CN111478035A

CN111478035A - Flexible double-stop-band UWB-MIMO antenna based on coplanar waveguide feed

Info

Publication number: CN111478035A
Application number: CN202010414173.3A
Authority: CN
Inventors: 杜成珠; 靳高雅; 赵卓琳; 郑炜晴; 徐家铭; 李凯佳
Original assignee: Shanghai Electric Power University
Current assignee: Shanghai University of Electric Power; Shanghai Electric Power University; University of Shanghai for Science and Technology
Priority date: 2020-05-15
Filing date: 2020-05-15
Publication date: 2020-07-31

Abstract

The invention provides a flexible double-stop band UWB-MIMO antenna based on coplanar waveguide feed, which is characterized by comprising the following components: a rectangular substrate; the two antenna units are positioned on the upper surface of the substrate and respectively provided with a circular radiation patch, a gradually-changed trapezoidal microstrip line, a first grounding plate and a second grounding plate, the microstrip line is connected to the circular radiation patch, the two microstrip lines are respectively and vertically connected with a first side line and a second side line which are adjacent to the substrate, and the first grounding plate and the second grounding plate are respectively arranged on two sides of the microstrip line; and the isolation minor matters of shape of falling F, set up between two antenna element, wherein, the one side of keeping away from the microstrip line of circular radiation paster has fan-shaped corner cut to still be provided with two length on the circular radiation paster and be the fan-shaped groove of 1/4 stop band frequency wavelength, two fan-shaped grooves all with circular radiation paster centre of a circle, all towards fan-shaped corner cut, the radius of two fan-shaped grooves is than being 8: and 3, the area of the first grounding plate is larger than that of the second grounding plate.

Description

Flexible double-stop-band UWB-MIMO antenna based on coplanar waveguide feed

Technical Field

The invention belongs to the field of antennas, and particularly relates to a flexible double-stop-band UWB-MIMO antenna based on coplanar waveguide feed.

Background

Since 2002, 3.1-10.6GHz is officially classified as civil ultra-wideband by FCC, and a new definition is provided for ultra-wideband: UWB signals are obtained with absolute bandwidths greater than 500MHz or relative bandwidths greater than 20% at-10 dB. Since the ultra-wideband technology has been greatly developed, ultra-wideband antennas have also emerged. Because the ultra-wideband communication has the characteristics of high transmission rate, strong penetration capability, strong anti-interference capability and the like, the ultra-wideband antenna has numerous applications in the aspects of short-distance wireless communication, mobile communication, medical imaging, ground penetrating radar and the like at present. For the research of ultra-wideband, the acknowledged research direction focuses on miniaturization, adopting MIMO structure, increasing stop band, etc. Meanwhile, the environment of wireless communication is relatively complex, so that when the electromagnetic wave propagates, it encounters an obstacle to generate direct radiation, refraction or reflection, which results in multipath fading. Multipath fading is a negative factor affecting communications. In the conventional Single-input Single-output (SISO) technology, multipath fading is reduced or avoided to improve channel capacity, but the shannon capacity limit cannot be broken through, and the MIMO (Multiple-input Multiple-output) technology developed later can improve the disadvantage. Although marconi proposed the use of MIMO technology to suppress fading as early as 1908, over eighty years later scholars in the united states bell laboratories formally used this technology for wireless communications. Especially in the current times when massive data needs to be transmitted, one of the currently popular 5G core technologies is the multi-channel MIMO technology. Combining ultra-wideband technology with MIMO antennas is therefore a good choice for the development of future wireless communications. However, with the increase of the number of antennas, the coupling effect between the antenna elements is not negligible. Generally, there are two main types of coupling that exist between antenna elements. The first is spatial coupling due to induction generated by the exciter antenna on the other antenna elements; the second is because the excitation current is coupled through a ground surface wave coupling from the common ground to the other ports. The presence of coupling effects can severely affect the performance parameters of the communication system. Such as input impedance, gain, and radiation efficiency, etc. How to reduce the coupling of antenna units while ensuring the miniaturization of antennas becomes a difficult point in the design of MIMO antennas.

