CN115548661B - Broadband circularly polarized patch antenna - Google Patents

Abstract

The invention discloses a broadband circularly polarized patch antenna which comprises a semicircular patch, a cross patch, a floor, a microstrip line, an upper dielectric substrate, a lower dielectric substrate and an annular patch, wherein the semicircular patch and the annular patch are arranged on the upper dielectric substrate, the cross patch is arranged between the upper dielectric substrate and the lower dielectric substrate, and the microstrip line is arranged on the lower surface of the lower dielectric substrate and feeds power upwards through the floor. The patch antenna has the advantages that the patch antenna receives both linearly polarized electromagnetic waves and circularly polarized electromagnetic waves, the patch antenna mainly increases impedance bandwidth of the patch by increasing gaps and using cross patches, and simultaneously, the axial ratio bandwidth of the antenna is adjusted by adjusting the positions of circular holes of the patch on the top layer, so that the antenna can perform required work better.

Description

A broadband circularly polarized patch antenna

Technical field

The present invention relates to the field of wireless communication technology, and more specifically, to a broadband circularly polarized patch antenna.

Background technique

As an important communication equipment in today's era, the antenna is the most important component of the current communication system. The antenna can convert current into electromagnetic wave radiation. For communication systems in today's society, antennas play a very important role in mobile communications. The function of the transmitting antenna is that the antenna acts as a relay to realize the conversion of current and electromagnetic waves, and then emits the electromagnetic waves; while for the receiving antenna, the opposite process of transformation is performed, converting the received electromagnetic waves into corresponding current.

With the development and progress of society, science and technology are also constantly developing, and in the field of wireless communications, the performance of antennas requires increasingly higher indicators. In the past, linearly polarized antennas were more commonly used, but with the development of society, it is difficult to meet the needs of today's society. In current communications, more people are paying attention to circularly polarized antennas. Compared with linearly polarized antennas, circularly polarized antennas have the following advantages: First, circularly polarized waves have great advantages over linearly polarized waves. Circular orthogonality is its unique characteristic. Only Only circularly polarized antennas can produce circularly polarized waves, and this characteristic of circularly polarized antennas makes them widely used in current aerospace, military and other communication fields: Second, compared with linearly polarized antennas, circularly polarized antennas The compatibility of polarized antennas is particularly good. It can receive circularly polarized waves with the old linear polarized antennas.

Nowadays, circularly polarized antennas are widely used in satellite communications, RFD, WLAN and other fields. However, most current circularly polarized antennas tend to have narrow bandwidth and low gain. Therefore, how to design a broadband antenna Circularly polarized antennas with high gain characteristics are still a difficulty in current research. Current research has proposed many methods to improve the impedance and axial ratio bandwidth of microstrip circularly polarized antennas, such as slot loading, wide-mouth slots fed by coplanar waveguides, parasitic patches, laminated structures, etc.

The circularly polarized bandwidth of the antenna is clearly defined in electromagnetics, which is the impedance bandwidth with an axial ratio less than 3db. The axial ratio is a very important parameter for the circularly polarized antenna, and it is also the most basic, because the antenna The degree of polarization basically depends on the width of the axis ratio. Circularly polarized waves have the characteristic that they can be decomposed into two orthogonal linearly polarized waves with equal amplitude and 90° phase difference in both time and space. The amplitudes of these two electric field components are completely consistent, and the phase difference of 90° is the basic principle of achieving circular polarization.

Therefore, it has always been difficult to solve the problems of bandwidth and axial ratio of circularly polarized antennas. It is very valuable to design a circularly polarized antenna with wide impedance bandwidth, high gain and wide axial ratio.

Contents of the invention

The purpose of the present invention is to solve the above technical problems and propose a broadband circularly polarized patch antenna with wide impedance bandwidth, high gain, and wide-axis ratio.

In order to achieve the above objects, the present invention adopts the following technical solutions:

A broadband circularly polarized patch antenna, including: an annular patch, a cross-shaped patch, a floor, a microstrip line, an upper dielectric substrate, a lower dielectric substrate and a semicircular patch. The annular patch and the semicircular patch are The patch is arranged on the upper dielectric substrate. The technology of opening an annular groove in the original semicircular patch is used to form a semicircular patch and an annular patch at its outer end. The annular patch is connected with the semicircular patch. The number of circular patches is two, and the two annular patches and the two semicircular patches form the top patch;

The number of the cross-shaped patches is two, which feeds the top patch. The cross-shaped patches are arranged between the upper dielectric substrate and the lower dielectric substrate. The microstrip line is arranged under the lower dielectric substrate. surface, and feed upward through the floor.

