A design method of a dual-frequency microwave rectifier circuit with harmonic suppression characteristics

Abstract

The application discloses a kind of dual-frequency microwave rectifier circuit design methods with harmonic suppression characteristics, it is related to rectifier circuit technical field, including constructing rectifier device nonlinear equivalent impedance model, extraction the dynamic input impedance of the rectifier device at two target frequency points;Build dual-band impedance conversion unit, convert the dynamic input impedance into standard system impedance by the dual-band impedance conversion unit;Direct current filtering and harmonic suppression unit is set at the output of the rectifier device;The application is nonlinear impedance modeling to rectifier device and extracts dynamic input impedance, constructs adaptive dual-band impedance conversion unit, which helps to improve the stability of dual-frequency matching;By setting direct current filtering and harmonic suppression unit, corresponding reflection effect is formed to target frequency point and its harmonic, which can reduce the leakage of microwave energy to the direct current side and improve the harmonic suppression effect.

Description

Technical Field

[0001] This invention relates to the field of rectifier circuit technology, and in particular to a design method for a dual-frequency microwave rectifier circuit with harmonic suppression characteristics. Background Technology

[0002] Microwave wireless power transfer technology can provide contactless power supply for low-power devices such as IoT terminals and portable sensing devices, and has wide application needs in wireless power supply, passive sensing and other fields. As the core component of the system, the microwave rectifier circuit can convert microwave energy in space into stable DC power to support the continuous operation of back-end devices. The dual-frequency rectifier circuit can be compatible with multi-frequency energy harvesting, adapt to the energy acquisition needs in complex environments, and has high practical value.

[0003] Existing dual-frequency microwave rectifier circuits mostly use rectifier diodes as the core conversion device, combined with dual-frequency impedance matching networks and filter structures to achieve RF to DC energy conversion. Some schemes use microstrip line structures to build matching and harmonic suppression units, and use distributed parameter components to complete energy transmission and conversion in dual-frequency operation.

[0004] However, the nonlinear characteristics of rectifier diodes cause their input impedance to fluctuate with the operating frequency and input power, increasing the design difficulty of dual-frequency impedance matching networks. Traditional matching structures are difficult to maintain dual-frequency matching simultaneously over a wide power range. High-order harmonics generated during diode operation will lose energy in the form of radiation or leakage, reducing the overall conversion efficiency. Conventional harmonic suppression structures have limited suppression effects on second and third harmonics, and will also make the overall circuit size larger and the integration lower. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a design method for a dual-frequency microwave rectifier circuit with harmonic suppression characteristics, which solves the technical problems of insufficient dual-frequency matching stability, limited harmonic suppression effect, and redundant circuit structure in existing technologies.

[0006] The technical means employed in this invention are as follows: In a first aspect, the present invention provides a design method for a dual-frequency microwave rectifier circuit with harmonic suppression characteristics, comprising: A nonlinear equivalent impedance model of the rectifier is constructed, and the dynamic input impedance of the rectifier at two target frequency points is extracted. A dual-band impedance transformation unit is constructed to convert the dynamic input impedance into a standard system impedance. A DC filter and harmonic suppression unit is provided at the output end of the rectifier.

[0007] Furthermore, the nonlinear equivalent impedance modeling of the rectifier device includes: constructing a diode equivalent parallel circuit model that includes junction capacitance, series resistance, and package parasitic parameters.

[0008] Furthermore, the step of extracting the dynamic input impedance of the rectifier at two target frequency points includes: extracting the dynamic input impedance of the rectifier at 2.45 GHz and 5.8 GHz frequency points.

[0009] Furthermore, the construction of the dual-band impedance transformation unit includes: constructing a dual-band impedance transformation unit comprising a series microstrip line segment and a parallel open-circuit stub.

[0010] Furthermore, the dynamic input impedance is converted into a standard system impedance by the dual-band impedance transformation unit, including: converting the dynamic input impedance into a 50Ω standard system impedance based on the step impedance transformation principle.

[0011] Furthermore, the provision of a DC filter and harmonic suppression unit at the output end of the rectifier includes: providing a DC filter and harmonic suppression unit at the output end of the rectifier, comprising multiple microstrip lines and fan-shaped stubs.

[0012] Furthermore, the rectifier is a Schottky diode.

[0013] Secondly, the present invention also provides a dual-frequency microwave rectifier circuit design system with harmonic suppression characteristics, comprising: The modeling and impedance extraction module is used to construct a nonlinear equivalent impedance model of the rectifier and extract the dynamic input impedance of the rectifier at two target frequency points. An impedance transformation unit construction module is used to construct a dual-band impedance transformation unit, which converts the dynamic input impedance into a standard system impedance. The filtering and harmonic suppression unit setting module is used to set a DC filtering and harmonic suppression unit at the output end of the rectifier.