The 3.1GHz-10.6GHz is an application frequency band of the ultra-wideband communication, and a plurality of other communication systems exist in the frequency band range at the same time, such as wireless local area networks (wian2.4GHz-2.483GHz, 5.125GHz-5.8GHz and 5.725GHz-5.825GHz), china 5G frequency bands (3.3GHz-3.6GHz and 4.8GHz-5.0GHz) released by the ministry of industry and correspondence, worldwide interoperability for microwave access (WiMAX 2.5GHz-2.69GHz, 3.4GHz-3.69GHz and 5.25GHz-5.85GHz), satellite communication (7.9GHz-8.4GHz/7.25GHz-7.75GHz), missile-borne system (3.9GHz-4.2GHz), and the like. In order to avoid the ultra-wideband antenna interfering with these known communication systems, a filtering device may be additionally designed at the front end of the communication system, but this occupies a large space, is not favorable for integration, and is not economical. The stop band characteristic of the antenna at the corresponding frequency band is simply and easily generated by etching different notch units on the structure of the antenna. Therefore, the UWB-MIMO antenna having the stop band characteristic becomes one of the important points of researchers.

Disclosure of Invention

The present invention is made to solve the above problems, and an object of the present invention is to provide a flexible dual stop band UWB-MIMO antenna based on coplanar waveguide feeding.

The invention provides a flexible double-stop band UWB-MIMO antenna based on coplanar waveguide feed, which is characterized by comprising the following components: the substrate is rectangular; the two antenna units are positioned on the upper surface of the substrate and are respectively provided with a circular radiation patch, a gradually-changed trapezoidal microstrip line, a first grounding plate and a second grounding plate, the microstrip line is connected to the circular radiation patch, the two microstrip lines are respectively and vertically connected with a first side line and a second side line which are adjacent to the substrate, and the first grounding plate and the second grounding plate are respectively arranged on two sides of the microstrip line and are connected with the side lines of the substrate; and keep apart the minor matters, set up between two antenna element, wherein, the one side of keeping away from the microstrip line of circular radiation paster has fan-shaped corner cut to still be provided with two length on the circular radiation paster and be the fan-shaped groove of 1/4 stop band frequency wavelength, two fan-shaped grooves all with circular radiation paster centre of a circle, and all towards fan-shaped corner cut, the radius ratio of two fan-shaped grooves is 8: and 3, the area of the first grounding plate is larger than that of the second grounding plate, and the isolation branch is in an inverted F shape.

In the flexible dual-stop band UWB-MIMO antenna based on coplanar waveguide feed provided by the invention, the antenna can also have the following characteristics: wherein, the size of fan-shaped corner cut does: the arc length is 3/10 of the perimeter of the circular radiating patch and the arc angle is 159 °.

In the flexible dual-stop band UWB-MIMO antenna based on coplanar waveguide feed provided by the invention, the antenna can also have the following characteristics: wherein the spacing between the two antenna elements is 2.5 mm.

In the flexible dual-stop band UWB-MIMO antenna based on coplanar waveguide feed provided by the invention, the antenna can also have the following characteristics: wherein, the arc angles of the two fan-shaped grooves are 290 degrees and 330 degrees respectively.

The flexible double-stop-band UWB-MIMO antenna based on the coplanar waveguide feed can also be characterized in that the flexible single-stop-band UWB-MIMO antenna based on the coplanar waveguide feed is used for isolating the 5.725-5.825 UWB band of WiMAX-3.5GHz and W L AN.

In the flexible dual-stop band UWB-MIMO antenna based on coplanar waveguide feed provided by the invention, the antenna can also have the following characteristics: wherein the isolation branch is connected with the first edge line and faces the second edge line, or the isolation branch is connected with the second edge line and faces the first edge line.

In the flexible dual-stop band UWB-MIMO antenna based on coplanar waveguide feed provided by the invention, the antenna can also have the following characteristics: the first ground plate and the second ground plate are both rectangular, a first ground plate gap is formed between the first ground plate and the microstrip line, a second ground plate gap is formed between the second ground plate and the microstrip line, and the first ground plate gap and the second ground plate gap are the same in size.

In the flexible dual-stop band UWB-MIMO antenna based on coplanar waveguide feed provided by the invention, the antenna can also have the following characteristics: wherein, the substrate is a liquid crystal polymer and the thickness of the substrate is 0.1 mm.

In the flexible dual-stop band UWB-MIMO antenna based on coplanar waveguide feed provided by the invention, the antenna can also have the following characteristics: the microstrip line adopts a coplanar waveguide feed structure.

