Hybrid ultra-wideband antenna based on tight coupled antenna and log-periodic antenna

Abstract

The application belongs to the technical field of antennas, and discloses a super wideband logarithmic periodic antenna based on tight coupling, which comprises a low-frequency tight coupling dipole unit part, a high-frequency logarithmic periodic antenna part and a baffle part for adjusting the low-frequency radiation pattern. The application can also be used as a super wideband detection antenna. When all the units of the array are excited, a signal with an end-fire direction of more than 60 times frequency can be generated, and a directional end-fire pattern can be generated, so that the signal detection and direction finding functions are realized. In addition, the antenna can also be used as a receiving antenna for receiving omnidirectional space incoming wave signals. The antenna array is arranged in a circular shape, and a plurality of the antennas are arranged in a circle, so that wideband omnidirectional radiation is realized.

Description

Technical Field

[0001] This invention belongs to the field of antenna technology, and particularly relates to an ultra-wideband log-periodic antenna based on tight coupling. Background Technology

[0002] Antennas are an indispensable component of all radio communication systems, primarily used for transmitting and receiving electromagnetic wave signals. In high-volume information transmission scenarios, modern communication systems such as radar, television, satellite communications, and telemetry require wider operating bandwidths to ensure transmission quality, which traditional narrowband antennas cannot handle. Furthermore, in military communication systems, interference between antennas severely impacts communication quality, a limitation of narrowband antennas. Therefore, the development of broadband antennas is an inevitable trend.

[0003] Log-periodic antennas (LPDAs) are a typical broadband antenna, first proposed in the early 1960s. They are simple in structure, offer excellent performance, and are commonly used for indoor coverage and elevator signaling. Due to their outstanding performance, they are frequently used in various testing applications, such as electromagnetic compatibility and narrow-range testing. Traditional log-periodic antennas are made of cylindrical dipoles, which suffer from problems such as heavy weight, complex manufacturing, and low precision. With the development of planar circuit technology, there is a demand for antennas that are lightweight, easy to manufacture, and have high precision. Therefore, research on printed log-periodic antennas has gradually increased.

[0004] Tightly coupled dipole arrays rely on strong mutual coupling between elements to generate their effects. Compared to traditional dipole elements, tightly coupled dipoles improve antenna performance by enhancing coupling. Wheeler proposed in 1948 that when the spacing between elements in an infinitely large array is less than one wavelength, each antenna element comprising an infinitely large continuous current sheet array can be equivalently placed in a "rectangular waveguide transmission line" supporting the transmission of TEM modes. Its upper and lower surfaces can be equivalent to ideal electric walls, and its two side surfaces can be equivalent to ideal magnetic walls. These conditions define a hypothetical waveguide that can propagate transverse electromagnetic modes, meaning it has no cutoff wavelength and all wavelengths propagate at the same speed. Therefore, tightly coupled dipole antenna arrays have extremely wide impedance bandwidths. Furthermore, tightly coupled dipoles have the characteristic that their element size is not constrained by half a wavelength.

[0005] Log-periodic antennas have a wide range of applications due to their broadband characteristics. For example, they can be used as cable TV antennas, receiving antennas for radio signals, transmitting antennas for digital base stations, and for radiation measurements.

[0006] Current log-periodic antenna designs all rely on traditional antenna design approaches to achieve miniaturization and broadband performance. Limited by the miniaturization method employed in traditional log-periodic antennas—extending the current path—the relative size of these antennas is at least 0.3 times the maximum wavelength. Due to inherent antenna limitations, the operating bandwidth of log-periodic antennas is typically less than 15 octaves. These inherent limitations also restrict the development of high-gain receiving antennas for detection purposes.

[0007] In 2021, Zhu Haibing et al. published a paper titled "A Log-Periodic Antenna with End Loading" in the field of electronic information countermeasures technology. This paper uses the fractal principle to achieve miniaturization of the antenna, with a lateral dimension of 0.35λ. L The bandwidth is 3.3 octaves. Zhang Qing et al. proposed a miniaturized log-periodic antenna for the 0.8-2 GHz range at the 2021 National Antenna Conference, with a size of 0.26λ. L *0.8λ L Jiang Xiangjun et al. applied for an invention patent on February 24, 2023, entitled "A Retractable Log-Periodic Antenna Based on a Soft Vibrator." This patent proposes a retractable log-periodic antenna operating in the 27-110MHz range, with dimensions of 5m x 5m. The antenna size is close to 0.5λ. L Furthermore, it only has a three-octave operating bandwidth. Li Rui from Xi'an University of Electronic Science and Technology filed an invention patent on July 4, 2022, entitled "A Miniaturized Log-Periodic Antenna with an n-shaped Bending Unit." The example provided by this patent can achieve an operating bandwidth of 50-200MHz within a size of 2490mm*2000mm. In this example, the antenna size is 0.4λ. L *0.33λ L The operating frequency band is a fourth harmonic.

