CN102299418B - Multilayer broadband microstrip antenna - Google Patents

Abstract

The invention discloses a multilayer broadband microstrip antenna, which comprises an upper dielectric substrate, an intermediate dielectric substrate, a lower dielectric substrate, an upper low dielectric constant insulating dielectric layer, a lower low dielectric constant insulating dielectric layer, a reflection plate and a feeder Electric probe. Wherein the lower surface of the upper dielectric substrate and the upper surface of the intermediate dielectric substrate are attached with metal copper patch rectangular radiators, and the radiators have U-shaped gap structures of different sizes. Due to the special double-layer inverted U-shaped slot coupling feeding method of the present invention, the symmetry of the E-plane or H-plane pattern of the antenna can be better, and the performance of the antenna in more directions is guaranteed to be more consistent, no matter it is used as a detection or communication antenna. It has practical significance. Compared with the traditional metal reflector, the reflector with EBG structure can better suppress the backward radiation at the specified frequency, improve the directivity of the antenna, and further increase the antenna gain.

Description

Multilayer Broadband Microstrip Antenna

technical field

The invention relates to a radiation terminal of a double-conductor microwave transmission line, in particular to a multilayer broadband microstrip antenna.

Background technique

Wireless local area network is the product of the combination of computer network and wireless communication technology. It uses wireless technology to replace all the functions of the traditional wired LAN, making the networking and use of the LAN more flexible and convenient.

IEEE802.11 is one of the first generation wireless LAN standards. This standard defines the specifications of the physical layer and the media access control (MAC) protocol, allowing manufacturers of wireless local area networks and wireless equipment to establish interoperable network equipment within a certain range. There are multiple protocol groups under this standard, among which IEEE802.11a, IEEE802.11n, IEEE802.11p and other extended protocols can work in the 5GHz-6GHz frequency band.

With the popularization of wireless local area network and wireless broadband access equipment, more and more wireless communication terminals or electronic products cannot lack the participation of wireless local area network technology. performance and other requirements.

As a wireless radiation terminal, the size and performance of the antenna largely determine the miniaturization and communication performance of communication equipment. Among the various antennas widely used at present, the microstrip antenna has the characteristics of small size and light weight, suitable for conformal with the carrier, etc., but the traditional microstrip antenna has the disadvantage of relatively narrow impedance bandwidth. With the innovations in the structure and design methods of near and modern microstrip antennas, the impedance bandwidth of the antenna can be effectively improved by means of slot coupling technology and stacking technology. However, the use of slot coupling technology and stacking technology will inevitably change the original radiation structure of the antenna, arouse interference factors such as surface waves, and cause back lobes and side lobes on the pattern, which will bring about a decline in the performance of the antenna pattern and affect the microstrip antenna. Application in some strong directivity scenes. So it is very necessary to optimize the design of the antenna pattern.

Electromagnetic Bandgap (EBG) structure is one of the research hotspots in recent years. Because the frequency band gap formed by it can effectively suppress the surface wave of the antenna and improve the radiation efficiency, it is widely used in the design of microstrip antennas. The parameters that determine antenna performance mainly include Working bandwidth, Radiation Pattern, Return Loss and Antenna Gain. The antenna pattern determines the transmitting and receiving performance of the antenna. An antenna for a specific application scenario should have good directivity. Therefore, suppressing the back lobe and side lobes of the pattern is an important technical feature of the directional antenna. The EBG structure reflector can well suppress the back lobe of the antenna pattern and improve the pattern characteristics. In addition, the suppression of the back lobe and side lobes can also increase the gain in the main radiation direction, effectively improve the effective radiation of the antenna, and suppress interference.

The EBG structure described in the present invention is a planar structure, and a periodic EBG structure can be easily obtained by using a PCB process to make an EBG reflector. For the existing EBG structure, such as the EBG structure involved in the invention of the 200910036654.9 patent application, the implementation of the EBG structure described in the present invention can adopt a simpler and more common process flow, thereby effectively reducing the cost of the antenna and improving performance stability. Degree, shorten the product cycle.

Contents of the invention

The purpose of the present invention is to provide a device that is easy to implement, low in processing and production costs, wide in operating frequency, high in gain, and good in directivity of the pattern, and can be used in the fields of wireless local area network communication equipment, satellite and ground communication, detection, etc., and has good compatibility. A multipurpose multilayer broadband microstrip antenna.

