Simple and compact ultra-wideband rectifying circuit and design method thereof

Abstract

The invention belongs to but not limited to the technical field of wireless energy transmission and electromagnetic energy collection, and particularly relates to a simple and compact ultra-wideband rectifying circuit and a design method thereof. Comprising a top-layer microstrip structure, a middle dielectric substrate and a bottom-layer metal floor, the top-layer microstrip structure and the bottom-layer metal floor are respectively positioned on the upper surface and the lower surface of the middle dielectric substrate; the top microstrip structure comprises a radio frequency input port, a broadband impedance matching network, a direct current blocking and passing capacitor, a diode topological structure, a harmonic suppression and harmonic recovery network and a direct current output port; the two diodes in the diode topology are directly connected with the direct current filter capacitor, so that the load impedance is effectively compressed, the harmonic suppression and harmonic recovery functions are realized, and the working frequency range of the rectification circuit is widened; according to the ultra-wideband rectification circuit, ultra-wideband impedance matching is realized through a section of short conical gradient transmission line, the design process of the rectification circuit is effectively simplified, and meanwhile, the ultra-wideband rectification circuit with a compact structure is realized.

Description

Technical Field

[0001] The present invention belongs to, but is not limited to, the technical fields of wireless energy transmission and electromagnetic energy harvesting, and in particular relates to a simple and compact ultra-wideband rectifier circuit and a design method thereof. Background Art

[0002] With the rapid development of the Internet of Things (IoT), wireless sensors, and smart devices, microwave wireless power transmission (WPT) technology has attracted widespread attention due to its advantages, including the lack of physical connections, high flexibility, and adaptability to complex environments. Microwave power transmission converts electrical energy into microwave signals and transmits them through space. A rectifier circuit at the receiving end ultimately converts this back into DC power to power various electronic devices. In this process, the rectifier circuit, as the core component for energy reception and conversion, directly determines the efficiency and practicality of the entire system.

[0003] Compared to traditional narrowband rectifiers, ultra-wideband rectifier circuits maintain high energy conversion efficiency across a wider frequency range, thereby improving the system's adaptability to multi-frequency or variable-frequency energy sources. They are particularly suitable for deployment in complex electromagnetic environments with unstable energy sources or the coexistence of multiple frequencies. Their broad frequency coverage and high energy conversion performance make them promising applications in future low-power, wirelessly powered smart devices.

[0004] At present, researchers have proposed a variety of ultra-wideband rectifier circuit design methods. For example, the rectifier circuit proposed in a new type of high-efficiency miniaturized ultra-wideband rectifier circuit (application number: CN202310519104.2) applied by the University of Electronic Science and Technology of China can cover an operating frequency range of 0.04-6.74GHz when the power conversion efficiency is greater than 50%; in a high-power and high-efficiency broadband rectifier circuit (application number: CN202311798097.0) applied by Xidian University, the operating frequency range of the rectifier circuit is 0.7-4.7GHz when the power conversion efficiency is greater than 50%; in the literature published by scholars from Kyushu University in Japan, "B. Gyawali, M. Aboualalaa, A. Barakat, and RK Pokharel, "Design of miniaturized Sub-6 GHz rectifier with self-Impedance matching technique," IEEE Trans. Circuits Syst.I, Reg.Papers, vol.71, no.7, pp.3413-3422, Jul.2024.”, when the power conversion efficiency is greater than 50%, the operating frequency range of the rectifier circuit is 3-5.8 GHz.

[0005] As can be seen, existing ultra-wideband rectifier circuits mostly operate below the X-band (8-12 GHz). With the development of future technology, more and more frequency resources will be used. Designing ultra-wideband rectifier circuits that cover a wider frequency range is becoming increasingly important. Therefore, it is necessary to design a simple and compact ultra-wideband rectifier circuit. Summary of the Invention

[0006] In response to the problems existing in the prior art, the present invention provides a simple and compact ultra-wideband rectifier circuit and a design method thereof. On the one hand, the ultra-wideband rectifier circuit designed in the present invention can operate up to the X-band, achieving wide absolute bandwidth and fractional bandwidth, as well as a large frequency ratio; on the other hand, the ultra-wideband rectifier circuit designed in the present invention has a simple design and a compact structure, and has broad application prospects in WPT systems.

