CN114464996B - Circularly polarized array antenna based on surface plasmon - Google Patents

Abstract

The invention discloses a circularly polarized array antenna based on surface plasmons, which comprises an upper medium substrate and a lower medium substrate; the upper surface of the upper medium substrate is provided with four radiation patches and four circular patches, the radiation patches and the circular patches are symmetrically arranged along the center rotation of the upper medium substrate, the radiation patches are crescent and square grooves are etched at the edges, and the square grooves are used for generating artificial surface plasmons; the circular patch comprises an inner circle and a circular ring sleeved on the edge of the inner circle, and a strip-shaped groove is etched on the circular ring along the circumference and is used for generating local surface plasmons; the upper surface of the lower medium substrate is provided with a phase-shifting feed network, the phase-shifting feed network comprises four signal output ports, metal probes are respectively arranged on the four signal output ports, and the metal probes are upwards and respectively connected with the radiation patches for feeding; the directivity of the antenna is improved by artificial surface plasmon technique and localized surface plasmon technique.

Description

A circularly polarized array antenna based on surface plasmons

Technical field

The invention relates to a circularly polarized array antenna based on surface plasmon polaritons and belongs to the technical field of electronic communication.

Background technique

With the continuous development of the communications industry, the demand for wireless spectrum continues to increase. Broadband wireless communication technology has the characteristics of fast transmission rate, large amount of information transmission, and high stability, and is an effective way to solve the demand for wireless spectrum. Broadband antennas can reduce costs by improving production materials and simplifying hardware structures.

Currently, the requirements for communication technology in satellite communications, radar detection and other aspects are constantly increasing, requiring antennas to cover wider bandwidths and have better directivity. Circularly polarized array antennas can improve the performance of communication systems, accept and radiate waves of arbitrary polarization, and are widely used in the military field. In fields such as mobile communications, global positioning systems, and satellite communications, circularly polarized array antennas can increase communication capacity and improve the system's ability to resist multipath effects.

With the development of technology, modern wireless communication technology has put forward higher requirements for the performance of antennas such as gain and directivity. However, the bandwidth of traditional single circularly polarized antennas is limited, and the existing methods for adjusting antenna directivity are relatively unstable. Poor, it can only achieve bandwidth extension in a narrow sense and cannot achieve directionality improvement.

Contents of the invention

The purpose of the present invention is to overcome the deficiencies in the prior art and provide a circularly polarized array antenna based on surface plasmons, which can achieve increased bandwidth and improved directivity.

In order to achieve the above objects, the present invention is achieved by adopting the following technical solutions:

A circularly polarized array antenna based on surface plasmons, including an upper dielectric substrate and a lower dielectric substrate; a radiation patch and a circular patch are provided on the upper surface of the upper dielectric substrate, and the radiation patch and the circular patch are arranged on the upper surface of the upper dielectric substrate. Each patch is provided with four and are arranged rotationally symmetrically along the center of the upper dielectric substrate. The radiation patch is crescent-shaped and has a square groove etched on the edge. The square groove is used to generate artificial surface plasmons; the circular The patch includes an inner circle and a ring set on the edge of the inner circle. A strip groove is etched along the circumference of the ring. The strip groove is used to generate localized surface plasmons; the lower dielectric substrate A phase-shifted feed network is provided on the upper surface. The phase-shifted feed network includes four signal output ports. Metal probes are respectively provided on the four signal output ports. The metal probes are respectively connected upward to radiation patches. Make a feed.

Optionally, the size of the circularly polarized array antenna is 1.27λg×1.27λg×0.18λg, where λg is the guided wavelength.

Optionally, both the upper dielectric substrate and the lower dielectric substrate adopt insulating F4B dielectric substrates with a dielectric constant of 2.2 and a loss tangent of 0.003.

Optionally, the radiation patch includes a base circle and a circular groove opened on the base circle, the center of the circular groove is located on the edge of the base circle, and the radius of the circular groove is smaller than the radius of the base circle; the circle The shaped patch is arranged inside the circular groove.

Optionally, four electromagnetic band gap structures are arranged rotationally symmetrically around the center on the upper dielectric substrate. The electromagnetic band gap structure includes a plurality of metal square pieces with equal radii, centers on the same straight line and spaced apart. Circular holes are etched in the centers of the square pieces, and the metal square pieces are arranged on the upper surface and the lower surface of the upper dielectric substrate in one-to-one correspondence.

