branch 1 and the ground branch 3 are reversed, the antenna polarization mode of the six-branch circularly polarized antenna at the working frequency f1 is left-hand circularly polarized antenna, and similarly, if the target antenna polarization mode in the f2 frequency band is left-hand circularly polarized antenna characteristics, only the tuning devices of the ground branch 2 and the ground branch 4 are reversed, the antenna polarization mode of the six-branch circularly polarized antenna at the working frequency f2 is left-hand circularly polarized antenna.

[0061] The six-branch antenna in the embodiment works in the f1 and f2 dual-frequency bands, and the circular polarization characteristics of the six-branch antenna can be the same or different, which can be adjusted arbitrarily according to the above mode, and the two frequency bands are not affected by each other. After the six-branch dual-frequency dual-circularly polarized antenna is designed according to the above dual-frequency dual-circularly polarized antenna design, the impedance matching circuit connected through the feed point adjusts the antenna characteristic impedance to adapt to the 50Ω input impedance effect, and the six-branch dual-frequency dual-circularly polarized antenna design is completed.

[0062] In some embodiments, the ground branch 1 and the ground branch 3 are different in length, or the intermediate connection tuning device values are not similar, and only according to Figure 4 , a tuning device with a respective inductance value is welded, which can directly form two antenna frequency bands with the feed branch 1. Similarly, if the ground branch 2 and the ground branch 4 are different in length, or the intermediate connection tuning device values are not similar, only according to Figure 4As shown, all the ground branches are welded with a tuning device of respective inductance value, and can directly form two other antenna frequency bands with the feeding branch 2, and the overall design is a six-branch four-frequency-band design, but the polarization mode of the antenna is linear polarization. Therefore, by configuring the four ground branches to have different resonant frequencies, the antenna can work in multiple frequency bands, and the polarization mode of each frequency band can be independently selected, and a mixed polarization mode of circular polarization and linear polarization can be supported. For example, the feeding branch 1 and the ground branches 1 and 3 can be configured to work in a circular polarization mode at the f1 frequency band, and the feeding branch 2 and the ground branches 2 and 4 are set to different lengths or device values, so as to work in a linear polarization mode at the f2 and f3 frequency bands. This enables a single antenna to simultaneously meet the requirements of multiple different communication modules inside a complex wireless device, and realizes extreme integration and design flexibility.

[0063] To further improve the flexibility and intelligent level of the antenna, the application proposes a scheme of replacing the fixed tuning device with a switch-type tuning circuit, as shown in the following figure. Figure 5 As shown, the fixed inductor L04 of the ground branch 1 is replaced with a switch-type tuning circuit, which includes an inductor L62 connected in series with the branch wire, and a branch connected in parallel with the inductor L62, the branch being formed by an inductor L61 and a single-pole single-throw (SPST) switch S3 connected in series, and the switch S3 is controlled by a GPIO pin of a controller (such as a CPU) U1. Based on the structure of the switch-type tuning circuit, when the controller U1 outputs a control signal to make the switch S3 open, the inductor L61 branch is not connected, and only the inductor L62 is connected in series with the ground branch 1. Assuming that the equivalent inductance at this time is Leq_off=L62, it corresponds to a resonant frequency F_off; when the controller U1 outputs a control signal to make the switch S3 conductive, the inductor L61 and the inductor L62 form a parallel relationship. The total equivalent value of the parallel inductance is Leq_on=(L61*L62) / (L61+L62), which is smaller than L62. Therefore, the equivalent inductance of the ground branch 1 becomes smaller, corresponding to another higher resonant frequency F_on.

[0064] Through the design of the switch-type tuning circuit, a single ground branch can be electrically switched between two preset frequencies. By applying such a switch circuit to all six branches and independently controlling all switches in binary, the antenna can theoretically be switched in up to 2^6=64 different frequency combination states. By carefully designing the values of the two inductors in the switch-type tuning circuit, it can stably work in four, eight or even more frequency bands that have practical value.

[0065] In some embodiments, by controlling the on-off of each switch, the individual frequency bands can be selected to be circularly polarized or linearly polarized. For example, ground branch 1 and ground branch 3 form a circularly polarized antenna operating at f1 frequency band with feed branch 1. Then, ground branch 2 and ground branch 4 can have different lengths or tuning devices, and form a linearly polarized antenna operating at f2 and f3 frequency bands with feed branch 2. In this way, the six-branch antenna can support three frequency bands, i.e., f1 frequency band with circularly polarized antenna characteristics, and f2 and f3 frequency bands with linearly polarized antenna characteristics. Similarly, ground branch 2 and ground branch 4 can form a circularly polarized antenna operating at f1 frequency band with feed branch 2, and ground branch 1 and ground branch 3 can form a linearly polarized antenna operating at f2 and f3 frequency bands with feed branch 1. In order to ensure good performance of each frequency band, appropriate antenna lengths and tuning device values need to be selected for balancing. The branches of the antenna can be reversed. Based on this, the six-branch antenna of the present embodiment can be extended to an antenna design supporting up to 8 frequency bands.