[0007] The present invention is implemented as follows: a simple and compact ultra-wideband rectifier circuit includes a top microstrip structure, an intermediate dielectric substrate, and a bottom metal floor; the top microstrip structure and the bottom metal floor are respectively located on the upper and lower surfaces of the intermediate dielectric substrate; the top microstrip structure includes a radio frequency input port, a broadband impedance matching network, a DC blocking capacitor, a diode topology structure, a harmonic suppression and harmonic recovery network, and a DC output port;

[0008] RF input port, used for welding a standard 50Ω SMA connector to input the RF signal into the broadband impedance matching network;

[0009] A broadband impedance matching network is used to match the input impedance between the RF source and the rectifier, so that as much energy as possible is transferred to the subsequent circuit;

[0010] The DC-blocking capacitor is used for the transmission of RF input signals to prevent the DC generated by the diode from flowing into the RF signal source;

[0011] Diode topology to generate the required DC component;

[0012] Harmonic suppression and harmonic recovery network, used to filter out the output clutter of the diode topology structure and input the fundamental wave and higher harmonics back into the diode topology;

[0013] DC output port, used to connect the rear-end load.

[0014] Furthermore, the RF input port is a microstrip line with a characteristic impedance of 50Ω.

[0015] Furthermore, the broadband impedance matching network is a section of tapered transmission line.

[0016] Furthermore, the DC-blocking and AC-passing capacitor is a high-frequency capacitor C1.

[0017] Furthermore, the diode topology structure includes a diode SR1 and a diode SR2.

[0018] Furthermore, the harmonic suppression and harmonic recovery network includes a parallel capacitor C2, a parallel capacitor C3 and a microstrip line.

[0019] Furthermore, the RF input port is connected to one end of the broadband impedance matching network, and the other end of the broadband impedance matching network is connected to the high-frequency capacitor C1; one end of the high-frequency capacitor C1 is connected to the broadband impedance matching network, and the other end is respectively connected to the anode of the diode SR1 and the cathode of the diode SR2; one end of the parallel capacitor C2 and the parallel capacitor C3 are respectively connected to the cathode of the diode SR1 and the DC output port, and the other end of the DC output port is connected to the load R L The other ends of the parallel capacitors C2 and C3 are connected to the anode of the diode SR2 through a microstrip line, and the anode of the diode SR2 and the other ends of the parallel capacitors C2 and C3 are connected to the underlying metal floor through metallized vias.

[0020] Another object of the present invention is to provide a simple and compact design method for an ultra-wideband rectifier circuit, comprising:

[0021] The top microstrip structure and the bottom metal floor are respectively arranged on the upper surface and the lower surface of the intermediate dielectric substrate;

[0022] The top microstrip structure includes a radio frequency input port, a broadband impedance matching network, a DC blocking capacitor, a diode topology structure, a harmonic suppression and harmonic recovery network, and a DC output port, which are connected in sequence.

[0023] In combination with the above technical solutions and the technical problems solved, the advantages and positive effects of the technical solutions to be protected by the present invention are as follows:

[0024] The present invention connects the two diodes in the diode topology directly to the DC filter capacitor, which not only effectively compresses the load impedance, but also realizes the harmonic suppression and harmonic recovery functions, and broadens the operating frequency range of the rectifier circuit; the present invention realizes ultra-wideband impedance matching through a short tapered transmission line, effectively simplifies the design process of the rectifier circuit, and realizes a compact ultra-wideband rectifier circuit.

[0025] The expected benefits and commercial value of the technical solution of the present invention after transformation are as follows: the ultra-wideband rectifier circuit proposed in the present invention can operate in the Sub-6GHz band and the X-band, can meet the needs of various wireless energy transmission scenarios, and has broad application prospects.