Action and Effect of the invention

According to the flexible double-stopband UWB-MIMO antenna based on coplanar waveguide feed, the flexible double-stopband UWB-MIMO antenna comprises two antenna units, each antenna unit is provided with a circular radiation patch, a gradually-changed trapezoidal microstrip line, a first grounding plate and a second grounding plate, one side, far away from the microstrip line, of the circular radiation patch is provided with a sector cut angle, the antenna can be miniaturized while the working bandwidth is guaranteed, two sector grooves with 1/4 stopband frequency wavelengths are arranged on the circular radiation patch, the two sector grooves are concentric with the circular radiation patch and face the sector cut angle, the radius ratio of the two sector grooves is 8:3, the antenna can isolate a WiMAX-3.5GHz frequency band and a 5.725-5.825 frequency band of W L AN, the area of the first grounding plate is larger than that of the second grounding plate, the asymmetrical structure can expand the working width of the antenna, a plurality of transmission paths can be generated by adopting the MIMO structure of the two antenna units, the influence of multipath fading is greatly reduced, the coupling current between the two antenna units can be effectively reduced, and the coupling current between the two antenna units of the antenna can be effectively reduced, and the antenna can meet the requirements of the W5-5.725-5.825 antenna on the UWB-5.5-5.825 frequency band of the antenna.

Drawings

FIG. 1 is a schematic structural diagram of a flexible dual stop band UWB-MIMO antenna based on coplanar waveguide feed in an embodiment of the invention;

FIG. 2 is an S of a flexible dual stop band UWB-MIMO antenna based on coplanar waveguide feeding in an embodiment of the invention₁₁A simulation result graph;

fig. 3 is a diagram illustrating the simulation result of the isolation of the flexible dual-stop band UWB-MIMO antenna based on coplanar waveguide feeding in the embodiment of the present invention.

Detailed Description

In order to make the technical means, the creation features, the achievement objects and the effects of the present invention easy to understand, the following embodiments specifically describe the flexible dual-stop-band UWB-MIMO antenna based on coplanar waveguide feeding according to the present invention with reference to the accompanying drawings.

Fig. 1 is a schematic structural diagram of a flexible dual-stop-band UWB-MIMO antenna based on coplanar waveguide feeding in an embodiment of the present invention.

As shown in fig. 1, the flexible dual-stop-band UWB-MIMO antenna 100 based on coplanar waveguide feeding of the present embodiment includes a substrate 10, a first antenna element 20, a second antenna element 30, and an isolation branch 40.

The substrate 10 is rectangular and has a first border line 11 and a second border line 12 adjacent to each other. The substrate 10 is a liquid crystal polymer and has a thickness of 0.1 mm.

The first antenna element 20 and the second antenna element 30 are both located on the upper surface of the substrate 10. In the present embodiment, the first antenna element 20 and the second antenna element 30 are placed on the upper surface of the substrate 10.

The first antenna element 20 comprises a circular radiating patch 21, a tapered trapezoidal microstrip line 22, a first ground plate 23 and a second ground plate 24.

The circular radiation patch 21 and the microstrip line 22 are connected together, and the microstrip line 22 is connected perpendicularly to the first side line 11. The side of the circular radiating patch 21 remote from the microstrip line 22 has a scalloped corner 211. The arc length of the scalloped cut angle 211 is 3/10 of the perimeter of the circular radiating patch and the arc angle is 159. The design of the sector cut angle 211 is to achieve miniaturization and ultra-wideband of the antenna, and specifically, by analyzing the current distribution on the radiating patch, the surface current is mainly concentrated on the bottom edge near the feed point and the current density of the upper half is small. Therefore, as a starting point, the upper half part of the circular patch is cut off, and the corner-cut circular radiation patch is provided, so that the miniaturization is realized and the working bandwidth is ensured.

The circular radiation patch 21 is further provided with two fan-shaped slots 212 having a length of 1/4 stop band frequency wavelengths. Both fan-shaped slots 212 are concentric with the circular radiating patch 21 and both face the fan-shaped tangential angle 211. By adjusting the positions, the radii and the angles of the two fan-shaped grooves 212, the dual-stop-band UWB-MIMO antenna 100 is finally obtained. In the present embodiment, the ratio of the radii of the two fan-shaped grooves 212 is 8:3, and the arc angles of the two fan-shaped grooves 212 are 290 ° and 330 °, respectively. Wherein the arc angle of the sector groove 212 having a small radius is larger. The fan-shaped slot 212 is formed by slotting the circular radiation patch 21 by using a slotting technology.

The microstrip line 22 adopts a coplanar waveguide feed structure and adopts a gradual change structure in the design of the microstrip line, thereby further expanding the working bandwidth of the antenna.

