A composite antenna

Abstract

This application provides a composite antenna, relating to the field of VHF antenna technology. The composite antenna includes a high-frequency radiator, a high-frequency choke coil, a low-frequency upper radiator, an impedance element, a low-frequency lower radiator, and a combiner assembly. The high-frequency radiator is a microstrip antenna with its antenna arm shorted to the central transmission line. The high-frequency choke coil is connected to both the high-frequency radiator and the low-frequency upper radiator. The impedance element is connected to both the low-frequency upper radiator and the low-frequency lower radiator. The combiner assembly combines the high-frequency signals transmitted and received by the high-frequency radiator and the low-frequency signals transmitted and received by the low-frequency upper and lower radiators for transmission. This design effectively ensures maximum antenna reuse within a limited space, improving antenna radiation efficiency, while also solving antenna coupling problems and enhancing antenna isolation.

Description

Technical Field

[0001] This application relates to the field of ultra-shortwave antenna technology, and more particularly to a composite antenna. Background Technology

[0002] The function of an antenna is to convert electromagnetic signals in free space into electrical signals on a transmission line, enabling the propagation of wireless signals between any two points. With the continuous development of portable communication devices, the demands on antennas themselves have become increasingly urgent. Antenna size is limited, and it is necessary to improve antenna gain within a confined space.

[0003] Existing antennas are divided into high-frequency and low-frequency antennas, and are mainly implemented using dipole elements. This type of antenna cannot achieve a high gain by increasing the electrical length of the radiator in a limited space; at the same time, it will generate interference during signal transmission, leading to coupling problems.

[0004] In summary, a composite antenna is needed to extend the electrical length of the radiator in a limited space, realize antenna multiplexing, improve antenna gain, and solve antenna coupling problems. Summary of the Invention

[0005] This application provides a composite antenna that solves the problems of increasing the electrical length of the radiator in a limited space, realizing antenna multiplexing, improving antenna gain, and antenna coupling.

[0006] This application provides a composite antenna, including a high-frequency radiator, a high-frequency choke coil, a low-frequency upper radiator, an impedance element, a low-frequency lower radiator, and a combiner assembly.

[0007] The high-frequency radiator is a microstrip antenna with its antenna arm shorted to the central transmission line.

[0008] The high-frequency choke coil is connected to the high-frequency radiator and the low-frequency upper radiator, respectively.

[0009] The impedance element is connected to the upper low-frequency radiator and the lower low-frequency radiator, respectively.

[0010] The combiner assembly is used to combine and transmit the high-frequency signals transmitted and received by the high-frequency radiator, the low-frequency signals transmitted and received by the upper low-frequency radiator and the lower low-frequency radiator.

[0011] In this embodiment of the invention, three radiators are included: a high-frequency radiator, a low-frequency upper radiator, and a low-frequency lower radiator. These are connected via a high-frequency choke coil and impedance elements. The primary function of the radiators is to receive or transmit electromagnetic waves. The high-frequency radiator is a microstrip antenna with its antenna arm shorted to the central transmission line, which reduces antenna size and increases gain. Furthermore, the high-frequency choke coil connects the high-frequency radiator and the low-frequency upper radiator, effectively treating the high-frequency radiator, high-frequency choke coil, and low-frequency upper radiator as a single unit within the low-frequency lower radiator, thus expanding bandwidth, improving antenna radiation efficiency, and enhancing antenna gain. In addition, this design employs a novel isolation method. The high-frequency choke coil, acting as a connector between the high-frequency and low-frequency upper radiators, increases the length, enabling reuse of the high-frequency radiator, while also providing isolation, significantly eliminating cable coupling issues and effectively solving the isolation problem.

[0012] In one possible design, the high-frequency choke coil is wound with a high-frequency radio frequency cable, and the high-frequency radio frequency cable does not have a magnetic core.

[0013] The high-frequency choke coil serves as the choke coil for the high-frequency radiator and as the loading inductor for the low-frequency radiator.

