CN114512826A - Microstrip array antenna, radar and vehicle - Google Patents

As shown in fig. 1, a conventional comb-shaped area array antenna includes a

3 and an

4, where the

3 includes an

31 and at least two

32, the

4 includes at least two

41, the at least two

41 are arranged at intervals, and the at least two

41 are sequentially connected to the at least two

32. In the comb-shaped planar antenna with such a structure, the cross polarization components radiated by the

41 cannot be mutually cancelled, and high cross polarization is easily generated.

As shown in fig. 2 to 4, in order to solve the above cross polarization problem, an embodiment of the present invention provides a

100, where the

100 includes a

1 and an

2, the

2 includes a

3 and an

4, the

3 is disposed on a first surface of the

1, and the

4 is disposed on the first surface of the

1. The

1 is used for bearing the

3 and the

4; the

3 is a passage for connecting an antenna port and the array unit, and realizes functions of impedance matching, amplitude phase distribution and the like, and the

3 is used for connecting the

4 with the antenna port; the

4 is used to convert a guided wave into an electromagnetic wave propagating in an unbounded medium (usually, free space) or vice versa.

With the

1, the normal to the

1 is parallel to the first direction. The material and thickness of the

1 have a great influence on the

100, wherein the material affects the dielectric constant. Materials with a relatively small dielectric constant can enhance the fringing fields at the radiating slot while at the same time increasing the antenna bandwidth. For the thickness of the

1, the antenna bandwidth increases with increasing h/λ, but the corresponding losses increase, so that the efficiency decreases, while if h is too small, the antenna bandwidth is affected, and the radiation efficiency also decreases. Wherein h is the thickness of the substrate and λ is the wavelength of the medium. Optionally, the

1 is Rogers Ro3003G2, the thickness of the

1 is 0.127mm, and the copper-clad thickness is 0.5 oz. Among them, Rogers Ro3003G2 is one of high frequency ceramic filled teflon laminates, designed specifically for millimeter wave automotive radar applications according to industry requirements, and has dielectric constants of 3.00 (clamp strip line method) and 3.07 (microstrip line differential phase method) at 10GHz and 77GHz with extremely low loss.

For the above-mentioned

3, as shown in fig. 3, the

3 includes an

31, at least one

32, and at least one

33, a phase difference between the

33 and the

32 is n pi, n is an odd number, that is, a phase difference between the

33 and the

32 is pi, 3 pi, 5 pi, 7 pi, and so on. The

31 is configured to be connected to an antenna port, and send a signal to the

32 and the

33, and the phase difference between the

33 and the

32 is n pi, so that the purpose of phase inversion between the

33 and the

32 can be achieved. Optionally, the characteristic impedance of the

3 is 50 ohms, and the width is 0.3 mm.

As shown in fig. 4, the

3 includes an

31, a

32, and a

33, where a phase difference between the

33 and the

32 is n pi, and n is an odd number.

As shown in fig. 3, in some embodiments, the

33 is provided with a

331. The

331 is configured to change the phase of the

33, and make the phase difference between the

33 and the

32 be n pi, where n is an odd number. Optionally, the

331 includes a microstrip transmission line having an electrical length of n/2, where n is an odd number, that is, a phase difference between the

33 and the

32 is n pi.

As for the

4, as shown in fig. 3, the

4 includes at least two

41, the at least two

41 are arranged at intervals along the second direction, the extending direction of the

41 is parallel to the third direction, two adjacent

41 are mirror-symmetric, and two adjacent

41 are respectively connected to the

32 and the

33. Wherein the first direction, the second direction and the third direction are perpendicular to each other. By making the phase difference between two adjacent linear array antennas 41 n pi, n an odd number, and making two adjacent

41 mirror-symmetrical along the arrangement direction, the main polarization components radiated by each

41 can be made in phase, and the cross polarization components are in opposite phase, so that the main polarization directional diagram changes little, and the cross polarizations cancel each other and decrease. Optionally, the pitch of the

41 is 2.5 mm. Optionally, the number of the

41 is even.

As shown in fig. 4, the

4 includes two

41, the two

41 are arranged at intervals along the second direction, the extending direction of the

41 is parallel to the third direction, the two

41 are mirror-symmetric, and the two

41 are respectively connected to the

32 and the

33.