The first ground plate 23 and the second ground plate 24 are respectively disposed on both sides of the microstrip line 22, and are connected to the first side line 11. The first ground plate 23 and the second ground plate 24 are both rectangular, and the area of the first ground plate 23 is larger than that of the second ground plate 24. A first ground plate gap is formed between the first ground plate 23 and the microstrip line 22, and a second ground plate gap is formed between the second ground plate 23 and the microstrip line 22. The first floor gap and the second floor gap are the same size. That is, the length of the first ground plate 23 is greater than the length of the second ground plate 24 in the extending direction of the first border 11, and the length of the first ground plate 23 is equal to the length of the second ground plate 24 in the extending direction of the second border 12.

The second antenna unit 30 has a structure similar to that of the first antenna unit 20, and also includes a circular radiation patch, a gradually-changing trapezoidal microstrip line, a first ground plate, and a second ground plate. The difference lies in that: the microstrip line of the second antenna unit 30 is vertically connected to the second edge line 12; the first ground plane and the second ground plane of the second antenna element 30 are connected to the second edge line 12. The rest structures are completely the same.

The first antenna element 20 and the second antenna element 30 are vertically arranged to form a binary ultra-wideband MIMO antenna. At this time, the coupling between the first antenna element 20 and the second antenna element 30 is severe, and further measures are required to reduce the coupling between the antennas. In the embodiment, the relative position between the two antenna units is adjusted, and the inverted-F-shaped isolation branch 40 is added between the two antenna units, so that the coupled current between the two antenna units is reduced, and the isolation of the antenna is lower than-20 dB. In this embodiment, the first antenna unit 20 and the second antenna unit 30 are perpendicular to each other, the distance is 2.5mm, and the second antenna unit 30 is adjusted upward by 2.5 mm.

The isolation stub 40, which is an inverted F-shape, is disposed between the first antenna element 20 and the second antenna element 30. The isolation branch 40 includes a first branch 41, a second branch 42, and a third branch 43. The first branch 41 is connected perpendicularly to the first edge line 33. The second branch 42 and the third branch 43 are both vertically connected to the first branch 41 and are both located on a side of the first branch 41 close to the second antenna unit 30, wherein the second branch 42 is connected to the first edge 33. I.e. the spacer branch 40 is directed towards the second edge line 12. The length of the first branch 41 is 12mm, and the length of the second branch 42 is smaller than that of the third branch 43. In the present embodiment, the lengths of the second and

third branches

42 and 43 are 3mm and 4mm, respectively. The widths of the first, second and

third branches

41, 42, 43 are all 1 mm.

FIG. 2 is an S of a flexible dual stop band UWB-MIMO antenna based on coplanar waveguide feeding in an embodiment of the invention₁₁A simulation result graph; fig. 3 is a diagram illustrating the simulation result of the isolation of the flexible dual-stop band UWB-MIMO antenna based on coplanar waveguide feeding in the embodiment of the present invention.

The flexible dual-stop-band UWB-MIMO antenna 100 based on coplanar waveguide feed of the embodiment is subjected to S₁₁The simulation experiment and the isolation simulation experiment are shown in fig. 2 and 3 respectively, and it can be seen from fig. 2 that the UWB-MIMO antenna 100 of the present embodiment can well block the interference of the frequency bands 5.725-5.825 of WiMAX-3.5GHz and W L AN under the requirement of ultra wide band, and it can be seen from fig. 3 that the isolation of the UWB-MIMO antenna 100 of the present embodiment is basically lower than-20 dB in the working frequency band, and the requirement for the isolation is satisfied.

Effects and effects of the embodiments

According to the flexible double-stopband UWB-MIMO antenna based on coplanar waveguide feed, the flexible double-stopband UWB-MIMO antenna comprises two antenna units, each antenna unit is provided with a circular radiation patch, a gradually-changed trapezoidal microstrip line, a first grounding plate and a second grounding plate, one side, far away from the microstrip line, of the circular radiation patch is provided with a sector cut angle, the antenna can be miniaturized while the working bandwidth is guaranteed, two sector grooves with 1/4 stopband frequency wavelengths are arranged on the circular radiation patch, the two sector grooves are concentric with the circular radiation patch and face the sector cut angle, the radius ratio of the two sector grooves is 8:3, the antenna can isolate a WiMAX-3.5GHz frequency band and a 5.725-5.825 frequency band of W L AN, the area of the first grounding plate is larger than that of the second grounding plate, the asymmetrical structure can expand the working width of the antenna, a plurality of transmission paths can be generated by adopting the structure of the two antenna units, the influence of multipath fading is greatly reduced, the inverted-F-shaped isolation joint is arranged between the two antenna units, the coupling current between the two antenna units can be effectively reduced, and the miniaturized UWB-5.725, the antenna can also meet the requirements of the antenna on the UWB-5.5-5.825 antenna, the UWB-5.5-5-5.825 antenna, and the antenna can be met.