[0014] The high-frequency choke coil, lacking a magnetic core, exhibits weak choking effect at low frequencies but strong choking effect at high frequencies. This prevents the low-frequency antenna from being effectively disconnected due to excessive choking, making it suitable as a choke coil for high-frequency antennas. The inductor in the low-frequency antenna acts as a phase inversion current, ensuring that the current flow in both the high-frequency and low-frequency radiators is upward. This allows the high-frequency choke coil, acting as an intermediate connector, to link the high-frequency and low-frequency radiators, achieving antenna reuse and improving gain. Therefore, by using a hollow inductor to wind the high-frequency RF cable around the low-frequency antenna, the length of the high-frequency radiator is increased, enabling high-frequency radiator reuse. Simultaneously, the high-frequency RF cable is isolated from the low-frequency radiator, significantly reducing cable coupling and resolving the issue of cable isolation.

[0015] In one possible design, the impedance element includes a grounding inductance formed by winding the outer conductor of the high-frequency radio frequency cable, a series inductance formed by the outer conductor of the high-frequency radio frequency cable between the core wire of the coaxial cable short circuit and the core wire of the low-frequency radio frequency cable; and a grounding capacitance formed by grounding the coaxial cable short circuit.

[0016] In this system, the impedance of the impedance element is proportional to the frequency, and it is used to change the current distribution. When operating with low-frequency signals, the impedance element, due to its low frequency, causes no change in the current distribution between the upper and lower radiators in the low-frequency band, thus remaining operational. When operating with high-frequency signals, the impedance element, due to its high frequency, causes a change in the current distribution between the upper and lower radiators in the low-frequency band, effectively short-circuiting the impedance element, rendering it inactive. In short, the impedance element uses a printed circuit board as its framework, with high-frequency RF cables wound around it. It can be equivalent to a grounding inductor, using inductance to pass DC and block AC, pass low frequencies and block high frequencies, effectively ensuring that low-frequency signals flow to ground while high-frequency signals pass smoothly, thus acting as a filter.

[0017] In one possible design, the upper radiator in the low-frequency band is the upper element of a dipole antenna and the lower radiator in the low-frequency band is the lower element of a dipole antenna.

[0018] Dipole antennas, also known as symmetrical dipole antennas, are among the earliest, simplest, and most widely used antennas in radio communication. A common dipole antenna consists of two coaxial straight wires. The radiation field produced by this type of antenna at a distance is axisymmetric and can be rigorously solved theoretically. The upper and lower dipoles mentioned above are symmetrical and of equal length. Furthermore, this type of antenna is widely used due to its small size, low cost, ease of integration, and ability to form arrays.

[0019] In one possible design, the high-frequency radiator is shorted to the central transmission line at λ / 4 and λ / 2 of the antenna arm, respectively.

[0020] In this embodiment of the invention, the high-frequency radiator is a microstrip antenna. The internal structure design is based on the H-type microstrip antenna, with the antenna arm's λ / 4 and λ / 2 shorted to the intermediate transmission line. This reduces the size and increases the gain, while also providing a basis for antenna multiplexing between the low-frequency dipole antenna and the high-frequency microstrip antenna.

[0021] In one possible design, the high-frequency radiator is shorted to the central transmission line at λ / 4 and λ / 2 of the antenna arm in a vertical manner to form a microstrip antenna with a grid-like structure.

[0022] In this design, the transmission lines at λ / 4 and λ / 2 of the antenna arm are shorted vertically, forming a grid-like structure. This vertical design maximizes material savings compared to other shorting methods while ensuring improved gain.

[0023] In one possible design, the microstrip antenna with the grid-like structure consists of two groups, and operates in the frequency band of 4400-5000MHz.

[0024] The operating frequency of an antenna refers to the frequency range within which both transmitting and receiving antennas operate. Typically, the antenna delivers the maximum power at its center frequency, and the power decreases as it deviates from the center frequency. This defines the antenna's frequency bandwidth. The typical operating frequency range for antennas is 225MHz to 5000MHz. Among these, the grid-shaped microstrip antenna serves as the high-frequency antenna in a composite antenna system, used to receive high-frequency signals. Antenna design is often constrained by size and weight requirements. Two grid-shaped microstrip antennas can achieve good transmission performance while maintaining a good balance between size and weight at high operating frequencies.

