Dual-frequency microwave rectifying circuit

Abstract

The invention relates to the technical field of rectifying circuits, and discloses a double-frequency microwave rectifying circuit which comprises a conjugate impedance matching unit based on an n-shaped structure, a fan-shaped four-branch harmonic suppression unit and a voltage doubling rectifying unit. One end of the conjugate impedance matching unit based on the n-shaped structure is connected with the feed interface, and the other end of the conjugate impedance matching unit based on the n-shaped structure is connected with one end of the fan-shaped four-branch harmonic suppression unit and one end of the voltage doubling rectifying unit; the other end of the fan-shaped four-branch harmonic suppression unit is connected with a grounding end; and the other end of the voltage doubling rectifying unit is connected with a power supply. According to the invention, dual-frequency microwave rectification with the working frequencies of 2.45 GHz and 5.80 GHz is realized, the overall efficiency of the microwave wireless energy transmission system is improved, and the microwave wireless energy transmission system adapts to application scenes with different frequencies.

Description

Technical Field

[0001] The invention relates to the technical field of rectifier circuits, and in particular to a dual-frequency microwave rectifier circuit. Background Art

[0002] Microwave Power Transmission (MPT) can effectively collect radio frequency energy in the environment and is an important research area in the field of wireless power transmission. The MPT system consists of three major parts: transmitting antenna, free space and rectifying antenna. The transmission efficiency of each part is 90%, 81.5% and 72.1% respectively, among which the rectifying antenna is the link with the highest loss in the system. In the rectifying antenna, it is divided into two parts: receiving antenna and rectifying circuit. The efficiency of the receiving antenna is about 95%, and the efficiency of the rectifying circuit is about 75.9%. The rectification efficiency of the rectifier circuit is also affected by many factors, such as input power, load impedance, diode performance, matching network design, etc. Therefore, improving the efficiency of the rectifier circuit is crucial to improving the overall efficiency of the entire MPT system.

[0003] Traditional rectifier circuits mostly adopt single-frequency design, which has the following problems: 1. Low energy transmission efficiency: unable to fully utilize spectrum resources, resulting in reduced energy transmission efficiency. 2. Poor adaptability: easily affected by interference and frequency drift, and system stability is reduced. 3. Insufficient flexibility: unable to meet the needs of different frequency bands, and application scenarios are limited. In contrast, dual-frequency rectifier circuits have better transmission, adaptability, and applicability. It can not only receive more output frequencies, but also improve the transmission efficiency of the entire rectifier circuit. Compared with single-frequency rectifier circuits, dual-frequency rectifier circuits can be applied to more fields, such as: multi-frequency wireless sensor networks, multi-mode communication systems, 5G technology, aerospace, solar energy and other hot fields, with significant advantages and broad application prospects. Therefore, studying dual-frequency rectifier circuits for microwave wireless energy transmission has become a new challenge facing microwave energy harvesting technology. Summary of the invention

[0004] In view of the above-mentioned deficiencies in the prior art, the present invention provides a dual-frequency microwave rectification circuit.

[0005] In order to achieve the above-mentioned object of the invention, the technical solution adopted by the present invention is:

[0006] A dual-frequency microwave rectification circuit, comprising a conjugate impedance matching unit based on a π-type structure, a fan-shaped four-branch harmonic suppression unit and a voltage doubling rectification unit;

[0007] One end of the conjugate impedance matching unit based on the π-type structure is connected to the feeding interface, and the other end of the conjugate impedance matching unit based on the π-type structure is respectively connected to one end of the fan-shaped four-branch harmonic suppression unit and one end of the voltage doubler rectification unit, so as to match the complex impedance at two frequency points of 2.45 GHz and 5.8 GHz to the microwave source;

[0008] The other end of the fan-shaped four-branch harmonic suppression unit is connected to the ground end, and is used to short-circuit the baseband signal and the second harmonic signal through four fan-shaped microstrip lines, so that the corresponding signal can be reflected to the voltage doubler rectifier unit for re-rectification, so as to suppress the baseband signal and the second harmonic signal at the DC output end;

[0009] The other end of the voltage doubler rectifying unit is connected to a power source and is used to rectify the transmission signal.

[0010] Furthermore, the conjugate impedance matching unit based on the Π-type structure includes:

[0011] The first rectangular microstrip line, the first open branch, the second rectangular microstrip line, the second open branch, the third rectangular microstrip line, the third open branch and the fourth rectangular microstrip line are connected in sequence.

[0012] Further, the first open branch node, the second open branch node and the third open branch node all include:

[0013] A convex microstrip line and a rectangular microstrip line connected to the convex microstrip line.

