A five-antenna communication device

Abstract

This application provides a five-channel antenna and communication device. The five-channel antenna includes a PCB board and five 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 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, which are connected to form a continuous spiral zigzag structure. A tuning device is connected in series in the middle of the spiral zigzag of each branch. The five branches include one feed branch and four ground branches. The first end of the feed branch is connected to the feed point, and the last end is suspended. The first ends of the four ground branches are connected to the reference ground plane, and the last ends are suspended. This application realizes the multi-band and circular polarization characteristics of the antenna through the zigzag routing design of the five branches, improving the flexibility of antenna tuning.

Description

Technical Field

[0001] This application relates to the field of wireless communication technology, and in particular to a five-channel 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 five-channel antenna and communication device, which realizes the multi-band and circular polarization characteristics of the antenna through a five-segment broken line routing design, thereby improving the flexibility of antenna debugging.

[0004] In a first aspect, this application provides a five-channel antenna, including a PCB board and five 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 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.

[0005] The five branches include a feed branch and four ground branches distributed around the feed branch. The head end of the feed branch is connected to the feed point, and the tail end is suspended. The head ends of the four ground branches are connected to the reference ground plane, and the tail ends are suspended.

[0006] After the feed branch is energized, an alternating electromagnetic field is generated around it, which excites the four ground branches respectively to achieve circular polarization radiation in multiple frequency bands.

[0007] As described above, the five-channel antenna provided in this application consists of five branches, one feed branch and four ground branches, arranged on a double-sided PCB board. Each branch adopts a unique spiral zigzag structure and is connected in series with a tuning device. The feed branch has its first end connected to the feed point and its last end suspended. The ground branches have their first ends connected to the reference ground plane and their last ends suspended. This unique asymmetrical suspended-ground structure allows the feed branch to excite the ground branch after being powered on, resulting in a mode with equal amplitude and a preset phase angle, thus achieving circular polarization radiation. This helps to improve the antenna's radiation performance and circular polarization characteristics. Furthermore, the tuning device in the middle of each branch can be individually adjusted to its resonant frequency, enabling the antenna to support multiple frequency bands.

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

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

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

[0011] As described above, by combining parallel and series tuning branches (L-type, Π-type, etc. networks), the input impedance of the antenna can be adjusted more precisely, so that it can better match the standard impedance (such as 50Ω) within the operating 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 of an inductor and a capacitor.

[0013] As mentioned above, the tuning device can be an inductor, a capacitor, or a combination thereof. By replacing or adjusting these devices, the resonant frequency and coupling strength of each branch can be finely tuned independently and precisely, providing a physical basis for subsequent implementation of functions such as multi-frequency and circular polarization.

[0014] Optionally, the four ground nodes are the first ground node, the second ground node, the third ground node, and the fourth ground node;

[0015] The first and third ground nodes are a pair of ground nodes, symmetrically distributed on the upper and lower sides of the power supply node;

[0016] The second and fourth ground branches are a pair of ground branches, symmetrically distributed on the left and right sides of the power supply branch.

[0017] As shown above, the four ground branches are clearly divided into two pairs, one above and one below, and one to the left and right, and arranged symmetrically. This spatial symmetry is conducive to exciting electric field components with equal amplitude, thus providing an ideal structure for generating high-quality circularly polarized waveforms. Furthermore, the symmetrical structure can also help maintain the symmetry of the antenna radiation pattern and avoid directional distortion.

[0018] Optionally, when the trace lengths of a pair of ground stubs are the same and the parameters of the tuned devices connected in series are configured to have a preset difference, the feed stub and the pair of ground stubs together generate two resonant modes with a preset included angle and a preset phase difference in the target frequency band, thereby causing the antenna to exhibit circularly polarized radiation characteristics in the target frequency band.

[0019] As described above, by setting the tuning device parameters of a pair of symmetrical stubs to a "preset difference," a slight split (one slightly higher, one slightly lower) can be artificially created between the two resonant mode frequencies generated by the coupling of this pair of stubs with the feed stub. At the center frequency, these two modes naturally form the desired phase difference, thereby reliably switching the antenna from linear polarization to circular polarization.