[0008] As can be seen from published papers and patents, traditional log-periodic antennas generally have narrow bandwidths, making it difficult to achieve ultra-wideband performance of tens of octaves. Furthermore, limited by the size and wavelength requirements of non-frequency-varying antennas, their miniaturization is also poor. Existing wideband antennas using log-periodic antennas can only achieve performance of no more than 20 octaves, and their size is generally around 0.3λ. L *0.5λ L above.

[0009] Based on the above analysis, the shortcomings of the existing technology are:

[0010] Existing ultra-wideband antennas suffer from relatively insufficient bandwidth and excessive size. Summary of the Invention

[0011] To address the problems existing in the prior art, this invention provides an ultra-wideband log-periodic antenna based on tight coupling.

[0012] This invention is implemented as follows: an ultra-wideband log-periodic antenna based on tight coupling includes:

[0013] The components include a low-frequency tightly coupled dipole unit, a high-frequency log-periodic antenna, and a baffle that adjusts the low-frequency radiation pattern.

[0014] After adding a baffle, the omnidirectional radiation pattern generated by the low-frequency radiation unit is converted into a directional radiation pattern.

[0015] The tight-coupled dipole and log-periodic antenna are matched by an impedance gradient line from 50 ohms to 150 ohms, and the antenna feed port can be directly fed by a coaxial line.

[0016] Furthermore, the low-frequency radiating element is divided into two parts: a tightly coupled dipole and a log-periodic antenna.

[0017] Furthermore, a reflective backplate is subsequently loaded onto the tightly coupled dipole antenna portion.

[0018] Furthermore, a matching layer is loaded onto the tightly coupled dipole portion to extend the operating bandwidth of the low-frequency portion of the antenna.

[0019] Furthermore, the high-frequency log-periodic antenna section is end-loaded.

[0020] Another objective of this invention is to provide a method for fabricating and manufacturing a tightly coupled ultra-wideband log-periodic antenna, comprising:

[0021] (1) The substrate made using Rogers 5880 printing process is used as the antenna substrate.

[0022] (2) The log-periodic antenna is designed as a printed dipole log-periodic antenna, and a low-frequency tightly coupled dipole antenna section is designed.

[0023] (3) Print the designed antenna on a PCB substrate of the corresponding size.

[0024] (4) Use a coaxial probe to feed the antenna, connect the outer shell to the ground of the antenna, connect the inner core to the transmission line, and fix it with a solder pad, depending on the use scenario of the antenna.

[0025] (5) Complete the processing and manufacturing of the antenna.

[0026] Based on the above technical solutions and the technical problems solved, the advantages and positive effects of the technical solution to be protected by this invention are as follows:

[0027] First, this invention proposes a hybrid ultra-wideband antenna with a bandwidth of 1-60 GHz, combining the broadband performance of tightly coupled dipole antennas and log-periodic antennas. Furthermore, by loading a metal baffle, the antenna exhibits excellent end-fire performance. The low-frequency radiation of this invention is generated by the tightly coupled dipole, while the high-frequency radiation pattern is generated by the log-periodic antenna. In the 1-5 GHz range, all elements can be excited, activating the tightly coupled dipole antenna. Without the baffle, the tightly coupled dipole portion, acting as the low-frequency radiating element, can generate omnidirectional radiation. With the baffle loaded, the low-frequency radiating portion can generate directional radiation. In the 5-60 GHz range, a single element can be excited, achieving the end-fire pattern of the high-frequency log-periodic antenna. Therefore, when the low-frequency radiating element generates directional radiation, the antenna can generate 60 octaves of directional radiation, achieving ultra-wideband detection. When the low-frequency radiating element generates omnidirectional radiation, the antenna will have the directional properties of a low-frequency antenna and the omnidirectional properties of a high-frequency antenna, enabling low-frequency communication and high-frequency detection functions, thus realizing an integrated detection and communication system.

[0028] This invention combines the characteristics of tightly coupled dipole antennas and log-periodic antennas to design a miniaturized broadband antenna. The invention comprises three parts: a tightly coupled dipole for generating low-frequency radiation, a log-periodic antenna for generating high-frequency radiation, and a baffle for adjusting the low-frequency radiation pattern. The antenna in the design example provided by this invention connects the tightly coupled dipole and the log-periodic antenna in series via an impedance-gradient line. In the simulation example provided by this invention, the antenna radiates using the tightly coupled dipole antenna in the 1-5 GHz range and the log-periodic antenna in the 5-60 GHz range. In this example, the antenna's lateral dimension is 28 mm, only 0.093λ. L The antenna's longitudinal dimension is 49mm, and it is only 0.16λ. L The distance between the baffle and the antenna is 30mm, which is 0.1λ. L Compared to other log-periodic antennas, the log-periodic antenna based on a tightly coupled structure designed in this invention has superior advantages in miniaturization and broadband performance. Therefore, this antenna has a wider range of applications in detection, reception, and communication.