[0025] In one possible design, the upper radiator in the low-frequency band is a metal strip; the lower radiator in the low-frequency band is a goose-top metal strip.

[0026] In this design, the upper radiator in the low-frequency band uses an inflexible metal strip, while the lower radiator in the low-frequency band is a goose-top metal strip, which effectively increases the flexibility of the composite antenna in this embodiment. Furthermore, the metal is conductive, thus enabling signal transmission.

[0027] In one possible design, the combiner assembly is a dual-core interface formed by winding two strands of low-frequency and high-frequency radio frequency cables onto a ferrite rod, used for dual-channel communication.

[0028] The combiner is used to combine signals with the same direction for output. In this embodiment of the invention, a dual-core interface is used to achieve dual-channel communication. Theoretically, dual-channel communication can provide twice the bandwidth, ensuring that antennas of different frequency bands communicate through specific channels. The ferrite rod uses a low-loss magnetic dielectric material to ensure minimal loss during signal transmission.

[0029] In one possible design, the combiner assembly consists of two strands of low-frequency and high-frequency radio frequency cables wound around a ferrite rod and connected to a duplexer for single-channel communication.

[0030] In the above design, the combiner component can also achieve single-channel communication. Single-channel communication involves the combiner component merging the received signals and then using a duplexer to selectively transmit one of them. Attached Figure Description

[0031] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0032] Figure 1This is an overall schematic diagram of a composite antenna provided in an embodiment of this application;

[0033] Figure 2 This is a schematic diagram of the internal structure of a composite antenna provided in an embodiment of this application;

[0034] Figure 3 A circuit diagram of the impedance element of a composite antenna is provided for an embodiment of this application;

[0035] Figure 4 An H-type microstrip antenna diagram is provided for the embodiments of the application;

[0036] Figure 5 This is a schematic diagram of the interior of a high-frequency radiator in a composite antenna according to an embodiment of the application.

[0037] Figure 6 This application provides a comparison chart of H-shaped and crisscross-shaped gain effects at 4400MHz for embodiments of the present application;

[0038] Figure 7 This application provides a comparison chart of H-shaped and crisscross-shaped gain effects at 4700MHz for embodiments of the present application. Detailed Implementation

[0039] To make the objectives, technical solutions, and advantages of this application clearer, the application will be further described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0040] An antenna is a transducer that transforms guided waves propagating on a transmission line into electromagnetic waves propagating in an unbounded medium (usually free space), or vice versa. An antenna is defined as one whose radiated energy is uniformly distributed 360° in the horizontal plane and has a certain beamwidth in the vertical plane, capable of receiving and radiating signals in all directions within the horizontal plane. Individual omnidirectional antennas are lightweight, simple in structure, and have relatively low design and manufacturing costs, thus possessing significant practical value and broad development prospects. Any transmission of signals via electromagnetic waves requires the use of antennas, hence the increasing importance placed on antennas. For devices needing to receive signals across multiple frequency bands, installing multiple antennas would increase the size and weight of the device; therefore, multiple frequency bands need to be combined onto a single antenna to solve this problem.

[0041] The current technology that solves the above problems mainly uses a composite antenna in the form of a dipole. This composite antenna design introduces a coaxial winding of a magnetic core. The high-frequency band antenna uses a dipole antenna, and the low-frequency band antenna also uses a dipole antenna. The coaxial winding is connected to the lower dipole element of the high-frequency band dipole antenna and the upper dipole element of the low-frequency band dipole antenna to achieve antenna connectivity. However, multiplexing cannot be achieved in this case because the choke coil of the current technology uses a coaxial winding of a magnetic core. This design has a strong current suppression effect on the outer sheath of the coaxial cable. For the low-frequency band, it is equivalent to a direct disconnection, making multiplexing impossible. At the same time, the upper and lower dipole elements of the dipole antenna are separate. Even if multiplexing could be achieved, the upper dipole element, which is used as a high-frequency band dipole antenna, cannot be multiplexed, resulting in relatively low antenna radiation efficiency.

