CN213753051U

CN213753051U - Broadband high-gain printed antenna

Info

Publication number: CN213753051U
Application number: CN202022531759.6U
Authority: CN
Inventors: 黄丘林; 黄佳祁; 史小卫
Original assignee: Xidian University
Current assignee: Xidian University
Priority date: 2020-11-05
Filing date: 2020-11-05
Publication date: 2021-07-20
Anticipated expiration: 2030-11-05

Abstract

The utility model discloses a wide band high gain printed antenna mainly solves the problem that current printed antenna gain is low, and it includes two dielectric substrate (1), and every dielectric substrate two sides is the printing respectively has radiating element (2) and microstrip feed balun structure (3), and two dielectric substrate (1) are the cross and place. Antenna radiating element (2) comprise a pair of L shape radiation array (5), 1/8 wavelength departments are equipped with directly over should to L shape radiation array and lead to array (4), in order to improve the input impedance matching of antenna, gain is improved, should lead to and open in the middle of array (4) and have isolation tank (7), and isolation tank opposite direction on two dielectric slabs, lead to the electrical contact between array (4) when avoiding two dielectric substrate (1) quadrature installation. The utility model discloses showing input impedance match and the radiation efficiency that has improved the antenna, having improved the gain of antenna, can be used to wireless communication equipment.

Description

Broadband high-gain printed antenna

Technical Field

The utility model belongs to the technical field of the antenna, especially, relate to a wide band high gain printed antenna, can be used to wireless communication equipment.

Background

With the development of wireless communication technology, the index requirements for base station antennas are also higher and higher. Modern wireless communication systems require that base station antennas have the characteristics of wide frequency band, high gain, dual polarization, miniaturization and the like, and also require that the antennas are easy to process and install, and the electrical performance is better after the antenna arrays are formed. The traditional antenna structures such as dipole antennas and yagi antennas have the defects of large size and the like, so that the development of base station antennas is hindered. Printed antennas are widely used in various wireless communication systems due to their small size, light weight, ease of integration, and conformability to carriers. However, the existing printed antenna also has the disadvantages of relatively narrow bandwidth, large loss, low gain and the like.

Many experts and scholars at home and abroad have made many studies on changing the feed structure in order to increase the bandwidth of the printed dipole antenna. Bo Pan et al in its "Equivalent-Circuit Analysis of a Broadband and Printed polarized With Adjusted impedance and an Array for Base Station Applications" (IEEE Transactions on Antennas and Propagation.) adopt a mode of directly adopting a 50 ohm microstrip impedance line to feed from the lower end of the antenna, overcoming the difficulty of impedance matching from the upper end of the antenna, but its VSWR ≦ 2 impedance matching bandwidth is only 40%. Patent CN103531895B published in 2017 discloses a novel broadband printed dipole antenna with branch line integrated feed balun, which includes an SMA joint, a dielectric plate, a radiating element, and a microstrip line feed integrated balun. The radiation unit and the microstrip line integrated balun are respectively and correspondingly printed on the front side and the back side of the dielectric plate and respectively correspond to the exterior of the SMA connector and the inner core for welding for feeding. The invention adopts a mode of adding branch lines in the center of the L-shaped microstrip feed, which is equivalent to series resistance, improves the impedance matching of the antenna, expands the bandwidth, and realizes the broadband characteristic, wherein the bandwidth with VSWR less than or equal to 1.5 is not less than 50%. However, this structure increases the bandwidth, but increases the loss due to the use of the series resistance, and significantly reduces the maximum gain to less than 5.5 dBi.

SUMMERY OF THE UTILITY MODEL

An object of the utility model is to the not enough of above-mentioned prior art, provide a wide band high gain printed antenna to improve the gain of antenna when guaranteeing the broadband.

In order to achieve the above purpose, the utility model adopts the following technical scheme.

1. A broadband high-gain printed antenna comprises two dielectric substrates, wherein a radiation unit and a microstrip feed balun structure are respectively printed on two surfaces of each dielectric substrate; the method is characterized in that:

the upper end of the radiation unit is provided with a guide array to improve the input impedance matching of the antenna and improve the gain;

an isolation groove is formed in the middle of the guide array, the directions of the isolation grooves on the two dielectric plates are opposite, and therefore electric contact between the guide arrays when the two dielectric substrates are installed in an orthogonal mode is avoided.

Further, the antenna radiation unit is composed of a pair of L-shaped radiation arrays; the director array is located at a wavelength of 1/8 directly above a pair of L-shaped radiating arrays.

Furthermore, an installation groove is formed in the middle of each dielectric substrate, and the two dielectric substrates are opposite in slotting direction and used for cross and orthogonal installation of the two dielectric substrates.

