A circularly polarized filter dielectric resonator antenna based on an all-dielectric circular polarizer

Abstract

The present invention discloses a circularly polarized filter dielectric resonator antenna based on an all-dielectric circular polarizer. The antenna comprises an all-dielectric circular polarizer, a rectangular dielectric resonator antenna, a ground plane, a dielectric substrate, and a stepped microstrip feeder. The all-dielectric circular polarizer consists of a 9×9 horizontally and vertically bent unit structure, rotated 45 degrees relative to the rectangular dielectric resonator antenna and supported by four struts connected to the dielectric substrate. The upper surface of the dielectric substrate serves as the ground plane, and the lower surface serves as the stepped microstrip feeder. The ground plane is provided with rectangular slots, C-shaped feed slots, and rectangular feed slots. The stepped microstrip feeder comprises an input microstrip feeder, an output microstrip feeder matching the antenna input impedance, and a quarter-wavelength impedance transformer connecting the input and output microstrip feeders. The circularly polarized filter dielectric resonator antenna of the present invention has a center frequency of 2.5 GHz and features a simple structure, low insertion loss, and low design complexity. It can be widely used in the field of communications with strong anti-interference capabilities.

Description

Technical Field

[0001] The present invention belongs to the technical field of microwave antennas, and more particularly relates to a circularly polarized filtering dielectric resonator antenna based on an all-dielectric circular polarizer. Background Art

[0002] In recent years, with the rapid development of modern wireless communication technology, communication systems have continuously placed higher performance requirements on RF front-end equipment. Filters and antennas, as important microwave components in the RF front-end, play a key role in wireless communication systems.

[0003] As a frequency-selective device in the RF front end, filters are an indispensable part of wireless RF systems. They also suppress stray noise signals and improve the overall anti-interference capabilities of communication systems. Antennas play the role of transmitting and receiving signals in wireless communication systems, and their communication performance determines the quality of the signals transmitted and received by the entire wireless communication system. In traditional designs, antennas and filters are two independent components connected by an additional impedance matching network. This occupies a considerable amount of space in a limited system and inevitably results in losses. To address this problem, filter antennas have been proposed that integrate antennas and filters. Filter antennas have both radiation and filtering characteristics, can reduce losses, and have advantages in size, making them a research hotspot both domestically and internationally.

[0004] Antenna polarization is also a key antenna specification. Compared to traditional single-polarization antennas, circularly polarized antennas can more effectively suppress multipath fading and reduce losses caused by polarization mismatch, thereby ensuring stable signal transmission between transmitter and receiver. Polarizers are a common and important method in the implementation of circularly polarized antennas. Polarizers are microwave devices that convert linearly polarized electromagnetic waves into circularly polarized waves. Compared to other circularly polarized antenna implementation methods, polarizers can be applied to different antenna types, are less restricted by feed network constraints, offer more stable performance, and offer high flexibility. Therefore, due to their advantages in circularly polarized antenna design, circular polarizers hold great promise for development and are of great research value.

[0005] The prior art "Linearly and circularly polarized filtering dielectric resonator antennas" discloses a circularly polarized filtering dielectric antenna designed by cutting a concave opening and inserting a metal post into a cylindrical dielectric resonator antenna. This filtering antenna exhibits two radiation modes within its radiation range and achieves gain performance consistent with filtering functionality. However, this design is complex and has very narrow 3dB axial ratio bandwidth and impedance bandwidth.

[0006] Judging from existing research results, the current circularly polarized filter dielectric resonator antenna has a complex design structure and a very narrow operating bandwidth. However, these problems need to be considered and solved in practical applications. Summary of the Invention

[0007] To address the design challenges of circularly polarized filter dielectric resonator antennas described in the background, the present invention proposes a circularly polarized filter dielectric resonator antenna based on an all-dielectric circular polarizer. By utilizing the circular polarization conversion properties of the all-dielectric circular polarizer, the linearly polarized wave of the filter dielectric resonator antenna is converted into a circularly polarized wave, thereby maintaining the antenna's filtering properties while generating a circularly polarized wave.

[0008] The technical solution adopted by the present invention is as follows: a circularly polarized filter dielectric resonator antenna based on an all-dielectric circular polarizer, comprising an all-dielectric circular polarizer from top to bottom, a rectangular dielectric resonator antenna, a ground plate, a dielectric substrate, and a stepped microstrip feeder.

[0009] The all-dielectric circular polarizer is composed of a 9×9 horizontally and vertically bent unit structure, which is supported above the rectangular dielectric resonator antenna by a support and rotated 45 degrees relative to the rectangular dielectric resonator antenna; the stepped microstrip feed line is located on the lower surface of the dielectric substrate.

[0010] The rectangular dielectric resonator antenna is located on the upper surface of the ground plane and constitutes the main radiating portion. The upper surface of the ground plane is sequentially provided with a rectangular feed slot, a C-shaped feed slot, and a rectangular slot. The rectangular dielectric resonator antenna is fed by a stepped microstrip feed line through the C-shaped feed slot and the rectangular feed slot on the ground plane.