Optionally, the phase-shifted feed network also includes a first equal-section Wilkinson power divider, two second equal-section Wilkinson power dividers, a microstrip line, two 90° phase shifters, and 180 °Phase shifter; the input terminal of the first bisecting Wilkinson power divider is connected to the signal source, and the output terminal of the first bisecting Wilkinson power divider is connected to two second The input end of the equally divided Wilkinson power divider, the output ends of the two second equal divided Wilkinson power dividers are respectively connected to four signal output ports through microstrip lines, and the 180° phase shifter is arranged at The two 90° phase shifters are respectively arranged on the microstrip line connected to the output end of one side of the first bisecting Wilkinson power divider, and are respectively arranged on the microstrip line connected to the two opposite signal output ports.

Optionally, the microstrip lines are arranged in an irregular curved shape.

Optionally, multiple strip patches are provided on the sides of the microstrip line connected to the 180° phase shifter, and rectangular grooves are etched on the inner sides of the strip patches.

Compared with the prior art, the beneficial effects achieved by the present invention are:

The invention provides a circularly polarized array antenna based on surface plasmons, in which the radiation patch is crescent-shaped and has a square groove etched on the edge, and the square groove is used to generate artificial surface plasmons; the circular patch It includes an inner circle and a ring set on the edge of the inner circle. There are strip grooves etched along the circumference of the ring. The strip grooves are used to generate localized surface plasmons; through artificial surface plasmon technology and localized Surface plasmon technology improves the directivity of the antenna and enhances the performance of the antenna.

Description of the drawings

Figure 1 is a schematic structural diagram of a circularly polarized array antenna provided by an embodiment of the present invention;

Figure 2 is a schematic structural diagram 2 of a circularly polarized array antenna provided by an embodiment of the present invention;

Figure 3 is a schematic diagram of the surface of an upper dielectric substrate provided by an embodiment of the present invention;

Figure 4 is a schematic diagram of the surface of the lower dielectric substrate provided by an embodiment of the present invention;

Figure 5 is a schematic diagram of the phase change of the circularly polarized array antenna provided by the embodiment of the present invention as a function of the input signal frequency;

Figure 6 is a schematic diagram of the radiation direction of the circularly polarized array antenna provided by the embodiment of the present invention at 5.6GHz and 6.3GHz;

Figure 7 is a schematic diagram |S11| comparing the measurement and simulation results of the circularly polarized array antenna provided by the embodiment of the present invention;

Figure 8 is a schematic diagram comparing the axial ratio of measurement and simulation results of the circularly polarized array antenna provided by the embodiment of the present invention;

Figure 9 is a schematic diagram comparing the gain of measurement and simulation results of the circularly polarized array antenna provided by the embodiment of the present invention;

Marked in the picture are:

1. Upper dielectric substrate, 2. Lower dielectric substrate, 3. Radiation patch, 31. Square slot, 32. Base circle, 33. Round slot, 4. Phase-shifting feed network, 41. Signal output port, 42. Chapter First-section Wilkinson power divider, 43. Second-section Wilkinson power divider, 44. Microstrip line, 45. 90° phase shifter, 46. 180° phase shifter, 5. Circular patch, 51. Inner circle, 52. Ring, 53. Strip groove, 6. Metal probe, 7. Electromagnetic band gap structure, 71. Metal square piece, 72. Round hole, 8. Strip patch, 81. Rectangular slot.

Detailed ways

The present invention will be further described below in conjunction with the accompanying drawings. The following examples are only used to more clearly illustrate the technical solutions of the present invention, but cannot be used to limit the scope of the present invention.

Example 1:

As shown in Figures 1-4, this embodiment provides a circularly polarized array antenna based on surface plasmons, including an upper dielectric substrate 1 and a lower dielectric substrate 2; a radiation patch is provided on the upper surface of the upper dielectric substrate 1 3 and circular patches 5. Each of the radiation patches 3 and the circular patches 5 is provided with four and are arranged rotationally symmetrically along the center of the upper dielectric substrate 1. The radiation patch 3 is crescent-shaped and has a square groove 31 etched on the edge. The groove 31 is used to generate artificial surface plasmons; the radiation patch 3 includes a base circle 32 and a circular groove 33 opened on the base circle 32. The center of the circular groove 33 is located at the edge of the base circle 32, and the radius of the circular groove 33 is Smaller than the radius of the base circle 32; the circular patch 5 is arranged inside the circular groove 33. The crescent-shaped structure reduces the influence between the phase-shifted feed network 4 and the radiation patch 3, and generates two orthogonal modes through perturbation to form circular polarization, which is beneficial to the improvement of bandwidth and directivity. The circular patch 5 includes an inner circle 51 and a ring 52 set on the edge of the inner circle 51. A strip groove 53 is etched along the circumference of the ring 52, and the strip groove 53 is used to generate localized surface plasmons; Artificial surface plasmon technology and localized surface plasmon technology effectively increase the bandwidth of circularly polarized array antennas and improve directivity.

