A compact broadband low-coupling tri-polarized dielectric resonator antenna based on non-uniform medium

Abstract

The application discloses a compact broadband low-coupling tri-polarized dielectric resonator antenna based on non-uniform medium, utilizes differential feeding to excite a pair of orthogonal horizontal polarization TE x and TE y resonance modes in the dielectric resonator antenna, adjusts the TE 111 and TE 113 resonance mode frequency points of the dielectric resonator to tend to be close, effectively improves the working bandwidth of the antenna due to the similar directional diagrams of the two modes, inserts a probe in the center of the dielectric resonator to excite the vertical polarization TM 011 mode of the dielectric resonator, the working frequency bands of the three modes are highly overlapped, and the design of the broadband tri-polarized antenna is realized; meanwhile, the working bandwidth of the antenna is increased by embedding a dielectric block with a dielectric constant higher than that of the original dielectric in the dielectric resonator; and the coupling between the ports is reduced by etching a circular ring gap on the floor around the probe; the tri-polarized common bandwidth of the application reaches 47.7%, the size is 0.326*0.326*0.326λ0 3 , and the bandwidth area ratio reaches 449% / λ0 2 .

Description

TECHNICAL FIELD

[0001] The present application relates to the field of antennas in communication technology, in particular to a compact broadband low-coupling tri-polarized dielectric resonator antenna based on non-uniform medium. BACKGROUND

[0002] With the continuous development of mobile communication technology, the MIMO (Multiple-Input Multiple-Output) technology for improving the channel capacity by increasing the number of antennas plays an increasingly important role in modern mobile communication. From 4 antennas, 8 antennas in the 3G era to dozens, hundreds of antennas in the 5G / 6G era, MIMO has gradually evolved from traditional small-scale systems to large-scale and super-large-scale systems. Large-scale MIMO systems have new requirements for antenna unit miniaturization, compactness, low coupling, and easy production. Tri-polarized antennas can multiplex three electromagnetic wave polarization states on the same radiating unit, and their application in MIMO communication systems can multiply the channel capacity. As a new type of antenna, dielectric resonator antennas have attracted the attention of researchers due to their small size, high radiation efficiency, rich resonance modes, and high design freedom. Therefore, designing a miniaturized compact tri-polarized dielectric resonator antenna will have great application prospects in tri-polarized MIMO systems.

[0003] In order to improve the information transmission rate of the communication system, the antenna bandwidth is a characteristic that researchers must pay attention to, and the tri-polarized antenna contains three ports, which requires not only that the operating frequency bands of each port remain coincident, but also that the coupling between the ports in the common operating frequency band be as small as possible. Although there are many solutions for existing broadband dual-polarized antennas, how to add a third polarization and simultaneously obtain a larger common bandwidth and lower coupling characteristics between the three polarization ports is a major problem in the design of tri-polarized antennas.

[0004] Document [1] proposes a tri-polarized dielectric resonator antenna based on a balanced feed structure. The antenna excites a pair of mutually orthogonal HE 11δ modes of the circular ring-shaped dielectric resonator and a vertical polarization mode of a monopole, four rectangular slots are etched in the antenna ground, which are respectively coupled and fed by two pairs of equal-length feed lines, and the monopole antenna feed port is increased on the lower layer of the substrate to expand the ground for soldering of the SMA interface. The relative bandwidth of the antenna is 15.9%, and the size of the dielectric block is π×0.12 2 ×0.20λ0 3 . Due to the use of a balanced feed structure, the antenna pattern, cross-polarization ratio, and inter-port coupling are all good, but the bandwidth is still limited.

[0005] Reference [2] proposed a low-profile three-port tri-polarized dielectric resonator antenna. The cylindrical dielectric resonator antenna is fed by a feed line through four gaps close to a ring. Two of the ports can excite a pair of orthogonal HE by feeding into the symmetrical gaps. 13δ mode, the third port provides equal amplitude and same direction signal input to the four slots, which can stimulate the TM of the dielectric resonator 02δ mode, producing a vertically polarized radiation pattern. The size of the antenna dielectric block is π×0.59 2 ×0.10λ0 3 , with a relative bandwidth of 5.1%. Although the antenna profile is only 0.10λ0 high, the low common bandwidth and large lateral size still limit its application scenarios.

[0006] Reference [3] proposed a three-polarized rectangular dielectric resonator antenna. x δ11 Mode, asymmetric TE y 1δ1 The mode realizes two orthogonal horizontal polarizations and symmetric TE y 1δ1 The mode achieves quasi-omnidirectional vertical polarization. The three modes are excited by the differential probe, the central slot and the peripheral slot respectively. The size of the antenna dielectric block is 0.29×0.31×0.13λ0 3 , the relative bandwidth is only 3.4%.