[0029] Compared to traditional methods such as fractal structures and end loading to extend the current path and achieve miniaturization of log-periodic antennas, the lateral size is limited by wavelength and current path length, typically to 0.3λ. L And above, the miniaturization of the longitudinal dimension is affected by the characteristics of the logarithmic periodic structure itself, typically around 0.4λ. L And above. This is because log-periodic antenna structures typically divide the antenna into a transmission region, a radiation region, and a dissipation region. As a result, in order to achieve radiation in a low-frequency antenna, several dissipation dipoles need to be added outside the low-frequency antenna, which greatly increases the antenna size.

[0030] The antenna designed in this invention is the first to combine tightly coupled dipole elements and log-periodic antenna elements, thereby realizing an ultra-wideband antenna. Simulation examples show that the antenna's impedance bandwidth can reach 60 octaves or more, and the antenna radiation pattern remains end-firing even after a baffle is applied. Furthermore, it has significant miniaturization advantages, with the lateral dimension of the antenna radiating section being only 0.093λ. L Furthermore, the antenna's longitudinal dimension is only 0.16λ. L .

[0031] This antenna uses an impedance transformation line to transfer the low-frequency radiation originally generated in a log-periodic antenna to a tightly coupled dipole, thus avoiding the large size of the low-frequency radiation and dissipation regions. Furthermore, by utilizing the characteristics of the tightly coupled dipole, it achieves miniaturization of the lateral dimensions, avoiding the size limitations of conventional non-frequency-varying antennas. L The problem of / 2 constraint.

[0032] This antenna employs a tightly coupled dipole transmission mode at low frequencies. By adding a ground plane after the dipole, the directivity of the dipole antenna is increased, enabling its use in radar detection systems. At high frequencies, it uses a log-periodic antenna for transmission, allowing for directional reception of high-frequency signals and thus enabling radar detection, signal relay amplification, and other functions.

[0033] Secondly, this invention can be used as an ultra-wideband detection antenna. When all elements of the array are excited, a signal with an end-fire direction exceeding 60 times the frequency can be generated, producing a directional end-fire pattern, thereby achieving signal detection and direction finding functions. Furthermore, this antenna can also be used as a receiving antenna to receive omnidirectional incoming space signals. By arranging the antennas in a circular array, and by arranging multiple of these antennas in a circle, broadband omnidirectional radiation can be achieved, realizing a broadband omnidirectional detection system.

[0034] This invention can also be used in integrated information and energy devices. Benefiting from the antenna's ultra-wideband characteristics, the antenna is frequency-divided and multiplexed. After removing the rear baffle, the low-frequency portion exhibits omnidirectional radiation characteristics, suitable for signal reception and transmission. The high-frequency portion possesses high gain characteristics, suitable for energy collection and transmission. When using this antenna in integrated information and energy devices, it is only necessary to distinguish the operating frequency band of the dipole antenna from that of the log-periodic antenna, and then use rectifier circuits and duplexers to receive incoming signals of different frequencies. By adjusting the antenna's operating frequency, the tightly coupled dipole's operating frequency can cover all commonly used communication frequency bands, such as 700-2600MHz. Therefore, this antenna has excellent signal reception and transmission capabilities and can be used in the signal section of integrated information and energy devices. After adjusting the frequency of the tightly coupled dipole portion of the antenna for signal transmission, the corresponding high-frequency portion can rely on its high gain and high directivity to provide wireless power to the signal transmission section. That is, free-floating electromagnetic energy in free space can be collected and stored in a battery through a rectifier circuit, increasing the system's energy reserves.

[0035] The antenna of this invention can also be used in green communication systems. It achieves this by utilizing the low-frequency omnidirectional property of the antenna after removing the low-frequency baffle, enabling the system's communication function. By utilizing the antenna's high-frequency directional capability, it harvests energy from space and stores the harvested energy in a battery via a rectifier circuit. The system should include a rectifier circuit, a signal booster, a battery, and the antenna itself. This system can achieve green communication by collecting and storing energy from ionized electromagnetic signals in space. Through this high-frequency energy harvesting, a self-powered communication device can be realized, achieving low-carbon and green communication.