[0066] To verify the feasibility and effect of the present application, a six-branch antenna model as shown in FIG. 1 can be established using three-dimensional electromagnetic simulation software, and the PCB diameter is set to 100 mm. Two representative simulation experiments are performed as follows: Figure 2

[0067] For example, to achieve 240 MHz and 320 MHz dual frequency bands, both of which are left-handed circularly polarized, a structure as shown in FIG. 2 is adopted, and the PCB diameter is 100 mm. The tuning device is a patch inductor, and the values are as follows: Figure 2

[0068] Mode A (240 MHz): L02=62nH, L04=68nH, L06=62nH (according to the left-handed rule, L04>L06);

[0069] Mode B (320 MHz): L03=10nH, L05=15nH, L07=10nH (according to the left-handed rule, L05>L07);

[0070] Impedance matching circuit: L1=36nH, C1=12pF (parallel); L2=75nH, C2=10pF (series).

[0071] After simulation, the antenna evaluation results are as shown in FIG. 3. The reflection coefficient S11 of the antenna at 240 MHz and 320 MHz is less than -10 dB, and the matching is good. The gain curve shows that the left-handed circularly polarized component is basically coincident with the maximum gain pattern. The axial ratio curve shows that the axial ratio is less than 3 dB. Figures 6a-6c Figure 6a Figure 6b Figure 6c ​​​​​At 240MHz, it is 1.4, and at 320MHz, it is 2.2, far less than the circular polarization threshold of 3dB, which proves excellent left-handed circular polarization performance.

[0072] In another simulation experiment, in order to demonstrate the ability to expand multiple frequency bands by adjusting the ground branch parameters, on the basis of the above simulation experiment, other devices are kept unchanged, only the inductance L06 of the ground branch 3 is changed to 24nH, the inductance L07 of the ground branch 4 is changed to 51nH, and the matching circuit is adjusted accordingly: L1=33nH, C1=10pF; L2=62nH, C2=9pF.

[0073] The simulation results are shown in Figure 7 As shown in the figure, the antenna reflection coefficient S11 curve has four obvious resonance valleys, which are located at 240MHz, 286MHz, 308MHz and 323MHz. This shows that by simply adjusting the tuning inductance value of the ground branch, the working mode of the antenna is successfully expanded to four closely adjacent frequency bands, effectively widening the working bandwidth of the antenna, which is suitable for scenarios that require wideband coverage.

[0074] In summary, in the mixed polarization antenna provided by the embodiments of the present application, through the innovative six-branch spiral folded line structure, the flexibly configurable tuning device network and the clear circular polarization generation and control method, a highly compact, flexible design and superior performance multi-frequency circular polarization antenna solution is provided. The antenna not only realizes miniaturization, dual / multi-frequency operation, but also has the advantages of independently configurable circular polarization rotation direction, reconfigurable working mode (fixed multi-frequency, switchable multi-frequency, mixed polarization), etc., and can be widely applied in satellite communication, Beidou / GPS navigation, radio frequency identification and modern multi-mode wireless communication systems.

[0075] It should be noted that the embodiments described in the present application are only part of the embodiments of the present application, not all embodiments. The components of the embodiments of the present application described and shown in the drawings can be arranged and designed in various different configurations. Therefore, the above detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the claimed application, but only represents selected embodiments of the present application. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0076] The words "first, second, third, etc." or modules A, B, C, etc. in the specification and claims, or similar terms, are only used to distinguish similar objects, and do not represent a specific order of the objects. It can be understood that the specific order or sequence can be interchanged as permitted, so that the embodiments of the present application described herein can be implemented in an order other than that illustrated or described herein.

[0077] In the above description, the labels indicating the steps do not necessarily mean that the steps will be executed. They may include intermediate steps or be replaced by other steps. Where permissible, the order of the steps may be interchanged or executed simultaneously.

[0078] The term "comprising" as used in the specification and claims should not be construed as limiting itself to what follows; it does not exclude other elements or steps. Therefore, it should be interpreted as specifying the presence of the mentioned feature, integral, step, or component, but does not exclude the presence or addition of one or more other features, integrals, steps, or components, or groups thereof. Thus, the statement "device comprising means A and B" should not be limited to a device consisting solely of components A and B.

[0079] The terms "an embodiment" or "an embodiment" as used in this specification mean that a particular feature, structure, or characteristic described in conjunction with that embodiment is included in at least one embodiment of this application. Therefore, the terms "in one embodiment" or "in an embodiment" appearing throughout this specification do not necessarily refer to the same embodiment, but may refer to the same embodiment. Furthermore, in the various embodiments of this application, unless otherwise specified or in case of logical conflict, the terminology and / or descriptions between different embodiments are consistent and can be mutually referenced. Technical features in different embodiments can be combined to form new embodiments based on their inherent logical relationships.