[0007] The literature [1] is Deng C, Feng Z, He Y.Hybrid cylindrical dielectric resonatorantenna with monopole for tri-polarized operation[J].Microwave and OpticalTechnology Letters, 2016, 58(3):635-638.

[0008] Document [2] is Fang XS, Luo L, Xu YJ, et al. Design of the low-profile tri-polarized diversity cylindrical dielectric resonator antenna utilizing high-order HEM 13δand TM 02δmodes[J]. IEEE Transactions on Antennas andPropagation, 2023,71(11):9060-9065..

[0009] Document [3] is Zhang B, Ren J, Luan Y, et al. Three-port three-polarized dielectric resonator antenna with omnidirectional radiation [J]. IEEE Antennasand Wireless Propagation Letters, 2023, 22(12): 3122-3126.

[0010] In summary, the shortcomings of existing tri-polarized dielectric resonator antennas and the challenges they face in design and application are as follows:

[0011] (1) The resonant modes of antennas with different polarizations are difficult to operate in the same frequency band and it is difficult to obtain a large bandwidth at the same time, so the common bandwidth is small;

[0012] (2) The complex feeding network has a significant impact on the antenna impedance matching, resulting in a smaller bandwidth;

[0013] (3) The coupling between some ports within the working bandwidth is high, causing the antenna's radiation pattern to be distorted. Summary of the Invention

[0014] Purpose of the Invention: To address the shortcomings of existing broadband dual-polarized dielectric resonator antennas and the challenges in their design and application, the present invention proposes a compact broadband low-coupling tri-polarized dielectric resonator antenna based on a non-uniform dielectric. This antenna solves the problems of complex feeding structure and low bandwidth of existing tri-polarized dielectric resonator antennas, achieves broadband tri-polarized radiation performance in a relatively compact structure, and can be applied to fields such as wireless communications and large-scale MIMO antenna arrays.

[0015] Technical solution: A compact broadband low-coupling tri-polarized dielectric resonator antenna based on an inhomogeneous medium, comprising: a dielectric substrate, a dielectric resonator, a first coaxial probe, a second coaxial probe, a third coaxial probe, a fourth coaxial probe, a fifth coaxial probe, a first Wilkinson power divider, a second Wilkinson power divider, a first feed port, a second feed port, a third feed port, and a floor;

[0016] The dielectric substrate is arranged on the lower surface of the floor, and the dielectric resonator is arranged on the upper surface of the floor; the first Wilkinson power divider and the second Wilkinson power divider are arranged on the lower surface of the dielectric substrate;

[0017] The dielectric resonator is a horizontal radial layered dielectric structure, which is composed of a cylindrical dielectric embedded in a rectangular dielectric resonator, wherein the dielectric constant of the cylindrical dielectric is higher than the dielectric constant of the surrounding dielectric.

[0018] The first coaxial probe is inserted into the center of the dielectric resonator, and the second coaxial probe, the third coaxial probe, the fourth coaxial probe and the fifth coaxial probe are respectively inserted into the interior of the dielectric resonator and close to the edge of the dielectric resonator;

[0019] Circular gaps are etched on the peripheral floors of the second coaxial probe, the third coaxial probe, the fourth coaxial probe, and the fifth coaxial probe;

[0020] The second coaxial probe and the fourth coaxial probe are symmetrically arranged to form a differential feed pair, the third coaxial probe and the fifth coaxial probe are symmetrically arranged to form another differential feed pair, and the two differential feed pairs are orthogonally arranged;

[0021] The first feeding port directly feeds the first coaxial probe to stimulate vertical polarization radiation TM with the polarization direction being the z-axis direction 011 model;

[0022] The second feeding port is connected to the input end of the second Wilkinson power divider, and the output end of the second Wilkinson power divider is connected to a differential feeding pair to stimulate the TE y 111 TE y 113 Mode; the third feed port is connected to the input of the first Wilkinson power divider, the output of the first Wilkinson power divider is connected to another differential feed pair, stimulating a TE x 111 TE x 113 Mode;TE 111 and TE 113 The directional patterns of the modes are similar and the resonant frequencies are close, which increases the bandwidth of the antenna and realizes three mutually orthogonal polarization modes in the same radiator.

[0023] Furthermore, holes are opened at the contact points between the second coaxial probe, the third coaxial probe, the fourth coaxial probe, and the fifth coaxial probe and the floor.

