CN111725620A - A circularly polarized millimeter-wave microstrip antenna loaded with L-shaped branches - Google Patents

Abstract

The invention relates to a circularly polarized millimeter-wave microstrip antenna loaded with L-shaped branches, belonging to the field of wireless communication. The antenna belongs to a single-layer structure, and the antenna radiation surface and the feeder structure are respectively located on the upper and lower surfaces of the dielectric plate. Including RT/duroid 5880 dielectric substrate, square groove, a pair of inverted L-shaped perturbation strips and hammer-shaped microstrip feeder; the square groove is located on the antenna radiation surface of the dielectric plate, and the outer boundary of the square groove coincides with the boundary of the dielectric plate; two The inverted L-shaped perturbation strips are located at the opposite corners of the square slot and are connected to the square slot; the hammer-shaped microstrip feeder is located on the lower surface of the dielectric plate, at the right position of the middle of the dielectric plate, and the bottom of the feeder is in contact with the boundary of the dielectric plate , forming the feed end of the antenna. The working frequency band of this antenna is within the 5G FR2 frequency band, the impedance bandwidth is significantly improved, the circularly polarized radiation performance is good, the structure is simple, and the size is small, which has certain application value.

Description

A circularly polarized millimeter-wave microstrip antenna loaded with L-shaped branches

technical field

The invention belongs to the field of wireless communication, and relates to a circularly polarized millimeter-wave microstrip antenna loaded with L-shaped branches.

Background technique

The fifth generation (5G) mobile communication technology is rapidly developing and popularizing. Compared with 4G, 5G communication has the advantages of high speed, ultra-low latency, large capacity, and high reliability, which can meet the increasing data transmission needs of today's society. For the first time, the 5G communication standard uses the millimeter wave frequency band as its FR2 communication frequency band, thereby providing the ultimate data transmission speed and large capacity for the 5G network. Therefore, the research and design of millimeter-wave antennas for 5G mobile devices has become a research hotspot in recent years.

Compared with linearly polarized antennas, circularly polarized antennas are more suitable for device-to-device (D2D) wireless communication in 5G networks due to their advantages of reducing polarization mismatch and effectively suppressing millimeter-wave multipath effects.

There are many existing technical solutions for designing circularly polarized millimeter-wave antennas, and here are a few of them: 1. Excite the circular pole by exciting two parallel electric dipoles and magnetic dipoles with a phase difference of 90°. chemical radiation properties. ② The circularly polarized radiation pattern is generated by a conformal polarizer with a double circular lens. ③ The circularly polarized wave is radiated by adding a special-shaped ring structure to the Archimedes helical radiator.

The diameter of the antenna in the first technical solution is only 0.38mm, the structure is relatively simple, the resonant frequency is 28GHz, but the impedance bandwidth is narrow, only 8%.

The resonant frequency of the antenna in the second technical solution is 29 GHz, and the impedance bandwidth reaches 34.5% (24 GHz to 32 GHz). However, the structure of the antenna is too complex, the actual antenna needs to be completed by 3D printing, the manufacturing process is relatively complicated, and the actual engineering application value of the antenna is small.

The impedance bandwidth of the antenna in the third technical solution can reach 46.63%, and the gain is up to 6.49dBi, but the physical size of the antenna is large, and the length reaches 30mm, which is not conducive to the integration of the antenna into communication equipment.

SUMMARY OF THE INVENTION

In view of this, the purpose of the present invention is to provide a circularly polarized millimeter-wave microstrip antenna loaded with L-shaped branches, so as to solve the problems of narrow antenna bandwidth and complex structure.

To achieve the above object, the present invention provides the following technical solutions:

A circularly polarized millimeter-wave microstrip antenna loaded with L-shaped branches, comprising an RT/duroid5880 dielectric substrate, a square slot, two inverted L-shaped perturbation strips and a hammer-shaped microstrip feeder;

The square slot is located on the antenna radiation surface of the dielectric plate, and the outer boundary of the square slot coincides with the boundary of the dielectric plate;

The two inverted L-shaped perturbation strips are respectively located at the opposite corners of the square slot and are connected with the square slot;

The hammer-shaped microstrip feed line is located on the lower surface of the dielectric plate, at the right position of the middle of the dielectric plate, and the bottom of the feed line is in contact with the boundary of the dielectric plate to form the feed end of the antenna;

The square grooves on the radiating surface of the antenna and two inverted L-shaped perturbation strips are used to excite two orthogonal modes with the same amplitude and a phase difference of 90°, thereby radiating circularly polarized waves.

Optionally, the working frequency band of the antenna is within the 5G FR2 frequency band, and the resonant frequency is 24.4 GHz.