[0036] Third, as supplementary evidence of the inventive step of the claims of this invention, it is also reflected in the following important aspects:

[0037] (1) The expected benefits and commercial value of the technical solution of this invention after transformation are as follows:

[0038] This invention can be used in ultra-wideband (UWB) detection equipment and applied to UWB detection systems. By covering a working bandwidth of more than 60 octaves, it enables the detection of incoming signals in different frequency bands. Products resulting from the technological transformation of this invention can also be applied to military detection systems, thus possessing market potential, economic value, and national defense value.

[0039] (2) The technical solution of this invention fills a technical gap in the industry both domestically and internationally:

[0040] This invention utilizes a combination of tightly coupled dipole antennas and log-periodic antennas to significantly expand the antenna bandwidth, realizing an ultra-wideband direction-finding antenna. Using an ultra-wideband antenna as the direction-finding unit can greatly improve the detection sensitivity and operating range of the direction-finding system, which is of great significance for the broadbanding of test systems.

[0041] (3) Whether the technical solution of the present invention solves the technical problem that people have long wanted to solve but have never been able to solve successfully:

[0042] This invention utilizes a series-fed tightly coupled dipole and a log-periodic antenna, combining the ultra-wideband characteristics of both antennas to achieve an ultra-wideband direction-finding antenna. Traditional direction-finding antennas typically employ the form of a traditional log-periodic antenna. Existing wideband antennas using log-periodic antennas can only achieve performance within 20 octaves, and their dimensions are generally around 0.3λ. L *0.5λ L The antenna provided in this invention's design example has a significant miniaturization advantage, with the lateral dimension of the antenna's radiating portion being only 0.093λ. L Furthermore, the antenna's longitudinal dimension is only 0.16λ. L .

[0043] Fourth, the invention of a tightly coupled ultra-wideband log-periodic antenna design provides solutions to some specific technical problems and brings about significant technological advancements. These technical problems and their corresponding advancements are as follows:

[0044] Technical problems to be solved:

[0045] 1. Bandwidth limitation: Existing antenna designs often face bandwidth limitations, especially in applications that require antennas to maintain good performance over a wide bandwidth.

[0046] 2. Directivity and gain issues: Many existing antenna designs often lack sufficient directivity and gain in the low-frequency range, which limits their effectiveness in specific applications such as directional communication and radar systems.

[0047] 3. Complex feeding and matching networks: Traditional antenna systems require complex feeding and impedance matching networks, which increases the complexity and cost of the design.

[0048] Significant technological advancements achieved:

[0049] 1. Extended operating bandwidth: By combining a tightly coupled dipole and a log-periodic antenna design, this antenna can cover a wide frequency range from very low to high frequencies. This makes the antenna suitable for a variety of communication and non-communication applications, such as broadband wireless communication, radar, and other radio frequency applications.

[0050] 2. Improved Directivity and Gain: By incorporating a baffle and reflective backplate design, this antenna offers better directivity and forward gain in the low-frequency band. This significantly improves the overall performance of the antenna, especially in applications requiring directional radiation and reception.

[0051] 3. Simplified feeding and impedance matching: The use of an impedance gradient line simplifies the feeding system and impedance matching requirements, allowing the antenna to be directly connected to a conventional coaxial cable, reducing the need for additional matching networks, and lowering system complexity and cost.

[0052] 4. Improved system efficiency and reliability: By optimizing the antenna design, the system's efficiency and reliability are improved. In particular, by reducing reflection losses caused by impedance mismatch, signal transmission efficiency is enhanced.

[0053] Through these technological advancements, the antenna design of this invention not only solves some of the technical problems faced by traditional antenna design, but also provides a more efficient, economical solution applicable to a variety of application scenarios. These innovations improve antenna performance while reducing design and maintenance costs, thus driving the development of related technological fields. Attached Figure Description

[0054] Figure 1 This is a structural diagram of a tightly coupled ultra-wideband log-periodic antenna provided in an embodiment of the present invention.

[0055] Figure 2 This is an infinitely large active VSWR diagram of the antenna design example provided in the embodiments of the present invention.

[0056] Figure 3 This is the E-plane radiation pattern of some frequency points from 1 to 5 GHz in an infinitely large environment provided by an embodiment of the present invention.

[0057] Figure 4 This is the E-plane radiation pattern of some frequency points in the 5-60GHz range under an infinitely large environment provided in the embodiments of the present invention.

[0058] Figure 5 This is a gain diagram of a unit antenna in an example of an infinitely large environment provided in the embodiments of the present invention.

[0059] Figure 6 This is a schematic diagram of an antenna 1*8 array provided in an embodiment of the present invention.

[0060] Figure 7 This is the S-parameter diagram of the central unit of the 1*8 antenna array provided in an embodiment of the present invention.

