Log-periodic antenna

Abstract

The utility model discloses a log-periodic antenna, which belongs to the technical field of radar communication, and comprises a radio frequency cable assembly, a PCB (printed circuit board), an antenna body and a base, the radio frequency cable assembly consists of a radio frequency coaxial connector and a radio frequency cable, the radio frequency coaxial connector is a standard SMA-J radio frequency coaxial connector, the PCB is provided with a microstrip circuit, and the antenna body is connected with the base. One side of the microstrip circuit is used for being connected with a radio frequency cable core wire of a radio frequency cable, the other side of the microstrip circuit is used for being connected with an antenna body, a plurality of grounding holes are symmetrically formed in the root of the PCB, and the grounding holes are used for being connected with a cable outer shielding layer of the radio frequency cable. Compared with an existing structure, the antenna body radiator and the radio frequency cable assembly are integrally welded, fusion welding can be adopted between the PCB and the antenna body, in addition, the coupling part of the antenna microstrip line is welded with the cable feed part, the radiation efficiency of the antenna is remarkably improved, and the antenna radiation efficiency is improved. And the whole antenna adopts a symmetrical design, so that the uniqueness of the antenna in an array panel and the stability of antenna indexes are ensured.

Description

Technical Field

[0001] The utility model belongs to the technical field of radar communication, and in particular relates to a logarithmic periodic antenna. Background Art

[0002] The antenna vibrator is the core component of the antenna, which has the function of guiding and amplifying electromagnetic waves. As a non-frequency-variable broadband antenna, the logarithmic periodic antenna relies on the self-similarity of the resonant vibrator to obtain a very wide bandwidth. It is widely used in the fields of communication, radar, electronic countermeasures, etc. The conventional logarithmic periodic antenna design method is relatively mature, but in the field of radar or electronic reconnaissance, the miniaturization design of shortwave antennas is often more important.

[0003] Common log-periodic antennas are in the form of microstrip antennas and dual-arm dipole antennas. Microstrip log-periodic antennas have the advantages of small size, light weight, easy processing and low cost; dipole log-periodic antennas have excellent performance such as strong environmental adaptability, high mechanical strength, simple assembly, reliable structure and low loss. The traditional log-periodic antenna is composed of N parallel symmetrical dipoles according to the structural period. The traditional manufacturing method is to directly weld the dipole to the feed line. Because the antenna body is large in size and has high thermal conductivity, the soldering time is long, which easily causes the surface of the antenna body to oxidize and blacken, affecting the production quality and welding efficiency.

[0004] Commonly used forms include log-periodic dipole antenna, monopole antenna, log-periodic spiral antenna, etc. Log-periodic dipole antenna can radiate electromagnetic waves in the horizontal or vertical direction. Its structure is simple and easy to manufacture, so it is widely used. The structure consists of two symmetrical radiators. The corresponding number of branches and the corresponding branch lengths are designed according to a certain rule. The branch distribution can be symmetrical or asymmetrical. The number and size of the branches have a significant effect on the gain and radiation pattern of the antenna. After the log-periodic oscillator antenna is fed, the electromagnetic energy only excites the part of the oscillator close to the resonant length along the collection line, forming antenna radiation. This part of the excited oscillator is called the effective area. The characteristics of the antenna mainly depend on the effective area, which moves with the change of frequency.

[0005] The shortcomings of the prior art are mainly:

[0006] (1) Microstrip logarithmic antennas require front protection, which increases their protection costs, and the loss of microstrip circuits increases significantly at high frequencies.

[0007] (2) The slot antenna processing technology is difficult, the production cost is high, and the size and weight are large.

[0008] (3) The monopole antenna is a one-dimensional structure. It radiates electromagnetic waves mainly in the vertical direction, has weak radiation capability in the horizontal direction, and has a narrow frequency band.

