A circularly polarized ka-band broadband rectenna based on dielectric resonator

Abstract

The application discloses a kind of circular polarization Ka wave band broadband rectenna based on dielectric resonator, it is related to electronic circuit technical field, including dielectric substrate, dielectric resonator being arranged above dielectric substrate and ground plate being arranged below dielectric substrate, and rectifier circuit;The edge of the long side of the dielectric substrate is equipped with a plurality of metal through holes that penetrate the dielectric substrate, and the plurality of through holes form a substrate integrated waveguide structure, a planar transmission microstrip line, a first gradual microstrip line and an SIW upper metal layer connected in sequence are printed on the dielectric substrate, a rectangular slot is formed in the middle of the SIW upper metal layer, and a third gradual microstrip line, a second gradual microstrip line and a radiation patch connected in sequence are arranged in the rectangular slot;One end of the planar transmission microstrip line is connected to the rectifier circuit.The application has the advantages of simple structure, wide impedance bandwidth, stable gain, small size, and realizes circular polarization and operation in the millimeter wave band.

Description

Technical Field

[0001] This invention relates to the field of electronic circuit technology, and in particular to a circularly polarized Ka-band broadband rectifier antenna based on a dielectric resonator. Background Technology

[0002] In recent years, with the development of millimeter-wave antenna technology, especially the widespread application of 5G millimeter-wave technology, the application of microwave millimeter-wave broadband antennas has received increasing attention. Millimeter waves have strong penetrating power through sand and smoke, meaning they can propagate almost without attenuation in foggy and dusty weather. Compared to ordinary microwave bands, millimeter-wave rectified antennas have advantages such as small size, long transmission distance, and high transmission efficiency. Furthermore, atmospheric loss is relatively low near 35 GHz in the millimeter-wave band, forming an attenuation "window." Therefore, current research on millimeter-wave microwave power transmission technology mainly focuses on frequencies near 35 GHz for medium- to long-distance high-power transmission. Circularly polarized antennas can effectively reduce transmission loss caused by polarization mismatch and avoid polarization mismatch between transmitting and receiving antennas.

[0003] Substrate integrated waveguides (SIWs) are a novel waveguide structure characterized by low insertion loss and low radiation. They represent a transmission line between microstrip and dielectric-filled waveguides, fabricated from an array of metallized vias on a dielectric substrate. Millimeter-wave components made from SIWs exhibit high Q-values, high power capacity, and ease of integration, enabling the realization of high-performance microwave and millimeter-wave planar circuits. Compared to traditional metallic waveguides, SIWs are more compact and smaller, and have received increasing attention in millimeter-wave broadband antenna design in recent years.

[0004] However, existing millimeter-wave broadband circularly polarized antenna technologies either introduce additional structures, increase the profile height and antenna complexity, or use large and complex feed networks to form antenna arrays. Many performance indicators are often mutually exclusive, limiting their widespread application in wireless communication systems.

[0005] The existing technology, "SIW cavity-backed circularly polarized dual loop antenna with broadband at Ka band," discloses a SIW cavity-backed dual loop antenna with broadband circular polarization in the Ka band. This antenna has two substrate layers. The top layer of the upper substrate is etched with double diamond-shaped rings. To reduce surface waves and improve gain, the double rings are surrounded by a square SIW cavity and fed by longitudinal slot coupling on the bottom metal layer of the upper substrate. The lower substrate has a SIW structure, fed through a microstrip-SIW asymptotic structure. It achieves good impedance and circular polarization bandwidth in the 34-38 GHz frequency range and has good gain. However, the multi-layer dielectric substrate structure increases the antenna height, the complex feeding network occupies considerable space, resulting in high cost, difficult fabrication, and poor broadband performance.

[0006] The prior art, "A slotted dielectric substrate loaded broadband Vivaldian antenna fed by SIW," discloses a novel compact slotted dielectric substrate loaded broadband Vivaldi antenna. This antenna consists of a typical antipodal SIW Vivaldi antenna and two FR4 substrates with non-uniform thickness and periodic slots. Loading such a non-uniformly thick slotted dielectric substrate onto a conventional SIW-fed Vivaldi antenna results in a wider impedance bandwidth and higher peak gain. While the antenna achieves broadband and excellent gain, it does not achieve circular polarization, and the non-uniformly thick dielectric substrate is more difficult to design and fabricate compared to conventional antennas.