[0020] Optionally, the positive and negative relationship of the preset difference is used to control the rotation direction of the circular polarization radiation characteristics; specifically:

[0021] 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.

[0022] 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.

[0023] As shown above, the circular polarization direction (left-handed LHCP or right-handed RHCP) is directly determined by setting the positive and negative relationship of the preset difference. This means that the circular polarization direction of the antenna can be reversed simply by swapping the parameter values ​​of a pair of tuning devices on the ground stub. This allows the same antenna platform to be adapted to communication systems with different polarization requirements, greatly improving the versatility and application range of the antenna.

[0024] Optionally, 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.

[0025] As described above, by configuring the four ground stubs with different resonant frequencies, the antenna can operate in multiple frequency bands, and each band can independently select its polarization (e.g., band A is right-hand circular polarization, and band B is linear polarization). This allows a single antenna to simultaneously meet the needs of multiple different communication modules within a complex wireless device (such as GPS circular polarization reception and Wi-Fi linear polarization transceiver), achieving ultimate integration and design flexibility.

[0026] Optionally, the tuning device is a switching tuning circuit, which is composed 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.

[0027] As described above, by replacing fixed tuning devices with controlled switching tuning circuits, the equivalent inductance of each stub can be switched in real time via electrical signals, thereby adjusting the resonant frequency of each stub. This upgrades the antenna from fixed multi-frequency to reconfigurable multi-frequency. By controlling all switches, the antenna can be selected to operate in up to eight preset frequency bands, or these frequency points can be combined to form an extremely wide bandwidth, dynamically adapting to different communication standards or frequency band requirements.

[0028] Optionally, adjusting the equivalent inductance of the ground stub by switching the on / off state of the switching device specifically includes:

[0029] 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;

[0030] When the switching device is disconnected, only the fourth inductor is connected to the circuit to form the second equivalent inductance value;

[0031] By switching the state of the switching device, the ground stub can be switched between two resonant frequencies.

[0032] As described above, by controlling the parallel inductor combination or the connection of a single inductor through a switch, two discrete and significantly different equivalent inductance values ​​can be obtained. This circuit structure has advantages such as simplicity, reliability, fast switching speed, and clear control logic, ensuring flexible adjustment of the equivalent inductance of each branch.

[0033] Secondly, this application provides a communication device, including the aforementioned five-channel antenna.

[0034] These and other aspects of this application will become more apparent in the description of the following embodiments(s). Attached Figure Description

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

[0036] Figure 2 A top view of a five-antenna structure provided in an embodiment of this application;

[0037] Figure 3a This is a schematic diagram of the straight traces on the top layer of the PCB board in an embodiment of this application;

[0038] Figure 3b This is a schematic diagram of the diagonal traces on the bottom layer of the PCB board in an embodiment of this application;

[0039] Figure 4 A circuit diagram of a first type of five-channel antenna provided in the embodiments of this application;

[0040] Figure 5 A circuit diagram of a second type of five-channel antenna provided in an embodiment of this application;

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

[0042] Figure 7 This is a schematic diagram showing the results of another simulation experiment provided in an embodiment of this application.

[0043] It should be understood that the dimensions and shapes of the block diagrams in the above structural diagrams are for reference only and should not constitute an exclusive interpretation of the embodiments of this application. The relative positions and inclusion relationships between the block diagrams presented in the structural diagrams are only schematic representations of the structural relationships between the block diagrams, and are not intended to limit the physical connection methods of the embodiments of this application. Detailed Implementation

[0044] The technical solutions provided in this application will be further described below with reference to the accompanying drawings and embodiments. It should be understood that the system architecture and business scenarios provided in the embodiments of this application are mainly for illustrating possible implementations of the technical solutions of this application and should not be construed as the sole limitation on the technical solutions of this application. Those skilled in the art will recognize that the technical solutions provided in this application are equally applicable to similar technical problems as system architectures evolve and new business scenarios emerge.