[0042] This application provides a composite antenna to solve the above-mentioned problems. For example... Figure 1 , Figure 1 This application provides an overall schematic diagram of a composite antenna. To protect the internal radiators of the antenna and increase its wear resistance and corrosion resistance, a ring-shaped fiberglass antenna cover 101 is provided on the outside of the antenna. The ring-shaped fiberglass antenna cover 101 can effectively protect the internal structure of the antenna from damage.

[0043] It should be noted that the ring-shaped fiberglass antenna shroud 101 can be made of any other material, as long as it can protect the internal structure of the antenna and increase the antenna's wear resistance and corrosion resistance. No specific restrictions are imposed here.

[0044] like Figure 2 , Figure 2 This application provides a schematic diagram of the internal structure of a composite antenna, including a high-frequency radiator 102, a high-frequency choke coil 103, a low-frequency upper radiator 104, an impedance element 105, a low-frequency lower radiator 106, and a combiner assembly 107; the high-frequency radiator 102 is a microstrip antenna and the antenna arm is short-circuited to the central transmission line.

[0045] In this embodiment, the high-frequency radiator 102 is a microstrip antenna. A microstrip antenna typically consists of a dielectric substrate, a radiator, and a ground plane. Compared to traditional dipole antennas, microstrip antennas are not only smaller, lighter, and have a lower profile, but they are also easier to conform to, easier to integrate, and lower in cost, making them suitable for mass production. Furthermore, they offer advantages such as diverse electrical performance. In this embodiment, the antenna arm of the microstrip antenna is shorted to the central transmission line; shorting specifically means connection. The shorting can be implemented in various ways, as long as connection is achieved.

[0046] The high-frequency choke coil 103 refers to a coil that is sometimes wound on a ferrite core and sometimes hollow, with hundreds or tens of turns and a self-inductance of a few millihenries. This type of choke coil 103 has a significant blocking effect on high-frequency alternating current, a very small blocking effect on low-frequency alternating current, and an even smaller blocking effect on DC. Therefore, it can be used to "pass DC, block AC, pass low frequencies, and block high frequencies".

[0047] The high-frequency choke coil 103 is connected to the high-frequency radiator 102 and the low-frequency upper radiator 104, respectively.

[0048] The high-frequency radiator 102 is connected to the first end of the low-frequency upper radiator 104 via a high-frequency choke coil 103. To prevent the connection from being unstable, the high-frequency radiator 102 and the high-frequency choke coil 103 are welded together, and the high-frequency choke coil 103 is then welded to the low-frequency upper radiator 104 for fixation, thereby ensuring smooth signal transmission.

[0049] It should be noted that the fixing method here is not limited to welding. Other fixing methods can be used, such as electrical connection, as long as the high-frequency radiator 102 is connected and fixed to the high-frequency choke coil 103 and the high-frequency choke coil 103 is connected and fixed to the low-frequency upper radiator 104. This embodiment of the invention does not impose any limitations here.

[0050] The impedance element 105 is connected to the low-frequency upper radiator 104 and the low-frequency lower radiator 106 respectively.

[0051] Impedance matching of an antenna is a common operating condition in radio technology, reflecting the power transfer relationship between the input and output circuits. When the circuit achieves impedance matching, maximum power transfer is achieved. Conversely, when the circuit impedance is mismatched, not only is maximum power transfer not achieved, but damage to the circuit may also occur. Impedance matching is commonly used between different stages of amplifier circuits, between amplifiers and loads, between measuring instruments and the circuit under test, and especially in the application of antenna impedance matching principles. Impedance matching is a common operating condition in radio technology, reflecting the power transfer relationship between the input and output circuits. In this example, the first terminal of impedance element 105 is connected to the second terminal of the upper radiator 104 in the low-frequency band, and the second terminal of impedance element 105 is connected to the lower radiator 106 in the low-frequency band, thus establishing a signal transmission channel.

[0052] The combiner assembly is used to combine and transmit the high-frequency signals transmitted and received by the high-frequency radiator 102, the low-frequency signals transmitted and received by the low-frequency upper radiator 104 and the low-frequency lower radiator 106.