[0061] Figure 8 This is the frequency E-plane pattern of a 1*8 array provided in an embodiment of the present invention.

[0062] Figure 1In the middle: 1. Low-frequency tightly coupled dipole unit; 2. High-frequency log-periodic antenna; 3. Baffle part used to adjust the low-frequency radiation pattern. Detailed Implementation

[0063] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0064] like Figure 1 As shown, an embodiment of the present invention provides an ultra-wideband log-periodic antenna based on tight coupling, comprising:

[0065] 1. Low-frequency tightly coupled dipole unit; 2. High-frequency log-periodic antenna; 3. Baffle part for adjusting low-frequency radiation pattern.

[0066] After adding a baffle, the omnidirectional radiation pattern generated by the low-frequency radiation unit is converted into a directional radiation pattern.

[0067] The tight-coupled dipole and log-periodic antenna are matched by an impedance gradient line from 50 ohms to 150 ohms, and the antenna feed port can be directly fed by a coaxial line.

[0068] The low-frequency radiating element provided in this embodiment of the invention consists of two parts: a tightly coupled dipole and a log-periodic antenna.

[0069] The tightly coupled dipole antenna provided in this embodiment of the invention has a rear-loaded reflective backplate.

[0070] The tightly coupled dipole portion of the antenna provided in this embodiment of the invention is loaded with a matching layer to extend the operating bandwidth of the low-frequency portion of the antenna.

[0071] The high-frequency log-periodic antenna provided in this embodiment of the invention is end-loaded.

[0072] The antenna design you described leverages the advantages of multiple antenna technologies, combining tightly coupled dipole antennas and log-periodic antennas to achieve the design goals of wide bandwidth and high directivity.

[0073] Tightly coupled dipole unit section (low-frequency radiating unit):

[0074] 1. Structural characteristics: Tightly coupled dipole antennas improve their bandwidth through tighter electrical coupling. These dipoles are typically designed to be wider than conventional dipoles to support a wider frequency band.

[0075] 2. Rear-loaded reflective backplate: By adding a reflective backplate behind the dipole, the forward gain of the antenna can be effectively improved, while reducing back radiation and enhancing the directivity of the antenna.

[0076] 3. Adding a matching layer: Adding a matching layer helps adjust the antenna's input impedance, making it more suitable for matching with traditional coaxial feed lines (typically 50 ohms). This also helps extend the antenna's low-frequency operating bandwidth.

[0077] High-frequency log-periodic antenna section:

[0078] 1. Structural characteristics: Log-periodic antennas are known for their natural frequency-independent characteristics, providing almost constant radiation characteristics and impedance over a very wide frequency range.

[0079] 2. End loading: By loading the end of the antenna, the size of the antenna can be effectively controlled while keeping the performance of the high-frequency band unaffected.

[0080] baffle section:

[0081] 1. Adjusting the radiation pattern: Adding a baffle to the antenna structure can transform the omnidirectional radiation pattern generated by the low-frequency radiating element into a directional pattern, thereby improving the overall radiation efficiency of the antenna and the signal quality in the target area.

[0082] Impedance gradient line:

[0083] 1. Impedance Matching: Impedance matching between the tightly coupled dipole and the log-periodic antenna is achieved using a tapered impedance line from 50 ohms to 150 ohms. This is a key design feature because it allows the antenna to maintain good matching over a wide frequency range, thereby reducing energy reflections caused by impedance mismatch.

[0084] Overall working mechanism:

[0085] At lower frequencies, the tightly coupled dipole section is primarily responsible for radiation and reception, and its broadband characteristics and afterloaded reflector help improve efficiency and directivity.

[0086] The log-periodic antenna section covers a higher frequency range, maintaining consistent antenna performance across the entire operating bandwidth.

[0087] By designing baffles and impedance gradient lines, the antenna's directivity and matching properties are further optimized, resulting in optimal overall performance.

[0088] This design makes full use of the characteristics of each component to achieve excellent performance over a wide frequency range.

[0089] The present invention provides a method for fabricating a tightly coupled ultra-wideband log-periodic antenna, comprising:

[0090] (1) The substrate made using Rogers 5880 printing process is used as the antenna substrate.

[0091] (2) The log-periodic antenna is designed as a printed dipole log-periodic antenna, and a low-frequency tightly coupled dipole antenna section is designed.

[0092] (3) Print the designed antenna on a PCB substrate of the corresponding size.

[0093] (4) Use a coaxial probe to feed the antenna, connect the outer shell to the ground of the antenna, connect the inner core to the transmission line, and fix it with a solder pad, depending on the use scenario of the antenna.

[0094] (5) Complete the processing and manufacturing of the antenna.