[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 this application belongs. In case of any inconsistency, the meaning set forth in this specification or derived from the content described herein shall prevail. Furthermore, the terminology used herein is for the purpose of describing embodiments of this application only and is not intended to limit the scope of this application.

[0046] The solutions provided in this application will now be described in detail with reference to the accompanying drawings and embodiments.

[0047] This application proposes a five-channel antenna, specifically implementing an innovative antenna physical structure and tuning method. Utilizing double-sided printed circuit board (PCB) technology, the antenna is designed with five centrally symmetrically distributed spiral zigzag stubs. By connecting tunable passive devices or switchable circuit networks in series in each stub, flexible configuration and reconfiguration of the antenna's operating frequency, bandwidth, polarization mode (linear / circular polarization), and circular polarization direction are achieved. This solution effectively solves the problems of large size, difficult tuning, and limited functionality of traditional circularly polarized antennas.

[0048] like Figures 2-3b As shown in the embodiment of this application, a five-channel antenna is provided. This antenna is constructed based on a dielectric substrate (i.e., a PCB board). A feed point and a reference ground plane are respectively disposed on the top layer of the PCB board. The feed point is located on the top layer of the PCB board, and the reference ground plane is located near the feed point. Five sets of radially distributed straight traces (such as...) are etched on the top layer of the PCB board. Figure 3a As shown), five sets of diagonal traces corresponding to the top layer traces are etched on the bottom layer of the PCB board (e.g., Figure 3b As shown), each group of top-layer traces and the corresponding bottom-layer traces are electrically connected through metal vias at both ends, forming a continuous spiral zigzag structure with a spatial spiral feel. Each spiral zigzag structure is a branch, and a tuning device is connected in series in the middle of the spiral zigzag structure of each branch.

[0049] Of the five branches, the one located directly above (with) Figure 2 Taking the orientation shown as an example, one node is defined as the feed stub, and the other four stubs are evenly distributed around it in the circumference, defined as ground stub 1, ground stub 2, ground stub 3 and ground stub 4 respectively. Among them, ground stub 1 and ground stub 3 are spatially symmetrical about the feed stub, forming a pair; ground stub 2 and ground stub 4 are symmetrical about the left and right, forming another pair. This symmetrical layout can provide a hardware physical basis for achieving good circular polarization characteristics in the future.

[0050] The feed stub's starting end (i.e., the beginning of the spiral-shaped structure, near the center of the PCB board) is connected to a feed point located at the center of the top layer of the PCB board. This feed point is connected to an external RF port through an impedance matching circuit to match the antenna's input impedance to the system's standard impedance (typically 50Ω). The end of the feed stub (i.e., the end of the spiral-shaped structure) is left floating. The starting ends of the four ground stubs are all connected to the reference ground plane, and the ends of the four ground stubs are left floating.

[0051] When the antenna is operating, the radio frequency signal directly excites the feed stubs through the impedance matching circuit and the feed point, causing them to generate alternating current and electromagnetic fields. Since the four ground stubs are tightly coupled to the feed stubs in space, their near-fields overlap. Therefore, the electromagnetic field of the feed stubs effectively excites the current on the four ground stubs. Each ground stub and the feed stub together form a resonant circuit, the resonant frequency of which is determined by the physical length (electrical length) of the feed stub and ground stub themselves, as well as the values ​​of the tuning devices connected in series. By setting different tuning device parameters for different ground stubs, multiple different resonant frequency points can be formed by coupling them with the feed stubs, thus enabling multi-band operation of the antenna.

[0052] To achieve good signal transmission, the impedance matching circuit in this application embodiment has been preferably designed. For example... Figure 4 As shown, the matching circuit can be specifically implemented as a two-stage tuning network.