[0009] (4) Traditional log-periodic antennas usually weld the feed line and the antenna body together. When using traditional antennas, the inverted F antenna and the SMA RF connector are combined together by screws. The inverted F antenna is a machined structural part, and the conductor inside the connector is fixed to the antenna by soldering or gluing. Utility Model Content

[0010] In view of the above technical problems, the utility model provides a log-periodic antenna, which realizes a design form in which the antenna body radiator and the radio frequency cable assembly are integrally welded. Fusion welding can be used between the PCB board and the antenna body. In addition, the welding of the coupling part of the antenna microstrip line and the cable feeding part significantly improves the radiation efficiency of the antenna. The overall symmetrical design ensures the uniqueness of the antenna installed in the array panel and the stability of the antenna indicators.

[0011] The utility model solves the above problems through the following technical means:

[0012] A logarithmic periodic antenna, characterized in that it includes a radio frequency cable assembly, a PCB board, an antenna body and a base, wherein: the radio frequency cable assembly consists of a radio frequency coaxial connector and a radio frequency cable, the radio frequency coaxial connector is a standard SMA-J radio frequency coaxial connector, and the radio frequency coaxial connector is arranged at one end of the base; the PCB board and the antenna body are arranged at the other end of the base, a microstrip circuit is arranged on the PCB board, one side of the microstrip circuit is used to connect the radio frequency cable core wire of the radio frequency cable, and the other side of the microstrip circuit is used to connect the antenna body, and a plurality of grounding holes are symmetrically arranged at the root of the PCB board, and the grounding holes are used to connect the cable outer shielding layer of the radio frequency cable.

[0013] Preferably, two positioning top holes are symmetrically arranged at one end of the PCB board, and positioning pins connected to the antenna body are installed in the positioning top holes.

[0014] Preferably, the antenna body is composed of a radiator and a base, wherein: the radiator adopts a curved symmetrical three-section structure, the base is arranged at the end of the radiator and is at a right angle to the radiator; a bottom groove is provided at the end of the radiator that contacts the PCB board, and positioning bottom holes are provided on both sides of the bottom groove, and the positioning bottom holes are used to connect positioning pins; a matching groove connected to the bottom groove is provided on the base, and two mounting top holes are provided at the bottom of the base, and a connecting base is installed in the mounting top hole for mounting screws.

[0015] Preferably, a bottom boss is provided at one end of the radiator close to the base.

[0016] Preferably, a square boss is provided on the base, and two mounting bottom holes and a cable hole are provided on the square boss. The mounting bottom holes are used to connect mounting screws, and the cable hole is used to install radio frequency cables. Side holes are installed around the base.

[0017] The utility model has the following beneficial effects:

[0018] This structure realizes the design form of integral welding of the antenna body radiator and the cable assembly. Fusion welding is used between the PCB and the antenna body, which improves the overall assembly reliability, realizes the welding of the coupling part of the antenna microstrip line and the cable feeding part, improves the radiation efficiency of the antenna, and adopts a symmetrical design to ensure the uniqueness of the antenna installed in the array panel and the stability of the antenna indicators. The simple and reliable structure of the entire antenna body reduces the process complexity of the product, thereby reducing the cost of the product and improving the consistency of the product.

[0019] The structure of the logarithmic periodic antenna can overcome the shortcomings of the existing technology and improve the reliability of the product, and solve the following problems: (1) The microstrip line and the antenna body are coupled to feed the antenna, which improves the antenna gain and directional characteristics; (2) The microstrip line and the antenna body are fixed with solder paste instead of traditional screws, which improves the grounding effect of the antenna body and increases the reliability of the overall assembly; (3) The three-section symmetrical structure is adopted, and the antenna body structure is simple and easy to assemble. The symmetrical structure facilitates the antenna to be designed as an array. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the technical solution of the present invention, the drawings required for use in the implementation mode will be briefly introduced below. Obviously, the drawings described below are only some implementation modes of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0021] Figure 1 It is a front structural schematic diagram of the utility model;

[0022] Figure 2 It is a schematic diagram of the back structure of the utility model;

[0023] Figure 3 It is a schematic diagram of the antenna body structure of the utility model.

[0024] Figure 4 This is a schematic diagram of the PCB board structure of the utility model;

[0025] Figure 5 This is a schematic diagram of the PCB board installation of the utility model;

[0026] Figure 6 This is a schematic diagram of the installation top hole structure of the utility model;

[0027] Figure 7 It is a schematic diagram of the base structure of the utility model.