Optionally, the hammer-shaped microstrip feed line on the lower surface of the dielectric substrate is not located on the same plane as the antenna radiating surface, and transmits energy to the antenna radiating surface by means of adjacent coupling feeding, thereby effectively expanding the antenna bandwidth. .

Optionally, the square slot is located on the antenna radiation surface and is a square structure with a side length of 5.5mm; the inverted L-shaped perturbation strip located at the diagonal corner of the square slot is 2.2mm long and 1.6mm wide.

Optionally, the microstrip feeder has a hammer-shaped structure with a lower width of 0.65 mm, an upper width of 0.904 mm and a height of 2.65 mm; the center of the microstrip feeder structure is located 0.225 mm to the right of the centerline of the square dielectric substrate.

The beneficial effects of the present invention are: the present invention adopts the adjacent coupling feeding technology, the antenna microstrip feeder and the radiating surface are not in the same plane, the bottom feeder and the antenna radiating surface exhibit capacitive coupling effect, and at the same time the bottom feeder is in an open state, and the impedance bandwidth Significant improvement. At the same time, the circularly polarized wave is radiated by loading two 90° "L-shaped" branches on the radiating surface of the antenna, the circularly polarized radiation performance is good, and the antenna structure is simplified. The antenna size is only 5.5*5.5*0.127mm, which has the advantages of miniaturization and easy integration. The structure is a single-layer structure, and the manufacturing difficulty is small.

Other advantages, objects, and features of the present invention will be set forth in the description that follows, and will be apparent to those skilled in the art based on a study of the following, to the extent that is taught in the practice of the present invention. The objectives and other advantages of the present invention may be realized and attained by the following description.

Description of drawings

In order to make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be preferably described in detail below with reference to the accompanying drawings, wherein:

Figure 1 is a schematic diagram of the structure of the antenna radiation surface;

FIG. 2 is a schematic diagram of the structure of the microstrip feeder at the bottom of the antenna;

3 is a side view of the antenna structure;

Figure 4 is a diagram of the antenna return loss S11;

Figure 5 is an AR diagram of the antenna axial ratio;

Figure 6 is an antenna gain diagram;

Figure 7 is an antenna radiation pattern (24.4GHz, XOZ);

Figure 8 is an antenna radiation pattern (24.4GHz, YOZ).

Detailed ways

The embodiments of the present invention are described below through specific specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the drawings provided in the following embodiments are only used to illustrate the basic idea of the present invention in a schematic manner, and the following embodiments and features in the embodiments can be combined with each other without conflict.

Among them, the accompanying drawings are only used for exemplary description, and represent only schematic diagrams, not physical drawings, and should not be construed as limitations of the present invention; in order to better illustrate the embodiments of the present invention, some parts of the accompanying drawings will be omitted, The enlargement or reduction does not represent the size of the actual product; it is understandable to those skilled in the art that some well-known structures and their descriptions in the accompanying drawings may be omitted.

The same or similar numbers in the drawings of the embodiments of the present invention correspond to the same or similar components; in the description of the present invention, it should be understood that if there are terms "upper", "lower", "left" and "right" The orientation or positional relationship indicated by , "front", "rear", etc. is based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the indicated device or element must be It has a specific orientation, is constructed and operated in a specific orientation, so the terms describing the positional relationship in the accompanying drawings are only used for exemplary illustration, and should not be construed as a limitation of the present invention. situation to understand the specific meaning of the above terms.

As shown in Figures 1-3, the present invention provides a circularly polarized millimeter-wave microstrip antenna loaded with L-shaped stubs, including an RT/duroid5880 dielectric substrate, a square slot, a pair of inverted L-shaped perturbation strips, and a hammer-shaped microstrip antenna. With feeder; the square slot is located on the antenna radiation surface of the dielectric plate, and the outer boundary of the square slot coincides with the boundary of the dielectric plate; two inverted L-shaped perturbation strips are located at the opposite corners of the square slot and are connected to the square slot; The hammer-shaped microstrip feed line is located on the lower surface of the dielectric plate, at the right position of the middle of the dielectric plate, and the bottom of the feed line is in contact with the boundary of the dielectric plate to form the feed end of the antenna;

The square groove on the radiation surface of the antenna and a pair of inverted L-shaped perturbation strips are used to excite two orthogonal modes with the same amplitude and a phase difference of 90°, thereby radiating circularly polarized waves;

The working frequency band of the antenna is within the 5G FR2 frequency band, and the resonant frequency is 24.4GHz.

The hammer-shaped microstrip feeder on the lower surface of the dielectric substrate is not located on the same plane as the antenna radiating surface, and transmits energy to the antenna radiating surface by means of adjacent coupling feeding, thereby effectively expanding the antenna bandwidth.