Preferably, the two annular patches and the semicircular patches of the upper dielectric substrate are symmetrical about the center of the circle on the square surface of the top layer.

Preferably, the shape of the microstrip line is composed of a rectangle and a hexagon, and the shape of the entire fed microstrip line is symmetrical along the x-axis.

Preferably, the upper surface of the lower dielectric substrate is covered with a metal floor. There is a certain gap between the floor and the upper cross-shaped patch, and a floor slot symmetrical along the X-axis and Y-axis is provided in the middle. The antenna The top patch is fed through coupling between the microstrip line and the floor slot.

Preferably, the cross-shaped patch is in the shape of a cross and is connected in the middle by a rectangular bracket. There is a certain angle between the cross-shaped patch and the y-axis.

Preferably, the lower dielectric substrate is provided with a port, the port is a power excitation port, and the port is fed to the floor through a microstrip line.

Preferably, the upper dielectric substrate and the lower dielectric substrate are both FR dielectric substrates, and the upper dielectric substrate, floor and lower dielectric substrate are symmetrically distributed.

Preferably, the microstrip line is a 50Ω microstrip line.

Compared with the existing technology, the present invention provides a broadband circularly polarized patch antenna, which has the following beneficial effects:

1. In the present invention, the excitation power supply in the microstrip line in the lower substrate is coupled with the slot and fed to the top ring patch and semicircular patch through the cross-shaped patch. By using the feed of the cross-shaped patch The structure enables the antenna to better perform impedance matching and at the same time better increase the impedance bandwidth.

2. The present invention adopts microstrip line and slot feeding in the form of top patch feeding, which can effectively improve the bandwidth, reduce reflection loss, and improve the coupling efficiency of the antenna. Moreover, due to the existence of the floor, it can reduce the impact of the feed on the radiating unit. Impact, and slotting in the floor can not only facilitate microstrip line coupling excitation but also provide better impedance matching to a certain extent.

3. In the present invention, the two semicircular patches on the top layer are equivalent to a pair of dipole patches, and an annular patch is loaded near the dipole to optimize the related amplitude response, thereby improving the antenna of this example. impedance bandwidth.

Description of drawings

Figure 1 is a general schematic diagram of this embodiment;

Figure 2 is a left view of the general schematic diagram of this embodiment;

Figure 3 is a structural diagram of the upper surface of the upper dielectric substrate of this embodiment;

Figure 4 is a cross-shaped patch structure diagram of this embodiment;

Figure 5 is a structural diagram of the upper surface floor of the lower dielectric substrate in this embodiment;

Figure 6 is a surface structural diagram of the lower dielectric substrate in this embodiment;

Figure 7 is a simulated S-parameter curve diagram of a single-polarized antenna with two resonant frequency points excited by a single port in this embodiment;

Figure 8 is a comparison diagram of the cylindrical feed and the cross-shaped feed used in the antenna of this example;

Figure 9 is an axial ratio diagram of the antenna of this embodiment;

Figure 10 is the test gain versus frequency curve of the antenna of this embodiment;

Figure 11(a) is the 10GHz E-plane test pattern of the antenna of this embodiment;

Figure 11(b) is the 10GHz H-plane test pattern of the antenna of this embodiment;

In the picture: 1. Ring patch; 2. Cross-shaped patch; 3. Floor; 4. Microstrip line; 5. Upper dielectric substrate; 6. Lower dielectric substrate; 7. Semicircular patch; 8. Floor slot ; 9. Bracket.

Detailed ways

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only some of the embodiments of the present invention, rather than all the embodiments.

In the description of the present invention, it should be understood that the terms "upper", "lower", "front", "back", "left", "right", "top", "bottom", "inner", " The orientation or positional relationship indicated by "outside" and so on is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation. Specific orientations of construction and operation are therefore not to be construed as limitations of the invention.