[0011] The stepped microstrip feeder mainly includes: a 50-ohm input microstrip feeder, an output microstrip feeder matching the antenna input impedance, and a quarter-wavelength impedance converter connecting the input microstrip feeder and the output microstrip feeder.

[0012] The unit structure of the all-dielectric circular polarizer adopts a transverse and longitudinal bending structure, which can make the all-dielectric circular polarizer structure more compact and have high incident angle stability.

[0013] The C-shaped feed slot provides an upper radiation null point, and the rectangular feed slot provides a lower radiation null point.

[0014] The circularly polarized electromagnetic wave is converted from the linearly polarized electromagnetic wave radiated by the rectangular dielectric resonator antenna to the all-dielectric circular polarizer with a 45-degree deflection.

[0015] The impedance matching characteristics of the filter dielectric resonator antenna are controlled by adjusting the physical parameters of the stepped microstrip feed line, the C-shaped feed slot and the rectangular feed slot.

[0016] Compared with the prior art, the present invention has the following beneficial effects:

[0017] 1. The present invention provides an all-dielectric circular polarizer design. The circular polarizer reduces the horizontal and vertical heights through a bending design to make the structure more compact. The cross-vertical unit structure gives it the advantages of wide operating bandwidth and wide incident angle stability. It can also be manufactured using 3D printing technology at a low cost.

[0018] 2. The present invention converts linearly polarized waves into circularly polarized waves through an all-dielectric circular polarizer, has a wide 3dB axial ratio bandwidth, and its circular polarization performance is stable and is not affected by the filter dielectric resonator antenna, and does not generate additional insertion loss.

[0019] 3. The all-dielectric circular polarizer and the filtering dielectric resonator antenna of the present invention are designed separately, the antenna design is easy and the working bandwidth is wide, and circularly polarized waves can be obtained while maintaining filtering characteristics. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is an overall diagram of a circularly polarized filter dielectric resonator antenna based on an all-dielectric circular polarizer according to an embodiment of the present invention;

[0021] Figure 2 is a structural diagram of a ground plate and a stepped microstrip feeder according to an embodiment of the present invention;

[0022] Figure 3 2. This is a side view of the structure of the all-dielectric circular polarizer unit according to an embodiment of the present invention;

[0023] Figure 4 2. This is a top view of the structure of the all-dielectric circular polarizer unit according to an embodiment of the present invention;

[0024] Figure 5 is a plan view of a ground plate according to an embodiment of the present invention;

[0025] Figure 6 is a schematic diagram of the lower surface of a dielectric substrate according to an embodiment of the present invention;

[0026] Figure 7 is an S-parameter simulation diagram of an embodiment of the present invention;

[0027] Figure 8 is a graph showing the change in axial ratio with frequency within the working range of an embodiment of the present invention;

[0028] Figure 9 FIG. 4 is a graph showing how gain varies with frequency within a working range according to an embodiment of the present invention.

[0029] Figure numerals: 1. All-dielectric circular polarizer; 2. Rectangular dielectric resonator antenna; 3. Ground plate; 4. Dielectric substrate; 5. Stepped microstrip feed line; 6. Rectangular feeding slot; 7. C-shaped feeding slot; 8. Rectangular slot; 9. Input microstrip feed line; 10. Impedance converter; 11. Output microstrip feed line; 12. Pillar. DETAILED DESCRIPTION

[0030] The accompanying drawings are for illustrative purposes only and should not be construed as limiting the present invention. The present invention will be described in detail below with reference to the accompanying drawings and embodiments.

[0031] The present invention provides a circular polarization filter dielectric resonator antenna based on an all-dielectric circular polarizer, the structure of which is as follows: Figure 1 As shown, the circular polarization filter dielectric resonator antenna includes, from top to bottom, an all-dielectric circular polarizer 1, a rectangular dielectric resonator antenna 2, a ground plane 3, a dielectric substrate 4, and a stepped microstrip feed line 5.

[0032] The all-dielectric circular polarizer 1, consisting of a 9×9 horizontally and vertically bent unit structure, is positioned above the rectangular dielectric resonator antenna 2 and rotated 45 degrees relative to the rectangular dielectric resonator antenna 2. It is supported by four struts 12 connected to a dielectric substrate 4, spaced apart from the rectangular dielectric resonator antenna 2. The dielectric substrate 4 has a ground plane 3 on its top surface and a stepped microstrip feed line 5 on its bottom surface. The rectangular dielectric resonator antenna 2, located above the ground plane 3, forms the primary radiating element.

[0033] like Figure 2 As shown, the top surface of the ground plane 3 has three slots: a rectangular feed slot 6, a C-shaped feed slot 7, and a rectangular slot 8, which suppress antenna harmonics. The rectangular dielectric resonator antenna 2 is fed by a stepped microstrip feed line 5, which couples the rectangular feed slot 6 and the C-shaped feed slot 7 on the ground plane 3. The stepped microstrip feed line 5 primarily comprises a 50-ohm input microstrip feed line 9, an output microstrip feed line 11 that matches the antenna input impedance, and a quarter-wavelength impedance transformer 10 connecting the input microstrip feed line 9 and the output microstrip feed line 11.