[0080] Note that the above are merely preferred embodiments and the technical principles employed in this application. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and various obvious changes, readjustments, and substitutions can be made without departing from the scope of protection of the present invention. Therefore, although the present application has been described in detail through the above embodiments, the present invention is not limited to the above embodiments, and may include many other equivalent embodiments without departing from the concept of the present invention, all of which fall within the scope of protection of the present invention.

Claims

1. A hybrid polarization antenna, characterized in that, The device includes a PCB board and six branches disposed on the PCB board. A feed point is disposed at the center of the top layer of the PCB board. The feed point is connected to the RF port of the antenna through an impedance matching circuit. A reference ground plane is also disposed on the top layer of the PCB board. Each branch includes a straight trace on the top layer of the PCB board and a diagonal trace on the bottom layer of the PCB board. They are connected to form a continuous spiral broken line structure through vias at both ends of the traces. A tuning device is connected in series in the middle of the spiral broken line of each branch. The six branches include two power supply branches and four ground branches, with two ground branches distributed on both sides of each power supply branch. The beginning ends of the two power supply branches are connected to the power supply point, and their ends are suspended. The beginning ends of the four ground branches are connected to the reference ground plane, and their ends are suspended. After the two feed stubs are energized, an alternating electromagnetic field is generated around them, which excites their corresponding two ground stubs, forming different antenna operating states to achieve circular polarization radiation in multiple frequency bands.

2. The hybrid polarization antenna according to claim 1, characterized in that, The impedance matching circuit includes at least one parallel tuning branch and at least one series tuning branch. The parallel tuning branch includes a first inductor and a first capacitor connected in parallel between the signal path and the reference ground, respectively. The series tuning branch includes a second inductor and a second capacitor connected in series in the signal path.

3. The hybrid polarization antenna according to claim 1, characterized in that, The tuning device is an inductor, a capacitor, or a combination of an inductor and a capacitor.

4. The hybrid polarization antenna according to claim 1, characterized in that, The two feed branches are the first feed branch and the second feed branch, respectively, and the four ground branches are the first ground branch, the second ground branch, the third ground branch, and the fourth ground branch, respectively. The first ground stub and the third ground stub are a pair of ground stubs, symmetrically distributed on both sides of the first feed stub, and together constitute the first antenna working state; The second and fourth ground branches are a pair of ground branches, symmetrically distributed on both sides of the second feed branch, and together constitute the second antenna working state.

5. The hybrid polarization antenna according to claim 4, characterized in that, When a pair of ground stubs have the same trace length and the parameters of the tuned devices connected in series are configured to have a preset difference, the pair of ground stubs and the corresponding feed stubs together generate two resonant modes with a preset angle and a preset phase difference in the target frequency band, thereby making the antenna exhibit circularly polarized radiation characteristics in the target frequency band.

6. The hybrid polarization antenna according to claim 5, characterized in that, The positive and negative relationship of the preset difference is used to control the rotation direction of the circular polarization radiation characteristics; specifically: When the tuning device parameter value of the first ground stub is greater than the tuning device parameter value of the third ground stub paired with it, the antenna exhibits circular polarization characteristics in the first direction in the corresponding target frequency band. When the tuning device parameter value of the first ground stub is less than the tuning device parameter value of the third ground stub, the antenna exhibits circular polarization characteristics with a second rotation direction opposite to the first rotation direction in the corresponding target frequency band.

7. The hybrid polarization antenna according to claim 1, characterized in that, The four ground stubs are configured to have at least two different resonant frequencies, enabling the antenna to operate in a hybrid polarization mode in at least two different frequency bands; wherein at least one frequency band is a circular polarization mode and the remaining frequency bands are linear polarization modes.

8. The hybrid polarization antenna according to claim 1, characterized in that, The tuning device is a switching tuning circuit, which consists of a third inductor and a switching device connected in series, and then connected in parallel with a fourth inductor. The switching device is controlled by a controller, and the equivalent inductance value of the ground stub is adjusted by switching the on and off state of the switching device, so that the antenna switches between multiple frequency bands.

9. The hybrid polarization antenna according to claim 8, characterized in that, The method of adjusting the equivalent inductance of the ground stub by switching the on / off state of the switching device specifically includes: When the switching device is turned on, the third inductor and the fourth inductor are connected in parallel to form the first equivalent inductance value; When the switching device is disconnected, only the fourth inductor is connected to the circuit to form the second equivalent inductance value; By switching the state of the switching device, the ground stub can be switched between two resonant frequencies.

10. A communication device, characterized in that, Includes a hybrid polarization antenna as described in any one of claims 1 to 9.

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