[0095] Specific implementation of the present invention:

[0096] This invention proposes a hybrid ultra-wideband antenna with a bandwidth of 1-60 GHz, combining the broadband performance of tightly coupled dipole antennas and log-periodic antennas. Furthermore, by adding a metal baffle, the antenna exhibits excellent end-fire performance. The low-frequency radiation is generated by the tightly coupled dipole, while the high-frequency radiation pattern is generated by the log-periodic antenna. In the 1-5 GHz range, all elements can be excited, activating the tightly coupled dipole antenna. Without the baffle, the tightly coupled dipole portion, acting as the low-frequency radiating element, can produce omnidirectional radiation. With the baffle added, the low-frequency radiating portion can produce directional radiation. In the 5-60 GHz range, a single element can be excited, achieving the end-fire pattern of the high-frequency log-periodic antenna. Therefore, when the low-frequency radiating element produces directional radiation, the antenna can generate 60 octaves of directional radiation, achieving ultra-wideband detection. When the low-frequency radiating element generates omnidirectional radiation, the antenna will have the directional properties of a low-frequency antenna and the omnidirectional properties of a high-frequency antenna, enabling low-frequency communication and high-frequency detection functions, thus realizing an integrated detection and communication system.

[0097] This invention combines the characteristics of tightly coupled dipole antennas and log-periodic antennas to design a miniaturized broadband antenna. The invention comprises three parts: a tightly coupled dipole for generating low-frequency radiation, a log-periodic antenna for generating high-frequency radiation, and a baffle for adjusting the low-frequency radiation pattern. The antenna in the design example provided by this invention connects the tightly coupled dipole and the log-periodic antenna in series via an impedance-gradient line. In the simulation example provided by this invention, the antenna radiates using the tightly coupled dipole antenna in the 1-5 GHz range and the log-periodic antenna in the 5-60 GHz range. In this example, the antenna's lateral dimension is 28 mm, only 0.093λ. L The antenna's longitudinal dimension is 49mm, and it is only 0.16λ. L The distance between the baffle and the antenna is 30mm, which is 0.1λ. LCompared to other log-periodic antennas, the log-periodic antenna based on a tightly coupled structure designed in this invention has superior advantages in miniaturization and broadband performance. Therefore, this antenna has a wider range of applications in detection, reception, and communication.

[0098] This invention is implemented as follows: an ultra-wideband miniaturized antenna based on tight coupling performance, comprising a low-frequency tightly coupled dipole element, a high-frequency log-periodic antenna, and a baffle element for adjusting the low-frequency radiation pattern. By adding the baffle, the omnidirectional radiation pattern generated by the low-frequency radiating element can be converted into a directional pattern. Matching of the tightly coupled dipole and the log-periodic antenna is achieved through an impedance gradient line from 50 ohms to 150 ohms. The antenna feed port can be directly fed using a coaxial cable, reducing production costs.

[0099] The antenna radiating section of this invention consists of two parts: a tightly coupled dipole and a log-periodic antenna. The tightly coupled dipole antenna can be a tightly coupled dipole with or without patch capacitors and directors. The log-periodic antenna can be a log-periodic antenna designed using miniaturization techniques such as fractal structures, or a traditional log-periodic antenna without fractal structures. The impedance transformer mentioned in this invention is a connecting line that matches the log-periodic antenna and the tightly coupled dipole antenna, and can be implemented in various forms, including but not limited to parallel double lines.

[0100] The present invention adds a reflective backplate after the tightly coupled dipole antenna section, which increases the antenna's directivity and ensures that the antenna maintains end-firing radiation patterns throughout the entire frequency band.

[0101] This invention extends the operating bandwidth of the low-frequency portion of the antenna and improves the low-frequency matching of the antenna by loading a matching layer onto the tightly coupled dipole portion.

[0102] This invention achieves miniaturization of the high-frequency section by loading the end of the log-periodic antenna in the high-frequency section, making it convenient to arrange the entire section in the same unit.

[0103] Using the design concept of this invention, ultra-wideband antennas of different sizes and frequencies can be designed, and they can have an operating bandwidth of more than 60 octaves. This invention can realize antennas with frequencies ranging from 0.1-6GHz to 1-60GHz while maintaining relative size, and all of them have the same performance.

[0104] This invention also provides a method for manufacturing an antenna for a portable direction-finding antenna system carried by a single soldier, characterized in that the method includes the following steps:

[0105] (1) Use substrates that can be manufactured using printing technology, such as Rogers 5880, as antenna substrates.

[0106] (2) The log-periodic antenna is designed as a printed dipole log-periodic antenna, and a low-frequency tightly coupled dipole antenna section is designed.