For realizing the above object, technical solution of the present invention is:

The invention is a multilayer broadband microstrip antenna, which comprises an upper dielectric substrate, an intermediate dielectric substrate, a lower dielectric substrate, an upper low dielectric constant insulating dielectric layer, a lower low dielectric constant insulating dielectric layer and a feeding probe; The lower surface of the upper dielectric substrate is attached with an upper rectangular metal patch as a radiator, and the upper rectangular metal patch is provided with a U-shaped groove; the upper surface of the intermediate dielectric substrate is also attached with a middle rectangular metal patch as a coupler. The middle rectangular metal patch is provided with a U-shaped groove; the lower surface of the intermediate dielectric substrate is integrally attached with a metal ground layer, and a small round hole is arranged in the center of the metal ground layer; between the upper dielectric substrate and the intermediate dielectric substrate There is an upper low dielectric constant insulating dielectric layer between them; the lower dielectric substrate is close to the lower surface of the intermediate dielectric substrate, and the lower surface of the lower dielectric substrate is the feeding structure of the antenna; the metal probe vertically penetrates the intermediate dielectric substrate, the lower dielectric substrate The dielectric substrate is located at the center of the intermediate dielectric substrate and the lower dielectric substrate. Its length is equal to the sum of the thicknesses of the two substrates, and its diameter is slightly smaller than the small round hole in the center of the metal ground layer. The feeding probe is connected to the middle rectangular metal sticker on the upper surface of the intermediate dielectric substrate The feeder microstrip lines on the lower surface of the lower dielectric substrate and the lower dielectric substrate are welded separately to form a feeder radiation path; the lower surface of the lower dielectric substrate is closely attached to the lower low dielectric constant insulating dielectric layer, and the lower layer of the lower low dielectric constant insulating dielectric layer is A reflector; the reflector is a reflector with an EBG structure; the U-shaped groove on the upper rectangular metal patch on the lower surface of the upper dielectric substrate and the middle rectangular metal patch on the upper surface of the intermediate dielectric substrate The notch of the U-shaped groove is opposite to each other, which is a gap coupling method.

The U-shaped groove attached to the upper rectangular metal patch on the lower surface of the uppermost dielectric substrate is spliced by two vertical rectangular grooves and one horizontal rectangular groove, and its splicing shape is similar to the English capital letter "U"; The U-shaped groove on the middle rectangular metal patch on the upper surface of the intermediate dielectric substrate is formed by splicing two vertical rectangular slots and one horizontal rectangular slot, and its size is smaller than the U-shaped groove on the upper rectangular metal patch.

The EBG holes are arranged periodically and orderly on the reflector with the EBG structure, wherein a single EBG hole is composed of 15 fixedly arranged rectangular holes with the same size, and the distance between the EBG holes and the EBG holes is horizontal and vertical There is a fixed interval, and the EBG hole size and the EBG hole interval should make the EBG structure period be 1/4 to 3/4 of the cut-off wavelength.

All metal patch radiators, EBG reflectors, grounding plates, microstrip feeders and substrates of the invention are realized by printed circuit board technology. The dielectric substrate can be realized by microwave dielectric board or PCB board, and the low dielectric constant insulating dielectric layer can be realized by means of suspension (air layer) or by foam or other materials with similar electrical properties. The bonding between the substrate and the low dielectric constant insulating medium layer can be done by low dielectric constant viscose solvent or external fastening.

After adopting the above scheme, due to the special double-layer inverted U-shaped slot coupling feeding method of the present invention, the symmetry of the E-plane or H-plane pattern of the antenna can be better, and the performance of the antenna in more directions is guaranteed to be more consistent. Detection or communication antenna is more practical. Compared with the traditional metal reflector, the reflector with EBG structure can better suppress the backward radiation at the specified frequency, improve the directivity of the antenna, and further increase the antenna gain. The special planar structure of the EBG reflecting plate of the present invention also provides convenience for processing and manufacturing the antenna reflecting plate of the EBG structure.

The invention is compatible with various wireless local area network protocols under the IEEE802.11 standard, and can be used as a wireless device receiving and transmitting antenna according to the protocol standard; the working frequency band of the invention is located in the satellite communication frequency band, and can also be used as a satellite or ground communication antenna or a detection antenna. The application of the present invention can effectively increase the bandwidth of the microstrip antenna, greatly improve the characteristics of the antenna pattern, make the antenna directivity stronger and the gain higher, and meet applications such as communication, detection, speed measurement, distance measurement, and imaging. The invention is simple in implementation, easy in processing, low in process complexity, can effectively reduce production cost, and has a wide range of applications.