[0024] Furthermore, the cylindrical dielectric and the rectangular dielectric resonator have the same height.

[0025] Furthermore, there is a certain gap between the periphery of the first coaxial probe and the dielectric resonator.

[0026] Furthermore, the first Wilkinson power splitter and the second Wilkinson power splitter implement differential feeding.

[0027] Furthermore, the first Wilkinson power divider and the second Wilkinson power divider each include a first microstrip line, a quarter-wavelength microstrip line, a second microstrip line and a limiting resistor;

[0028] For any one of the first and second Wilkinson power dividers, its input end is connected to the first microstrip line, and then connected to two parallel quarter-wavelength microstrip lines. A limiting resistor is connected to the ends of the two quarter-wavelength microstrip lines. Finally, the second microstrip line is connected to the output end. The length of the second microstrip line connected to the two output ends differs by half the wavelength of the microstrip line waveguide, so that the output signal power of the two output ends is the same and there is a phase difference of 180 degrees. The two output ends are fed to symmetrical coaxial probes respectively to achieve differential feeding.

[0029] Furthermore, the first microstrip line and the second microstrip line are both microstrip lines with a characteristic impedance of 50 ohms.

[0030] Furthermore, the quarter-wavelength microstrip line is a quarter-wavelength microstrip line with a characteristic impedance of 70.7 ohms.

[0031] Furthermore, the limiting resistor is a 100 ohm limiting resistor.

[0032] Beneficial effects: Compared with the prior art, the present invention has the following advantages:

[0033] (1) The present invention first uses differential feeding to excite a pair of orthogonal TE x and TE y resonant mode and adjust the TE of the dielectric resonator 111 and TE 113 The resonant mode frequencies are close to each other. Since the radiation patterns of the two modes are similar, this will effectively increase the working bandwidth of the antenna. On this basis, the probe is inserted into the center of the dielectric resonator to stimulate the TM 011 mode, the radiation performance of this mode is similar to that of a vertically placed monopole antenna. At the same time, a broadband vertically polarized radiation pattern is achieved by using a non-uniform dielectric structure. The operating frequency bands of the three modes are highly overlapped, realizing the design of a broadband tri-polarized antenna.

[0034] (2) The present invention changes the horizontal radial dielectric distribution of the dielectric resonator by embedding a dielectric block with a higher dielectric constant than the original dielectric inside the dielectric resonator, thereby changing the field distribution in the resonant cavity of the dielectric resonator antenna at different frequencies; when the antenna is at a lower resonant frequency, the dielectric resonator as a whole maintains a resonant state, and the dielectric constant is the equivalent dielectric constant of the non-uniform medium; when the frequency increases, the horizontal radial layered structure can suppress the generation of high-order modes. At this high-frequency resonance point, the energy in the cavity is mainly concentrated in the high-dielectric-constant dielectric block, which plays the role of main resonance and outward radiation, ultimately increasing the working bandwidth of the antenna;

[0035] (3) The application proposes a certain gap between the coaxial probe inserted in the center and the dielectric resonator, and the impedance matching effect of the coaxial probe and the dielectric resonator is improved by adjusting the gap distance;

[0036] (4) The application proposes to etch a circular ring gap around the probe on the floor, so as to reduce the coupling between the ports; when one probe of the antenna is excited, the circular ring gap around the other probe will change the field distribution around the surrounded probe, reduce the size of the field around the probe, thereby reducing the mutual influence between the probes and increasing the isolation between the ports;

[0037] (5) The application proposes to use a Wilkinson power divider as the feeding network of the dielectric resonator, and by changing the length of the transmission line at the output end of the Wilkinson power divider, the phase difference of the two output signals is kept close to 180 degrees at the working frequency band of the dielectric resonator, so as to realize differential feeding and keep a large bandwidth of the antenna;

[0038] (6) The application realizes the low coupling characteristic between the second and third ports through differential feeding, which is equivalent to forming a virtual ground at the center position between the two feeding probes, so that the field distribution under the two polarizations is more orthogonal and less likely to affect each other, thereby reducing the coupling between the two ports;

[0039] (7) The three-polarized dielectric resonator antenna proposed by the application meets the application requirements of miniaturization and compactness, the working frequency band of the three-polarized antenna is 1.77-2.88GHz, the common bandwidth is up to 47.7%, and the isolation between the three ports is in the range of 15-48dB. The size of the dielectric resonator is 0.326x0.326x0.326λ0 3 , and the bandwidth area ratio reaches 449% / λ0 2 . BRIEF DESCRIPTION OF DRAWINGS

