Dual frequency microwave rectifier circuit

Abstract

The application relates to the technical field of rectifier circuits, and discloses a dual-frequency microwave rectifier circuit which comprises a conjugate impedance matching unit based on a Pi type structure, a fan-shaped four-branch harmonic suppression unit and a voltage doubling rectifier unit; one end of the conjugate impedance matching unit based on the Pi type structure is connected with a feeding interface; the other end of the conjugate impedance matching unit based on the Pi type structure is connected with one end of the fan-shaped four-branch harmonic suppression unit and one end of the voltage doubling rectifier unit respectively; 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 rectifier unit is connected with a power supply. The dual-frequency microwave rectifier realizes working frequencies of 2.45 GHz and 5.80 GHz, and improves the overall efficiency of a microwave wireless energy transmission system and the application scene adaptability to different frequencies.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of rectifier circuit, and particularly relates to a dual-frequency microwave rectifier circuit. BACKGROUND

[0002] Microwave Power Transmission (MPT) can effectively collect radio frequency energy in the environment, and is an important research aspect in the field of wireless power transmission. The MPT system is composed of three parts: transmitting antenna, free space and rectenna. The transmission efficiency of each part is 90%, 81.5% and 72.1% respectively, and the rectenna is the highest loss link in the system. In the rectenna, it is divided into two parts: receiving antenna and rectifier circuit. The efficiency of the receiving antenna is about 95%, and the efficiency of the rectifier 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, and matching network design. Therefore, improving the efficiency of the rectifier circuit is crucial to improving the overall efficiency of the MPT system.

[0003] Traditional rectifier circuits mostly use single-frequency point 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, system stability decreases. 3. Lack of flexibility: unable to meet the needs of different frequency bands, application scenarios are limited. In contrast, dual-frequency rectifier circuits have better transmission, adaptability, and applicability. It not only can receive more output frequency points, but also can 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 popular fields, with significant advantages and broad application prospects. Therefore, researching dual-frequency rectifier circuits for microwave wireless power transmission has become a new challenge in microwave energy collection technology. SUMMARY

[0004] In view of the above problems in the prior art, the present application provides a dual-frequency microwave rectifier circuit.

[0005] In order to achieve the above-mentioned application purposes, the technical scheme adopted by the present application is as follows:

[0006] A dual-frequency microwave rectifier circuit, comprising a conjugate impedance matching unit based on a Π-type structure, a fan-shaped four-stub harmonic suppression unit, and a voltage doubling rectifier unit.

[0007] One end of the conjugate impedance matching unit based on Π type structure is connected with the feeding interface, and the other end of the conjugate impedance matching unit based on Π type structure is connected with one end of the fan-shaped four-stub harmonic suppression unit and one end of the voltage doubling rectifier unit respectively, for matching the complex impedance of the two frequency points of 2.45GHz and 5.8GHz to the microwave source respectively.

[0008] The other end of the fan-shaped four-stub harmonic suppression unit is connected with the ground end, for short-circuiting the fundamental frequency signal and the second harmonic signal through the four fan-shaped microstrip lines, so that the corresponding signal can be reflected to the voltage doubling rectifier unit for rectification again, so as to suppress the fundamental frequency signal and the second harmonic signal of the direct current output end.

[0009] The other end of the voltage doubling rectifier unit is connected with the power supply, for rectifying the transmission signal.

[0010] Further, the conjugate impedance matching unit based on Π type structure comprises:

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

[0012] Further, the first open stub, the second open stub and the third open stub each comprise:

[0013] The convex microstrip line and the rectangular microstrip line connected with the convex microstrip line.

[0014] Further, the fan-shaped four-stub harmonic suppression unit comprises:

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

[0016] Further, the first fan-shaped open stub and the second fan-shaped open stub each comprise:

[0017] The cross-shaped microstrip line and the one fan-shaped microstrip line and the other fan-shaped microstrip line connected with two sides of the cross-shaped microstrip line respectively.