The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments.

Description of drawings

Fig. 1 is an axonometric view of an embodiment of the present invention;

Fig. 2 is a side view of an embodiment of the present invention;

3 is a top view of an upper dielectric substrate according to an embodiment of the present invention;

4 is a top view of an interlayer dielectric substrate according to an embodiment of the present invention;

5 is a top view of a metal ground layer according to an embodiment of the present invention;

6 is a bottom view of the lower surface of the lower dielectric substrate according to an embodiment of the present invention;

Fig. 7 is a top view of a metal reflector according to an embodiment of the present invention;

Fig. 8 is a measurement data diagram of standing wave ratio in an embodiment of the present invention;

Fig. 9 is a pattern diagram of the E-plane and H-plane of the antenna (operating frequency 5.55 GHz) according to an embodiment of the present invention.

Detailed ways

As shown in Figure 1 and Figure 2, the present invention is a multilayer broadband microstrip antenna, which includes an upper dielectric substrate 1, an intermediate dielectric substrate 2, a lower dielectric substrate 3, an upper low dielectric constant insulating dielectric layer 4, a lower dielectric substrate Low dielectric constant insulating medium layer 5 , feeding probe 6 , upper rectangular metal patch 7 , middle rectangular metal patch 8 , metal ground layer 9 , and reflection plate 10 .

The lower surface of the upper dielectric substrate 1 is attached with an upper rectangular metal patch 7 as a radiator, and the upper rectangular metal patch 7 is provided with a U-shaped groove 71 (as shown in FIG. 3 ). The upper surface of the intermediate dielectric substrate 2 is also attached with a middle rectangular metal patch 8 as a coupler. The middle rectangular metal patch 8 is provided with a U-shaped groove 81 (as shown in FIG. 4 ), and its size is the same as that of the upper rectangular metal patch 7. Different; the lower surface of the intermediate dielectric substrate 2 is provided with a metal ground layer 9 as a whole, and a circular hole 91 is provided in the center of the metal ground layer 9 (as shown in FIG. 5 ); the upper dielectric substrate 1 and the intermediate dielectric substrate 2 There is an upper low-permittivity insulating dielectric layer 4 between them; the lower dielectric substrate 3 is close to the lower surface of the intermediate dielectric substrate 2, and the lower surface of the lower dielectric substrate 3 is the feeding structure of the antenna; the metal probe 6 penetrates vertically The intermediate dielectric substrate 2 and the lower dielectric substrate 3 are located at the center of the intermediate dielectric substrate 2 and the lower dielectric substrate 3, the length of which is equal to the sum of the thicknesses of the two substrates, and its diameter is slightly smaller than the small circular hole 91 in the center of the metal grounding layer 9. The feed probe The needle 6 is welded to the middle rectangular metal patch 8 and the feeding microstrip line 20 respectively to form a feeding radiation path. The feeding probe 6 is a metal cylinder with a smooth surface and good electrical conductivity. When soldering, ensure that the connection is good, and the solder joints are in the metal patch and should be as flat and compact as possible.

。上层低介电常数绝缘介质层4、下层低介电常数绝缘介质层5为介电常数

的泡沫。 The thickness of the upper dielectric substrate 1 , the intermediate dielectric substrate 2 and the lower dielectric substrate 3 is 1.5 mm. The dielectric constants of the upper dielectric substrate 1 and the lower dielectric substrate 3 are , the dielectric constant of the interlayer dielectric substrate 2

. The upper low dielectric constant insulating dielectric layer 4 and the lower low dielectric constant insulating dielectric layer 5 are dielectric constant

bubbles.

The U-shaped groove 71 on the upper rectangular metal patch 7 on the lower surface of the upper dielectric substrate 1 is opposite to the U-shaped groove 81 on the middle rectangular metal patch 8 on the upper surface of the intermediate dielectric substrate 2, which is a gap coupling method. , that is, the direction of the "U"-shaped grooves differs by 180 degrees, and from a top-down perspective, the small "U"-shaped groove is inside the large "U"-shaped groove, and its form is similar to the word "back" in Chinese characters: The small "mouth" is inside the big "mouth".