[0040] Figure 1 is a structure diagram of a compact broadband low-coupling three-polarized dielectric resonator antenna based on non-uniform medium proposed by the application; wherein, Figure 1 (a) in the figure is a whole structure diagram of the compact broadband low-coupling three-polarized dielectric resonator antenna based on non-uniform medium, Figure 1 (b) in the figure is a side view of the compact broadband low-coupling three-polarized dielectric resonator antenna based on non-uniform medium;

[0041] Figure 2 is a port S parameter diagram of the compact broadband low-coupling three-polarized dielectric resonator antenna based on non-uniform medium proposed by the application;

[0042] Figure 3This is a distribution diagram of the magnetic field size on the bottom surface of a compact broadband low-coupling tri-polarized dielectric resonator antenna based on an inhomogeneous medium proposed by the present invention when the first feeding port is excited separately and operates at different frequencies; wherein, Figure 3 (a) is the magnetic field distribution diagram of the bottom surface of the dielectric resonator when it works at 1.8 GHz. Figure 3 (b) is the magnetic field distribution diagram of the bottom surface of the dielectric resonator when it works at 2.2GHz. Figure 3 (c) is the magnetic field distribution diagram of the bottom surface of the dielectric resonator when it works at 2.5GHz. Figure 3 (d) is the magnetic field distribution at the bottom of the dielectric resonator when it works at 2.8 GHz;

[0043] Figure 4 This is a diagram of the electric field distribution on the surface of the dielectric resonator when the second feeding port of the compact broadband low-coupling tri-polarized dielectric resonator antenna based on non-uniform medium proposed by the present invention is excited separately and operates at different frequencies; wherein, Figure 4 (a) is the surface electric field distribution of the dielectric resonator when it works at 1.8 GHz. Figure 4 (b) is the surface electric field distribution of the dielectric resonator when it works at 2.2GHz. Figure 4 (c) is the surface electric field distribution of the dielectric resonator when it works at 2.5 GHz. Figure 4 (d) is the surface electric field distribution of the dielectric resonator when it works at 2.8 GHz;

[0044] Figure 5 This is a diagram of the electric field distribution on the dielectric resonator surface when the third feeding port of a compact broadband low-coupling tri-polarized dielectric resonator antenna based on an inhomogeneous medium proposed by the present invention is excited separately and operates at different frequencies; wherein, Figure 5 (a) is the surface electric field distribution of the dielectric resonator when it works at 1.8 GHz. Figure 5 (b) is the surface electric field distribution of the dielectric resonator when it works at 2.2GHz. Figure 5 (c) is the surface electric field distribution of the dielectric resonator when it works at 2.5 GHz. Figure 5 (d) is the surface electric field distribution of the dielectric resonator when it works at 2.8 GHz;

[0045] Figure 6 The electric field pattern of the compact broadband low-coupling tri-polarized dielectric resonator antenna based on an inhomogeneous medium proposed by the present invention when operating at 1.8 GHz and exciting the first feeding port alone; wherein, Figure 6 (a) in the figure is the XOZ plane. Figure 6 (b) in the figure is the XOY plane;

[0046] Figure 7 An antenna electric field directional pattern of a compact broadband low-coupling tri-polarized dielectric resonator antenna based on non-uniform medium according to the present application when working at 2.2GHz and the first feeding port is excited alone; wherein, Figure 7 (a) in the above is XOZ plane, Figure 7 (b) in the above is XOY plane;

[0047] Figure 8 An antenna electric field directional pattern of a compact broadband low-coupling tri-polarized dielectric resonator antenna based on non-uniform medium according to the present application when working at 2.5GHz and the first feeding port is excited alone; wherein, Figure 8 (a) in the above is XOZ plane, Figure 8 (b) in the above is XOY plane;

[0048] Figure 9 An antenna electric field directional pattern of a compact broadband low-coupling tri-polarized dielectric resonator antenna based on non-uniform medium according to the present application when working at 2.8GHz and the first feeding port is excited alone; wherein, Figure 9 (a) in the above is XOZ plane, Figure 9 (b) in the above is XOY plane;

[0049] Figure 10 An antenna electric field directional pattern of a compact broadband low-coupling tri-polarized dielectric resonator antenna based on non-uniform medium according to the present application when working at 1.8GHz and the second feeding port is excited alone; wherein, Figure 10 (a) in the above is XOZ plane, Figure 10 (b) in the above is YOZ plane;

[0050] Figure 11 An antenna electric field directional pattern of a compact broadband low-coupling tri-polarized dielectric resonator antenna based on non-uniform medium according to the present application when working at 2.2GHz and the second feeding port is excited alone; wherein, Figure 11 (a) in the above is XOZ plane, Figure 11 (b) in the above is YOZ plane;