[0018] Further, the voltage doubling rectifier unit comprises:

[0019] The diode and the eighth rectangular microstrip line; the negative electrode of the diode is connected with the conjugate impedance matching unit based on Π type structure and the fan-shaped four-stub harmonic suppression unit respectively, and the positive electrode of the diode is connected with the power supply through the eighth rectangular microstrip line.

[0020] Further, the conjugate impedance matching unit based on Π type structure and the feeding interface comprise a direct current isolation unit.

[0021] Further, the direct-current isolation unit comprises:

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

[0023] Further, the fan-shaped four-stub harmonic suppression unit comprises a load unit between the fan-shaped four-stub harmonic suppression unit and the ground terminal.

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

[0025] The present application adopts the conjugate impedance matching unit based on the Π type structure for impedance matching, and adopts the microstrip line fan-shaped four-stub structure for harmonic suppression, realizes the dual-frequency microwave rectification of 2.45GHz and 5.80GHz, and improves the overall efficiency of the microwave wireless energy transmission system and the application scene of adapting to different frequencies. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 Fig. 1 is a schematic diagram of a dual-frequency microwave rectification circuit;

[0027] Figure 2 Fig. 2 is a joint layout of a dual-frequency microwave rectification circuit;

[0028] Figure 3 Fig. 3 is a physical diagram of a dual-frequency microwave rectification circuit;

[0029] Figure 4 Fig. 4 is a schematic diagram of an impedance matching microstrip line structure;

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

[0031] Figure 6 Fig. 6 is a schematic diagram of a Schottky diode structure;

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

[0033] The specific embodiments of the present application are described below to facilitate the understanding of the present application by those skilled in the art, but it should be clear that the present application is not limited to the scope of the specific embodiments, and for those skilled in the art, it is obvious that various changes are within the spirit and scope of the present application defined and determined by the appended claims, and all the application and creation utilizing the concept of the present application are within the scope of protection.

[0034] As Figures 1 to 7As shown, the embodiment of the present application provides a dual-frequency microwave rectifier circuit, which comprises a conjugate impedance matching unit based on Π type structure, a fan-shaped four-stub harmonic suppression unit and a voltage doubling rectifier unit.

[0035] One end of the conjugate impedance matching unit based on Π type structure is connected with a feeding interface, and the other end of the conjugate impedance matching unit based on Π type structure is connected with one end of the fan-shaped four-stub harmonic suppression unit and one end of the voltage doubling rectifier unit respectively, for matching the complex impedance at two frequency points of 2.45 GHz and 5.8 GHz to a microwave source respectively.

[0036] The other end of the fan-shaped four-stub harmonic suppression unit is connected with a grounding end, for short-circuiting the fundamental frequency signal and the second harmonic signal through four fan-shaped microstrip lines, so that the corresponding signals can be reflected to the voltage doubling rectifier unit for rectification again, to suppress the fundamental frequency signal and the second harmonic signal at the direct current output end.

[0037] The other end of the voltage doubling rectifier unit is connected with a power supply, for rectifying the transmission signal.

[0038] The embodiment can solve some technical problems of single-frequency point circuit, such as that the single-frequency point design cannot fully utilize the frequency spectrum resources, and in the case of limited frequency selection, it is easy to cause the energy transmission efficiency to be reduced. The single-frequency point design is easy to be affected by interference and frequency drift in a complex electromagnetic environment, causing the system stability to be reduced, and the single-frequency point system cannot flexibly cope with the use demand of different frequency bands, limiting the diversity of application scenarios. The embodiment designs a dual-frequency microwave rectifier circuit with working frequencies of 2.45 GHz and 5.80 GHz, to improve the overall efficiency of the microwave wireless energy transmission system and adapt to different frequency application scenarios.