[0007] The existing technology, "Singly-Fed Dual-Band Circularly Polarized Dielectric Resonator Antenna," discloses a dual-frequency circularly polarized dielectric resonator antenna. This antenna places a rectangular dielectric resonator on a dielectric substrate, introduces a diagonal groove on the top surface of the resonator, and removes two opposite corners of its rectangle to generate a circularly polarized wave. However, because some dielectric is removed during the cutting of the corners and groove, the effective dielectric constant decreases, causing a shift in the antenna's resonant frequency and increasing the difficulty of tuning.

[0008] The prior art, "A High-Efficiency 35GHz Circular-Polarized Rectenna with Rotating Array," discloses a high-efficiency 35GHz circularly polarized rectified antenna. The antenna employs a coupled cross-slot fed patch antenna, composed of a double-layer substrate, achieving an impedance bandwidth of 31.16–36.60 GHz with a relative bandwidth of 15.5%. To achieve circular polarization, a rotating array of four antenna elements is used. The rectifier consists of two series-parallel MA4E1310 Schottky diodes, a microstrip line impedance transformer, two symmetrical open-branch pass-through filters, and a DC patch. The rectification efficiency, measured at 600Ω, is 54% when the received power is 63mW. Although this antenna achieves circular polarization in the Ka-band and incorporates a rectifier circuit, its broadband performance is suboptimal. Summary of the Invention

[0009] To address the aforementioned problems, this invention provides a circularly polarized Ka-band broadband rectified antenna based on a dielectric resonator, aiming to solve the issues of narrow bandwidth, linear polarization, and limited application scope of current SIW antennas.

[0010] The present invention adopts the following technical solution:

[0011] A circularly polarized Ka-band broadband rectified antenna based on a dielectric resonator includes a dielectric substrate, a dielectric resonator disposed above the dielectric substrate, a ground plane disposed below the dielectric substrate, and a rectifier circuit.

[0012] The long edge of the dielectric substrate has multiple conductive vias penetrating the substrate, which together form a substrate integrated waveguide structure. A planar transmission microstrip line, a first progressive microstrip line, and an SIW upper metal layer are printed on the dielectric substrate in sequence. A rectangular groove is formed in the middle of the SIW upper metal layer, and a third progressive microstrip line, a second progressive microstrip line, and a radiating patch are arranged in sequence within the rectangular groove. The widths of the first and third progressive microstrip lines are different at their left and right ends, and the widths gradually change from one end to the other.

[0013] The upper metal layer of the SIW is connected to the via; the third progressive microstrip line, the second progressive microstrip line, and the radiating patch are located below the dielectric resonator, which serves as a dielectric resonant cavity and achieves broadband characteristics through multi-mode resonance; the radiating patch is a rectangle with one pair of opposite corners cut off, generating two linearly polarized waves with equal amplitude, perpendicular polarization direction, and a 90° phase difference. After superposition, a circularly polarized wave is obtained to form a radiating element that achieves circular polarization. The axial ratio characteristics of the antenna are adjusted by adjusting the size of the cut angle.

[0014] One end of the planar transmission microstrip line is connected to a rectifier circuit.

[0015] Preferably, the center distance between two adjacent vias is less than one-quarter of the waveguide wavelength of the substrate integrated waveguide, and the spacing between two adjacent vias is less than four times the diameter of the via.

[0016] Preferably, the left end of the dielectric resonator is aligned with the left end of the third progressive microstrip line, the right end of the dielectric resonator is aligned with the right end of the dielectric substrate, and the upper and lower ends are aligned with the line connecting the centers of the multiple vias.

[0017] Preferably, the width of the first progressive microstrip line gradually increases from left to right; the width of the third progressive microstrip line gradually decreases from left to right.

[0018] Preferably, the rectifier circuit includes a first matching stub, a third-order low-pass filter, a rectifier diode circuit, a second matching stub, a through output filter, and a second rectangular patch connected in sequence. The third-order low-pass filter is also connected to a parallel rectifier diode circuit and the first rectangular patch. The first matching stub, the first rectangular patch, and the second rectangular patch are all grounded.

[0019] Preferably, the through output filter includes a microstrip connection line, and each end of the microstrip connection line is provided with a pair of fan-shaped open-circuit stubs that are symmetrical about the microstrip connection line. The two pairs of fan-shaped open-circuit stubs suppress the high-order harmonics of the broadband circularly polarized SIW antenna frequency point one-to-one.

[0020] Preferably, the planar transmission microstrip line, the first progressive microstrip line, the SIW upper metal layer, the third progressive microstrip line, the second progressive microstrip line, and the radiating patch are integrally formed.