[0053] First, a parallel tuning branch is set up immediately adjacent to the feed point. This branch consists of an inductor L1 connected in parallel to ground and a capacitor C1 connected in parallel to ground. This parallel structure is mainly used for coarse adjustment of the antenna's input impedance. Second, after the parallel branch, a series tuning branch is connected in series on the signal path. This branch consists of a series inductor L2 and a series capacitor C2. This series structure is mainly used for fine adjustment of the input resistance and further impedance compensation. By properly selecting the values ​​of L1, C1, L2, and C2, the impedance flowing from Port1 (i.e., the RF port) to the antenna within the target operating frequency band can be made close to the standard impedance of 50Ω, thereby maximizing power transmission efficiency and improving the antenna's VSWR and return loss performance.

[0054] In some embodiments, the series tuning branch of the impedance matching circuit is further provided with an inductor L3 connected in parallel to ground at the rear end, which works in conjunction with the two-stage matching network at the front end to perform "final compensation" on the impedance after the first two stages of transformation. By carefully selecting the value of L3, an additional parallel inductance can be provided at a specific frequency to accurately cancel the small capacitive reactance that may remain at the antenna port at that frequency, or it can be used to fine-tune the real part of the input resistance, thereby making the return loss more deeply and widely recessed in the target frequency band.

[0055] 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 4As shown, the tuning device can be an inductor, where L02 is the tuning device for the feed stub, and L03, L04, L05, and L06 correspond to the tuning devices for ground stubs 1, 2, 3, and 4, respectively. Port1 is connected to the antenna feed point through an impedance matching circuit. In practical applications, the length and spacing of the broken lines are first designed 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 lower the resonant frequency of the antenna trace. The closer the frequency is to the target frequency, the more the antenna can be adjusted to the target operating frequency by supplementing it with intermediate series tuning devices. However, the smaller the spacing, the longer the traces, and the denser the traces, 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 fold lines, the shorter the traces, and the better the radiation performance of the fold lines. However, larger tuning devices are required for supplementation, 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 fold lines 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.

[0056] The following is based on Figure 2 Antenna structure and Figure 4 The circuit structure is used to illustrate how to achieve circular polarization in a specific target frequency band:

[0057] First, connect only the feed stub and ground stub 1, disconnecting all other ground stubs 2, 3, and 4. Determine the values ​​of the tuning device L02 in the middle of the feed stub's broken line and the tuning device L03 in ground stub 1 based on the target antenna operating frequency f1, ensuring their device (generally an inductor) values ​​are close and the antenna operating frequency is at the target operating frequency f1. Then disconnect ground stub 1 and connect ground stub 2. Adjust the value of the tuning device L02 in the middle of the feed stub and the value of the tuning device L03 in series with the middle of ground stub 2. The value of 4 is adjusted to the antenna resonant mode operating frequency f2 formed by stub 2 and the feed branch directly above. Then, the tuning device L02 of the feed branch is taken to a value close to the average of the two frequency adjustment devices, taking into account both frequency bands. Then, the inductance value of the tuning device L04 of stub 2 is readjusted to LF2, and adjusted to the antenna resonant mode operating frequency f2 formed by stub 2 and the feed branch directly above. Then, according to the rotation requirements of the antenna's target circular polarization characteristics, whether the antenna needs to be left-hand circularly polarized or not is determined. For right-hand circular polarization antenna design, based on the tuning device value LF2 of ground stub 2, the value of tuning device L04 of ground stub 2 is determined to be slightly larger than the latest adjusted inductance value, and the value of tuning device L06 of ground stub 4 is determined to be slightly smaller than the inductance value LF2. With this design, the feed stub, ground stub 2, and ground stub 4 respectively form two antenna resonance modes with similar operating frequencies f2. The antenna resonance mode formed by the feed stub and ground stub 2... The operating frequency is slightly lower than the target operating frequency f2 by f2-k (k value is greater than zero and very small). At the f2 frequency, the phase lag is behind. The antenna resonant mode formed by the feed stub and ground stub 4 operates at a frequency slightly higher than the target operating frequency f2 by f2+k (k value is greater than zero and very small). At the f2 frequency, the phase is ahead. And the angle of the two resonant modes is rotated by 120 degrees. In this way, the antenna scheme design with right-hand circular polarization formed by the feed stub and ground stub 2 and ground stub 4 operating at the f2 frequency band can be realized.