[0039] In an optional embodiment of the present application, the dual-frequency microwave rectifier circuit is closely attached to the upper surface of a dielectric substrate by taking the dielectric substrate as the main support part, and directly contacts the upper surface of the dielectric substrate; an equivalent grounding plate is placed at the lower part of the dielectric substrate, as an equivalent ground. The feeding interface is connected from the side of the dielectric substrate, connected with a large capacitance of the direct-through intersection through a microstrip line, and then connected with the Π type microstrip line. The Π type microstrip line is connected with the four-stub fan-shaped harmonic suppression network. The four-stub fan-shaped harmonic suppression network is connected with a Schottky diode HSMS-2860 below for voltage doubling rectification, and the lower end of the diode is connected with a rectangular microstrip line and a power supply, and the end of the harmonic suppression network is punched with the dielectric substrate and the equivalent grounding plate to form a grounding through hole.

[0040] The F4BM265 dielectric substrate has significant advantages in the design of the 2.45 GHz and 5.80 GHz dual-frequency rectifier circuit, mainly in the following aspects: 1. low dielectric constant and low dissipation factor. ① The dielectric constant (εr ):about 2.65. ② Dissipation factor (tan delta): about 0.0018; 2. Frequency stability. F4BM265 performs stably in a high-frequency environment, especially suitable for 2.45GHz and 5.80GHz dual-frequency operation. 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 work 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 ground plate of the embodiment is essentially a very thin gallium-indium alloy, which plays the role of equivalent grounding and is located on the lower side of the dielectric substrate, with a thickness much smaller than that of the dielectric substrate and approximately equal to the thickness of the flexible rectifier circuit.

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

[0043] In an optional embodiment of the present application, the conjugate impedance matching unit based on the Π-type structure adopted by the embodiment comprises:

[0044] The first, second, third, and fourth rectangular microstrip lines are connected in sequence.

[0045] The first, second, and third open-circuit stubs each comprise:

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

[0047] The embodiment adopts three open-circuit stubs and a plurality of connecting stubs to form an impedance matching network. According to the impedance transformation principle, these stubs are added at the front end of the voltage doubling 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 two frequency points of 2.45GHz and 5.8GHz is matched to 50Ω of the microwave source.

[0048] In an optional embodiment of the present application, the fan-shaped four-stub harmonic suppression unit adopted by the embodiment comprises:

[0049] The fifth, sixth, and seventh rectangular microstrip lines are connected in sequence.

[0050] The first and second fan-shaped open-circuit stubs each comprise:

[0051] a cross-shaped microstrip line, and a first sector-shaped microstrip line and a second sector-shaped microstrip line connected to two sides of the cross-shaped microstrip line respectively.

[0052] The embodiment adopts a microstrip line sector-shaped branch structure to design a harmonic suppression structure in a dual-frequency rectifier circuit, thereby improving rectifier efficiency. The structure can filter out radio frequency components (energy highest fundamental frequency (2.45 GHz and 3.50 GHz) signals and second harmonic (4.90 GHz and 7.00 GHz) signals) on a direct current signal in the circuit. The sector-shaped four-branch harmonic suppression unit mainly comprises four sector-shaped microstrip lines, the input port impedance is 50.00 Ω, the output port impedance is 50.00 Ω, the central angles of the four sector-shaped microstrip lines are 45, 60, 33 and 63 degrees respectively, and the radii are 4.68, 7, 10 and 15.26 mm respectively, corresponding to the fundamental frequency and the second harmonic signals. The optimization of parameters is mainly carried out through a simulation software, and then the simulation results are used for reverse fine tuning, so as to ensure the correctness of the circuit function. The transmission line under the dual-frequency condition of the circuit can be equivalent to a quarter wavelength transmission line at the same time in two frequency bands. This design greatly reduces power loss and improves the conversion efficiency from direct current to radio frequency (DC-RF) or radio frequency to direct current (RF-DC). The sector-shaped harmonic suppression network effectively controls the impedance state of the harmonic, significantly improves the efficiency, optimizes the output waveform, reduces the harmonic distortion, and provides wideband matching capability.