[0014] Furthermore, the fan-shaped four-branch harmonic suppression unit includes:

[0015] The fifth rectangular microstrip line, the first fan-shaped open branch, the sixth rectangular microstrip line, the second fan-shaped open branch and the seventh rectangular microstrip line are connected in sequence.

[0016] Furthermore, the first fan-shaped open-circuit branch node and the second fan-shaped open-circuit branch node both include:

[0017] A cross-shaped microstrip line and a fan-shaped microstrip line and another fan-shaped microstrip line respectively connected to two sides of the cross-shaped microstrip line.

[0018] Furthermore, the voltage doubler rectifying unit comprises:

[0019] A diode and an eighth rectangular microstrip line; the cathode of the diode is respectively connected to a conjugate impedance matching unit based on a Π-type structure and a fan-shaped four-branch harmonic suppression unit, and the anode of the diode is connected to a power supply through the eighth rectangular microstrip line.

[0020] Furthermore, a DC isolation unit is included between the conjugate impedance matching unit based on the Π-type structure and the feeding interface.

[0021] Furthermore, the DC isolation unit comprises:

[0022] A capacitor and a ninth rectangular microstrip line; one end of the capacitor is connected to the feeding interface through the ninth rectangular microstrip line, and the other end of the capacitor is connected to one end of a conjugate impedance matching unit based on a π-type structure.

[0023] Furthermore, a load unit is included between the fan-shaped four-branch harmonic suppression unit and the ground terminal.

[0024] The present invention has the following beneficial effects:

[0025] The present invention adopts a conjugate impedance matching unit based on a Π-type structure for impedance matching, and adopts a microstrip line fan-shaped four-branch structure for harmonic suppression, to achieve dual-frequency microwave rectification with operating frequencies of 2.45 GHz and 5.80 GHz, thereby improving the overall efficiency of the microwave wireless energy transmission system and adapting to application scenarios of different frequencies. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a schematic diagram of the principle of a dual-frequency microwave rectification circuit;

[0027] Figure 2 It is a joint layout of a dual-frequency microwave rectifier circuit;

[0028] Figure 3 This is a physical picture of a dual-frequency microwave rectification circuit;

[0029] Figure 4 This is a schematic diagram of the impedance matching microstrip line structure;

[0030] Figure 5 This is a schematic diagram of the fan-shaped harmonic suppression network structure;

[0031] Figure 6 It is a schematic diagram of the structure of Schottky diode;

[0032] Figure 7 A side view of a dielectric substrate. DETAILED DESCRIPTION

[0033] The specific implementation modes of the present invention are described below so that those skilled in the art can understand the present invention. However, it should be clear that the present invention is not limited to the scope of the specific implementation modes. For those of ordinary skill in the art, as long as various changes are within the spirit and scope of the present invention as defined and determined by the attached claims, these changes are obvious, and all inventions and creations utilizing the concept of the present invention are protected.

[0034] like Figures 1 to 7As shown, an embodiment of the present invention provides a dual-frequency microwave rectification circuit, including a conjugate impedance matching unit based on a Π-type structure, a fan-shaped four-branch harmonic suppression unit and a voltage doubling rectification unit;

[0035] One end of the conjugate impedance matching unit based on the π-type structure is connected to the feeding interface, and the other end of the conjugate impedance matching unit based on the π-type structure is respectively connected to one end of the fan-shaped four-branch harmonic suppression unit and one end of the voltage doubler rectification unit, so as to match the complex impedance at two frequency points of 2.45 GHz and 5.8 GHz to the microwave source;

[0036] The other end of the fan-shaped four-branch harmonic suppression unit is connected to the ground end, and is used to short-circuit the baseband signal and the second harmonic signal through four fan-shaped microstrip lines, so that the corresponding signal can be reflected to the voltage doubler rectifier unit for re-rectification, so as to suppress the baseband signal and the second harmonic signal at the DC output end;

[0037] The other end of the voltage doubler rectifying unit is connected to a power source and is used to rectify the transmission signal.

[0038] This embodiment can solve some technical problems of single-frequency circuits, such as the inability of single-frequency design to fully utilize spectrum resources, which can easily lead to reduced energy transmission efficiency when frequency selection is limited. Single-frequency design is susceptible to interference and frequency drift in complex electromagnetic environments, resulting in reduced system stability. Single-frequency systems cannot flexibly respond to the use requirements of different frequency bands, limiting the diversity of application scenarios. This embodiment designs a dual-frequency microwave rectifier circuit with operating frequencies of 2.45 GHz and 5.80 GHz to improve the overall efficiency of the microwave wireless energy transmission system and adapt to application scenarios of different frequencies.