Furthermore, the pair of L-shaped radiating arrays have the same structure and are in mirror symmetry in the vertical direction.

Further, the microstrip feed balun structure comprises a feed port connected with the SMA connector, a 50 ohm impedance line, an impedance matching transformation section and an open-circuit stub.

Furthermore, the middle part of the microstrip feed balun structure is bent, and the bending directions of the microstrip feed balun structures on the two dielectric substrates are opposite, so that the microstrip feed balun structure is prevented from being electrically contacted when the two dielectric substrates are orthogonally installed.

Furthermore, the medium substrate is an FR4 medium plate with the relative dielectric constant of 2-4.4 and the thickness of 0.7-0.8 mm.

Compared with the prior art, the utility model discloses owing to 1/8 wavelength departments have add directly over the radiation array and have led to the array, have changed the resistance of antenna itself to improve the input impedance matching of antenna, improved antenna radiation efficiency, reduced the loss, strengthened the directionality simultaneously, makeed half power beam width narrow, the antenna maximum gain improves.

Drawings

Fig. 1 is a schematic perspective view of the present invention;

FIG. 2 is a schematic view of the structure of the radiation unit of the present invention;

fig. 3 is a schematic structural diagram of the center-fed microstrip feed balun of the present invention;

fig. 4 is a graph of S-parameter simulation value-frequency curve of embodiment 1 of the present invention;

fig. 5 is an E-plane simulated directional diagram of embodiment 1 of the present invention at different frequency points;

fig. 6 is a maximum gain simulation value-frequency curve diagram of embodiment 1 of the present invention.

Detailed Description

The present invention will be described in further detail with reference to the following examples and drawings, but the present invention is not limited thereto.

Example 1

Referring to fig. 1, the present embodiment includes two dielectric substrates 1, a radiating element 2, a microstrip feed balun structure 3 and a director array 4. FR4 dielectric board with dielectric constant of 3, thickness of 0.762mm, height of 40mm and width of 51mm is selected for each dielectric substrate 1. The radiating element 2 and the microstrip feed balun structure 3 are respectively printed on two sides of the same dielectric substrate, and the leading array 4 is positioned right above the radiating element. The middle of each dielectric substrate is provided with a mounting groove 6 with the width of 0.9mm, and the directions are opposite. The two dielectric substrates are vertically erected on the ground in a cross manner.

Referring to fig. 2, the radiation unit 2 is composed of a pair of L-shaped radiation arrays 5 with the same structure, and the two L-shaped radiation arrays are both 1/4 wavelengths in length and half wavelengths in height, and are mirror-symmetrical in the vertical direction. The directing array 4 is located 1/8 wavelength positions directly over the L-shaped radiation array, the width is 2mm, the length is half wavelength, an isolation groove 7 with the width of 0.8mm is arranged between the directing array 4 and the L-shaped radiation array, the directions of the isolation grooves 7 on the two dielectric substrates are opposite, and the directing array is used for avoiding electrical contact between the directing array when the two dielectric substrates are orthogonally installed.

Referring to fig. 3, the microstrip feeding balun structure 3 includes a feeding port 31, a 50-ohm impedance line 32, an impedance matching transformation section 33 and an open stub 34, wherein the middle portion of the impedance matching transformation section 33 is bent, and the bending directions of the impedance matching transformation sections 33 on the two dielectric substrates are opposite to each other, so as to avoid electrical contact between the feeding structures when the two dielectric substrates are orthogonally mounted. The feed port 31 is located at the lower right of the dielectric substrate. The 50 ohm impedance line 32 is 1/4 wavelengths high and is located directly above the feed port 31. The impedance matching transformation section 33 is located right above the 50 ohm impedance line 32, and both sides thereof are connected to the open stub 34 and the 50 ohm impedance line 32, respectively. The open stub 34 is located below the impedance matching transformation section 33 and is parallel to the 50 ohm impedance line 32.

When the antenna works, the inner core of the SMA joint is connected with the microstrip feed balun structure 3, and the outer core is connected with the radiation unit 2. When feeding, the current on the microstrip feeding balun structure 3 is conducted to the radiation unit 2 through the dielectric substrate 1 and excites the radiation unit 2 to generate an electromagnetic field. The electromagnetic field generated by the radiating element 2 in turn excites the upper director element 4, causing it to generate another electromagnetic field. The two electromagnetic fields overlap and interfere with each other, thereby changing the internal impedance of the antenna.

Example 2

Referring to fig. 1, 2, and 3, the structure of the present embodiment is basically the same as that of embodiment 1. The difference is that each dielectric substrate 1 is made of FR4 dielectric board with dielectric constant of 2 and thickness of 0.7 mm; the width of the mounting groove 6 in the middle of the medium substrate is 0.8 mm; the width of the guiding array 4 is 1.5mm, and the width of the isolation groove 7 arranged in the middle of the guiding array is 1 mm.

