A circularly polarized folded dielectric resonator MIMO antenna

Abstract

The present invention discloses a circularly polarized folded dielectric resonator MIMO antenna, which couples the signal to the top folded dielectric resonator through a rectangular slot via a microstrip line, and stimulates the TM of the dielectric resonator. 11 Two folded dielectric resonators are closely arranged along the side, and the dielectric resonator is transformed into a folded type, so that the dielectric resonator antenna array has a good isolation improvement effect while being closely arranged. At the same time, the antenna has the advantage of low ECC.

Description

Technical Field

[0001] The present invention relates to a microwave communication device, in particular to a dielectric resonator MIMO antenna. Background Art

[0002] Circularly polarized MIMO antennas offer several advantages over traditional MIMO antennas. First, they offer advantages in signal reception and transmission, such as the ability to receive signals of any polarization and immunity to multipath effects. Second, they offer robust interference immunity and adaptability. Third, they offer advantages in a wide range of applications, including satellite communications, radar systems, and mobile communications. Furthermore, compared to traditional metal patch antennas, dielectric resonator antennas offer numerous advantages, such as low loss, high Q, and greater design freedom. When multiple dielectric resonator antennas form a multi-element antenna array, they can effectively improve channel capacity and transmission reliability. However, when dielectric resonator antennas are closely arranged to save space, mutual interference between antennas can lead to numerous adverse effects, such as poor matching, distorted patterns, and reduced radiation performance. Therefore, research on circularly polarized dielectric resonator MIMO antennas with decoupling properties is of great significance.

[0003] Currently, there are three main decoupling methods for circularly polarized dielectric resonator MIMO antennas. The first is a self-decoupling method based on polarization orthogonality, which achieves self-decoupling by adjusting the size of the dielectric resonator antenna; the second is decoupling through the addition of additional structures, such as metal patches; and the third is decoupling through sequential rotation feeding technology, such as the appropriate design of the feeding structure. However, most of these decoupling antennas currently operate in the range of 0.35 λ0-0.5 λ0, where λ0 is the free-space wavelength corresponding to the center frequency. Therefore, it is particularly necessary to design circularly polarized dielectric resonator MIMO antennas that can be used in close-packed applications. Summary of the Invention

[0004] Purpose of the invention: In view of the above-mentioned existing technologies, a circularly polarized folded dielectric resonator MIMO antenna is proposed to solve the problems of complex structure, increased size and increased loss of the current circularly polarized dielectric resonator MIMO antenna.

[0005] Technical solution: A circularly polarized folded dielectric resonator MIMO antenna, wherein the 1×2 antenna unit array of the antenna includes two folded dielectric resonators on the top layer, an upper substrate, a middle metal ground, a lower substrate, and a bottom feeder structure; the two folded dielectric resonators are arranged in parallel on the surface of the upper substrate layer; the folded dielectric resonator is a stepped structure formed by cutting a small rectangular block of different sizes from the upper and lower layers of the rectangular linear polarization antenna; the two folded dielectric resonators are closely arranged along the long sides; two rectangular slots are provided on the middle metal ground, and the rectangular slots are respectively located directly below the two folded dielectric resonators; the bottom feeder structure includes two microstrip feeders, which are respectively located below the two rectangular slots and arranged perpendicular to the rectangular slots.

[0006] Furthermore, the signal is fed into the microstrip feeder of the bottom feeder structure and coupled to the folded dielectric resonator on the top layer through the rectangular slot. Different equivalent capacitances to ground are formed on both sides of the folded dielectric resonator. The different equivalent capacitances to ground make the polarization electric field components on both sides have different initial phases. The mutual coupling between the upper layers and the mutual coupling between the lower layers of the two folded dielectric resonators have different coupling phases. By adjusting the size and position relationship of the two folded dielectric resonators, the different initial phase differences of the polarization electric fields and the coupling phase differences at different coupling positions are superimposed to form a cancellation effect of the two coupling paths, thereby forming a mutual coupling zero point within the working frequency band.

[0007] Furthermore, the overall length of the area occupied by the folded dielectric resonator is 0.21λ0~0.22λ0, the overall width is 0.195λ0~0.198λ0, the height is 0.125λ0~0.130λ0, and the center spacing between the two folded dielectric resonators is 0.2λ0~0.25λ0, where λ0 is the free space wavelength corresponding to the center frequency.

[0008] Furthermore, the size of the first cuboid cut off at the rear of the upper layer of the folded dielectric resonator is 0.123 λ0×0.197 λ0×0.008 λ0, and the size of the second cuboid cut off at the front of the lower layer is 0.086 λ0×0.197 λ0×0.012 λ0.

[0009] Furthermore, the length of the rectangular groove on the middle metal ground is between 0.10λ0 and 0.12λ0, and the width is between 0.29λ0 and 0.30λ0.