The length of each part of the circularly polarized millimeter-wave microstrip antenna loaded with L-shaped branches is shown in Table 1, and the unit is (mm).

Table 1 Length of each part of circularly polarized millimeter-wave microstrip antenna

Wherein, the square slot on the antenna radiation surface is a square structure with a length of 5.5mm, and the length of the inverted L-shaped perturbation strip at the diagonal corner of the square slot is 2.2mm and the width is 1.6mm.

The microstrip feeder is a hammer-shaped structure with a lower width of 0.65mm, an upper width of 0.904mm and a height of 2.65mm; the center of the microstrip feeder structure is located 0.225mm to the right of the centerline of the square dielectric substrate.

The circularly polarized millimeter-wave microstrip antenna of the invention has simple structure and good circularly polarized radiation performance. The main parameters of the circularly polarized millimeter-wave microstrip antenna are return loss (S11) and axial ratio (AR). The S11 parameter diagram is shown in Figure 4. From Figure 4, it can be concluded that the resonant frequency of the antenna is 24.4GHz, and the return loss at the resonant frequency is -32.79dB. The relative bandwidth of the return loss less than -10dB is 25.8% (21.13GHz～27.43GHz); the AR parameter diagram is shown in Figure 5. From Figure 5, it can be concluded that the relative bandwidth of the axial ratio AR less than 3dB is 47.1%, and the frequency range It is 17.99GHz - 29.5GHz. In addition, it can be seen from Figure 8 that the frequency band where the antenna return loss is less than -10dB is 21.13GHz to 27.43GHz, so the frequency band where the antenna axial ratio is less than 3dB just covers the frequency band where the return loss S11 is less than -10dB.

The gain of the antenna is shown in Figure 6. From Figure 6, it can be concluded that in the frequency range where the antenna return loss S11 is less than -10dB (21.13GHz ~ 27.43GHz), the antenna gain is at least 3.93dBi, and the gain is at the resonant frequency of 24.4GHz. The maximum is 4.32dBi.

The far-field patterns of the resonant frequency of the circularly polarized antenna of the present invention of 24.4 GHz in the XOZ plane and the YOZ plane are shown in FIGS. 7 and 8 . It can be seen from the figure that the antenna radiates left-handed circularly polarized (LHCP) waves along the positive half-axis direction of the Z-axis, and radiates right-handed circularly polarized (RHCP) waves along the negative half-axis direction of the Z-axis. The circularly polarized radiation performance good.

Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present invention can be Modifications or equivalent replacements, without departing from the spirit and scope of the technical solution, should all be included in the scope of the claims of the present invention.

Claims (5)

1. a circularly polarized millimeter-wave microstrip antenna for loading L-type branches, it is characterized in that: comprise RT/duroid 5880 dielectric substrate, square groove, two inverted L-type perturbation strips and hammer-shaped microstrip feeder; The square slot is located on the antenna radiation surface of the dielectric plate, and the outer boundary of the square slot coincides with the boundary of the dielectric plate; The two inverted L-shaped perturbation strips are respectively located at the opposite corners of the square slot and are connected with the square slot; The hammer-shaped microstrip feed line is located on the lower surface of the dielectric plate, at the right position of the middle of the dielectric plate, and the bottom of the feed line is in contact with the boundary of the dielectric plate to form the feed end of the antenna; The square grooves on the radiating surface of the antenna and two inverted L-shaped perturbation strips are used to excite two orthogonal modes with the same amplitude and a phase difference of 90°, thereby radiating circularly polarized waves. 2 . The circularly polarized millimeter-wave microstrip antenna loaded with L-shaped branches according to claim 1 , wherein the working frequency band of the antenna is within the 5G FR2 frequency band, and the resonant frequency is 24.4 GHz. 3 . 3 . The circularly polarized millimeter-wave microstrip antenna loaded with L-shaped branches according to claim 1 , wherein the hammer-shaped microstrip feeder on the lower surface of the dielectric substrate is not located in the same radiating surface as the antenna. 4 . On the plane, the energy is transferred to the radiating surface of the antenna by means of adjacent coupling feeding, thereby effectively expanding the bandwidth of the antenna. 4. The circularly polarized millimeter-wave microstrip antenna loaded with L-shaped branches according to claim 1, wherein the square groove is located on the antenna radiation surface, is a square structure, and has a side length of 5.5 mm; The inverted L-shaped perturbation strips at the opposite corners of the slot are 2.2 mm long and 1.6 mm wide. 5. The circularly polarized millimeter-wave microstrip antenna loaded with L-shaped branches according to claim 1, wherein the microstrip feeder is a hammer with a lower width of 0.65mm, an upper width of 0.904mm and a height of 2.65mm The center of the microstrip feeder structure is located 0.225mm to the right of the centerline of the square dielectric substrate.

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