[0053] Combiners are common products used in the antenna field; as the name suggests, they combine signals. Any device that combines signals with the same direction and outputs the same signal can be called a combiner. In the embodiments of this application, the combiner component provides two signal implementation methods: dual-channel communication and single-channel communication. For combiner components using a dual-core interface, the low-frequency and high-frequency RF cables are wound in pairs around a ferrite rod to form a dual-core interface for dual-channel communication. For combiners using different frequencies, the low-frequency and high-frequency RF cables are wound in pairs around a ferrite rod and then connected to a duplexer for single-channel communication.

[0054] In this embodiment of the invention, the high-frequency radiator is a microstrip antenna, and the antenna arm is short-circuited to the central transmission line. This reduces the antenna size and increases gain. Furthermore, the high-frequency choke coil connects the high-frequency radiator and the low-frequency upper radiator, effectively treating the high-frequency radiator, choke coil, and low-frequency upper radiator as a single entity, thus expanding the bandwidth, improving the antenna's radiation efficiency, and enhancing its gain. In addition, the design employs a novel isolation method. The high-frequency choke coil, acting as a connector between the high-frequency and low-frequency upper radiators, increases the overall length while providing isolation, significantly reducing cable coupling and effectively solving the isolation problem.

[0055] The high-frequency choke coil 103 is used to connect the high-frequency radiator 102 and the low-frequency radiator 104; it only needs to fulfill the function of a choke coil. In this embodiment, in addition to ensuring that the high-frequency choke coil 103 functions as a choke coil, other functions are also provided.

[0056] In one possible implementation, the high-frequency choke coil is wound with a high-frequency radio frequency cable, and the high-frequency radio frequency cable does not have a magnetic core.

[0057] In simple terms, the choke coil works by generating a magnetic field that, due to self-induction, hinders the current's flow, thus delaying its passage. High-frequency choke coils use a winding method without a magnetic core, resulting in weak choke effect on low frequencies; therefore, they are not equivalent to disconnecting a low-frequency antenna.

[0058] The high-frequency choke coil 103 serves as the choke coil for the high-frequency radiator 102 and as the loading inductor for the low-frequency radiator 104.

[0059] Because no magnetic core is incorporated, the choke effect on low frequencies is weak, while the suppression effect on high frequencies is strong. The high-frequency choke coil 103 is connected to the high-frequency radiator 102 and the low-frequency upper radiator 104, thus indirectly connecting the high-frequency radiator 102 and the low-frequency upper radiator 104. This allows the high-frequency radiator 102 and the low-frequency upper radiator 104 to be regarded as a whole as the low-frequency upper radiator 108 of the low-frequency lower radiator 106.

[0060] In one possible implementation, the impedance element 105 includes a grounding inductance formed by winding the outer conductor of the high-frequency radio frequency cable, and a series inductance formed by the core wire of the coaxial cable short circuit and the core wire of the low-frequency radio frequency cable; the coaxial cable short circuit is grounded to form a grounding capacitor.

[0061] Impedance element 105 is essentially an impedance matching circuit. Its impedance is proportional to the frequency, and it alters the current distribution. When the antenna operates with low-frequency signals, the impedance of element 105 is low due to the low frequency, resulting in no change in the current distribution of the upper radiator 108 and lower radiator 106 in the low-frequency band. In other words, both radiators 108 and 106 carry current, functioning as a single radiator in operation. Conversely, when operating with high-frequency signals, the impedance of element 105 is high due to the high frequency, causing a change in the current distribution of the lower radiators 108 and 106. In this case, impedance element 105 functions as an open circuit and is not in operation.