The upper surface of the lower dielectric substrate 2 is provided with a phase-shifting feed network 4. The phase-shifting feed network 4 includes four signal output ports 41. The four signal output ports 41 are respectively provided with metal probes 6. The metal probes 6 are respectively arranged upward. Connect radiation patch 3 for power feeding. The phase-shifted feed network 4 also includes a first equal-section Wilkinson power divider 42, two second equal-section Wilkinson power dividers 43, a microstrip line 44, two 90° phase shifters 45 and a 180° Phase shifter 46; the input end of the first equal Wilkinson power divider 42 is connected to the signal source, and the output end of the first equal Wilkinson power divider 42 is connected to the two second equal parts through microstrip lines 44. The input end of the divided Wilkinson power divider 43 is connected to the four signal output ports 41 through microstrip lines 44 respectively. The 180° phase shifter 46 is arranged at On the microstrip line 44 connected to one side of the output end of the first bisecting Wilkinson power divider 42, two 90° phase shifters 45 are respectively disposed on the microstrip line 44 connected to the two opposite signal output ports 41. On the top, the microstrip lines 44 are arranged in an irregular curved shape. The input signal is divided into two signals by a Wilkinson power divider, which can achieve more balanced power distribution and increase bandwidth. The two 90° phase shifters 45 realize a 90° phase difference through microstrip lines with a quarter wavelength difference, and the 180° phase shifter 46 realizes a 180° phase difference through the microstrip lines 44 with a half wavelength difference. ; Use a phase shifter to adjust the phase over a wider frequency band, converting the phase from 0° to 90°, 180°, and 270° to achieve directivity adjustment and improvement. There are multiple strip patches on the side of the microstrip line connected by the 180° phase shifter, and rectangular grooves are etched on the inner sides of the strip patches.

Four electromagnetic bandgap structures 7 are provided on the upper dielectric substrate 1 rotationally symmetrically along the center to suppress the propagation of harmonics and electromagnetic surface waves and improve the performance of the antenna. The electromagnetic band gap structure 7 includes a plurality of metal square pieces 71 with equal radii, centers on the same straight line and spaced apart. The metal square pieces 71 are each etched with circular holes 72 in the center. The metal square pieces 71 are arranged on the upper dielectric substrate 1 in one-to-one correspondence. upper surface and lower surface.

The size of the circularly polarized array antenna in this embodiment is 1.27λg×1.27λg×0.18λg, where λg is the guided wavelength. The upper dielectric substrate 1 and the lower dielectric substrate 2 both use insulating F4B dielectric substrates with a dielectric constant of 2.2 and a loss tangent of 0.003.

The specific dimensions of the circularly polarized array antenna provided in this embodiment are as shown in Table 1.

Table I:

parameter l ₁ w ₁ w ₂ w ₃ w ₄ w ₅ r ₁ r ₂ r ₃ Value(mm) 60 1.5 0.5 0.84 1.1 0.2 12 0.4 4 parameter h ₁ h ₂ h ₃ a ₁ a ₂ a ₃ a ₄ a ₅ a ₆ Value(mm) 0.5 0.5 6 0.5 0.3 0.2 0.3 0.5 0.9 parameter d ₁ d ₂ d ₃ d ₄ d ₅ d ₆ d ₇ Value(mm) 1 1 6 0.74 4 0.7 2.44

As shown in Figure 5, it can be seen that the impedance bandwidth is from 3.11GHz to 6.74GHz, and the phase difference between adjacent output ports can be maintained at around 90° from 3GHz to 7GHz.

As shown in Figure 6, the radiation pattern of the array at 5.8GHz and 6.3GHz in the embodiment of the present invention. It can be seen that after adding the localized surface plasmon structure, the cross-polarization is significantly suppressed. At 5.8GHz, the angle at which cross-polarization suppression is greater than 15dB can reach 50°, which is 12° better than without adding a localized surface plasmon structure. At 6.3GHz, the cross-polarization suppression can reach an angle greater than 15dB to 63°, which is 33° better than without adding a localized surface plasmon structure. This antenna achieves improved directivity.