[0058] Similarly, disconnect ground stub 2 and ground stub 4, reconnect ground stub 1, keep the tuning device value of the feed stub unchanged, and then readjust the tuning device L03 value of ground stub 1 to LF1, adjusting it to the antenna resonance mode operating frequency f1 formed by ground stub 1 and the feed zigzag stub directly above. Then, according to the rotation requirements of the antenna's target circular polarization characteristics, determine whether the antenna needs left-hand circular polarization or right-hand circular polarization. If it is a right-hand circular polarization antenna design, then based on the tuning device value LF1 of ground stub 1, determine the value of the tuning device L03 of ground stub 1 to be slightly larger than the newly adjusted inductance value, and determine the value of the tuning device L05 of ground stub 3 to be slightly smaller than the inductance value LF1. With this design, the feed stub and ground stub 1 and ground stub 3 respectively form two antenna resonant modes with similar operating frequencies f1. The antenna resonant mode formed by the feed stub and ground stub 1 has an operating frequency slightly lower than the target operating frequency f1 by f1-k (k value is greater than zero and very small), with phase lag at f1 frequency. The antenna resonant mode formed by the feed stub and ground stub 3 has an operating frequency slightly higher than the target operating frequency f1 by f1+k (k value is greater than zero and very small), with phase lead at f1 frequency. Furthermore, the two resonant modes are rotated by 120 degrees. In this way, the antenna scheme design with right-hand circular polarization formed by the feed stub and ground stub 1 and ground stub 3 operating at the f1 frequency band can be realized.

[0059] Conversely, if the target antenna polarization is a left-hand circular polarization antenna in the f1 band, simply reversing the tuning devices of ground stub 1 and ground stub 3 will make the five-stub circular polarization antenna a left-hand circular polarization antenna at the operating frequency f1. Similarly, if the target antenna polarization is a left-hand circular polarization antenna in the f2 band, simply reversing the tuning devices of ground stub 2 and ground stub 4 will make the five-stub circular polarization antenna a left-hand circular polarization antenna at the operating frequency f2.

[0060] In this embodiment, the five-segment antenna operates in dual-band dual-circular polarization with the directions of f1 and f2. These directions can be the same or different and can be adjusted arbitrarily according to the above method. The two frequency bands do not affect each other. After the five-segment antenna is designed using the dual-band dual-circular polarization antenna scheme described above, the characteristic impedance of the antenna can be adjusted to match the 50Ω input impedance through the impedance matching circuit connected to the feed point. This completes the design of the five-segment dual-band dual-circular polarization antenna scheme.

[0061] In some embodiments, if the lengths of ground spur 1 and ground spur 3 are different, or the values ​​of the intermediate connecting tuning devices are not similar, it can also be done according to only... Figure 4 As shown, by connecting the tuning devices with their respective inductance values, two antenna frequency bands can be directly formed with the feed stub. Similarly, if ground stub 2 and ground stub 4 have different lengths, or the values ​​of the tuning devices connected in the middle are not similar, they can also be connected according to... Figure 4As shown, by connecting the tuning devices with their respective inductance values, two additional antenna bands can be formed directly with the feed stubs, resulting in a five-stub, four-band design. However, the antenna polarization in this case is linear. Therefore, by configuring the four ground stubs with different resonant frequencies, the antenna can operate in multiple bands, and each band can independently select its polarization mode, supporting a hybrid polarization mode of circular and linear polarization. For example, ground stubs 1 and 3 can be configured to operate in circular polarization mode in band f1, while ground stubs 2 and 4 can be set to different lengths or device values, allowing them to operate in linear polarization mode in bands f2 and f3. This enables a single antenna to simultaneously meet the needs of multiple different communication modules within a complex wireless device, achieving ultimate integration and design flexibility.