[0062] like Figure 3 , Figure 3 This application provides a circuit diagram of the impedance element of a composite antenna. A grounding inductor formed by winding the outer conductor of a high-frequency radio frequency (RF) cable allows low-frequency signals to flow into the ground while high-frequency signals pass smoothly. An impedance matching circuit is formed by soldering a coaxial cable short circuit and the core wire of the low-frequency RF cable onto this grounding inductor. The internal structure of the high-frequency RF cable includes an inner conductor, an outer conductor, and a dielectric. The core wire is its inner conductor. The outer conductor is connected to the core wire through the dielectric for conductivity. L6 represents the high-frequency RF cable 103, L5 represents the low-frequency RF cable 105, and the coaxial cable short circuit grounding can be equivalent to a grounding capacitor. Figure 3 In the diagram, C1, C2, C3, and C4 represent the core wires of the short-circuit coaxial cable and the core wires of the low-frequency RF cable. The outer conductor of the high-frequency RF cable can be considered as a series inductor. Figure 3 L1, L2, L3, and L4 in the diagram.

[0063] In one possible implementation, the low-frequency upper radiator 104 is the upper element of a dipole antenna and the low-frequency lower radiator 106 is the lower element of a dipole antenna.

[0064] In the above design, the composite antenna proposed in this application embodiment uses a microstrip antenna for the high-frequency band and a dipole antenna for the low-frequency band. The upper and lower elements of the dipole antenna are symmetrical, also known as a symmetrical dipole, which is a classic and the most widely used antenna to date. In this application embodiment, the dipole antenna is used as a low-frequency antenna, mainly for receiving low-frequency signals, such as signals in the 225-678MHz range.

[0065] In summary, in the embodiments of this application, Figure 2 The 103 high-frequency band coaxial winding coil in the antenna acts as a choke for the field-type microstrip antenna. Since the coil made of the coaxial outer conductor presents high impedance, it prevents the current from overflowing from the coaxial outer conductor. For the dipole antenna, the connection of 102, 103, and 104 makes 102, 103, and 104 together form the upper element of the dipole antenna, which achieves perfect multiplexing in a limited space. At the same time, 103 can also be used as the loading inductor of the dipole antenna. By using loading technology, the miniaturization of the antenna is further realized.

[0066] In one possible implementation, the high-frequency radiator 102 is shorted to the central transmission line at λ / 4 and λ / 2 of the antenna arm, respectively.

[0067] A short circuit can be understood as connecting a line at a designated point. The high-frequency radiator 102 adopts the form of a microstrip antenna, and the upper and lower elements of the high-frequency radiator 102 are fixed on both sides of a printed circuit board. For example, the upper element is provided on the first side of the printed circuit board, and the lower element is provided on the second side of the printed circuit board.

[0068] One possible implementation is that the high-frequency radiator 102 is based on the original H-type microstrip antenna, with the antenna arm and the central transmission line short-circuited.

[0069] Multiple shorting points can be selected. One possible implementation is to short-circuit the antenna arm of the existing H-type antenna at one-quarter and one-half of its length with the central transmission line, such as... Figure 4 , Figure 4 An H-type microstrip antenna diagram is provided for the application embodiment. Figure 4 The value at the center circle is λ / 2, and the value at the straight line is λ / 4. Figure 4 To make it easier to understand, the printed circuit board is made transparent, so that both the upper and lower oscillators can be seen at the same time.

[0070] In one possible implementation, the high-frequency radiator 102 is shorted to the central transmission line at λ / 4 and λ / 2 of the antenna arm in a vertical manner to form a microstrip antenna with a grid-like structure.

[0071] In the high-frequency radiator 102, vertical short circuits are made at λ / 4 and λ / 2 on the basis of H, forming a grid-like structure, as shown below. Figure 5 , Figure 5 This is a schematic diagram of the internal structure of the high-frequency radiator in a composite antenna according to an embodiment of the application. This grid-shaped design, fixed on a printed circuit board, allows the upper and lower elements of the high-frequency radiator 102 to be connected as a single unit to the high-frequency choke coil 103, achieving antenna multiplexing. Furthermore, changing the original H-type antenna structure to a grid-shaped structure reduces size and increases gain. The upward extension of the central transmission line ensures that the two grid-shaped microstrips are identical; this is a series-fed two-element array antenna.

[0072] In one possible implementation, the microstrip antenna with the grid-like structure consists of two groups, and the operating frequency band is 4400-5000MHz.