As shown in fig. 3 to 4, in some embodiments, the

41 includes a

411 and

412, the

411 is used to connect the

412, the

412 are radiating elements, the

411 extends along the third direction, and the

412 are arranged on the

411 at intervals along the third direction. The

412 are spaced in the third direction, so that the

41 extend linearly, the directions of main polarization components of adjacent

41 are opposite or the same, the directions of cross polarization components are the same or opposite, the

41 are arranged conveniently, and the main polarization components radiated by adjacent

41 are in the same phase and the cross polarization components are in the opposite phase through phase adjustment. Optionally, the distance between the

412 in the third direction is 1.33mm, and the length of the

412 is 1.21 mm. Alternatively, the widths of the

412 may be set to be the same or different, and when the widths are set to be different, unequal amplitude excitation may be obtained, and side lobes of the pattern may be reduced. Alternatively, the

412 may be arranged at intervals along a serpentine line, that is, the

41 is a serpentine linear array antenna. The

412 is generally a regular shaped geometric body, and optionally, the

412 may be one or more of rectangular, circular, annular, and triangular.

As shown in fig. 3 to 4, in some embodiments, two

412 are respectively disposed on two sides of the

411 along the third direction. The

412 are arranged on two sides of the

411 at intervals, so that the radiation efficiency of a single

41 is increased, and the space is fully utilized.

As shown in fig. 3-4, in some embodiments, the normal to the

412 is parallel to the first direction. The

412 is directly attached to the first side of the

1, the

412 being parallel to the first side.

In some embodiments, the distance between two

412 is half of the wavelength of the medium along the third direction. The half medium wavelength interval makes the iron sheet radiate without grating lobe and obtain directivity as large as possible.

As shown in fig. 2, in some embodiments, the

100 further includes a

5, where the

5 is disposed on a second side of the

1, and the second side is disposed opposite to the first side. The

5 is used to reflect electromagnetic waves. Optionally, the

5 is a copper sheet.

The

100 and the conventional comb-shaped area array antenna of the embodiment of the invention are tested and verified, and the test data of the

100 and the conventional comb-shaped area array antenna which are mainly the same are as follows: the

1 is Rogers Ro3003G2, the thickness of the

1 is 0.127mm, and the thickness of copper cladding is 0.5 oz; the characteristic impedance of the

3 is 50 ohms, and the width is 0.3 mm; the distance between the

41 is 2.5 mm; the distance between the

412 along the third direction is 1.33mm, the

412 are rectangular, the length of the

412 is 1.21mm, and the widths of the

412 are equal; along the third direction, two

412 are respectively disposed on two sides of the

411.

The different test data of the

100 and the conventional comb-shaped area array antenna are as follows:

as shown in fig. 1, a conventional comb-shaped area array antenna includes a

3 and an

4, where the

3 includes an

31 and two

32, the

4 includes two

41, the

41 are arranged at intervals along the second direction, and the

41 are sequentially connected to the

32;

as shown in fig. 4, the

100 includes a

3 and an

4, where the

3 includes an

31, a

32, and a

33, and a phase difference between the

33 and the

32 is pi; the

33 is provided with a

331, the

331 comprises a microstrip transmission line with an electrical length of 1/2, and the

331 is configured to change the phase of the

33 and make the phase difference between the

33 and the

32 pi; the

4 includes two

41, the two

41 are arranged at intervals along the second direction, the extending direction of the

41 is parallel to the third direction, the two

41 are in mirror symmetry, and the two

41 are respectively connected with the

32 and the

33.

The main polarization and cross polarization tests are respectively performed on the

100 and the conventional comb-shaped area array antenna of the embodiment of the invention, and the ratio of the power density of signals generated by the actual antenna and an ideal isotropic point source at the same point in space is obtained. Wherein, the frequency Freq is 76.5 GHz. Specifically, the main polarization H-plane directional pattern, the main polarization E-plane directional pattern, the cross polarization H-plane directional pattern, and the cross polarization E-plane directional pattern of the

100 and the conventional comb-shaped area array antenna according to the embodiment of the present invention are obtained, and the specific results are as follows:

As shown in fig. 5, fig. 5 is a main polarization H-plane directional diagram of the microstrip array antenna and the conventional combed area array antenna according to the embodiment of the present invention, where a solid line is the main polarization H-plane directional diagram of the

100 shown in fig. 4, a dotted line is the main polarization H-plane directional diagram of the conventional combed area array antenna shown in fig. 1, and fig. 5 is a simulation diagram. As can be seen from fig. 5, the main lobes of the solid line and the dashed line and the side lobes adjacent to the main lobe are almost overlapped, that is, the main polarized H-plane pattern of the

100 according to the embodiment of the present invention and the main polarized H-plane pattern of the conventional comb-shaped area array antenna do not change much, and the main polarized H-plane pattern of the technical scheme according to the embodiment of the present invention will not be greatly affected.