[0062] To further enhance the flexibility and intelligence of antennas, this invention proposes a scheme to replace fixed tuning devices with switched tuning circuits, such as... Figure 5 As shown, taking ground stub 1 as an example, its fixed inductor L03 is replaced by a switching tuning circuit. This switching tuning circuit includes an inductor L32 connected in series with the stub trace and a branch connected in parallel with the inductor L32. This branch consists of an inductor L31 and a single-pole single-throw (SPST) switch S2 connected in series. The switch S2 is controlled by a GPIO pin of the controller (such as the CPU) U1. Based on the structure of this switching tuning circuit, when the controller U1 outputs a control signal to open the switch S2, the branch of inductor L31 is not connected, and only inductor L32 is connected in series with ground stub 1. Let the equivalent inductance at this time be Leq_off = L32, corresponding to a resonant frequency F_off; when the controller U1 outputs a control signal to open the switch S2, inductor L31 and inductor L32 form a parallel relationship. The total equivalent value of the parallel inductors, Leq_on, is equal to (L31*L32) / (L31+L32), which is less than L32. Therefore, the equivalent inductance of ground stub 1 decreases, corresponding to a higher resonant frequency, F_on.

[0063] By designing a switching tuning circuit, a single stub can electrically switch between two preset frequencies. Applying this switching circuit to all five stubs and independently controlling each switch using binary logic, the antenna can theoretically switch between up to 2^5 = 32 different frequency combinations. Through careful design of the values ​​of the two inductors in the switching tuning circuit, it can be made to operate stably on four, eight, or even more practically valuable frequency bands.

[0064] In some embodiments, by controlling the on / off states of individual switches, a design can be selected where some frequency bands are circularly polarized and others are linearly polarized. For example, ground stubs 1 and 3, together with the feed stub, form a circularly polarized antenna characteristic operating in the f1 frequency band. Then, ground stubs 2 and 4, with different lengths or different tuning devices, can, together with the feed stub, form two more antenna operating frequency bands, f2 and f3. In this way, a five-stub antenna can achieve a tri-band antenna design that simultaneously supports the requirements of circularly polarized antenna characteristics in the f1 frequency band and linearly polarized antenna characteristics in the f2 and f3 frequency bands. Similarly, ground stubs 2 and 4, together with the feed stub, can form a circularly polarized antenna characteristic operating at the f1 frequency. Ground stubs 1 and 3, together with the feed stub, can again form two more antenna operating frequency bands, f2 and f3. To ensure good performance of the antenna in each frequency band, only appropriate antenna lengths and tuning device values ​​need to be selected for balancing. The antenna stubs can be interchanged. Based on this, the five-segment antenna of this embodiment can be extended to support antenna design schemes that support up to 8 frequency bands.

[0065] To verify the feasibility and effectiveness of this application, three-dimensional electromagnetic simulation software can also be used to establish, for example... Figure 2 The five-segment antenna model shown has a PCB board diameter of 100mm. Two representative simulation experiments were conducted:

[0066] For example, aiming to achieve dual-band operation at 240MHz and 320MHz, with both bands being left-hand circularly polarized, the tuning components were set to L02=39nH, L03=62nH, L04=10nH, L05=68nH, and L06=15nH. The impedance matching circuit parameters were set to L1=36nH, C1=11pF, L2=75nH, and C2=8pF. The antenna evaluation results were obtained through simulation, such as... Figures 6a-6c As shown, the antenna's reflection coefficient S11 curve ( Figure 6a A significant dip occurs near 240MHz and 320MHz, below -10dB, confirming effective resonance of the antenna in these two frequency bands. Gain curve ( Figure 6b The results show that at 240MHz and 320MHz, the left-hand circular polarization gain (LHCP Gain) is very close to the antenna's maximum gain, while the right-hand circular polarization gain (RHCP Gain) is about 15-20dB lower. This indicates that the radiated energy is mainly concentrated in the left-hand circular polarization direction, resulting in excellent axial ratio (AR) performance. Axis ratio curves ( Figure 6c The results directly show that the axial ratio is approximately 0.8 dB at 240 MHz and approximately 1.9 dB at 320 MHz (both much smaller than the 3 dB circular polarization threshold), strongly demonstrating that the present invention can achieve high-performance dual-frequency circular polarization radiation with a size much smaller than that of a traditional half-wave antenna.