[0039] In an optional embodiment of the present invention, this embodiment uses a dielectric substrate as the main supporting part, and the dual-frequency microwave rectifier circuit is closely attached to the dielectric substrate and directly contacts the upper surface of the dielectric substrate; an equivalent grounding plate is placed at the bottom of the dielectric substrate, which serves as an equivalent grounding. The feeding interface is connected from the side of the dielectric substrate, connected with a large capacitor that isolates the direct current and passes the alternating current with a section of microstrip line, and then connected to the Π-type microstrip line. The Π-type microstrip line is then connected to a four-branch fan-shaped harmonic suppression network. A Schott diode HSMS-2860 is connected below the four-branch fan-shaped harmonic suppression network for voltage doubling rectification, and the lower end of the diode is then connected to the rectangular microstrip line and the power supply. The end of the harmonic suppression network is punched with holes in the dielectric substrate and the equivalent grounding plate to form a ground connection.

[0040] The F4BM265 dielectric substrate used in this embodiment has significant advantages in designing a 2.45GHz and 5.80GHz dual-frequency rectifier circuit, which is mainly reflected in the following aspects: 1. Low dielectric constant and low dissipation factor. ① Dielectric constant (εr ): about 2.65. ② Dissipation factor (tanδ): about 0.0018; 2. Frequency stability. F4BM265 performs stably in high-frequency environments and is particularly suitable for dual-band operation at 2.45GHz and 5.80GHz. It can maintain low dielectric loss and high dielectric stability, which is very important for high-frequency applications. 3. Thermal and mechanical properties. It has excellent thermal and mechanical properties, can operate in a wide temperature range, and has good dimensional stability and bending resistance. These characteristics make it more reliable during production and use.

[0041] The equivalent grounding plate of this embodiment is actually a very thin layer of gallium-indium alloy, which plays the role of equivalent grounding. It is located on the lower side of the dielectric substrate and has a thickness much smaller than that of the dielectric substrate and approximately equal to that of the flexible rectifier circuit.

[0042] The material of the dual-frequency microwave rectification circuit of this embodiment is gallium-indium alloy, which is printed on a 003-medium substrate by liquid metal printing technology, and is used to convert the received dual-frequency microwave energy into DC energy.

[0043] In an optional embodiment of the present invention, the conjugate impedance matching unit based on the Π-type structure adopted in this embodiment includes:

[0044] The first rectangular microstrip line, the first open branch, the second rectangular microstrip line, the second open branch, the third rectangular microstrip line, the third open branch and the fourth rectangular microstrip line are connected in sequence.

[0045] Wherein, the first open branch node, the second open branch node and the third open branch node all include:

[0046] A convex microstrip line and a rectangular microstrip line connected to the convex microstrip line.

[0047] This embodiment uses three open-circuit branches and several connecting branches to form an impedance matching network. According to the impedance transformation principle, these branches are added to the front end of the voltage doubler rectifier unit, and the impedance of the circuit is transformed by adjusting the length and width of the transmission line so that the complex impedance at the two frequency points of 2.45 GHz and 5.8 GHz is matched to 50Ω of the microwave source.

[0048] In an optional embodiment of the present invention, the fan-shaped four-branch harmonic suppression unit used in this embodiment includes:

[0049] The fifth rectangular microstrip line, the first fan-shaped open branch, the sixth rectangular microstrip line, the second fan-shaped open branch and the seventh rectangular microstrip line are connected in sequence.

[0050] Wherein, the first fan-shaped open branch node and the second fan-shaped open branch node both include:

[0051] A cross-shaped microstrip line and a fan-shaped microstrip line and another fan-shaped microstrip line respectively connected to two sides of the cross-shaped microstrip line.

[0052] This embodiment uses a microstrip line fan-shaped branch structure in a dual-frequency rectifier circuit to design a harmonic suppression structure to improve the rectification efficiency. This structure can filter out the RF components on the DC signal in the circuit (the fundamental frequency (2.45GHz and 3.50GHz) signals with the highest energy and the second harmonic (4.90GHz and 7.00GHz) signals). The fan-shaped four-branch harmonic suppression unit is mainly composed of four fan-shaped microstrip lines, the input port impedance is 50.00Ω, the output port impedance is 50.00Ω, the center angles of the four fan-shaped microstrip line branches are 45, 60, 33, and 63 degrees, respectively, and the radii are 4.68, 7, 10, and 15.26mm, respectively, corresponding to the fundamental frequency and second harmonic signals. The optimization of parameters is mainly carried out through simulation software, and then reverse fine-tuning is performed through the simulation results to ensure the correct function of the circuit. The transmission line under the circuit dual-frequency condition can be equivalent to a quarter-wavelength transmission line in both frequency bands. This design greatly reduces power loss and improves the conversion efficiency from DC to RF (DC-RF) or RF to DC (RF-DC). The fan-shaped harmonic suppression network significantly improves efficiency, optimizes output waveform, reduces harmonic distortion, and provides broadband matching capability by effectively controlling the impedance state of harmonics.