Referring to Figures 1-11, a broadband circularly polarized patch antenna of the present invention includes a ring patch 1, a cross patch 2, a floor 3, a microstrip line 4, an upper dielectric substrate 5, and a lower dielectric substrate 6 and two semi-circular patches 7, the two annular patches 1 and the two semi-circular patches 7 are arranged on the upper dielectric substrate 5, in which circular rings are opened in the original semi-circular patches. Using the technology of shaped grooves, a semicircular patch 7 and an annular patch 1 at its outer end are formed. The number of the annular patch 1 and the semicircular patch 7 is two, and the two annular patches 1 and Two semicircular patches 7 form the top patch;

The number of the cross-shaped patches 2 is two, which feed the top patch. The cross-shaped patches 2 are arranged in the middle of the upper dielectric substrate 5 and the lower dielectric substrate 6. The microstrip line 4 is arranged in The lower surface of the lower dielectric substrate 6 is fed upward through the floor 3; the number of the annular patches 1 and the semicircular patches 7 is two, and the two annular patches 1 and the two semicircular patches are The two annular patches 1 and the semicircular patches 7 of the upper dielectric substrate 5 are symmetrical to the center of the circle on the square surface of the top layer.

Among them, referring to Figure 1, the antenna is mainly radiated by an annular patch 1 and a semicircular patch 7. These patches are fed by a cross-shaped patch 2 symmetrical along the z-axis. The two semicircular patches 7 It is placed symmetrically in the center and is excited in 180° opposite directions. The antenna uses slot-coupled microstrip line 4, which can easily provide a source for the antenna, adjust impedance matching, and easily obtain a large impedance bandwidth. The lower slot feeder, the suspended cross-shaped patch 2 and the semicircular patch together form a current loop, and the relative position of the loop and the slot can produce right circular polarization.

Figure 8 shows the surface current vector distribution diagram of the patch at GHZ. From the simulation results, it can be seen that the current on the patch mainly rotates to the right, forming a right-handed circular polarization. The angle between the grooves between the semicircular patches 7 and the x-axis can be used to adjust the amplitude of the orthogonal linear polarization component. The height between the two substrates of the antenna and the digging of holes in the floor slot 8 will relatively increase the radiation intensity on the surface of the floor 3 after digging. These methods can better achieve impedance matching. In order to better feed the semicircular patch 7, the antenna in this example uses a cylindrical metal and a cross-shaped patch 2 for feeding comparison. As shown in Figure 8, a cylindrical metal is used at the same position. The ARWB is narrower than the ARBW when using cross-shaped patch 2 feed, and the impedance matching is also worse. Through comparison, it can be seen that in this example antenna, the cross-shaped patch feed is used for the top patch feed, which can achieve better impedance matching and increase the impedance bandwidth. In order to further broaden the impedance bandwidth and improve the impedance matching characteristics in the antenna, the technology of opening a circular groove in the original semicircular patch is used to form the semicircular patch 7 and its outer For the annular patch 1 at the end, calculated from the figure, the ARBW value range is 5.68-14.75GHZ at a center frequency of 10.3GHZ, and the relative bandwidth is 88.77%.

As shown in Figure 1, the shape of the microstrip line 4 of the present invention is composed of a rectangle and a hexagon. The shape of the entire fed microstrip line 4 is symmetrical along the x-axis; the upper surface of the lower dielectric substrate 6 The floor 3 is covered with metal. There is a certain gap between the floor 3 and the cross-shaped patch 2 above. There is also a floor slot 8 symmetrical along the X-axis and the Y-axis in the middle. The antenna is connected to the floor through the microstrip line 4. The coupling between slots 8 feeds the patch on the top layer; the microstrip line 4 is a 50Ω microstrip line.

Among them, the present invention uses the microstrip line 4 and the floor slot 8 to feed the top patch, which can effectively improve the bandwidth, reduce the reflection loss, and improve the coupling efficiency of the antenna. Moreover, due to the existence of the floor 3, the feed can be reduced. It has an impact on the radiating unit, and slotting in the floor 3 can not only facilitate the coupling excitation of the microstrip line 4, but also provide better impedance matching to a certain extent.

As shown in Figure 1, the number of the cross-shaped patches 2 of the present invention is two, the shape is cross-shaped, and the middle is connected by a rectangular bracket 9. The cross-shaped patches 2 have a certain angle with the y-axis. ; The lower dielectric substrate 6 is provided with a port, the port is a power excitation port, and the port is fed through the microstrip line 4 and the floor 3.

Among them, in the present invention, the excitation power supply in the microstrip line 4 in the lower dielectric substrate 6 is coupled with the floor slot 8 and then feeds the top ring patch 1 and the semicircular patch 7 through the cross-shaped patch 2 , by using the feed structure of the cross-shaped patch 2, the antenna can achieve better impedance matching and at the same time better increase the impedance bandwidth; the two semicircular patches 7 on the top layer are equivalent to a pair of dipole patches , a ring patch 1 is loaded near the dipole to optimize the relevant amplitude response and further improve the impedance bandwidth of the antenna in this example.