[0026] The technical solution of the present invention solves a technical problem that people have long been eager to solve but have never been able to successfully solve: the ultra-wideband rectifier circuit proposed in the present invention not only covers the Sub-6GHz frequency band, but can also operate in the K band. It has the advantages of simple design and compact structure, and shows broad application prospects in WPT systems. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 is a circuit topology schematic diagram provided by an embodiment of the present invention;

[0028] Figure 2 is a dimensioned layout provided by an embodiment of the present invention;

[0029] Figure 3 Z provided by the embodiment of the present invention in1 Input impedance variation trajectory with input power;

[0030] Figure 4 Z provided by the embodiment of the present invention in Input impedance variation trajectory with input power;

[0031] Figure 5 The embodiment of the present invention provides a curve diagram showing the power conversion efficiency changing with input frequency under different input powers, as simulated and measured;

[0032] Figure 6 This is a measured curve diagram showing the change of power conversion efficiency with load impedance at different input powers and input frequencies provided by an embodiment of the present invention;

[0033] Figure 7 This is a measured curve diagram showing the change of power conversion efficiency with input power at different input frequencies provided by an embodiment of the present invention;

[0034] In the figure: 1. High-frequency capacitor C1; 2. Diode SR1; 3. Diode SR2; 4. High-frequency capacitor C2; 5. High-frequency capacitor C3; 101. Broadband impedance matching network; 102. Structure with both harmonic recovery and harmonic suppression functions. DETAILED DESCRIPTION

[0035] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0036] like Figure 1As shown, an embodiment of the present invention provides a simple and compact ultra-wideband rectifier circuit, including a top microstrip structure, an intermediate dielectric substrate, and a bottom metal floor; the top microstrip structure and the bottom metal floor are respectively located on the upper surface and the lower surface of the intermediate dielectric substrate; the top microstrip structure includes an RF input port, a broadband impedance matching network, a DC blocking capacitor, a diode topology structure, a harmonic suppression and harmonic recovery network, and a DC output port.

[0037] The top microstrip structure provided by the embodiment of the present invention specifically includes a radio frequency input port, a broadband impedance matching network 101, a high-frequency capacitor C1, a diode SR1, a diode SR2, a high-frequency capacitor C2, a high-frequency capacitor C3, a structure 102 with both harmonic suppression and harmonic recovery functions, and a DC load R L .

[0038] The RF input port is a microstrip line with a characteristic impedance of 50Ω, which is used to weld a standard 50Ω SMA connector to input the RF signal into a broadband impedance matching network;

[0039] The broadband impedance matching network 101 is a short tapered transmission line TL1, which is used to achieve impedance matching within a broadband range so that as much energy as possible is transmitted to the diode;

[0040] The high-frequency capacitor C1 is a high-frequency lumped capacitor used to pass the radio frequency input signal and prevent the direct current generated by the diode from flowing into the radio frequency signal source;

[0041] The diode SR1 and the diode SR2 are Schottky diodes used to convert radio frequency energy into direct current energy;

[0042] The structure 102 for harmonic suppression and harmonic recovery includes a high-frequency capacitor C2, a high-frequency capacitor C3, and a microstrip line TL2, which is used to filter out the clutter output by the Schottky diode and re-input the fundamental wave and higher harmonics into the Schottky diode. The high-frequency capacitor C2 and the high-frequency capacitor C3 are both high-frequency lumped capacitors. The microstrip line TL2 is used to connect the anode of the diode SR2 and the high-frequency capacitor C1 and the high-frequency capacitor C3.

[0043] The DC output port is used to connect the rear load R L .