[0053] The fan-shaped four-branch harmonic suppression unit of this embodiment includes four fan-shaped microstrip lines, two cross-shaped microstrip lines and three rectangular microstrip lines. The central angles of the four fan-shaped microstrip lines are 45°, 60°, 33° and 63°, respectively, and the radii are 4.68mm, 7mm, 10mm and 15.26mm, respectively; the widths of the three rectangular microstrip lines are all 0.3mm, and the lengths are 12mm, 13mm and 11.6mm, respectively. This structure short-circuits the fundamental frequency signal and the second harmonic signal, so that the corresponding signal can be reflected to the diode for rectification again, effectively suppressing the fundamental frequency and second harmonic signals at the DC output end. This structure not only improves the circuit efficiency, but also reduces the circuit size, optimizes the performance, has a certain degree of versatility, and is suitable for the design of dual-frequency rectifier circuits. This embodiment uses a microstrip line fan-shaped four-branch structure for harmonic suppression, which effectively improves the signal quality and rectification efficiency of the rectifier circuit.

[0054] In an optional embodiment of the present invention, the voltage doubler rectifier unit used in this embodiment includes:

[0055] A diode and an eighth rectangular microstrip line; the cathode of the diode is respectively connected to a conjugate impedance matching unit based on a Π-type structure and a fan-shaped four-branch harmonic suppression unit, and the anode of the diode is connected to a power supply through the eighth rectangular microstrip line.

[0056] In this embodiment, a Schottky diode HSMS-2860 is connected under the fan-shaped four-branch harmonic suppression unit for rectification, and the lower end of the diode is connected to the microstrip line and the power supply. The forward voltage drop of the HSMS-2860 Schottky diode is usually low, generally between 0.2V and 0.3V. The Schottky diode HSMS-286C used in this embodiment has a small series resistance R S , zero bias junction capacitance C j0 , fast response time and low parasitic capacitance make HSMS-286C excel in high frequency applications. Their ability to maintain good performance over a high frequency range makes them an ideal choice in RF and microwave circuit design.

[0057] In an optional embodiment of the present invention, a DC isolation unit is provided between the conjugate impedance matching unit based on the Π-type structure and the feeding interface.

[0058] Wherein, the DC isolation unit comprises:

[0059] A capacitor and a ninth rectangular microstrip line; one end of the capacitor is connected to the feeding interface through the ninth rectangular microstrip line, and the other end of the capacitor is connected to one end of a conjugate impedance matching unit based on a π-type structure.

[0060] In this embodiment, a Murata capacitor is placed at the front end of the circuit and connected to a large capacitor that blocks direct current and passes alternating current by a section of microstrip line.

[0061] In an optional embodiment of the present invention, a load unit is arranged between the fan-shaped four-branch harmonic suppression unit and the ground terminal, wherein the load unit comprises a resistor, and a resistor and a ground port are connected at the end of the harmonic suppression network.

[0062] The dual-frequency microwave rectifier circuit designed by the present invention can work effectively at frequencies of 2.45GHz and 5.8GHz. The innovation lies in the use of a harmonic suppression network with a microstrip line fan-shaped four-branch structure, which effectively suppresses harmonic interference and improves signal quality. At the same time, the conjugate impedance matching method based on the Π-type structure is used for dual-frequency impedance matching, which effectively solves the impedance matching problem at different frequencies and improves the rectification efficiency. Schottky diode HSMS-286C and RO4350B plate are selected to ensure circuit performance and stability. Overall, the present invention has high innovation and practicality in solving the harmonic suppression and impedance matching problems in dual-frequency rectifier circuits. Since 2.45GHz and 5.8GHz are both commonly used microwave frequency bands, the dual-frequency microwave rectifier circuit can realize the rectification of microwave energy with high efficiency in two microwave frequency bands under complex electromagnetic environments, has strong anti-interference ability and high reliability, and provides an efficient and reliable solution for fields such as microwave energy transmission.