[0051] Figure 12 An antenna electric field directional pattern of a compact broadband low-coupling tri-polarized dielectric resonator antenna based on non-uniform medium according to the present application when working at 2.5GHz and the second feeding port is excited alone; wherein, Figure 12 (a) in the above is XOZ plane, Figure 12 (b) in the above is YOZ plane;

[0052] Figure 13A compact broadband low-coupling tri-polarized dielectric resonator antenna based on non-uniform medium according to the present application works at 2.8GHz when the second feeding port is excited alone, and the antenna electric field pattern is shown in the figure, wherein, Figure 13 (a) in the figure is XOZ plane, Figure 13 (b) in the figure is YOZ plane.

[0053] Figure 14 A compact broadband low-coupling tri-polarized dielectric resonator antenna based on non-uniform medium according to the present application works at 1.8GHz when the third feeding port is excited alone, and the antenna electric field pattern is shown in the figure, wherein, Figure 14 (a) in the figure is XOZ plane, Figure 14 (b) in the figure is YOZ plane.

[0054] Figure 15 A compact broadband low-coupling tri-polarized dielectric resonator antenna based on non-uniform medium according to the present application works at 2.2GHz when the third feeding port is excited alone, and the antenna electric field pattern is shown in the figure, wherein, Figure 15 (a) in the figure is XOZ plane, Figure 15 (b) in the figure is YOZ plane.

[0055] Figure 16 A compact broadband low-coupling tri-polarized dielectric resonator antenna based on non-uniform medium according to the present application works at 2.5GHz when the third feeding port is excited alone, and the antenna electric field pattern is shown in the figure, wherein, Figure 16 (a) in the figure is XOZ plane, Figure 16 (b) in the figure is YOZ plane.

[0056] Figure 17 A compact broadband low-coupling tri-polarized dielectric resonator antenna based on non-uniform medium according to the present application works at 2.8GHz when the third feeding port is excited alone, and the antenna electric field pattern is shown in the figure, wherein, Figure 17 (a) in the figure is XOZ plane, Figure 17 (b) in the figure is YOZ plane. DETAILED DESCRIPTION

[0057] The technical solutions of the present application will be further described in combination with the drawings and examples.

[0058] As Figure 1As shown, this embodiment discloses a compact, broadband, low-coupling, tri-polarized dielectric resonator antenna based on an inhomogeneous dielectric, achieving wide bandwidth, low coupling, and a simple structure. The antenna primarily comprises a dielectric substrate 1, an inhomogeneous dielectric resonator 2, a first coaxial probe 3, a second coaxial probe 4, a third coaxial probe 5, a fourth coaxial probe 6, a fifth coaxial probe 7, a first Wilkinson power divider 8, a second Wilkinson power divider 9, a first feed port 10, a second feed port 11, a third feed port 12, and a floor 13. The dielectric resonator 2 is positioned above the floor 13. The first coaxial probe 3 is inserted into the center of the dielectric resonator 2, with a gap around it. The second coaxial probe 4, the fourth coaxial probe 6, the third coaxial probe 5, and the fifth coaxial probe 7 each form two pairs of probes and are inserted into the interior, near the edge, of the dielectric resonator 2. Each pair of symmetrical coaxial probes forms a differential feed pair. Circular gaps are etched into the floor 13 surrounding the probes to reduce coupling between the ports. Each coaxial probe has an opening where it contacts the floor. The lower surface of the dielectric substrate 1 includes a first Wilkinson power divider 8, a second Wilkinson power divider 9, and a first feed port 10. The first feed port 10 uses an SMA coaxial interface with a characteristic impedance of 50 ohms and directly feeds power to the dielectric resonator 2 via the first coaxial probe 3. The second and third feed ports 11 and 12 also use SMA coaxial interfaces with a characteristic impedance of 50 ohms and feed power to the dielectric resonator 2 by stimulating the corresponding coaxial probes through the corresponding Wilkinson power dividers.

[0059] The dielectric resonator 2 of the inhomogeneous medium of this embodiment is a horizontal radial layered dielectric structure, consisting of a cylindrical dielectric block with a high dielectric constant embedded within a rectangular dielectric block with a low dielectric constant. A certain gap is left around the first coaxial probe and the dielectric resonator, that is, an air column is left in the center of the dielectric resonator to adjust the input impedance. This structure changes the dielectric distribution of the dielectric resonator 2 in the horizontal radial direction.