[0107] (3) Print the designed antenna on a PCB substrate of the corresponding size, which is 28mm*49mm*1mm in this example.

[0108] (4) Use a coaxial probe to feed the antenna, connect the outer shell to the ground of the antenna, connect the inner core to the transmission line, and fix it with a solder pad. Depending on the use scenario of the antenna, add a baffle behind it and adjust the antenna pattern.

[0109] (5) Complete the processing and manufacturing of the antenna, reduce the processing and manufacturing cost of the antenna, and improve the practicality and application value of the direction finding system.

[0110] The innovation lies in the fact that, compared to traditional methods such as fractal structures and end loading to extend the current path and achieve miniaturization of log-periodic antennas, the lateral size is limited by wavelength and current path length, typically to 0.3λ. L At and above, the miniaturization of the longitudinal dimension is affected by the characteristics of the logarithmic periodic structure itself, typically around 0.4λ. L And above. This is because log-periodic antenna structures typically divide the antenna into a transmission region, a radiation region, and a dissipation region. As a result, in order to achieve radiation in a low-frequency antenna, several dissipation dipoles need to be added outside the low-frequency antenna, which greatly increases the antenna size.

[0111] The antenna designed in this invention is the first to combine tightly coupled dipole elements and log-periodic antenna elements, thereby realizing an ultra-wideband antenna. Simulation examples show that the antenna's impedance bandwidth can reach 60 octaves or more, and the antenna radiation pattern remains end-firing even after a baffle is applied. Furthermore, it has significant miniaturization advantages, with the lateral dimension of the antenna's radiating section being only 0.093λ. L Furthermore, the antenna's longitudinal dimension is only 0.16λ. L .

[0112] This antenna uses an impedance transformation line to transfer the low-frequency radiation originally generated in a log-periodic antenna to a tightly coupled dipole, thus avoiding the large size of the low-frequency radiation and dissipation regions. Furthermore, by utilizing the characteristics of the tightly coupled dipole, it achieves miniaturization of the lateral dimensions, avoiding the size limitations of conventional non-frequency-varying antennas. L The problem of / 2 constraint.

[0113] This antenna employs a tightly coupled dipole transmission mode at low frequencies. By adding a ground plane after the dipole, the directivity of the dipole antenna is increased, enabling its use in radar detection systems. At high frequencies, it uses a log-periodic antenna for transmission, allowing for directional reception of high-frequency signals and thus enabling radar detection, signal relay amplification, and other functions.

[0114] This invention can also be used as an ultra-wideband detection antenna. When all elements of the array are excited, a signal with an end-fire direction exceeding 60 times the frequency can be generated, producing a directional end-fire pattern, thereby achieving signal detection and direction finding functions. Furthermore, this antenna can also be used as a receiving antenna to receive omnidirectional incoming space signals. By arranging the antennas in a circular array, and by arranging multiple of these antennas in a circle, broadband omnidirectional radiation can be achieved.

[0115] This invention can also be used in integrated information and energy devices. Benefiting from the antenna's ultra-wideband characteristics, the antenna is frequency-divided and multiplexed. After removing the rear baffle, the low-frequency portion exhibits omnidirectional radiation characteristics, suitable for signal reception and transmission. The high-frequency portion possesses high gain characteristics, suitable for energy collection and transmission. When using this antenna in integrated information and energy devices, it is only necessary to distinguish the operating frequency band of the dipole antenna from that of the log-periodic antenna, and then use rectifier circuits and duplexers to receive incoming signals of different frequencies. By adjusting the antenna's operating frequency, the tightly coupled dipole's operating frequency can cover all commonly used communication frequency bands, such as 700-2600MHz. Therefore, this antenna has excellent signal reception and transmission capabilities and can be used in the signal section of integrated information and energy devices. After adjusting the frequency of the tightly coupled dipole portion of the antenna for signal transmission, the corresponding high-frequency portion can rely on its high gain and high directivity to provide wireless power to the signal transmission section. That is, free-floating electromagnetic energy in free space can be collected and stored in a battery through a rectifier circuit, increasing the system's energy reserves.

[0116] The antenna of this invention can also be used in green communication systems. It achieves this by utilizing the low-frequency omnidirectional property of the antenna after removing the low-frequency baffle, enabling the system's communication function. By utilizing the antenna's high-frequency directional capability, it harvests energy from space and stores the harvested energy in a battery via a rectifier circuit. The system should include a rectifier circuit, a signal booster, a battery, and the antenna itself. This system can achieve green communication by collecting and storing energy from ionized electromagnetic signals in space. Through this high-frequency energy harvesting, a self-powered communication device can be realized, achieving low-carbon and green communication.