[0063] The present invention achieves high rectification efficiency in different frequency bands by optimizing the harmonic suppression network and the dual-frequency matching network. In particular, the rectification efficiency reaches 77.137% in the 2.45GHz frequency band and 68.077% in the 5.8GHz frequency band, showing the high efficiency of the circuit design. According to simulation and experimental results, the rectification efficiency of the present invention in the 2.45GHz and 5.8GHz frequency bands reaches 77.137% and 68.077% respectively. This high efficiency rectification performance shows that the circuit design has high practical value in practical applications.

[0064] The present invention is described with reference to flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to embodiments of the present invention. It should be understood that each process and / or block in the flowchart and / or block diagram, as well as the combination of processes and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0065] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0066] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0067] The present invention uses specific embodiments to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core idea. At the same time, for those skilled in the art, according to the idea of ​​the present invention, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as a limitation on the present invention.

[0068] Those skilled in the art will appreciate that the embodiments described herein are intended to help readers understand the principles of the present invention, and should be understood that the protection scope of the present invention is not limited to such specific statements and embodiments. Those skilled in the art can make various other specific variations and combinations that do not deviate from the essence of the present invention based on the technical revelations disclosed by the present invention, and these variations and combinations are still within the protection scope of the present invention.

Claims

1. A dual-frequency microwave rectifier circuit, characterized in that: It includes a conjugate impedance matching unit based on a π-type structure, a fan-shaped four-branch harmonic suppression unit and a voltage doubler rectification unit; One end of the conjugate impedance matching unit based on the π-type structure is connected to the feeding interface, and the other end of the conjugate impedance matching unit based on the π-type structure is respectively connected to one end of the fan-shaped four-branch harmonic suppression unit and one end of the voltage doubler rectification unit, so as to match the complex impedance at two frequency points of 2.45 GHz and 5.8 GHz to the microwave source; The other end of the fan-shaped four-branch harmonic suppression unit is connected to the ground end, and is used to short-circuit the baseband signal and the second harmonic signal through four fan-shaped microstrip lines, so that the corresponding signal can be reflected to the voltage doubler rectifier unit for re-rectification, so as to suppress the baseband signal and the second harmonic signal at the DC output end; The other end of the voltage doubler rectifying unit is connected to a power source and is used to rectify the transmission signal.

2. A dual-frequency microwave rectifier circuit according to claim 1, characterized in that: The conjugate impedance matching unit based on the π-type structure includes: The first rectangular microstrip line, the first open branch, the second rectangular microstrip line, the second open branch, the third rectangular microstrip line, the third open branch and the fourth rectangular microstrip line are connected in sequence.

3. A dual-frequency microwave rectifier circuit according to claim 2, characterized in that: The first open branch node, the second open branch node and the third open branch node all include: A convex microstrip line and a rectangular microstrip line connected to the convex microstrip line.

4. A dual-frequency microwave rectifier circuit according to claim 1, characterized in that: The fan-shaped four-branch harmonic suppression unit comprises: The fifth rectangular microstrip line, the first fan-shaped open branch, the sixth rectangular microstrip line, the second fan-shaped open branch and the seventh rectangular microstrip line are connected in sequence.

5. A dual-frequency microwave rectifier circuit according to claim 4, characterized in that: The first fan-shaped open-circuit branch node and the second fan-shaped open-circuit branch node both include: A cross-shaped microstrip line and a fan-shaped microstrip line and another fan-shaped microstrip line respectively connected to two sides of the cross-shaped microstrip line.

6. A dual-frequency microwave rectifier circuit according to claim 1, characterized in that: The voltage doubler rectifying unit comprises: A diode and an eighth rectangular microstrip line; the cathode of the diode is respectively connected to a conjugate impedance matching unit based on a Π-type structure and a fan-shaped four-branch harmonic suppression unit, and the anode of the diode is connected to a power supply through the eighth rectangular microstrip line.

7. A dual-frequency microwave rectifier circuit according to claim 1, characterized in that: A DC isolation unit is included between the conjugate impedance matching unit based on the Π-type structure and the feeding interface.

8. A dual-frequency microwave rectifier circuit according to claim 7, characterized in that: The DC isolation unit comprises: A capacitor and a ninth rectangular microstrip line; one end of the capacitor is connected to the feeding interface through the ninth rectangular microstrip line, and the other end of the capacitor is connected to one end of a conjugate impedance matching unit based on a π-type structure.

9. A dual-frequency microwave rectifier circuit according to claim 1, characterized in that: A load unit is included between the fan-shaped four-branch harmonic suppression unit and the grounding terminal.

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