[0060] In this embodiment, the first coaxial probe 3 is inserted directly into the center of the dielectric resonator 2. The other four coaxial probes are inserted near the edges of the four sides of the dielectric resonator 2. Each pair of probes is symmetrically positioned, and each pair of probes has an opening where it contacts the floor. The bottom of each coaxial probe is directly connected to the transmission line at the output end of the Wilkinson power divider. The second coaxial probe 4 and the fourth coaxial probe 6 are connected to the two output ends of the first Wilkinson power divider 8, and the third coaxial probe 5 and the fifth coaxial probe 7 are connected to the two output ends of the second Wilkinson power divider 9.

[0061] The Wilkinson power divider in this embodiment consists of multiple microstrip lines and isolation resistors. The input is connected to a microstrip line with a characteristic impedance of 50 ohms, which is then connected to two parallel quarter-wavelength microstrip transmission lines with a characteristic impedance of 70.7 ohms. The two quarter-wavelength microstrip transmission lines are terminated by a 100-ohm limiting resistor, and the output signal is finally output through a microstrip line with a characteristic impedance of 50 ohms. The output power of the signals at both output ends is the same. The difference in transmission line length at the output ends, equal to half the microstrip line waveguide wavelength, achieves a 180-degree phase difference between the output signals at both ends. The two output ends feed symmetrical probes, achieving differential feeding.

[0062] The first coaxial probe 3 is inserted into the center of the dielectric resonator 2, which is equivalent to introducing a current source into the center of the dielectric resonator 2, which can stimulate the TM of the dielectric resonator antenna. 011 Mode. In this resonant mode of the dielectric resonator antenna, the electric field distribution inside the resonant cavity is mainly horizontally radially distributed. By changing the horizontal radial dielectric distribution of the dielectric resonator 2, the field distribution of the resonant cavity at different frequencies can be changed. When the antenna is at a lower resonant frequency, the dielectric resonator 2 as a whole remains in a resonant state. When the frequency increases, the horizontal radial layered structure can suppress the generation of higher-order modes. At this high-frequency resonance point, the energy in the resonant cavity is mainly concentrated in the high-dielectric constant dielectric block. The high-dielectric constant dielectric block mainly resonates and radiates outward, ultimately achieving a broadband vertically polarized radiation mode.

[0063] The second coaxial probe 4 and the fourth coaxial probe 6 introduce two current sources into the dielectric resonator 2 to stimulate the TE of the dielectric resonator antenna. y 111 TE y 113 Similarly, the third coaxial probe 5 and the fifth coaxial probe 7 excite the TE dielectric resonator x 111 TE x 113 Mode.TE 111 and TE 113 The patterns are similar and the resonant frequencies are close, which increases the antenna bandwidth. The modes excited by the two pairs of probes are mutually orthogonal, achieving a pair of mutually orthogonal broadband dual-polarization radiation patterns.

[0064] In summary, the tri-polarized radiation pattern of the antenna proposed in this embodiment is realized by feeding three feeding ports separately, wherein the first feeding port excites a vertically polarized radiation pattern with a polarization direction in the z-axis direction, and the second feeding port and the third feeding port excite a pair of horizontally polarized radiation patterns with orthogonal polarization directions, ultimately realizing three mutually orthogonal polarization modes in the same radiator.

[0065] like Figure 2As shown, the S-parameter diagrams of each port of a compact, broadband, low-coupled, tri-polarized dielectric resonator antenna based on an inhomogeneous medium proposed in this embodiment are shown. The figure shows that the -10dB common impedance bandwidth of the proposed antenna is 1.11GHz, the operating frequency band is 1.77 to 2.88GHz, and the relative bandwidth is 47.7%. The isolation between the first feeding port 10 and the second feeding port 11 is 16 to 30dB within the operating frequency band, the isolation between the first feeding port 10 and the third feeding port 12 is 15 to 48dB within the operating frequency band, and the isolation between the second feeding port 11 and the third feeding port 12 is 23 to 34dB within the operating frequency band. Over most of the operating frequency band, the isolation between the three ports is higher than 18dB.

[0066] Figure 3 The following is a diagram showing the magnetic field distribution at the bottom surface of the dielectric resonator of a compact, broadband, low-coupling, tri-polarized dielectric resonator antenna based on an inhomogeneous medium, when the first feed port is excited individually at operating frequencies of 1.8 GHz, 2.2 GHz, 2.5 GHz, and 2.8 GHz, respectively. It can be seen that as the frequency increases, the magnetic field energy in the resonant cavity gradually concentrates at the center, and no significant higher-order modes are generated. The antenna resonant mode always primarily exhibits the TM mode. 011 model.