As shown in Figure 1, the upper dielectric substrate 5 and the lower dielectric substrate 6 of the present invention are both FR4 dielectric substrates. The upper dielectric substrate 5, the floor 3 and the lower dielectric substrate 6 are symmetrically distributed.

Among them, in the present invention, the upper dielectric substrate 5, the floor 3 and the lower dielectric substrate 6 are arranged to be symmetrically distributed. This design is simple and reasonable, and the symmetrical distribution facilitates the combination of each layer for power feeding.

Figures 2, 3, 4, 5, and 6 are dimensioned drawings of the electrical structure of each part. Combined with the dimensions of Figure 1, Figure 2, Figure 3, Figure 4, Figure 5, and Figure 6, the specific parameters of the antenna in this example are as follows. The upper and lower substrates are both F4BME220 dielectric substrates, and the relative dielectric constant of the substrate is 2.2. The thickness is 1mm and the loss tangent value is 0.001. The values of the remaining antenna structure variables are as follows: H1 is 0.3mm, H2 is 3.48mm, WP is 50mm, WS is 0.6mm, D1 is 38mm, D2 is 22mm, D3 is 27.5mm, r1 is 2.3mm, R1 is 47°, R2 is 45°, coordinates (x2, y2) are (11, 0) in mm, H3 is 4.18mm, H4 is 1.5mm, L3 is 14mm, L4 is 8mm, L1 is 17.1mm, L2 is 10.1mm , W1 is 3.69mm, W2 is 4.58mm, D4 is 4mm, (x1, y1) is (-3, 0) unit mm, (x2, y2) is (3, 0) unit mm, Wt is 7mm, Lt is 6.46mm, Wf is 2.5mm.

The above are only preferred specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any person familiar with the technical field can, within the technical scope disclosed in the present invention, implement the technical solutions of the present invention. Equivalent substitutions or changes of the inventive concept thereof shall be included in the protection scope of the present invention.

Claims (7)

1. A broadband circularly polarized patch antenna, characterized by: including a ring patch (1), a cross-shaped patch (2), a floor (3), a microstrip line (4), and an upper dielectric substrate (5) , the lower dielectric substrate (6) and the semicircular patch (7), the annular patch (1) and the semicircular patch (7) are arranged on the upper dielectric substrate (5), in which the original semicircular patch is used. The technology of opening a circular groove in a circular patch forms a semicircular patch (7) and an annular patch (1) at its outer end. The annular patch (1) and the semicircular patch (7) are ) The number is two, and the two annular patches (1) and the two semicircular patches (7) form the top patch; The number of the cross-shaped patches (2) is two, which feed the top patch. The cross-shaped patches (2) are arranged in the middle of the upper dielectric substrate (5) and the lower dielectric substrate (6). The microstrip line (4) is arranged on the lower surface of the lower dielectric substrate (6) and feeds power upward through the floor (3); The upper surface of the lower dielectric substrate (6) is covered with a metal floor (3). There is a certain gap between the floor (3) and the upper cross-shaped patch (2), and there is also a middle along the X-axis. And the Y-axis symmetrical floor slot (8), the antenna feeds the patch on the top layer through the coupling between the microstrip line (4) and the floor slot (8). 2. A broadband circularly polarized patch antenna according to claim 1, characterized in that: the two annular patches (1) and the semicircular patches (7) of the upper dielectric substrate (5) are in The square surface of the top layer is symmetrical about the center of the circle. 3. A broadband circularly polarized patch antenna according to claim 1, characterized in that: the shape of the microstrip line (4) consists of a rectangle and a hexagon, and the entire feeding microstrip line The shape of (4) is symmetrical along the x-axis. 4. A broadband circularly polarized patch antenna according to claim 1, characterized in that: the cross-shaped patch (2) is in the shape of a cross and is connected in the middle by a rectangular bracket (9), The cross-shaped patch (2) has a certain angle with the y-axis. 5. A broadband circularly polarized patch antenna according to claim 1, characterized in that the lower dielectric substrate (6) is provided with a port, the port is a power excitation port, and the port passes through a microstrip Line (4) and floor (3) feed. 6. A broadband circularly polarized patch antenna according to claim 1, characterized in that: the upper dielectric substrate (5) and the lower dielectric substrate (6) are both FR4 dielectric substrates, and the upper dielectric substrate ( 5), the floor (3) and the lower dielectric substrate (6) are symmetrically distributed. 7. A broadband circularly polarized patch antenna according to claim 1, characterized in that: the microstrip line (4) is a 50Ω microstrip line.