[0021] Beneficial effects of the present invention

[0022] 1. This invention employs a patch antenna and utilizes a SIW structure for waveguided operation. A progressive microstrip structure is used at the feed end and the connection point with the patch to achieve mutual conversion between TE and TEM modes. By chamfering the diagonal positions on the patch, two mutually orthogonal linearly polarized waves are excited on the patch, thus forming a circularly polarized wave. An FR4 dielectric resonator structure is loaded along the antenna's radiation direction to improve impedance bandwidth.

[0023] 2. This invention has the advantages of simple structure, wide impedance bandwidth, stable gain, and small size, and achieves circular polarization and operation in the millimeter wave band. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 This is a schematic diagram of the antenna structure of the present invention;

[0026] Figure 2 This is a schematic diagram of the cross-sectional structure of the antenna of the present invention;

[0027] Figure 3 This is a schematic diagram of the rectifier circuit structure of the present invention;

[0028] Figure 4 This is a schematic diagram of the through-output filter structure of the present invention;

[0029] Figure 5 This is a schematic diagram of the simulation results of the antenna return loss variable as a function of frequency according to the present invention.

[0030] Figure 6 This is a schematic diagram showing the simulation results of antenna impedance changing with frequency;

[0031] Figure 7 The simulation results show the change of the antenna axial ratio of the present invention with frequency at the direction of maximum radiation.

[0032] Figure 8 The simulation results show the rectification efficiency of the rectifier circuit of this invention as a function of frequency.

[0033] As shown in the figure:

[0034] 1—Dielectric substrate; 2—Ground plate; 3—Through-hole; 4—First progressive microstrip line; 5—Radiating patch; 6—Dielectric resonator; 7—SIW upper metal layer; 8—Feed port; 9—Planar transmission microstrip line; 10—Second progressive microstrip line; 11—Third progressive microstrip line; 12—First matching stub; 13—Ground via; 15—Low-pass filter; 16—Parallel rectifier diode circuit; 17—First rectangular patch; 18—Rectifier diode circuit; 19—Second matching stub; 20—Straight-through filter; 21—Second rectangular patch; 211—Microstrip connection line; 212—Fan-shaped open-circuit stub. Detailed Implementation

[0035] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0036] like Figures 1 to 4 As shown,

[0037] A circularly polarized Ka-band broadband rectified antenna based on a dielectric resonator includes a dielectric substrate 1 using Rogers RT / duroid5880(tm), a dielectric resonator 6 disposed above the dielectric substrate 1, a ground plane 2 disposed below the dielectric substrate 1, and a rectifier circuit.

[0038] The long side of the dielectric substrate 1 is provided with a plurality of through holes 3 penetrating the dielectric substrate 1, while the short side is not provided with such through holes 3. The plurality of through holes 3 constitute a substrate integrated waveguide structure. By arranging metallized vias in this way to replace the waveguide, the transmission characteristics of the traditional metal waveguide are realized on the dielectric substrate 1.

[0039] An irregularly shaped metal layer is printed on the dielectric substrate 1, and the surface of the metal layer is plated with gold; the ground plane 2 is also a metal layer with a gold-plated surface. The through-hole 3 is made of one of the following materials: metal, alloy, or composite polymer conductive material, and is used to connect the irregularly shaped metal layer on the dielectric substrate 1 and the metal layer on the ground plane 2.

[0040] The metal layer includes a planar transmission microstrip line 9, a first progressive microstrip line 4, and an SIW upper metal layer 7 connected in sequence. A rectangular groove is formed in the middle of the SIW upper metal layer 7, and a third progressive microstrip line 11, a second progressive microstrip line 10, and a radiating patch 5 are connected in sequence in the rectangular groove. The planar transmission microstrip line 9, the first progressive microstrip line 4, the SIW upper metal layer 7, the third progressive microstrip line 11, the second progressive microstrip line 10, and the radiating patch 5 are integrally formed.

[0041] The third progressive microstrip line 11 feeds the radiating patch 5, which radiates towards the dielectric resonator 6.

[0042] The first progressive microstrip line 4 gradually increases in width from left to right, forming an isosceles trapezoidal shape; the third progressive microstrip line 11 gradually decreases in width from left to right, forming an isosceles trapezoidal shape.

[0043] The planar transmission microstrip line 9, the first progressive microstrip line 4, the SIW upper metal layer 7, and the via 3 are connected to form an SIW-microstrip line converter. The other end of the planar transmission microstrip line 9 is connected to a feed port 8, which is located on the left side of the dielectric substrate 1. The rectifier circuit feeds the antenna through the planar transmission microstrip line 9 and the feed port 8.