[0067] In another simulation experiment, with the goal of demonstrating the ability to achieve multi-band extension by adjusting the ground stub parameters, based on the above simulation experiment, only L05=51nH, L06=24nH were changed, and the impedance matching circuit was finely adjusted to L1=43nH, C1=11pF, L2=68nH, C2=8pF.

[0068] Simulation results are as follows Figure 7 As shown, the reflection coefficient S11 curve reveals four distinct resonance valleys, located at 241MHz, 252MHz, 268MHz, and 322MHz, respectively. This confirms that by setting the ground stub to different resonance states (in this embodiment, due to the lack of deliberate symmetry in parameter configuration, it mainly exhibits linear polarization characteristics), the antenna's operating frequency band can be easily extended to three or four, effectively increasing the antenna's bandwidth or enabling it to cover more discrete frequency points, thus verifying the flexibility of this application in multi-frequency / wideband applications.

[0069] In summary, the five-channel antenna provided in this application embodiment comprises five branches consisting of one feed branch and four ground branches on a double-sided PCB board. Each branch adopts a unique spiral zigzag structure and is connected in series with a tuning device. The feed branch is connected to the feed point at its first end and left suspended at its last end. The ground branches are connected to a reference ground plane at their first ends and left suspended at their last ends. This unique asymmetrical suspended-ground structure allows the feed branch to excite the ground branches after being powered on, thereby generating a mode with equal amplitude and a preset phase angle, achieving circular polarization radiation. This helps to improve the antenna's radiation performance and circular polarization characteristics. Furthermore, the tuning device in the middle of each branch can be individually adjusted to its resonant frequency, enabling the antenna to support multiple frequency bands. This has significant practical value and broad application prospects.

[0070] It should be noted that the embodiments described in this application are merely some embodiments, not all embodiments. The components of the embodiments of this application typically described and shown in the accompanying drawings can be arranged and designed in various different configurations. Therefore, the above detailed description of the embodiments of this application provided in the accompanying drawings is not intended to limit the scope of the claimed application, but merely represents selected embodiments of this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0071] The terms "first, second, third, etc." or similar terms such as module A, module B, module C, etc., used in the specification and claims are only used to distinguish similar objects and do not represent a specific ordering of objects. It is understood that a specific order or sequence may be interchanged where permitted so that the embodiments of this application described herein can be implemented in an order other than that illustrated or described herein.

[0072] 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.

[0073] 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.

[0074] 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.

[0075] 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 five-channel antenna, characterized in that, The device includes a PCB board and five branches that are radially distributed on the PCB board. The top layer of the PCB board has a feed point at its center, which is connected to the RF port of the antenna through an impedance matching circuit. The top layer of the PCB board also has a reference ground plane. 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, which 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 five branches include a feed branch and four ground branches evenly distributed around the feed branch in a circumferential direction. The four ground branches are designated as the first ground branch, the second ground branch, the third ground branch, and the fourth ground branch. The first ground branch and the third ground branch form a pair of ground branches, and the second ground branch and the fourth ground branch form a pair of ground branches. The first end of the feed branch is connected to the feed point, and the last end is suspended. The first ends of the four ground branches are all connected to the reference ground plane, and the last ends are suspended. After the feed branch is energized, an alternating electromagnetic field is generated around it, which excites the four ground branches respectively to achieve circular polarization radiation in multiple frequency bands.

2. The five-channel 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 five-channel 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 five-channel antenna according to claim 1, characterized in that, When the trace lengths of a pair of ground stubs are the same and the parameters of the tuned devices connected in series are configured to have a preset difference, the feed stub and the pair of ground stubs together generate two resonant modes with a preset angle and a preset phase difference in the target frequency band, thereby causing the antenna to exhibit circularly polarized radiation characteristics in the target frequency band.

5. The five-channel antenna according to claim 4, 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.

6. The five-channel 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.

7. The five-channel 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.

8. The five-channel antenna according to claim 7, 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.

9. A communication device, characterized in that, Includes a five-channel antenna as described in any one of claims 1 to 8.

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