[0010] Beneficial Effects: Most of the existing circularly polarized dielectric resonator MIMO antennas are not suitable for closely spaced dielectric resonator antennas. In addition, some antennas have problems of high design complexity, high cost and increased loss. The present invention couples the signal to the top layer of the folded dielectric resonator through the rectangular slot via a microstrip line, and then stimulates the TM of the dielectric resonator.11 Two folded dielectric resonators are closely arranged along the side, and the dielectric resonator is transformed into a folded type, so that the dielectric resonator antenna array has a good isolation improvement effect while being closely arranged. At the same time, the antenna has the advantage of low ECC.

[0011] Specifically, the dielectric resonator adopts a stepped folded structure, forming different equivalent capacitances to ground on both sides of the resonator unit. The different equivalent capacitances to ground make the polarized electric field components on both sides have different initial phases. At the same time, under the condition of close arrangement, the coupling between the upper layer and the coupling between the lower layer of the two antenna units have different coupling phases. Ultimately, the superposition of the different initial phase differences of the polarized electric fields and the coupling phase differences of different coupling parts forms a cancellation effect of the two coupling paths, thereby forming a mutual coupling zero point within the operating frequency band, reducing the coupling of the entire operating frequency band, and having the advantages of pattern recovery and low ECC. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 Schematic diagram of the cross-sectional structure of the circularly polarized folded dielectric resonator MIMO antenna of the present invention;

[0013] Figure 2 Schematic diagram of the top view of the antenna;

[0014] Figure 3 Schematic diagram of the intermediate metal ground structure of the antenna;

[0015] Figure 4 Schematic diagram of the upward-looking structure of the transmitting antenna;

[0016] Figure 5 This is the S-parameter diagram of the antenna according to the embodiment of the present invention;

[0017] Figure 6 : is the gain diagram of the antenna of the embodiment of the present invention;

[0018] Figure 7 The antenna of the embodiment of the present invention is at 4.95 GHz E / H Simulation pattern of the surface;

[0019] Figure 8 This is an ECC simulation diagram of the antenna according to the embodiment of the present invention;

[0020] Figure 9 Axial ratio simulation diagram of the antenna of this embodiment. DETAILED DESCRIPTION

[0021] The present invention will be further explained below with reference to the accompanying drawings.

[0022] A circularly polarized folded dielectric resonator MIMO antenna, the structure of its 1×2 antenna element array is as follows Figures 1 to 4 As shown, it mainly consists of two high-dielectric-constant folded dielectric resonators 1 on the top layer, an upper substrate 2 with a low dielectric constant, an intermediate metal ground 4, a lower substrate 6 with a low dielectric constant, and a bottom feeder structure 5.

[0023] Two folded dielectric resonators 1 are arranged in parallel on the surface of the upper substrate layer 2. The folded dielectric resonator 1 is a stepped structure formed by cutting out a small rectangular block of different sizes from the upper and lower layers of the rectangular linear polarization antenna. The two folded dielectric resonators 1 are closely arranged along the long sides. Two rectangular grooves 3 are etched on the middle metal ground 4, and the rectangular grooves 3 are respectively located directly below the two folded dielectric resonators 1. The bottom feed structure 5 includes two microstrip feed lines, which are respectively located below the two rectangular grooves 3 and arranged perpendicular to the rectangular grooves 3. The signal is fed in through the microstrip feed line of the bottom feed structure 5, and the signal is coupled to the folded dielectric resonator 1 on the top layer through the rectangular grooves 3.

[0024] In this embodiment, the folded dielectric resonator 1 has an overall length of 0.21λ0 to 0.22λ0, an overall width of 0.195λ0 to 0.198λ0, and a height of 0.125λ0 to 0.130λ0. The center-to-center spacing between two folded dielectric resonators 1 is 0.2λ0 to 0.25λ0, where λ0 is the free-space wavelength corresponding to the center frequency. The folded dielectric resonator 1 is a rectangular linearly polarized antenna. Along its length, the first rectangular block 7 is cut away from the rear of the upper layer, and the second rectangular block 8 is cut away from the front of the lower layer. The dimensions of the cut first and second rectangular blocks 7, 8, are 0.123λ0 × 0.197λ0 × 0.008λ0 and 0.086λ0 × 0.197λ0 × 0.012λ0, respectively. The length of the rectangular groove 3 on the intermediate metal ground 4 is between 0.10λ0 and 0.12λ0, and the width is between 0.29λ0 and 0.30λ0.