[0044] The third progressive microstrip line 11, the second progressive microstrip line 10, and the radiating patch 5 are located below the dielectric resonator 6. The dielectric resonator 6 serves as a dielectric resonant cavity, achieving broadband characteristics through multi-mode resonance. The radiating patch 5 is a rectangle with one pair of opposite corners cut off, generating two linearly polarized waves with equal amplitude, perpendicular polarization directions, and a 90° phase difference. These waves are superimposed to form a circularly polarized wave, thus forming a radiating element that achieves circular polarization. Since the axial ratio performance of the antenna is related to the size of the cut angle, the axial ratio characteristics of the antenna can be adjusted by adjusting the size of the cut angle.

[0045] The left end of the dielectric resonator 6 is aligned with the left end of the third progressive microstrip line 11, the right end of the dielectric resonator 6 is aligned with the right end of the dielectric substrate 1, and the upper and lower ends are aligned with the line connecting the centers of the multiple through holes 3. The dielectric resonator 6 is a rectangular dielectric plate, which is used as a dielectric resonant cavity to achieve broadband characteristics through multi-mode resonance.

[0046] Dielectric resonator 6 is a cuboid with a length of 11.25 mm, a width of 6.18 mm, and a thickness of 1.524 mm. It achieves broadband characteristics through multimode resonance. FR4_epoxy, a material with a low dielectric constant, is selected to reduce the quality factor of the dielectric resonator, thereby further widening the impedance bandwidth.

[0047] The center distance between two adjacent vias 3 is less than one-quarter of the waveguide wavelength of the substrate integrated waveguide, and the spacing between two adjacent vias 3 is less than four times the diameter of the via 3. Satisfying this relationship mainly ensures that the transmitted energy within the waveguide does not leak. The radiating patch 5 is located in the dielectric resonant cavity, and the substrate integrated waveguide couples and feeds the chamfered patch unit, allowing the antenna to better exhibit axial ratio performance.

[0048] The rectifier circuit includes a first matching stub 12, a third-order low-pass filter 15, a rectifier diode circuit 18, a second matching stub 19, a direct-through output filter 20, and a second rectangular patch 21 connected in sequence. The third-order low-pass filter 15 is also connected to a parallel rectifier diode circuit 16 and a first rectangular patch 17. The first matching stub 12 and the first rectangular patch 17 are both grounded through a grounding via 13. The second rectangular patch 21 is grounded and connected to the load through the grounding via 13.

[0049] The grounding through hole 13 is a solid metal pillar that connects the upper metal layer 7 of SIW to the lower grounding plate 2. The left side of the first matching branch 12 is connected to the power supply terminal 8.

[0050] The through-output filter 20 includes a microstrip connection line 211. Both ends of the microstrip connection line 211 are provided with a pair of fan-shaped open-circuit stubs 212 that are symmetrical about the microstrip connection line 211. The two pairs of fan-shaped open-circuit stubs 212 suppress the high-order harmonics of the broadband circularly polarized SIW antenna frequency point one-to-one.

[0051] The rectifier diode circuit 18 includes an inductor L1, with the right side of the inductor L1 grounded through a capacitor C1; an inductor L2 is connected in series with the right side of the inductor L1, and the inductor L2 is then connected in series with the parallel capacitor C2 and diode D1, with diode D1 conducting unidirectionally to the right. At the same time, capacitor C3 is connected in parallel with the inductor L2, capacitor C2, and diode D1; the right side of this parallel structure is grounded through a capacitor C4, and then connected in series with an inductor L3 to the right.

[0052] The inductor L3 is connected to the second matching stub 19, and the inductor L1 is connected to the third-order low-pass filter 15. The diode D1 is an MA4E1317 Schottky diode.

[0053] The rectifier diode circuit 18 has the same structure as the parallel rectifier diode circuit 16.

[0054] This embodiment uses HFSS for simulation, such as Figure 5 As shown, the horizontal axis represents the frequency variable in GHz, and the vertical axis represents the return loss variable. Test results show that, with a port impedance of 50Ω, the invention achieves |S11| < -10dB in the frequency range of 29.2GHz to above 50GHz.

[0055] like Figure 6 As shown in the figure, the horizontal axis represents the frequency variable and the vertical axis represents the impedance. The results show that the impedance fluctuates around 50Ω+0j, changes gradually, and is easy to match.