[0053] The sector-shaped four-branch harmonic suppression unit of the embodiment comprises four sector-shaped microstrip lines, two cross-shaped microstrip lines and three rectangular microstrip lines. The central angles of the four sector-shaped microstrip lines are 45°, 60°, 33° and 63° respectively, and the radii are 4.68 mm, 7 mm, 10 mm and 15.26 mm respectively. The widths of the three rectangular microstrip lines are all 0.3 mm, and the lengths are 12 mm, 13 mm and 11.6 mm respectively. The structure short-circuits the fundamental frequency signals and the second harmonic signals, so that the corresponding signals can be reflected to the diode for rectification again, thereby effectively suppressing the fundamental frequency and the second harmonic signals at the direct current output end. This structure improves the circuit efficiency, reduces the circuit size, optimizes the performance, has certain universality, and is suitable for the design of a dual-frequency rectifier circuit. The embodiment adopts a microstrip line sector-shaped four-branch structure for harmonic suppression, thereby effectively improving the signal quality and rectifier efficiency of the rectifier circuit.

[0054] In an optional embodiment of the present application, the voltage doubling rectifier unit adopted in the embodiment comprises:

[0055] a diode and an eighth rectangular microstrip line; the negative electrode of the diode is connected with the conjugate impedance matching unit based on the Π type structure and the sector-shaped four-branch harmonic suppression unit respectively, and the positive electrode of the diode is connected with a power supply through the eighth rectangular microstrip line.

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

[0057] In an optional embodiment of the present application, a direct-current isolation unit is arranged between the conjugate impedance matching unit based on the Π type structure and the feed interface.

[0058] The direct-current isolation unit comprises:

[0059] a capacitor and a ninth rectangular microstrip line; one end of the capacitor is connected with the feed interface through the ninth rectangular microstrip line, and the other end of the capacitor is connected with one end of the conjugate impedance matching unit based on the Π type structure.

[0060] In this embodiment, a Murata capacitor is placed at the front end of the circuit, and a microstrip line is connected with the large capacitor of the direct-current isolation unit.

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

[0062] The double-frequency microwave rectifier circuit designed in the present application can effectively work at frequencies of 2.45GHz and 5.8GHz. The innovation lies in the use of the harmonic suppression network with the microstrip line fan-shaped four-branch structure, which effectively suppresses harmonic interference and improves signal quality. At the same time, the conjugate impedance matching mode based on the Π type structure is used for double-frequency impedance matching, effectively solving the impedance matching problem at different frequencies and improving the rectification efficiency. The selection of the Schottky diode HSMS-286C and the RO4350B board ensures the circuit performance and stability. Overall, the present application has high innovation and practicality in solving the problems of harmonic suppression and impedance matching in double-frequency rectifier circuits. Since 2.45GHz and 5.8GHz are common microwave frequencies, the double-frequency microwave rectifier circuit can realize microwave energy rectification at two microwave frequencies with high efficiency in a complex electromagnetic environment, has strong anti-interference ability and high reliability, and provides a high-efficiency and reliable solution for the field of microwave energy transmission.

[0063] The present application realizes high rectification efficiency in different frequency bands by optimizing the harmonic suppression network and the dual-frequency matching network, especially in the 2.45GHz frequency band, the rectification efficiency reaches 77.137%, and in the 5.8GHz frequency band, the rectification efficiency reaches 68.077%, which shows the high efficiency of the circuit design.

[0064] The present application is described with reference to flowcharts and / or block diagrams of the method, device (system), and computer program product according to the embodiments of the present application. It should be understood that each flow and / or block in the flowcharts and / or block diagrams, and the combination of the flows and / or blocks in the flowcharts and / or block diagrams can be implemented by computer program instructions. These computer program instructions can be provided to the processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing devices to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing devices generate a means for implementing the functions specified in the flowcharts and / or block diagrams. Figure 1 one or more flows and / or blocks Figure 1 an apparatus that carries out the functions specified in one or more flows and / or blocks.

[0065] These computer program instructions can also be stored in a computer-readable memory that can guide the computer or other programmable data processing devices to work in a specific way, so that the instructions stored in the computer-readable memory produce a product including instruction apparatus, which implements the functions specified in the flowcharts and / or block diagrams. Figure 1 one or more flows and / or blocks Figure 1 an apparatus that carries out the functions specified in one or more flows and / or blocks.