[0117] This invention can be used as an ultra-wideband detection antenna. When all elements of the array are excited, it generates end-firing signals exceeding 60 octaves, producing a directional wide-beam pattern for signal detection and direction finding. When arranged in a circular array, it achieves omnidirectional radiation, making it suitable for ultra-wideband detection systems. Furthermore, thanks to the antenna's miniaturization, this invention can also be used in portable detection systems, playing a role in radio detection, search and rescue in the field, and battlefield radio reconnaissance and transmission systems.

[0118] This invention can also be used in integrated communication and energy transmission devices. Benefiting from its ultra-wideband and directional radiation characteristics, this invention offers applications integrating communication and energy transmission. By combining this invention with common integrated communication and energy transmission devices, ionized electromagnetic energy can be absorbed within the ultra-wideband frequency band in which this invention operates, thereby significantly improving the energy reception efficiency of the integrated communication and energy transmission devices. By storing the absorbed electromagnetic energy in a battery, energy utilization is improved, and power consumption is reduced.

[0119] The antenna of this invention can also be used in green communication systems. It achieves this by utilizing the low-frequency omnidirectional property of the antenna after removing the low-frequency baffle, enabling the system's communication function. By utilizing the antenna's high-frequency directional capability, it harvests energy from space and stores the harvested energy in a battery via a rectifier circuit. The system should include a rectifier circuit, a signal booster, a battery, and the antenna itself. This system can achieve green communication by collecting and storing energy from ionized electromagnetic signals in space. Through this high-frequency energy harvesting, a self-powered communication device can be realized, achieving low-carbon and green communication.

[0120] The positive effect of this invention is that it realizes a miniaturized ultra-wideband antenna. The designed antenna has a lateral dimension of 28mm, which is only 0.093λ. L The antenna's longitudinal dimension is 49mm, and it is only 0.16λ. L The distance between the baffle and the antenna is 30mm, which is 0.1λ. L Traditional log-periodic antennas generally have narrow bandwidths, making it difficult to achieve ultra-wideband performance of tens of octaves. Furthermore, limited by the size and wavelength requirements of non-frequency-varying antennas, their miniaturization is also poor. Existing broadband antennas using log-periodic antennas can only achieve performance of no more than 20 octaves, and their size is generally around 0.3λ. L *0.5λ L In conclusion, compared to other log-periodic antennas, the log-periodic antenna based on a tightly coupled structure designed in this invention offers superior miniaturization and broadband advantages. Therefore, this antenna has wider applications in detection, reception, and communication. Figure 2It can be seen that the present invention has excellent ultra-wideband characteristics, through Figure 3 As can be seen from 4 and 5, the antenna designed in this invention has a directional wide beam pattern within the operating frequency band, and the antenna pattern has consistency. Figure 6 The application of the antenna in the configuration of a 1x8 linear array is provided. Figure 7 This demonstrates that the antenna has good operating bandwidth when configured as a linear array. Figure 8 This demonstrates that the antenna, when configured as a linear array, exhibits a directional wide beam pattern within its operating frequency band.

[0121] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any modifications, equivalent substitutions, and improvements made by those skilled in the art within the scope of the technology disclosed in the present invention, and within the spirit and principles of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A tightly coupled ultra-wideband log-periodic antenna, characterized in that, include: The system comprises a low-frequency tightly coupled dipole unit, a high-frequency log-periodic antenna, and a baffle portion for adjusting the low-frequency radiation pattern. The low-frequency tightly coupled dipole unit and the high-frequency log-periodic antenna are connected in a tightly coupled manner to achieve wideband coverage. The baffle portion is located in front of the low-frequency tightly coupled dipole unit to convert the omnidirectional radiation mode into a directional radiation mode. The low-frequency tightly coupled dipole unit and the high-frequency log-periodic antenna are connected by an impedance gradient line to achieve series feeding. The high-frequency log-periodic antenna section is loaded at the end; the low-frequency tightly coupled dipole unit section is loaded with a matching layer.

2. A method for fabricating and manufacturing a tightly coupled ultra-wideband log-periodic antenna as described in claim 1, characterized in that, The fabrication method for the tightly coupled ultra-wideband log-periodic antenna includes: (1) The substrate made using Rogers 5880 printing process is used as the antenna substrate; (2) Design the log-periodic antenna as a printed dipole log-periodic antenna and design the low-frequency tightly coupled dipole antenna part; (3) Print the designed antenna onto a PCB substrate of the corresponding size; (4) Use a coaxial probe to feed the antenna, connect the outer shell to the ground of the antenna, connect the inner core to the transmission line, and fix it with a solder pad, depending on the use scenario of the antenna; (5) Complete the processing and manufacturing of the antenna.

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