Circular polarization folding type dielectric resonator MIMO antenna

Abstract

The invention discloses a circularly polarized folded dielectric resonator MIMO antenna, which is characterized in that a signal is coupled to a folded dielectric resonator at the top layer through a microstrip line via a rectangular groove, and a TM11 mode of the dielectric resonator is excited. The two folded dielectric resonators are closely arranged along the side edges, and the dielectric resonators are transformed into folded dielectric resonators, so that the dielectric resonator antenna array has a good isolation and improvement effect while being closely arranged, and meanwhile, the antenna has the advantage of low ECC (Error Correction Code).

Description

Technical Field

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

[0002] Compared with traditional MIMO antennas, circularly polarized MIMO antennas have many advantages. First, they have advantages in signal reception and transmission, such as being able to receive waves of any polarization and being unaffected by multipath effects. Second, they have anti-interference capabilities and adaptability. Third, they have application scenario advantages and are widely used in satellite communications, radar systems, and mobile communications. At the same time, compared with traditional metal patch antennas, dielectric resonator antennas have many advantages, such as low loss, high Q value, and large design freedom. When multiple dielectric resonator antennas form a multi-unit antenna array, the channel capacity and transmission reliability can be effectively improved. However, when dielectric resonator antennas are closely arranged to save space, mutual interference between antennas will bring many adverse effects, such as poor matching, distorted patterns, and reduced radiation performance. Therefore, it is of great significance to carry out research on circularly polarized dielectric resonator MIMO antennas with decoupling characteristics.

[0003] At present, 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 to achieve decoupling by adding additional structures, such as adding metal patches, etc.; the third is to achieve decoupling through sequential rotation feeding technology, such as reasonably designing 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 arrangements. Summary of the invention

[0004] Purpose of the invention: In view of the above-mentioned prior art, 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 a 1×2 antenna unit array of the antenna comprises 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 step structure formed by cutting off a small rectangular block of different sizes from the upper and lower layers of a rectangular linear polarized antenna; the two folded dielectric resonators are closely arranged along the long sides; two rectangular grooves are provided on the middle metal ground, and the rectangular grooves are respectively located directly below the two folded dielectric resonators; the bottom feeder structure comprises two microstrip feeders, which are respectively located below the two rectangular grooves and are arranged perpendicular to the rectangular grooves.

[0006] Furthermore, the signal is fed in through the microstrip feeder of the bottom feeder structure, and the signal is coupled to the folded dielectric resonator on the top layer through the rectangular slot, and different equivalent capacitances to the ground are formed on both sides of the folded dielectric resonator. The different equivalent capacitances to the ground make the polarization electric field components on both sides have different initial phases; the mutual coupling between the upper layers of the two folded dielectric resonators and the mutual coupling between the lower layers 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 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.

[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, the center distance between two folded dielectric resonators is 0.2λ0~0.25λ0, and 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 0.10 λ0 and 0.12 λ0, and the width is between 0.29 λ0 and 0.30 λ0.

[0010] Beneficial effects: Most of the existing circularly polarized dielectric resonator MIMO antennas are not suitable for closely arranged 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 folded dielectric resonator through the rectangular slot through the 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, and the antenna has the advantage of low ECC.

[0011] Specifically, the dielectric resonator adopts a stepped folding structure to form different equivalent capacitances to the ground on both sides of the resonator unit. The different equivalent capacitances to the 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 layers and the coupling between the lower layers of the two antenna units have different coupling phases. Ultimately, the different initial phase differences of the polarized electric fields and the coupling phase differences 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, reducing the coupling of the entire working frequency band, and having the advantages of pattern recovery and low ECC. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 It is a schematic cross-sectional structure diagram of the circularly polarized folded dielectric resonator MIMO antenna of the present invention; Figure 2 Schematic diagram of the top view structure of the antenna; Figure 3 It is a schematic diagram of the structure of the intermediate metal ground of the antenna; Figure 4 Schematic diagram of the structure of the transmitting antenna when viewed from above; Figure 5 The S parameter diagram of the antenna of the embodiment of the present invention; Figure 6 is a gain diagram of the antenna of the embodiment of the present invention; Figure 7 The antenna of the present embodiment is at 4.95 GHz. E / H Simulation direction diagram of the surface; Figure 8 This is an ECC simulation diagram of the antenna of the embodiment of the present invention; Fig. 9 The axial ratio simulation diagram of the antenna of the present invention embodiment. DETAILED DESCRIPTION

[0013] The present invention will be further explained below in conjunction with the accompanying drawings.