[0073] The microstrip antenna with a grid-like structure provided in this application is mainly used to receive high-frequency signals. Taking 4400-5000MHz as an example, when there are two groups of grid-like microstrip antennas, the gain can reach 4-6dBi, and the gain effect will increase. Figure 6 , Figure 6 This application provides a comparison chart of H-shaped and cross-shaped gain effects at 4400MHz for embodiments of the present application. Figure 7 This application provides a comparison diagram of H-type and grid-shaped gain effects at 4700MHz for embodiments of the present application. The left half shows the prior art H-type gain effect diagram, and the right half shows the grid-shaped gain effect diagram of the present application embodiment. Figure 6 The gain effect (Maximum Available Gain, Mag) shows that the H-shaped part has Mag=3.3508 at -90 degrees and Mag=2.8444 at +90 degrees at 4400 MHz. The right half of the square-shaped part has Mag=5.6409 at -90 degrees and Mag=4.5258 at +90 degrees at 4400 MHz. Figure 7 It can be seen that the H-shape has a Mag=5.2167 at -90 degrees Celsius and a Mag=4.6460 at +90 degrees Celsius at 4700 MHz. The right half of the grid-shaped part has a Mag=5.6467 at -90 degrees Celsius and a Mag=4.9433 at +90 degrees Celsius at 4700 MHz.

[0074] In summary, it can be seen that the field-shaped microstrip antenna on the right side has a better gain effect than the H-shaped microstrip antenna. Figure 6 and Figure 7 This example only compares the gain effects at 4400MHz and 4700MHz. The gain effect comparison charts for other operating frequencies are not shown one by one, but they are not limited to the two cases mentioned above.

[0075] It should be noted that the grid-shaped microstrip antenna provided in this embodiment has two groups. The gain increases with the cumulative number of groups, but the gain remains basically unchanged after accumulating to four groups, and the gain can reach 8-9 dBi. The number of high-frequency groups can be adjusted according to the actual application scenario; it can be two or three groups. There is no specific limitation here. The antenna can be adjusted to the optimal size and weight according to actual needs.

[0076] In one possible implementation, the upper radiator 104 in the low-frequency band is a metal strip; the lower radiator 106 in the low-frequency band is a goose-top metal strip.

[0077] The gooseneck-shaped metal strip has a relatively large range and strong signal radiation, especially for outdoor antennas. To increase the flexibility of the composite antenna, the upper radiator 104 in the low-frequency band is a non-bendable metal strip, while the lower radiator 106 in the low-frequency band is a gooseneck-shaped metal strip. The lower radiator 106 is made of a wear-resistant and corrosion-resistant material, and the gooseneck-shaped metal strip can be a serpentine tube or similar, allowing for bending and rotation.

[0078] It should be noted that the form and function of the radiator are not limited here and can be changed according to the usage scenario. For example, the low-frequency upper radiator 104 and the low-frequency lower radiator 106 are both gooseneck metal strips or both are non-bendable metal strips, or the low-frequency lower radiator 106 is a non-bendable metal strip and the low-frequency upper radiator 104 is a gooseneck metal strip.

[0079] In one possible implementation, the combiner assembly is a dual-core interface formed by winding two strands of low-frequency and high-frequency radio frequency cables onto a ferrite rod, used for dual-channel communication.

[0080] A dual-core interface means that there are two cables in the antenna used to receive signals of different frequency bands. The low-frequency cable is used to receive low-frequency signals, such as 225-678MHz signals, and the high-frequency cable is used to receive high-frequency signals, such as 4400-5000MHz signals. The received signals are then transmitted out through the dual-core interface.

[0081] In one possible implementation, the combiner assembly consists of two strands of low-frequency and high-frequency radio frequency cables wound around a ferrite rod and connected to a duplexer for single-channel communication.

[0082] A combiner is a common product in the antenna field. As the name suggests, it combines signals. Any device that combines signals with the same direction and outputs the same signal can be called a combiner. An antenna combiner is an integrated circuit that allows multiple radio stations to share the same load antenna. It combines received high-frequency and low-frequency signals into a single channel for transmission. Specifically, the combiner can assign different signals to different channels and then combine them into a single channel. For example, it can combine a low-frequency signal of 225-678MHz and a high-frequency signal of 4400-5000MHz into a single channel for communication.