[0044] The RF input port is connected to a broadband impedance matching network 101; the broadband impedance matching network 101 is connected to the high-frequency capacitor C1; one end of the high-frequency capacitor C1 is connected to the broadband impedance matching network 101, and the other end is respectively connected to the anode of the diode SR1 and the cathode of the diode SR2; the cathode of the diode SR1 is connected to the parallel capacitor C2 and the parallel capacitor C3; the anode of the diode SR2 is connected to the underlying metal floor through a metallized via, and the anode of the diode SR2 is connected to the parallel capacitor C2 and the parallel capacitor C3 through the microstrip line TL2; one end of the parallel capacitor C2 and the parallel capacitor C3 is connected to the cathode of the diode SR1 and the DC output port, and the other end is connected to the underlying metal floor through a metallized via, and is connected to the anode of the diode SR2 through the microstrip line TL2; one end of the DC output port is connected to the parallel capacitor C2 and the parallel capacitor C3, and one end is connected to the load R L connected.

[0045] In ultra-wideband RF energy harvesting and rectification applications, traditional rectifier circuits commonly suffer from low rectification efficiency, narrow bandwidth, and significant harmonic interference. Especially in high-frequency applications, impedance mismatch and energy transmission losses prevent RF energy from being effectively rectified into a stable DC voltage, limiting the performance of rectifier systems in applications such as wireless energy harvesting and RFID.

[0046] Existing rectifier circuits are often composed of multiple separate structures, occupying a large area and having a complex system structure. They cannot adapt to the development needs of integration and miniaturization, especially in application scenarios that need to be embedded in portable or wearable devices, where circuit volume and integration become limiting factors.

[0047] To address the problem of low energy transmission efficiency, the present invention designs a broadband impedance matching network 101, which adopts a short tapered gradient microstrip transmission line structure to enable efficient impedance matching of the input RF signal within a wider frequency band, thereby effectively introducing more RF energy into the diode rectifier structure and improving energy utilization.

[0048] To address the problem of DC signal feedback interfering with the RF source, a high-frequency capacitor C1 is introduced into the circuit as a DC-blocking and AC-passing element. This not only ensures the smooth transmission of the RF signal, but also effectively prevents the rectified DC component from crosstalking with the front stage, thereby improving the stability and controllability of the system.

[0049] Traditional rectifier circuits are prone to generating harmonic signals at high frequencies, which can interfere with rectification efficiency. This invention utilizes a composite structure constructed with high-frequency capacitors C2 and C3 and microstrip line TL2 to filter out the Schottky diode's output harmonics and recycle the fundamental wave. This allows unused higher-order energy to be fed back into the rectification path, improving overall energy conversion efficiency.

[0050] By integrating RF input, impedance matching, rectification, filtering, harmonic recovery, and load output into a three-layer structure (top microstrip - middle substrate - bottom metal floor), a compact and fully functional rectification circuit solution is formed. This structure not only facilitates mass manufacturing and embedded applications, but also allows flexible adjustment of design parameters in different frequency bands to achieve ultra-wideband high-efficiency rectification, solving the problem of traditional solutions that struggle to balance efficiency, size, and bandwidth.

[0051] In this embodiment, the dielectric substrate is made of Rogers 4350B material (dielectric constant of 3.66, loss tangent of 0.004), the thickness of the dielectric substrate is 0.508 mm, and the thickness of the top microstrip structure and the bottom metal floor are both 0.035 mm.

[0052] like Figure 2 As shown in the diagram and specific dimensions of the embodiment of the present invention, the overall size of the rectifier circuit is 10.5mm×1.7mm. High-frequency capacitors C1, C2, and C3 are all CBR04C101F3GAC with a capacitance of 100pF.

[0053] like Figure 3 and Figure 4 As shown in Figure 3, the input impedance of the rectifier circuit was simulated before and after the addition of the ultra-wideband impedance matching network to verify its performance. The results show that after adding the tapered transmission line TL1, the input impedance of the rectifier circuit converges to around 50Ω, demonstrating good impedance matching capability.