[0034] Specifically, the height of the rectangular dielectric resonator antenna 2 is 17 mm, the length and width are both 17 mm, and the relative dielectric constant ε is r1 =10, the relative dielectric constant ε of the material of the all-dielectric circular polarizer 1 r2 =15, the relative dielectric constant ε of the dielectric substrate 4 r3 =3.38, the distance between the two is 3.5mm.

[0035] like Figure 3-4 As shown in the figure, the geometric parameters of the unit structure of the all-dielectric circular polarizer 1 are as follows: the height h is 40.7 mm, the length of the dielectric plate in the y direction is t y 15mm, thickness tgy The length of the short bending strip l1 is 5.5 mm, the length of the long bending strip l2 is 11 mm, the angle θ1 between the vertical strip and the bending strip is 135°, the angle θ2 between the bending strips is 45°, and the length of the dielectric plate in the x direction is t x 17.2mm, thickness tg x The length of the bending plate and the vertical plate is lg1, 2.75 mm, lg2, 1.62 mm, and lg3, 5.56 mm.

[0036] Specifically, if Figure 5 As shown, the width W of the dielectric substrate 4 g 70mm, length L g 53mm; the width of the three slots on the ground plate 3 is W s is 0.5 mm, the length L of the rectangular feed slot 6 s1 The length L of the C-shaped feed slot 7 is 16.5 mm. s2 is 35.5 mm, which also includes the length W a is 2.7 mm and length L a The bending arm is composed of 13.8mm, and the rectangular slot is 8 in length L s3 It is 22mm.

[0037] Specifically, starting from the +y edge of the lower surface of the dielectric substrate 4, there are provided a 50 ohm input microstrip feed line 9, an output microstrip feed line 11 matching the antenna input impedance, and a quarter-wavelength impedance transformer 10 connecting the input microstrip feed line 9 and the output microstrip feed line 11; Figure 6 As shown, the length L of the 50 ohm input microstrip feed line 9 is f3 6.5mm, the same width as the output microstrip feed line 11 width W f1 The length L of the quarter-wavelength impedance transformer 10 is also 1.8 mm. f2 31.7mm, width W f2 8.7mm; the length L of the output microstrip feed line 11 f1 It is 10.05mm.

[0038] The present invention adopts a full dielectric circular polarizer, which not only retains the filtering characteristics of the dielectric resonator antenna but also achieves the circular polarization effect. The simulation results are as follows: Figure 7-9 shown. Figure 7 This is the S-parameter simulation diagram of the circularly polarized filter dielectric resonator antenna; Figure 8 This is a simulation diagram of the axial ratio of the circularly polarized filter dielectric resonator antenna; Figure 9 The gain simulation diagram of the circular polarization filter dielectric resonator antenna is shown in Figure 2. The simulation results show that the working bandwidth of the circular polarization filter dielectric resonator antenna is 24.4% (S 11<-10dB), the 3dB axial ratio bandwidth is 24.4%, and two radiation nulls are generated at 2.1GHz and 3.145GHz, which improves the frequency selectivity of the antenna.

[0039] The above examples are merely examples of preferred effects for illustrating the present invention and are not intended to limit the present invention. For those skilled in the art, any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A circularly polarized filter dielectric resonator antenna based on an all-dielectric circular polarizer, characterized by: It includes a top-down all-dielectric circular polarizer (1), a rectangular dielectric resonator antenna (2), a ground plane (3), a dielectric substrate (4), and a stepped microstrip feed line (5); The all-dielectric circular polarizer (1) is composed of a 9×9 horizontally and vertically bent unit structure, supported above the rectangular dielectric resonator antenna (2) by a support (12) and rotated 45 degrees relative to the rectangular dielectric resonator antenna (2); the stepped microstrip feed line (5) is located on the lower surface of the dielectric substrate (4); the unit structure of the all-dielectric circular polarizer (1) adopts a horizontally and vertically bent structure; the circularly polarized electromagnetic wave is converted from the linearly polarized electromagnetic wave radiated by the rectangular dielectric resonator antenna (2) and propagated to the 45-degree deflected all-dielectric circular polarizer (1); The ground plate (3) is located between the lower surface of the rectangular dielectric resonator antenna (2) and the upper surface of the dielectric substrate (4), and the upper surface of the ground plate (3) is provided with a rectangular feeding slot (6), a C-shaped feeding slot (7), and a rectangular slot (8) in sequence; the rectangular dielectric resonator antenna (2) is fed by a stepped microstrip feed line (5) through the rectangular feeding slot (6) and the C-shaped feeding slot (7) on the ground plate (3); The C-shaped feed slot (7) provides an upper radiation null point, and the rectangular feed slot (6) provides a lower radiation null point; The stepped microstrip feed line (5) comprises: an input microstrip feed line (9), an output microstrip feed line (11) matching the antenna input impedance, and a quarter-wavelength impedance converter (10) connecting the input microstrip feed line (9) and the output microstrip feed line (11).

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