[0014] A circularly polarized folded dielectric resonator MIMO antenna, the structure of which is a 1×2 antenna element array. Figures 1 to 4 As shown, it is mainly composed of two high dielectric constant folded dielectric resonators 1 on the top layer, a low dielectric constant upper substrate 2, an intermediate metal ground 4, a low dielectric constant lower substrate 6, and a bottom feeder structure 5.

[0015] 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 step structure formed by cutting off a small rectangular block 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 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 line structure 5 includes two microstrip feed lines, which are respectively located below the two rectangular grooves 3 and are arranged perpendicular to the rectangular grooves 3. The signal is fed in through the microstrip feed line of the bottom feed line structure 5, and the signal is coupled to the folded dielectric resonator 1 on the top layer through the rectangular grooves 3.

[0016] In this embodiment, 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 two folded dielectric resonators 1 is 0.2λ0~0.25λ0, where λ0 is the free space wavelength corresponding to the center frequency. The folded dielectric resonator 1 is a rectangular linear polarized antenna, and a step structure is formed by cutting off the first rectangular block 7 at the rear of the upper layer and the second rectangular block 8 at the front of the lower layer along the length direction. The sizes of the cut first rectangular block 7 and the second rectangular block 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 middle metal ground 4 is between 0.10 λ0 and 0.12 λ0, and the width is between 0.29 λ0 and 0.30 λ0.

[0017] The present invention can introduce a mutual coupling zero point in the band by adopting a folded dielectric resonator, 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 excites the TM of the two folded dielectric resonator structures 1. 11 The dielectric resonator adopts a stepped folding structure. Due to the different ground areas and heights between the upper and lower layers of the structure, different equivalent capacitances to the ground can be formed on the left and right sides (x-axis direction) of the resonator. Different equivalent capacitances to the ground make the polarized electric field components on both sides have different initial phases. At the same time, under the condition that the two folded dielectric resonators 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. Finally, according to the design frequency of the antenna, by adjusting the size and position relationship of the radiator, the initial phase difference of the different polarized electric fields and the coupling phase difference of different coupling parts can be superimposed to form a cancellation effect of the two coupling paths, thereby forming a mutual coupling zero point within the working frequency band and reducing the coupling of the entire working frequency band.

[0018] In this embodiment, the metal material 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; and the center distance between the two folded dielectric resonators is 0.21λ0. Figure 5 As shown in FIG. 1 , the 10dB impedance matching bandwidth of this embodiment is 2.02% (4.90GHz – 5.00GHz), and the in-band isolation is increased 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. Fig. 9 1 is an axial ratio diagram of the antenna of this embodiment, and the axial ratio bandwidth of the antenna is 1.7%. Compared with the existing circularly polarized dielectric resonator MIMO antenna, the circularly polarized folded dielectric resonator MIMO antenna of the present invention has the advantages of simple decoupling method and applicability to close arrangement.

[0019] 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 principle of the present invention. These improvements and modifications should also be regarded as 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 layer (2); the folded dielectric resonator (1) is a step structure formed by cutting off a small rectangular block 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 grooves (3) are provided on the middle metal ground (4), and the rectangular grooves (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 grooves (3) and are arranged perpendicular to the rectangular grooves (3).

2. The circularly polarized folded dielectric resonator MIMO antenna according to claim 1, characterized in that: The signal is fed in through the microstrip feed line of the bottom feed line structure (5), and the signal 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 positional 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 positions are superimposed to form a cancellation effect of 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, characterized in that: 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, the center distance between two folded dielectric resonators (1) is 0.2λ0~0.25λ0, and λ0 is the free space wavelength corresponding to the center frequency.

4. The circularly polarized folded dielectric resonator MIMO antenna according to claim 3, characterized in that: 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 middle metal ground (4) is between 0.10 λ0 and 0.12 λ0, and the width is between 0.29 λ0 and 0.30 λ0.

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