[0056] like Figure 7 As shown, the horizontal axis represents the frequency variable, and the vertical axis represents the axial ratio. Simulation and test results show that the 3dB axial ratio bandwidth at the maximum radiation direction is 0.3GHz, which includes the 35GHz atmospheric window frequency.

[0057] like Figure 8 As shown, the rectification characteristic of the rectifier circuit described in this embodiment is the rectification efficiency; where the horizontal axis represents the frequency variable and the vertical axis represents the rectification efficiency. Test results show that the operating frequency range with a rectification efficiency of over 50% is 28GHz to 39.6GHz, with an absolute bandwidth of 11.6GHz, a center frequency of 33.8GHz, and a relative bandwidth of 34.3%, satisfying the broadband rectification characteristics.

[0058] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A circularly polarized Ka-band broadband rectified antenna based on a dielectric resonator, characterized in that, It includes a dielectric substrate (1), a dielectric resonator (6) disposed above the dielectric substrate (1), a ground plane (2) disposed below the dielectric substrate (1), and a rectifier circuit. The long side edge of the dielectric substrate (1) is provided with a plurality of through holes (3) penetrating the dielectric substrate (1). The plurality of through holes (3) constitute a substrate integrated waveguide structure. The dielectric substrate (1) is printed with a planar transmission microstrip line (9), a first progressive microstrip line (4) and an SIW upper metal layer (7) connected in sequence. A rectangular groove is opened in the middle of the SIW upper metal layer (7). A third progressive microstrip line (11), a second progressive microstrip line (10) and a radiating patch (5) are connected in sequence in the rectangular groove. The widths of the first progressive microstrip line (4) and the third progressive microstrip line (11) are different at the left and right ends, and the widths gradually change from one end to the other end. The upper metal layer (7) of the SIW is connected to the via (3); the third progressive microstrip line (11), the second progressive microstrip line (10), and the radiating patch (5) are located below the dielectric resonator (6). The dielectric resonator (6) serves as a dielectric resonant cavity and achieves broadband characteristics through multi-mode resonance; the radiating patch (5) is a rectangle with one pair of opposite corners cut off to form a degenerate orthogonal mode unit. The axial ratio characteristics of the antenna can be adjusted by adjusting the size of the cut angle of the radiating patch (5); One end of the planar transmission microstrip line (9) is connected to a rectifier circuit.

2. The circularly polarized Ka-band broadband rectified antenna based on a dielectric resonator according to claim 1, characterized in that, The center distance between two adjacent vias (3) is less than one-quarter of the waveguide wavelength of the substrate integrated waveguide, and the spacing between two adjacent vias (3) is less than 4 times the diameter of the via (3).

3. The circularly polarized Ka-band broadband rectified antenna based on a dielectric resonator according to claim 1, characterized in that, The left end of the dielectric resonator (6) is aligned with the left end of the third progressive microstrip line (11), the right end of the dielectric resonator (6) is aligned with the right end of the dielectric substrate (1), and the upper and lower ends are aligned with the line connecting the centers of the multiple vias (3).

4. The circularly polarized Ka-band broadband rectified antenna based on a dielectric resonator according to claim 1, characterized in that, The width of the first progressive microstrip line (4) gradually increases from left to right; the width of the third progressive microstrip line (11) gradually decreases from left to right.

5. A circularly polarized Ka-band broadband rectified antenna based on a dielectric resonator according to claim 1, characterized in that, The rectifier circuit includes a first matching stub (12), a third-order low-pass filter (15), a rectifier diode circuit (18), a second matching stub (19), a direct-through output filter (20), and a second rectangular patch (21) connected in sequence. The third-order low-pass filter (15) is also connected to a parallel rectifier diode circuit (16) and a first rectangular patch (17). The first matching stub (12), the first rectangular patch (17), and the second rectangular patch (21) are all grounded.

6. A circularly polarized Ka-band broadband rectified antenna based on a dielectric resonator according to claim 5, characterized in that, The through-output filter (20) includes a microstrip connection line (211), and both ends of the microstrip connection line (211) are provided with a pair of fan-shaped open-circuit stubs (212) that are symmetrical about the microstrip connection line (211). The two pairs of fan-shaped open-circuit stubs suppress the high-order harmonics of the broadband circularly polarized SIW antenna frequency point one-to-one.

7. A circularly polarized Ka-band broadband rectified antenna based on a dielectric resonator according to claim 1, characterized in that, The planar transmission microstrip line (9), the first progressive microstrip line (4), the SIW upper metal layer (7), the third progressive microstrip line (11), the second progressive microstrip line (10), and the radiating patch (5) are integrally formed.

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