[0067] Figure 4 and Figure 5 This is a diagram of the surface electric field distribution of a compact broadband low-coupling tri-polarized dielectric resonator antenna based on an inhomogeneous medium proposed in this embodiment when the second feeding port and the third feeding port are excited separately at operating frequencies of 1.8GHz, 2.2GHz, 2.5GHz, and 2.8GHz respectively. Figure 4 and Figure 5 It can be concluded that at the three frequency points of 1.8GHz, 2.2GHz and 2.5GHz, the proposed antenna mainly performs as TE 111 mode; at 2.8GHz frequency, the proposed antenna mainly exhibits TE 113 The difference in the electric field distribution when stimulating the two ports is primarily due to the orthogonal directions of the electric fields. This indicates that dual-mode resonance significantly improves the antenna's operating bandwidth.

[0068] Figures 6 to 9The radiation pattern of a compact broadband low-coupled tri-polarized dielectric resonator antenna based on an inhomogeneous medium proposed in this embodiment when the first feed port is individually excited at operating frequencies of 1.8GHz, 2.2GHz, 2.5GHz, and 2.8GHz. The XOZ plane is the antenna radiation H plane, and the XOY plane is the antenna radiation E plane. It can be seen from the H-plane pattern that the proposed antenna has good radiation capability at low pitch angles. It can be seen from the E-plane pattern that the proposed antenna also performs well in omnidirectional radiation. Combining the various antenna patterns, it can be seen that the proposed antenna has strong radiation performance at all frequencies, and the patterns have no obvious directional deviation, and the vertical polarization radiation performance is strong overall.

[0069] Figures 10 to 13 The radiation patterns of a compact, broadband, low-coupled, tri-polarized dielectric resonator antenna based on an inhomogeneous medium proposed in this embodiment, when operating at 1.8GHz, 2.2GHz, 2.5GHz, and 2.8GHz, are shown when the second feed port is individually excited. The XOZ plane is the antenna's H-plane, and the YOZ plane is the antenna's E-plane. As can be seen from the various patterns, the proposed antenna has good radiation performance at all frequencies, with cross-polarization ratios exceeding 20dB in almost all cases, and the basic patterns are similar. The pattern's radiation direction is slightly offset from the top direction, which is due to the asymmetric structure of the Wilkinson power divider.

[0070] Figures 14 to 17 This embodiment presents the radiation patterns of a compact, broadband, low-coupled, tri-polarized dielectric resonator antenna based on an inhomogeneous dielectric, when the third feed port is excited independently at operating frequencies of 1.8 GHz, 2.2 GHz, 2.5 GHz, and 2.8 GHz. The third feed port is excited in a dual relationship with the second feed port, with the XOZ plane serving as the antenna's E-plane and the YOZ plane as the antenna's H-plane. However, because the Wilkinson power dividers connected to the two ports are not identical, the radiation patterns under the two excitation methods differ slightly. However, the overall radiation performance is similar, with both exhibiting stable radiation characteristics within the operating frequency band.

[0071] The antenna proposed in this invention has a relative bandwidth of up to 47.7%. In most operating frequency bands, the isolation between each port is higher than 18dB. The size of the dielectric block is 0.326×0.326×0.326λ0. 3 , compact structure, and has obvious advantages over existing three-polarization dielectric resonator antennas.

[0072] The tri-polarized dielectric resonator antenna proposed in this embodiment is compared with existing tri-polarized dielectric resonator antennas, and some key characteristics are summarized in Table 1, where λ0 represents the wavelength of the electromagnetic wave in free space at the center frequency of the antenna's operating frequency band. It is easy to see from the table that existing tri-polarized antennas generally have low relative bandwidth. The main reason for the low bandwidth of tri-polarized dielectric resonator antennas is that it is difficult to simultaneously achieve high bandwidths for each polarization, thereby maintaining a high common bandwidth. High coupling between ports also limits the antenna's bandwidth performance. In addition, the complex feed network has a significant impact on antenna impedance matching, thereby affecting the antenna bandwidth. Continuing to increase bandwidth while maintaining a small size is a challenge that must be overcome in the current development and application of tri-polarized antennas. Compared with existing tri-polarized dielectric resonator antennas, the tri-polarized dielectric resonator antenna proposed in this embodiment has a compact structure, a simpler feeding structure, a relatively large bandwidth area, and a high common bandwidth, which are significant advantages.