As shown in Figure 7, the comparison between the measured and simulated |S11| (input reflection coefficient, used to measure whether the impedance matching between the antenna and the excitation source is good, and is one of the indicator parameters of the antenna performance) results. The measured impedance bandwidth is 3.15GHz to 6.75GHz, and the relative bandwidth is 72%, which is basically consistent with the simulation results.

As shown in Figure 8, a comparison between measured and simulated axle ratio results is shown. The measured axial ratio bandwidth is 3.97GHz to 6.72GHz, and the relative bandwidth is 55%,

As shown in Figure 9, a comparison of measured and simulated gains is shown. The measured peak gain is 11.11dBi.

It can be seen from the measurement and simulation results that the antenna array designed in the present invention has certain advantages in size and can improve the directivity.

The above are only preferred embodiments of the present invention. It should be pointed out that those skilled in the art can also make several improvements and modifications without departing from the technical principles of the present invention. These improvements and modifications It should also be regarded as the protection scope of the present invention.

Claims (8)

1. A circularly polarized array antenna based on surface plasmons, characterized in that it includes an upper dielectric substrate and a lower dielectric substrate; a radiation patch and a circular patch are provided on the upper surface of the upper dielectric substrate, and the There are four radiation patches and four circular patches, and they are arranged rotationally symmetrically along the center of the upper dielectric substrate. The radiation patches are crescent-shaped and have square grooves etched on their edges. The square grooves are used to generate artificial surface plasma excitation. Yuan; the circular patch includes an inner circle and a ring set on the edge of the inner circle. A strip groove is etched along the circumference of the ring. The strip groove is used to generate localized surface plasmons. ; A phase-shifting feed network is provided on the upper surface of the lower dielectric substrate. The phase-shifting feed network includes four signal output ports. Metal probes are respectively provided on the four signal output ports. The metal probes Connect the radiation patches upward respectively for power feeding. 2. A circularly polarized array antenna based on surface plasmons according to claim 1, characterized in that the size of the circularly polarized array antenna is 1.27λg×1.27λg×0.18λg, and λg is the conductor. wavelength. 3. A circularly polarized array antenna based on surface plasmon polaritons according to claim 1, characterized in that both the upper dielectric substrate and the lower dielectric substrate adopt a dielectric constant of 2.2 and a loss tangent of 0.003. Insulated F4B dielectric substrate. 4. A circularly polarized array antenna based on surface plasmons according to claim 1, characterized in that the radiation patch includes a base circle and a circular groove opened on the base circle, and the circular groove The center of the circle is located at the edge of the base circle, and the radius of the circular groove is smaller than the radius of the base circle; the circular patch is arranged inside the circular groove. 5. A circularly polarized array antenna based on surface plasmons according to claim 1, characterized in that four electromagnetic bandgap structures are rotationally symmetrically arranged along the center on the upper dielectric substrate, and the electrical The tape gap structure includes a plurality of metal squares with equal radii, centers on the same straight line and spaced apart. The metal squares are all etched with circular holes in their centers. The metal squares are arranged in one-to-one correspondence on the upper surface and the upper surface of the upper dielectric substrate. lower surface. 6. A circularly polarized array antenna based on surface plasmon polaritons according to claim 1, characterized in that the phase-shifted feed network further includes a first bisecting Wilkinson power divider, two A second bisecting Wilkinson power divider, a microstrip line, two 90° phase shifters and a 180° phase shifter; the input end of the first bisecting Wilkinson power divider is connected to a signal source, and the The output terminals of the first halved Wilkinson power divider are respectively connected to the input terminals of the two second halved Wilkinson power dividers through microstrip lines, and the two second halved Wilkinson power dividers have The output ends are respectively connected to four signal output ports through microstrip lines. The 180° phase shifter is arranged on the microstrip line connected to the output end of one side of the first bisecting Wilkinson power divider. The two The 90° phase shifters are respectively arranged on the microstrip lines connected to the two opposite signal output ports. 7. A circularly polarized array antenna based on surface plasmon polaritons according to claim 6, characterized in that the microstrip lines are arranged in an irregular curved shape. 8. A circularly polarized array antenna based on surface plasmons according to claim 6, characterized in that multiple strip patches are provided on the sides of the microstrip line connected to the 180° phase shifter. , the inner sides of the strip-shaped patches are etched with rectangular grooves.