[0028] Among them, 1-RF cable assembly, 101-RF coaxial connector, 102-RF cable, 103-RF cable core wire, 104-cable outer shielding layer, 2-PCB board, 201-microstrip circuit, 202-grounding hole, 203-positioning top hole, 204-positioning pin, 3-antenna body, 301-radiator, 302-base, 303-bottom groove, 304-positioning bottom hole, 305-matching groove, 306-mounting top hole, 307-mounting screw, 308-bottom boss, 4-base, 401-square boss, 402-mounting bottom hole, 403-cable hole, 404-side hole. DETAILED DESCRIPTION

[0029] In the description of the present utility model, it should be understood that the terms "center", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present utility model and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present utility model. The terms "first" and "second" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present utility model, unless otherwise specified, "multiple" means two or more.

[0030] The utility model will be described in detail below with reference to the accompanying drawings.

[0031] like Figures 1 to 7 As shown, the logarithmic periodic antenna includes a radio frequency cable assembly 1, a PCB board 2, an antenna body 3 and a base 4. In the figure, the radio frequency cable assembly 1 is composed of a radio frequency coaxial connector 101 and a radio frequency cable 102. The radio frequency coaxial connector 101 is a standard SMA-J radio frequency coaxial connector. The radio frequency coaxial connector 101 is arranged at one end of the base 4, and the radio frequency cable 102 passes through the base 4. The PCB board 2 and the antenna body 3 are arranged at the other end of the base 4. A microstrip circuit 201 is arranged on the PCB board 2. One side of the microstrip circuit 201 is used to connect the radio frequency cable core wire 103 of the radio frequency cable 102, and the other side of the microstrip circuit 201 is used to connect the antenna body 3. A plurality of grounding holes 202 are symmetrically arranged at the root of the PCB board 2, and the grounding holes 202 are used to connect the cable outer shielding layer 104 of the radio frequency cable 102.

[0032] In the figure, the existing solder paste welding process is used between the PCB board 2 and the antenna body 3, the RF cable core wire 103 and the PCB board 2 are connected by soldering, and the cable outer shielding layer 104 is connected to the grounding hole 202 of the PCB board 2 by soldering. The number of grounding holes 202 is honeycomb-shaped, which can quickly dissipate heat on the one hand, reduce weight on the other hand, and is also convenient for soldering.

[0033] In this embodiment, two positioning top holes 203 are symmetrically arranged at one end of the PCB board 2 , and positioning pins 204 connected to the antenna body 3 are installed in the positioning top holes 203 .

[0034] In the figure, the antenna body 3 is composed of a radiator 301 and a base 302, wherein: the radiator 301 adopts a three-section structure with curved symmetry, the base 302 is arranged at the end of the radiator 301 and is at a right angle to the radiator 301; a bottom groove 303 is provided at one end of the radiator 301 contacting the PCB board 2, and positioning bottom holes 304 are provided on both sides of the bottom groove 303, and the positioning bottom holes 304 are used to connect the positioning pins 204; a matching groove 305 connected to the bottom groove 303 is provided on the base 302, and two mounting top holes 306 are provided at the bottom of the base 302, and the connecting base 4 is installed in the mounting top holes 306 for mounting screws 307. In addition, a bottom boss 308 is provided at one end of the radiator 301 close to the base 302.

[0035] Specifically, the antenna body 3 is integrally processed from copper alloy. To improve the loss of the antenna body, the existing silver plating process can be used on the outer surface of the antenna body. The design of the antenna body 3 adopts a curved symmetrical distribution form, which improves the beam width of the antenna at high frequencies.

[0036] It should be noted that the antenna body 3 adopts a curved symmetrical three-section structure. Figure 3 As shown, the branch structure is formed by integral machining, and a mounting base is provided under the antenna body. The base and the antenna body are fastened with screws. The assembly process is simple and reliable, which improves product performance indicators and reduces production and installation costs.

[0037] In the figure, a square boss 401 is provided on the base 4, and two mounting bottom holes 402 and a cable hole 403 are provided on the square boss 401. The mounting bottom hole 402 is used to connect the mounting screw 307, and the cable hole 403 is used to install the RF cable 102. Side holes 404 are installed around the base 4. Specifically, the base 4 adopts a symmetrical structure, which simplifies the assembly form of the vibrator when the array is assembled later.