[0073] Table 1

[0074]

Claims

1. A compact, broadband, low-coupling, three-polarized dielectric resonator antenna based on an inhomogeneous dielectric, characterized by: include: a dielectric substrate, a dielectric resonator, a first coaxial probe, a second coaxial probe, a third coaxial probe, a fourth coaxial probe, a fifth coaxial probe, a first Wilkinson power divider, a second Wilkinson power divider, a first feeding port, a second feeding port, a third feeding port, and a floor; The dielectric substrate is arranged on the lower surface of the floor, and the dielectric resonator is arranged on the upper surface of the floor; The first Wilkinson power divider and the second Wilkinson power divider are arranged on the lower surface of the dielectric substrate; The dielectric resonator is a horizontal radial layered dielectric structure, which is composed of a cylindrical dielectric embedded in a rectangular dielectric resonator, wherein the dielectric constant of the cylindrical dielectric is higher than the dielectric constant of the surrounding dielectric. The first coaxial probe is inserted into the center of the dielectric resonator, and the second coaxial probe, the third coaxial probe, the fourth coaxial probe and the fifth coaxial probe are respectively inserted into the interior of the dielectric resonator and close to the edge of the dielectric resonator; Circular gaps are etched on the peripheral floors of the second coaxial probe, the third coaxial probe, the fourth coaxial probe, and the fifth coaxial probe; The second coaxial probe and the fourth coaxial probe are symmetrically arranged to form a differential feed pair, the third coaxial probe and the fifth coaxial probe are symmetrically arranged to form another differential feed pair, and the two differential feed pairs are orthogonally arranged; The first feeding port directly feeds the first coaxial probe to stimulate vertical polarization radiation TM with the polarization direction being the z-axis direction 011 model; The second feeding port is connected to the input end of the second Wilkinson power divider, and the output end of the second Wilkinson power divider is connected to a differential feeding pair to stimulate the TE y 111 TE y 113 Mode; the third feed port is connected to the input of the first Wilkinson power divider, the output of the first Wilkinson power divider is connected to another differential feed pair, stimulating a TE x 111 TE x 113 Mode;TE 111 and TE 113 The directional patterns of the modes are similar and the resonant frequencies are close, which increases the bandwidth of the antenna and realizes three mutually orthogonal polarization modes in the same radiator.

2. The compact broadband low-coupling tri-polarized dielectric resonator antenna based on an inhomogeneous medium according to claim 1, characterized in that: Holes are opened at the contact points between the second coaxial probe, the third coaxial probe, the fourth coaxial probe, and the fifth coaxial probe and the floor.

3. The compact broadband low-coupling tri-polarized dielectric resonator antenna based on an inhomogeneous medium according to claim 1, characterized in that: The cylindrical dielectric is at the same height as the rectangular dielectric resonator.

4. The compact broadband low-coupling tri-polarized dielectric resonator antenna based on an inhomogeneous medium according to claim 1, characterized in that: There is a certain gap between the periphery of the first coaxial probe and the dielectric resonator.

5. The compact broadband low-coupling tri-polarized dielectric resonator antenna based on an inhomogeneous medium according to claim 1, characterized in that: The first Wilkinson power divider and the second Wilkinson power divider implement differential feeding.

6. The compact broadband low-coupling tri-polarized dielectric resonator antenna based on an inhomogeneous medium according to claim 5, characterized in that: The first Wilkinson power divider and the second Wilkinson power divider each include a first microstrip line, a quarter-wavelength microstrip line, a second microstrip line and a limiting resistor; For any one of the first and second Wilkinson power dividers, its input end is connected to the first microstrip line, and then connected to two parallel quarter-wavelength microstrip lines. A limiting resistor is connected to the ends of the two quarter-wavelength microstrip lines. Finally, the second microstrip line is connected to the output end. The length of the second microstrip line connected to the two output ends differs by half the wavelength of the microstrip line waveguide, so that the output signal power of the two output ends is the same and there is a phase difference of 180 degrees. The two output ends are fed to symmetrical coaxial probes respectively to achieve differential feeding.

7. The compact broadband low-coupling tri-polarized dielectric resonator antenna based on an inhomogeneous medium according to claim 6, characterized in that: The first microstrip line and the second microstrip line are both microstrip lines with a characteristic impedance of 50 ohms.

8. The compact broadband low-coupling tri-polarized dielectric resonator antenna based on an inhomogeneous medium according to claim 6, characterized in that: The quarter-wavelength microstrip line is a quarter-wavelength microstrip line with a characteristic impedance of 70.7 ohms.

9. The compact broadband low-coupling tri-polarized dielectric resonator antenna based on an inhomogeneous medium according to claim 6, characterized in that: The limiting resistor is a 100 ohm limiting resistor.

Images