The U-shaped groove 71 attached to the upper rectangular metal patch 7 on the lower surface of the uppermost dielectric substrate 1 is spliced by two vertical rectangular grooves 711 and one horizontal rectangular groove 712, and its splicing shape is similar to English capital letters The letter "U"; the U-shaped groove 81 on the middle rectangular metal patch 8 on the upper surface of the intermediate layer dielectric substrate 2 is spliced by two vertical rectangular grooves 811 and one horizontal rectangular groove 812, and its size is smaller than that of the upper layer U-shaped groove 71 on the rectangular metal patch 7 .

As shown in FIG. 3 , the upper rectangular metal patch 7 attached to the lower surface of the upper dielectric substrate 1 has a thickness of 0.043 mm, W=17.5, and L=16.5. There is a "U"-shaped hole 71 on the upper rectangular metal patch 7, and the slot exposes a part of the lower surface of the upper dielectric substrate 1 (d=2mm, h=12mm, h1=2.3mm, h2=5mm), wherein the upper rectangular The metal patch 7, the U-shaped groove 71 and the upper dielectric substrate 1 are partly realized by printed circuit board technology.

As shown in FIG. 4 , the middle rectangular metal patch 8 attached to the upper surface of the middle dielectric substrate 2 has a thickness of 0.043 mm, W=8.5, and L=16. There is a reverse U-shaped groove 81 on the metal patch, and the hole exposes part of the upper surface of the intermediate dielectric substrate 2 (d=1.1mm, h=7.5mm, h1=5mm, h2=2mm, h3=7mm). Among them, the rectangular metal patch 8 in the middle, the reverse "U" groove and the dielectric substrate 2 in the middle layer are realized by printed circuit board technology. A feeding probe 6 with a diameter of 0.5 mm at the center of the interlayer dielectric substrate 2 vertically penetrates the interlayer dielectric substrate 2 and is welded to the middle rectangular metal patch 8 attached to the surface of the interlayer dielectric substrate 2 .

As shown in FIG. 5 , the metal ground layer 9 is fully attached on the lower surface of the interlayer dielectric substrate 2 with a thickness of 0.043 mm. There is a small round hole 91 with a diameter of 1 mm at the center of the metal ground layer 9 , and the small round hole 91 exposes part of the lower surface of the interlayer dielectric substrate 2 . Wherein, the metal patches, the ground layer and the slots on the upper and lower surfaces of the interlayer dielectric substrate 2 are all realized by printed circuit board technology.

Referring to FIG. 6 , the feeding microstrip line 20 is attached to the lower surface of the lower dielectric substrate 3 . The rectangular pads of the feeding microstrip line 20 are spliced with the metal microstrip line. The microstrip feeder extends from one end of the lower dielectric substrate 3 to the center of the substrate, and forms a rectangular pad at the center. The center of the bonding pad 201 coincides with the center of the lower dielectric substrate 3 . The size parameters of each part of the microstrip feeder 20 are: d=1.4mm, d1=2.6mm, l1=25.9mm, l2=4.8mm. The feeding probe 6 vertically penetrates the lower dielectric substrate 3 and the feeding microstrip line 20 at the center of the lower dielectric substrate 3 . The feeding probe 6 and the feeding microstrip line 20 are connected by welding. The welding process should ensure that the surface is smooth and conductive, and that the well-connected solder joints are inside the metal sheet and are as flat and compact as possible. Among them, the metal patch, the feeding microstrip line 20, the grounding plate, the slot part and the substrate part are realized by printed circuit board technology.

As shown in Figure 7, the reflector 10 described is a reflector 10 with an EBG structure, which should have the characteristics of a periodic EBG hole structure, and the EBG holes are arranged periodically in an orderly manner on the metal reflector, and the EBG holes There is a fixed interval between the EBG holes in the horizontal and vertical directions, and a single EBG hole is composed of 15 rectangular holes in a fixed arrangement and the same size. The EBG hole size and the EBG hole spacing should make the EBG structure period be 1/4 to 3/4 of the cut-off wavelength, preferably 1/2 of the cut-off wavelength. This EBG reflector has the characteristics of PCB planar structure, and it is easy to use PCB technology to realize. In this embodiment, there are 4×7 EBG holes 101 in total, and the horizontal and vertical (top-to-bottom) hole intervals are 0.1mm and 0.2mm respectively. Formed with rectangular holes.