[0083] The connections described in the embodiments of this invention are generally electrical connections that can transmit signals, and are not specifically limited herein.

[0084] The overall operation of the antenna is as follows: When the antenna is configured with a dual-core interface, if a high-frequency signal is received, the high-frequency signal flows through the high-frequency radiator 102, the high-frequency choke coil 103, the low-frequency upper radiator 104, the impedance element 105, and the low-frequency lower radiator 106, and finally flows into the high-frequency cable interface of the dual-core interface used to receive the high-frequency signal. If a low-frequency signal is received, the low-frequency signal flows through the low-frequency upper radiator 104, the impedance element 105, and the low-frequency lower radiator 106 before flowing into the low-frequency cable interface of the dual-core interface used to receive the low-frequency signal. When both high-frequency and low-frequency signals are received simultaneously, they flow into the corresponding interfaces of the dual-core interface in the same manner as described above.

[0085] When the antenna is configured as a frequency combiner, when a high-frequency signal is received, the high-frequency signal passes through the high-frequency radiator 102 and the high-frequency choke coil 103, then through the low-frequency upper radiator 104, the impedance element 105, and the low-frequency lower radiator 106, and is finally combined into a single channel for transmission via the frequency combiner. When a low-frequency signal is received, the low-frequency signal passes through the low-frequency upper radiator 104, the impedance element 105, and the low-frequency lower radiator 106, and is then combined into a single channel for transmission via the frequency combiner. When both high-frequency and low-frequency signals are received simultaneously, they are simultaneously transmitted via a duplexer in the manner described above.

[0086] Those skilled in the art can make various modifications and variations to this application without departing from the spirit and scope of this application. Therefore, if such modifications and variations fall within the scope of the claims of this application and their equivalents, this application also intends to include such modifications and variations.

Claims

1. A composite antenna, characterized by, Includes high-frequency radiators, high-frequency choke coils, low-frequency upper radiators, impedance elements, low-frequency lower radiators, and combiner assemblies; The high-frequency radiator is a microstrip antenna, and it is shorted to the central transmission line at λ / 4 and λ / 2 of the antenna arm in a vertical manner to form a microstrip antenna with a grid-shaped structure. The high-frequency choke coil is wound from a high-frequency radio frequency cable, and the high-frequency radio frequency cable does not have a magnetic core; the high-frequency choke coil is connected to the high-frequency radiator and the low-frequency upper radiator respectively, serving as the choke coil of the high-frequency radiator and as the loading inductor of the low-frequency upper radiator; the low-frequency upper radiator is a metal strip; the low-frequency lower radiator is a gooseneck metal strip; the impedance element is connected to the low-frequency upper radiator and the low-frequency lower radiator respectively; The combiner assembly is used to combine and transmit the high-frequency signals transmitted and received by the high-frequency radiator, the low-frequency signals transmitted and received by the upper low-frequency radiator and the lower low-frequency radiator.

2. The composite antenna of claim 1, wherein, The impedance element includes a grounding inductance formed by winding the outer conductor of the high-frequency radio frequency cable, a series inductance formed by the outer conductor of the high-frequency radio frequency cable between the core wire of the coaxial cable short circuit and the core wire of the low-frequency radio frequency cable; and a grounding capacitor formed by grounding the coaxial cable short circuit.

3. The composite antenna of claim 1, wherein, The upper radiator of the low-frequency band is the upper dipole antenna and the lower radiator of the low-frequency band is the lower dipole antenna.

4. The composite antenna of claim 1, wherein, The microstrip antenna with the grid-shaped structure consists of two groups, and operates in the frequency band of 4400-5000MHz.

5. The composite antenna as described in claim 1, characterized in that, The combiner assembly is a dual-core interface formed by winding two strands of low-frequency and high-frequency radio frequency cables onto a ferrite rod, used for dual-channel communication.

6. The composite antenna as described in claim 1, characterized in that, The combiner assembly consists of two strands of low-frequency and high-frequency radio frequency cables wound around a ferrite rod and connected to a duplexer for single-channel communication.

Images