Furthermore, the substrate is made of liquid crystal polymer (L CP), the thickness of the substrate is 0.1mm, the novel high-performance special engineering plastic developed in the early 80 s has the advantages of excellent thermal stability, heat resistance, chemical resistance, electric insulation performance, low thermal expansion coefficient, low cost, small loss, ultrathin property and the like, and the UWB-MIMO antenna can be more stable in performance.

Furthermore, the microstrip line adopts a coplanar waveguide feed structure, the coplanar waveguide feed has the advantages of low loss, low cost, low dispersion, easy connection with various microwave components and parts and the like, and due to the unique planar structure, the UWB-MIMO antenna has the advantages of wide frequency band, easy processing, only need of a single metal layer and the like.

Further, the UWB-MIMO antenna of the embodiment, after simulation testing, can achieve isolation of the WiMAX-3.5GHz band and the 5.725-5.825 band of W L AN on the premise of meeting the ultra-wideband, and the performance meets the requirements, and has great research and application prospects.

The above embodiments are preferred examples of the present invention, and are not intended to limit the scope of the present invention.

Claims

1. A flexible dual stop band UWB-MIMO antenna based on coplanar waveguide feed, characterized by, includes:

the substrate is rectangular;

two antenna units located on the upper surface of the substrate and each having a circular radiation patch, a gradually-changing trapezoidal microstrip line, a first ground plate and a second ground plate,

the microstrip lines are connected on the circular radiation patch, and the two microstrip lines are respectively and vertically connected with the adjacent first side line and the second side line of the substrate,

the first grounding plate and the second grounding plate are respectively arranged on two sides of the microstrip line and are connected with the side line of the substrate; and

an isolation stub disposed between the two antenna units,

wherein, one side of the circular radiation patch far away from the microstrip line is provided with a sector cut angle, and the circular radiation patch is further provided with two sector grooves with the length of 1/4 stop band frequency wavelengths, the two sector grooves are concentric with the circular radiation patch and face the sector cut angle, and the ratio of the radiuses of the two sector grooves is 8:3,

the first ground plate has a larger area than the second ground plate,

the isolation branch is in an inverted F shape.

2. The flexible dual stop-band UWB-MIMO antenna based on coplanar waveguide feed of claim 1, wherein:

wherein the size of the fan-shaped cutting angle is as follows: the arc length is 3/10 of the perimeter of the circular radiating patch and the arc angle is 159 °.

3. The flexible dual stop-band UWB-MIMO antenna based on coplanar waveguide feed of claim 1, wherein:

wherein the distance between the two antenna units is 2.5 mm.

4. The flexible dual stop-band UWB-MIMO antenna based on coplanar waveguide feed of claim 1, wherein:

wherein, the arc angles of the two fan-shaped grooves are 290 degrees and 330 degrees respectively.

5. The flexible dual stop band UWB-MIMO antenna based on coplanar waveguide feed of claim 4, characterized in that:

the flexible double-stop band UWB-MIMO antenna based on the coplanar waveguide feed is used for isolating the 5.725-5.825 ultra-wideband frequency band of WiMAX-3.5GHz and W L AN.

6. The flexible dual stop-band UWB-MIMO antenna based on coplanar waveguide feed of claim 1, wherein:

wherein the isolation branch is connected with the first edge line and faces the second edge line, or the isolation branch is connected with the second edge line and faces the first edge line.

7. The flexible dual stop-band UWB-MIMO antenna based on coplanar waveguide feed of claim 1, wherein:

the first ground plate and the second ground plate are both rectangular, a first ground plate gap is formed between the first ground plate and the microstrip line, a second ground plate gap is formed between the second ground plate and the microstrip line, and the first ground plate gap and the second ground plate gap are the same in size.

8. The flexible dual stop-band UWB-MIMO antenna based on coplanar waveguide feed of claim 1, wherein:

wherein, the substrate is a liquid crystal polymer, and the thickness of the substrate is 0.1 mm.

9. The flexible dual stop-band UWB-MIMO antenna based on coplanar waveguide feed of claim 1, wherein:

the microstrip line adopts a coplanar waveguide feed structure.