[0025] The present invention, by adopting a folded dielectric resonator, can introduce a mutual coupling zero point in the band, so that it has a good isolation improvement. Specifically, when the antenna is working, the signal is fed through the microstrip feeder corresponding to the bottom feeder structure 5, and the signal is coupled to the folded dielectric resonator 1 through the rectangular slot 3 and stimulates the TM of the two folded dielectric resonator structures 1. 11The dielectric resonator adopts a stepped folded structure. Due to the different ground areas and heights between the upper and lower layers of the structure, different equivalent capacitances to the ground are formed on the left and right sides (x-axis direction) of the resonator. The different equivalent capacitances to the ground result in different initial phases of the polarized electric field components on both sides. At the same time, when the two folded dielectric resonators, serving as radiators, are closely arranged, the mutual coupling between the upper layers and the mutual coupling between the lower layers of the two radiators have different coupling phases. Ultimately, by adjusting the size and position of the radiators according to the design frequency of the antenna, the superposition of the different initial phase differences of the polarized electric fields and the coupling phase differences at different coupling locations can form a cancellation effect of the two coupling paths, thereby forming a mutual coupling zero point within the operating frequency band and reducing coupling across the entire operating frequency band.

[0026] In this embodiment, the metal material used is copper; the dielectric substrate has a dielectric constant of 3.55 and a loss angle of 0.0027; the material of the high dielectric constant folded dielectric resonator is ceramic, with a dielectric constant of 89.5 and a loss angle of 0.0006; the center distance between the two folded dielectric resonators is 0.21λ0. Figure 5 As shown in FIG, the 10dB impedance matching bandwidth of this embodiment is 2.02% (4.90GHz – 5.00GHz), and the in-band isolation is improved from 3.86dB to 18.56dB. Figure 6 As shown, the maximum gain within the working band is restored from 3.24dBi to 6.74dBi. Figure 7 The antenna is at 4.95GHz E / H-plane simulation radiation pattern. Figure 8 This is an ECC simulation diagram of the antenna array of this embodiment. It can be seen that the ECC of the antenna array of this embodiment is reduced to 0.0056. Figure 9 The axial ratio diagram of the antenna of this embodiment is shown in FIG. The axial ratio bandwidth of the antenna is 1.7%. Compared with existing circularly polarized dielectric resonator MIMO antennas, the circularly polarized folded dielectric resonator MIMO antenna of the present invention has the advantages of simple decoupling and applicability to close arrangement.

[0027] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A circularly polarized folded dielectric resonator MIMO antenna, characterized in that: The 1×2 antenna unit array of the antenna comprises two folded dielectric resonators (1) on the top layer, an upper substrate (2), a middle metal ground (4), a lower substrate (6), and a bottom feeder structure (5); the two folded dielectric resonators (1) are arranged in parallel on the surface of the upper substrate (2); the folded dielectric resonator (1) is a step structure formed by cutting off a small rectangular parallelepiped of different sizes from the upper and lower layers of a rectangular linear polarization antenna; the two folded dielectric resonators (1) are closely arranged along the long sides; two rectangular slots (3) are provided on the middle metal ground (4), and the rectangular slots (3) are respectively located directly below the two folded dielectric resonators (1); and the bottom feeder structure (5) comprises two microstrip feeders, which are respectively located below the two rectangular slots (3) and are arranged perpendicular to the rectangular slots (3).

2. The circularly polarized folded dielectric resonator MIMO antenna according to claim 1, wherein: The signal is fed into the microstrip feeder of the bottom feeder structure (5), and is coupled to the folded dielectric resonator (1) on the top layer through the rectangular slot (3). Different equivalent capacitances to the ground are formed on both sides of the folded dielectric resonator (1). The different equivalent capacitances to the ground make the polarized electric field components on both sides have different initial phases. The mutual coupling between the upper layers and the mutual coupling between the lower layers of the two folded dielectric resonators (1) have different coupling phases; by adjusting the size and position relationship of the two folded dielectric resonators (1), the initial phase difference of different polarization electric fields and the coupling phase difference of different coupling parts are superimposed to form a cancellation effect of the two coupling paths, thereby forming a mutual coupling zero point within the working frequency band.

3. The circularly polarized folded dielectric resonator MIMO antenna according to claim 1, wherein: The overall length of the area occupied by the folded dielectric resonator (1) is 0.21λ0~0.22λ0, the overall width is 0.195λ0~0.198λ0, the height is 0.125λ0~0.130λ0, and the center distance between the two folded dielectric resonators (1) is 0.2λ0~0.25λ0, where λ0 is the free space wavelength corresponding to the center frequency.

4. The circularly polarized folded dielectric resonator MIMO antenna according to claim 3, wherein: The size of the first cuboid (7) cut off at the rear of the upper layer of the folded dielectric resonator (1) is 0.123 λ0×0.197 λ0×0.008 λ0, and the size of the second cuboid (8) cut off at the front of the lower layer is 0.086 λ0×0.197 λ0×0.012 λ0.

5. The circularly polarized folded dielectric resonator MIMO antenna according to claim 3 or 4, characterized in that: The length of the rectangular groove (3) on the intermediate metal ground (4) is between 0.10 λ0 and 0.12 λ0, and the width is between 0.29 λ0 and 0.30 λ0.

Images