[0054] The rectifier circuit layout was prepared and tested, and the simulation and measured results are shown as follows: Figure 5 、 Figure 6 and Figure 7 As shown in the figure, the measured results show that at an input power of 23dBm, the rectifier circuit has a power conversion efficiency greater than 50% in the 0.03-12GHz frequency range, an absolute bandwidth of 11.97GHz, a fractional bandwidth of 199%, and a frequency ratio of 400. With a DC load of 300Ω, an input frequency of 1GHz, and an input power of 24dBm, it reaches a peak efficiency of 70.33%. This shows that the ultra-wideband rectifier circuit in this embodiment can cover the Sub-6GHz and K-band bands, and with a size of only 10.5mm×1.7mm, it has broad application prospects in WPT.

[0055] The above description is only a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any modifications, equivalent substitutions and improvements made by any technician familiar with this technical field within the technical scope disclosed by the present invention and within the spirit and principles of the present invention should be covered by the scope of protection of the present invention.

Claims

1. A simple and compact ultra-wideband rectifier circuit, characterized in that: The device comprises a top microstrip structure, an intermediate dielectric substrate and a bottom metal floor; the top microstrip structure and the bottom metal floor are respectively located on the upper surface and the lower surface of the intermediate dielectric substrate; the top microstrip structure comprises an RF input port, a broadband impedance matching network, a DC blocking capacitor, a diode topology structure, a harmonic suppression and harmonic recovery network and a DC output port; RF input port, used for welding a standard 50Ω SMA connector to input the RF signal into the broadband impedance matching network; A broadband impedance matching network is used to match the input impedance between the RF source and the rectifier, so that as much energy as possible is transferred to the subsequent circuit; The DC-blocking capacitor is used to pass the RF input signal and prevent the DC generated by the diode from flowing into the RF signal source; Diode topology to generate the required DC component; Harmonic suppression and harmonic recovery network, used to filter out the output clutter of the diode topology structure and input the fundamental wave and higher harmonics back into the diode topology; DC output port, used to connect the rear-end load.

2. The simple and compact ultra-wideband rectifier circuit according to claim 1, characterized in that: The radio frequency input port is a microstrip line with a characteristic impedance of 50Ω.

3. The simple and compact ultra-wideband rectifier circuit according to claim 1, characterized in that: The broadband impedance matching network is a short tapered transmission line.

4. The simple and compact ultra-wideband rectifier circuit according to claim 1, characterized in that: The DC-blocking and AC-passing capacitor is a high-frequency capacitor C1.

5. The simple and compact ultra-wideband rectifier circuit according to claim 1, characterized in that: The diode topology includes a diode SR1 and a diode SR2.

6. The simple and compact ultra-wideband rectifier circuit according to claim 1, characterized in that: The harmonic suppression and harmonic recovery network includes a parallel capacitor C2, a parallel capacitor C3 and a microstrip line.

7. The simple and compact ultra-wideband rectifier circuit according to claim 1, characterized in that: The RF input port is connected to one end of the broadband impedance matching network, and the other end of the broadband impedance matching network is connected to the high-frequency capacitor C1; one end of the high-frequency capacitor C1 is connected to the broadband impedance matching network, and the other end is respectively connected to the anode of the diode SR1 and the cathode of the diode SR2; one end of the parallel capacitor C2 and the parallel capacitor C3 are respectively connected to the cathode of the diode SR1 and the DC output port, and the other end of the DC output port is connected to the load R L The other ends of the parallel capacitors C2 and C3 are connected to the anode of the diode SR2 through a microstrip line, and the anode of the diode SR2 and the other ends of the parallel capacitors C2 and C3 are connected to the underlying metal floor through metallized vias.

8. A method for designing a simple and compact ultra-wideband rectifier circuit according to any one of claims 1 to 7, characterized in that: include: The top microstrip structure and the bottom metal floor are respectively arranged on the upper surface and the lower surface of the intermediate dielectric substrate; The top microstrip structure includes a radio frequency input port, a broadband impedance matching network, a DC blocking capacitor, a diode topology structure, a harmonic suppression and harmonic recovery network, and a DC output port, which are connected in sequence.

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