As shown in fig. 6, fig. 6 is a main polarization E-plane directional diagram of the microstrip array antenna and the conventional combed area array antenna according to the embodiment of the present invention, where a solid line is the main polarization E-plane directional diagram of the

100 shown in fig. 4, a dotted line is the main polarization E-plane directional diagram of the conventional combed area array antenna shown in fig. 1, and fig. 6 is a simulation diagram. As can be seen from fig. 6, the main lobes of the solid line and the dashed line and the side lobes adjacent to the main lobe are almost overlapped, that is, the main polarized E-plane pattern of the

100 according to the embodiment of the present invention and the main polarized E-plane pattern of the conventional comb-plane array antenna do not change much, and the main polarized E-plane pattern of the technical scheme of the conventional comb-plane array antenna is not greatly affected by the technical scheme of the embodiment of the present invention.

As shown in fig. 7, fig. 7 is an H-plane cross-polarization directional diagram of a microstrip array antenna and a conventional combed area array antenna according to an embodiment of the present invention, where a solid line is the H-plane cross-polarization directional diagram of the

100 shown in fig. 4, a dotted line is the H-plane cross-polarization directional diagram of the conventional combed area array antenna shown in fig. 1, and fig. 7 is a simulation diagram. As can be seen from fig. 7, the main lobe of the solid line and the dashed line and the side lobe adjacent to the main lobe are not overlapped at all, i.e. compared with the technical solution of the conventional comb-shaped area array antenna, the

100 of the embodiment of the present invention has a large variation of cross-polarization H-plane patterns and has different degrees of reduction in the main beam range, especially in the 0 ° direction, the reduction value of the H-plane exceeds 5 dB.

As shown in fig. 8, fig. 8 is a cross-polarization E-plane directional diagram of the microstrip array antenna and the conventional combed area array antenna according to the embodiment of the present invention, where a solid line is the cross-polarization E-plane directional diagram of the

100 shown in fig. 4, a dotted line is the cross-polarization E-plane directional diagram of the conventional combed area array antenna shown in fig. 1, and fig. 8 is a simulation diagram. As can be seen from fig. 8, the main lobe of the solid line and the dashed line and the side lobe adjacent to the main lobe are not overlapped at all, i.e. compared with the technical solution of the conventional comb-shaped area array antenna, the cross-polarization E-plane pattern of the

100 of the embodiment of the present invention is greatly changed, and has different degrees of reduction in the main beam range, which is reduced by about 3dB on average, and particularly in the 0 ° direction, the reduction value of the E-plane exceeds 5 dB.

An embodiment of the present invention further provides a radar including the

100 as described above. By providing the

100, cross polarization is reduced, and radiation efficiency is improved.

The embodiment of the invention also provides a vehicle which comprises the radar. By providing the radar including the

100, cross polarization is reduced, and radiation efficiency is improved.

According to the microstrip array antenna, the radar and the vehicle provided by the embodiment of the invention, the phase difference of the two adjacent

41 is n pi, n is an odd number, and the two adjacent

41 are in mirror symmetry along the arrangement direction, so that the main polarization components radiated by the

41 are in the same phase, and the cross polarization components are in opposite phase, therefore, the main polarization directional diagram has small change, the cross polarization is mutually counteracted to reduce, the radiation efficiency is improved, and the antenna has a simple structure.

1. A microstrip array antenna comprising:

a substrate, a normal of the substrate being parallel to a first direction;

the feed network is arranged on the first surface of the substrate and comprises an input port, at least one first output port and at least one second output port, the phase difference between the second output port and the first output port is n pi, and n is an odd number; and the number of the first and second groups,

the planar array antenna is arranged on the first surface of the substrate and comprises at least two linear array antennas, the at least two linear array antennas are arranged at intervals along a second direction, the extending direction of the linear array antennas is parallel to a third direction, two adjacent linear array antennas are in mirror symmetry, and the two adjacent linear array antennas are respectively connected with the first output port and the second output port;

wherein the first direction, the second direction and the third direction are perpendicular to each other.

2. A microstrip array antenna according to claim 1, wherein the second output port is provided with a phase shifter.

3. The microstrip array antenna of claim 2, wherein the phase shifter comprises a microstrip transmission line having an electrical length of a dielectric wavelength n/2, where n is an odd number.

4. The microstrip array antenna of claim 1, wherein the linear array antenna comprises a main feed line and patches, the main feed line extending along the third direction, the patches being spaced apart along the third direction from the main feed line.

5. The microstrip array antenna according to claim 4, wherein two adjacent patches are respectively disposed on two sides of the main feed line along the third direction.

6. A microstrip array antenna according to claim 4 wherein the normal to the patch is parallel to the first direction.

7. The microstrip array antenna of claim 4, wherein the distance between two adjacent patches is half of the dielectric wavelength along the third direction.

8. The microstrip array antenna of claim 1, further comprising a metal layer disposed on a second side of the substrate, the second side being disposed opposite the first side.

9. A radar comprising a microstrip array antenna according to any of claims 1 to 8.

10. A vehicle comprising a radar as claimed in claim 9.