Example 3

Referring to fig. 1, 2, and 3, the structure of the present embodiment is basically the same as that of embodiment 1. The difference is that each dielectric substrate 1 is made of FR4 dielectric board with dielectric constant of 4.4 and thickness of 0.8 mm; the width of the mounting groove 6 in the middle of the medium substrate is 0.9 mm; the width of the guiding array 4 is 2mm, and the width of the separation groove 7 arranged in the middle of the guiding array is 1.2 mm.

The effect of the utility model can be further explained by the following simulation experiment.

Simulation 1, it is right that the simulation software is used to simulate the S parameter of embodiment 1 of the present invention, and the result is shown in fig. 4. As can be seen from FIG. 4, in the frequency band from 2.45GHz to 3.25GHz, the return loss S11 of the port 1 and the return loss S22 of the port 2 are better than-15 dB, and the isolation S21 between the port 1 and the port 2 is better than-30 dB.

Emulation 2, it is right at different frequency points the utility model discloses embodiment 1's E face direction graph is simulated with emulation software, and the result is shown as figure 5, wherein:

fig. 5a is an E-plane simulated directional diagram at a 2.5GHz frequency point according to embodiment 1 of the present invention;

fig. 5b is an E-plane simulated directional diagram at the 2.8GHz frequency point according to embodiment 1 of the present invention;

fig. 5c is an E-plane simulated directional diagram at the frequency point of 3.2GHz in embodiment 1 of the present invention.

As can be seen from fig. 5, the embodiment of the present invention provides a wide-band high-gain antenna with good radiation characteristics.

Simulation 3, to the maximum gain of the embodiment 1 of the present invention, simulation software is used for simulation, and the result is shown in fig. 6. As can be seen from FIG. 6, the embodiment 1 of the present invention has the maximum gain within the range of 8.0 dBi-9.4 dBi within the frequency band of 2.45 GHz-3.25 GHz, which is improved by 2-4 dBi compared with the existing broadband printed dipole antenna.

Synthesize, the utility model discloses a wide band high gain printed antenna has realized the characteristic of broadband and high gain, and has realized good radiation characteristic.

Claims

1. A broadband high-gain printed antenna comprises two dielectric substrates (1), wherein a radiation unit (2) and a microstrip feed balun structure (3) are respectively printed on two sides of each dielectric substrate; the method is characterized in that:

the upper end of the radiation unit (2) is provided with a guide array (4) to improve the input impedance matching of the antenna and increase the gain;

an isolation groove (7) is formed in the middle of the guiding array (4), the directions of the isolation grooves on the two dielectric boards are opposite, and therefore electric contact between the guiding array (4) when the two dielectric substrates (1) are installed in an orthogonal mode is avoided.

2. The antenna of claim 1, wherein: the radiation unit (2) is composed of a pair of L-shaped radiation arrays (5); the director array (4) is located at a wavelength of 1/8 directly above a pair of L-shaped radiating arrays.

3. The antenna of claim 1, wherein: the middle of each dielectric substrate (1) is provided with a mounting groove (6), and the two dielectric substrates are opposite in grooving direction and used for cross and orthogonal mounting of the two dielectric substrates (1).

4. The antenna of claim 1, wherein: the pair of L-shaped radiating arrays (5) have the same structure and are in mirror symmetry in the vertical direction; and the length of the L-shaped radiation array (5) is 1/4 wavelengths, and the height is a half wavelength.

5. The antenna of claim 1, wherein: the microstrip feed balun structure (3) comprises a feed port (31) connected with the SMA connector, a 50 ohm impedance line (32), an impedance matching transformation section (33) and an open-circuit stub (34).

6. The antenna of claim 1, wherein: the middle part of the microstrip feed balun structure (3) is bent, and the bending directions of the microstrip feed balun structures on the two dielectric substrates are opposite, so that the microstrip feed balun structure (3) is prevented from being electrically contacted when the two dielectric substrates (1) are orthogonally installed.

7. The antenna of claim 1, wherein: the dielectric substrate (1) is an FR4 dielectric board with a relative dielectric constant of 2-4.4 and a thickness of 0.7-0.8 mm.

8. The antenna of claim 1, wherein:

the length of the guiding array (4) is 1/2 wavelengths, and the width of the guiding array is 1-2 mm.

9. The antenna of claim 5, wherein:

the 50 ohm impedance line (32) has a height of 1/4 wavelengths.

10. The antenna of claim 3, wherein:

the width of the mounting groove (6) is 0.8-0.9 mm;

the width of the isolation groove (7) is 0.8-1.2 mm.