[0038] In actual operation, a microstrip circuit is printed on the PCB board. The existing solder paste melting welding process can be used between the PCB board and the antenna body to ensure good contact between the ground on the back of the PCB board and the antenna body. A matching groove is set at the gap in the middle of the antenna body to realize the coupling of the vibrator, which is coupled with the groove type at the bottom of the antenna body, reducing the overall voltage standing wave ratio of the antenna. Its coupling structure avoids direct welding and feeding of the cable core wire and the antenna body, making it easier to weld the antenna body and the cable assembly, improving the welding efficiency. The PCB board and the antenna body are positioned with positioning pins to ensure that the PCB and the cable can be accurately positioned to ensure welding accuracy.

[0039] It should be further explained that the PCB board and the antenna body adopt a new coupling feeding form, which can improve product performance and reliability while improving assembly efficiency. Users can flexibly increase or decrease the number of antenna units according to specific usage requirements to form a planar array structure with a large number of antenna units. The antenna body adopts a curved symmetrical structure to improve the beam width of the antenna at the high-frequency end. This logarithmic periodic antenna design can be applied to the integrated design of other similar symmetrical dipole antennas. The input RF impedance is 50Ω, and a standard RF connector is used as an interface to feed the antenna unit. The antenna body's oscillator curve shape and branch length and its structural form can be used as a reference to optimize the design of related antennas of the same type. It can not only be used for airborne equipment, but also provide modularity for vehicle-mounted equipment and ground fixed equipment.

[0040] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the utility model, rather than to limit it. Although the utility model has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the utility model.

Claims

1. A log-periodic antenna, characterized in that: It comprises a radio frequency cable assembly (1), a PCB board (2), an antenna body (3) and a base (4), wherein: The radio frequency cable assembly (1) is composed of a radio frequency coaxial connector (101) and a radio frequency cable (102); the radio frequency coaxial connector (101) is a standard SMA-J radio frequency coaxial connector; the radio frequency coaxial connector (101) is arranged at one end of the base (4); The PCB board (2) and the antenna body (3) are arranged at the other end of the base (4); a microstrip circuit (201) is arranged on the PCB board (2); one side of the microstrip circuit (201) is used to connect to a radio frequency cable core wire (103) of a radio frequency cable (102); the other side of the microstrip circuit (201) is used to connect to the antenna body (3); a plurality of grounding holes (202) are symmetrically arranged at the root of the PCB board (2); the grounding holes (202) are used to connect to an outer cable shielding layer (104) of the radio frequency cable (102).

2. The log-periodic antenna according to claim 1, characterized in that: Two positioning top holes (203) are symmetrically arranged at one end of the PCB board (2), and positioning pins (204) connected to the antenna body (3) are installed in the positioning top holes (203).

3. The log-periodic antenna according to claim 1, characterized in that: The antenna body (3) is composed of a radiator (301) and a base (302), wherein: The radiator (301) adopts a three-section structure with curved symmetry, and the base (302) is arranged at the end of the radiator (301) and is at a right angle to the radiator (301); A bottom groove (303) is provided at one end of the radiator (301) contacting the PCB board (2), and positioning bottom holes (304) are provided on both sides of the bottom groove (303), and the positioning bottom holes (304) are used to connect positioning pins (204); The base (302) is provided with a matching groove (305) connected to the bottom groove (303), and the bottom of the base (302) is provided with two mounting top holes (306), and the mounting top holes (306) are provided with a connecting base (4) for mounting screws (307).

4. The log-periodic antenna according to claim 3, characterized in that: A bottom boss (308) is provided at one end of the radiator (301) close to the base (302).

5. The log-periodic antenna according to claim 1, characterized in that: The base (4) is provided with a square boss (401), and the square boss (401) is provided with two mounting bottom holes (402) and a cable hole (403), the mounting bottom hole (402) is used to connect the mounting screws (307), and the cable hole (403) is used to install the radio frequency cable (102), and the base (4) is provided with side holes (404) around its periphery.

Images