[0066] These computer program instructions can also be loaded into a computer or other programmable data processing device, so that a series of operation steps are performed on the computer or other programmable device to produce a computer-implemented process, so that the instructions executed on the computer or other programmable device provide a means for implementing the functions specified in the flowcharts and / or block diagrams. Figure 1 one or more flows and / or blocks Figure 1 an apparatus that carries out the functions specified in one or more flows and / or blocks.

[0067] The principles and implementation modes of the present application are described in the specific embodiments, and the above embodiment description is only used to help understand the method of the present application and its core idea; at the same time, for those skilled in the art, according to the idea of the present application, the specific implementation mode and application range will be changed, and the above description should not be understood as the limitation of the present application.

[0068] Those skilled in the art will appreciate that the embodiments described herein are presented for purposes of illustration and that the inventive principles are not limited to these particular embodiments. Other variations and modifications can be made to the embodiments without departing from the spirit and scope of the inventive principles.

Claims

1. A dual frequency microwave rectifier circuit, characterized by, The application relates to a microwave power supply device, which comprises a conjugate impedance matching unit based on a Pi structure, a fan-shaped four-stub harmonic suppression unit and a voltage doubling rectification unit. The conjugate impedance matching unit based on the Pi structure comprises: a first rectangular microstrip line, a first open stub, a second rectangular microstrip line, a second open stub, a third rectangular microstrip line, a third open stub and a fourth rectangular microstrip line connected in sequence; the first open stub, the second open stub and the third open stub each comprise a convex microstrip line and a rectangular microstrip line connected with the convex microstrip line; The fan-shaped four-stub harmonic suppression unit comprises: a fifth rectangular microstrip line, a first fan-shaped open stub, a sixth rectangular microstrip line, a second fan-shaped open stub and a seventh rectangular microstrip line connected in sequence; the first fan-shaped open stub and the second fan-shaped open stub each comprise a cross-shaped microstrip line and one fan-shaped microstrip line and another fan-shaped microstrip line connected with two sides of the cross-shaped microstrip line respectively; The voltage doubling rectification unit comprises: a diode and an eighth rectangular microstrip line; the negative electrode of the diode is connected with the conjugate impedance matching unit based on the Pi structure and the fan-shaped four-stub harmonic suppression unit respectively, and the positive electrode of the diode is connected with a power supply through the eighth rectangular microstrip line; One end of the conjugate impedance matching unit based on the Pi structure is connected with a feeding interface, and the other end of the conjugate impedance matching unit based on the Pi structure is connected with one end of the fan-shaped four-stub harmonic suppression unit and one end of the voltage doubling rectification unit respectively, so as to match the complex impedance of the two frequency points of 2.45GHz and 5.8GHz to a microwave source respectively; The other end of the fan-shaped four-stub harmonic suppression unit is connected with a grounding end, so as to short-circuit the fundamental frequency signal and the second harmonic signal through the four fan-shaped microstrip lines, and make the corresponding signals be reflected to the voltage doubling rectification unit for rectification again, so as to suppress the fundamental frequency signal and the second harmonic signal of the direct current output end; The other end of the voltage doubling rectification unit is connected with a power supply, so as to rectify the transmission signal.

2. A dual frequency microwave rectifier circuit as claimed in claim 1, characterized in that A direct-current isolation unit is arranged between the conjugate impedance matching unit based on the Pi structure and the feeding interface.

3. A dual frequency microwave rectifier circuit as claimed in claim 2, characterized in that The direct-current isolation unit comprises: a capacitor and a ninth rectangular microstrip line; one end of the capacitor is connected with the feeding interface through the ninth rectangular microstrip line, and the other end of the capacitor is connected with one end of the conjugate impedance matching unit based on the Pi structure.

4. A dual frequency microwave rectifier circuit as claimed in claim 1, wherein, A load unit is arranged between the fan-shaped four-stub harmonic suppression unit and the grounding end.

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