，厚度为6.5mm。所有基板、泡沫、反射板长宽一致，长为23.7mm宽为16.5mm。并且长宽可以根据应用环境要求任意放大或略微减小。只需保证中心位置一致，并延长馈电微带线20即可。 As shown in FIG. 1 and FIG. 2, between the lower dielectric substrate 3 and the reflection plate 10 is the lower dielectric constant insulating dielectric layer 5 (foam), the dielectric constant

, the thickness is 6.5mm. All substrates, foams, and reflectors have the same length and width, with a length of 23.7mm and a width of 16.5mm. And the length and width can be arbitrarily enlarged or slightly reduced according to the requirements of the application environment. It is only necessary to ensure that the center positions are consistent, and to extend the feeding microstrip line 20 .

The inventive multi-layer broadband microstrip antenna has good impedance bandwidth and radiation characteristics. Fig. 8 is a diagram of measurement data of standing wave ratio of a multi-layer broadband microstrip antenna according to a preferred embodiment of the present invention. When the working center frequency of the antenna is 5.38GHz, if the standing wave ratio VSWR<2 is used as the benchmark, the relative bandwidth reaches 1.24GHz from 4.76GHz to 6GHz, and the relative bandwidth reaches 23%.

Fig. 9 is a 5.38 GHz pattern of a multi-layer broadband microstrip antenna in a preferred embodiment of the present invention. It can be seen from the figure that the multi-layer broadband microstrip antenna of the present invention has quite excellent directional radiation field and low backlobe characteristics, and the gain is relatively high, which is sufficient to meet the needs of users.

Certainly, the present invention can also have other multiple embodiments, without departing from the spirit and essence of the present invention, those skilled in the art can implement various corresponding deformations according to the present invention, but these corresponding changes and deformations All should belong to the protection scope of the claims of the present invention.

Claims (1)

1. broadband multilayer microstrip antenna, it comprises upper layer medium substrate, intermediate layer medium substrate, layer dielectric substrate, upper strata low dielectric constant insulation dielectric layer, lower floor's low dielectric constant insulation dielectric layer and feed probes; The lower surface of described upper layer medium substrate is with the upper strata rectangular metal paster as radiator, and this upper strata rectangular metal paster offers U-shaped groove; With the intermediate rectangular metal patch as coupler, the intermediate rectangular metal patch offers U-shaped groove to intermediate layer medium substrate upper surface equally; Described intermediate layer medium substrate lower surface is whole with metal ground plane, is provided with small sircle hole at the metal ground plane center; Between upper layer medium substrate and intermediate layer medium substrate, accompany upper strata low dielectric constant insulation dielectric layer; Being close to intermediate layer medium substrate lower surface is the layer dielectric substrate, and the lower surface of layer dielectric substrate is the feed structure of antenna; Metal probe vertically runs through intermediate layer medium substrate, layer dielectric substrate and is positioned at intermediate layer medium substrate, layer dielectric substrate center position, its length equal two substrates thickness and, its diameter is slightly less than metal ground plane center small sircle hole, the feed microstrip line of feed probes and intermediate layer medium substrate upper surface intermediate rectangular metal patch and layer dielectric base lower surface welds respectively, forms feed radiation path; Be close to lower floor's low dielectric constant insulation dielectric layer at the layer dielectric base lower surface, the lower floor of lower floor's low dielectric constant insulation dielectric layer is reflecting plate; It is characterized in that: described reflecting plate is the reflecting plate that has the EBG structure; U-shaped groove on the upper strata rectangular metal paster of described upper layer medium substrate lower surface is relative with U-shaped groove notch on the medium substrate upper surface intermediate rectangular metal patch of intermediate layer, is the slit coupled modes; U-shaped groove on the described upper strata rectangular metal paster that is attached to the superiors' medium substrate lower surface is slotted by two vertical rectangles flutings and a horizontal rectangular and is spliced, and it splices the similar English capitalization of shape " U "; U-shaped groove on the medium substrate upper surface intermediate rectangular metal patch of described intermediate layer is spliced by two vertical rectangle flutings and a horizontal rectangular fluting, and its size is less than the U-shaped groove on the rectangular metal paster of upper strata; Orderly periodic arrangement the EBG hole on the reflecting plate of the described EBG of having structure, wherein single EBG hole is made of the rectangular opening of 15 stationary arrangement, consistent size, horizontal and vertical fixed intervals are arranged between EBG hole and the EBG hole, and EBG hole dimension and EBG span should to make the EBG structural cycle be 1/4th to 3/4ths cut-off wavelength.

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