[0014] Thirdly, the present invention also provides a computer device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, when the processor executes the computer program, it implements a dual-frequency microwave rectifier circuit design method with harmonic suppression characteristics according to the first aspect.

[0015] Fourthly, the present invention also provides a computer-readable storage medium storing a computer program, characterized in that, when the computer program is executed by a processor, it implements a dual-frequency microwave rectifier circuit design method with harmonic suppression characteristics according to the first aspect.

[0016] This invention constructs a suitable dual-band impedance transformation unit by performing nonlinear impedance modeling on rectifier devices and extracting dynamic input impedance, which helps improve the stability of dual-band matching. At the same time, by setting up DC filtering and harmonic suppression units, corresponding reflection effects are formed on the target frequency and its harmonics, which can reduce microwave energy leakage to the DC side and improve the harmonic suppression effect. The overall compact topology of microstrip lines and stubs also helps to simplify the circuit structure, reduce parasitic losses, and adapt to the requirements of integrated design.

[0017] Based on the above reasons, this invention can be widely applied in fields such as rectifier circuits. Attached Figure Description

[0018] 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 some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a flowchart illustrating a design method for a dual-frequency microwave rectifier circuit with harmonic suppression characteristics according to the present invention. Figure 2 This is a schematic diagram of the circuit structure for a nonlinear equivalent model. Figure 3 This is a schematic diagram of the circuit structure of a dual-band impedance transformation unit; Figure 4 This is a schematic diagram of a harmonic suppression circuit. Figure 5 A comparison chart of simulation and test results of return loss of dual-frequency rectifier circuit; Figure 6 The graph shows the relationship between rectification efficiency and input power at different operating frequencies. Detailed Implementation

[0020] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0021] It should be noted that the terms "comprising" and "having" and any variations thereof in this invention are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or device that includes a series of steps or units is not necessarily limited to those steps or units that are explicitly listed, but may include other steps or units that are not explicitly listed or that are inherent to such process, method, product, or device.

[0022] The embodiments of the present invention will now be described with reference to the accompanying drawings.

[0023] Please see Figure 1 , Figure 1 This is a flowchart illustrating a design method for a dual-frequency microwave rectifier circuit with harmonic suppression characteristics.

[0024] At the hardware level, the present invention preferably uses Rogers4350B, which has excellent high-frequency characteristics, as the dielectric substrate. Its relative permittivity is set to 3.66, the loss tangent is 0.0037, and the substrate thickness is precisely set to 0.508mm.

[0025] This application provides an embodiment of the invention that provides a design method for a dual-frequency microwave rectifier circuit with harmonic suppression characteristics, comprising the following steps: Step 101: Construct a nonlinear equivalent impedance model of the rectifier device and extract the dynamic input impedance of the rectifier device at two target frequency points.

[0026] In some embodiments, the rectifier is a Schottky diode; the Schottky diode can be from the HSMS-286x series. The nonlinear characteristics of the Schottky diode cause its input impedance to change with the operating frequency and input power. A nonlinear equivalent impedance model can be established to reflect its actual operating state.

[0027] In some embodiments, nonlinear equivalent impedance modeling of the rectifier device includes: constructing a diode equivalent parallel circuit model that includes junction capacitance, series resistance, and package parasitic parameters.

[0028] Specifically, such as Figure 2 As shown, Figure 2 This is a schematic diagram of the circuit structure for a nonlinear equivalent model. Figure 2The diagram shows the complete topology of the dual-frequency Class F parallel RF-DC rectifier designed in this paper. It consists of four core functional modules cascaded sequentially: a dual-frequency input impedance matching network, a multi-order Class F harmonic suppression network, an HSMS286 Schottky diode rectifier unit, and a DC filter output load network. A nonlinear equivalent model of the diodes was established using full-wave simulation software. This model comprehensively considers non-ideal factors such as pin parasitic inductance and package capacitance. It can characterize the nonlinear operating characteristics of the rectifier device, more closely approximating its operating state in actual circuits, and helps reduce deviations in impedance matching design.

[0029] In some embodiments, extracting the dynamic input impedance of the rectifier at two target frequencies includes: extracting the dynamic input impedance of the rectifier at 2.45 GHz and 5.8 GHz.

[0030] Specifically, using a harmonic balance simulation controller, the dynamic input complex impedance of the diode at two target operating frequencies is extracted at a standard reference point with an input power of 10dBm. This dynamic input complex impedance reflects the actual impedance state of the rectifier at the target frequency and reference power, providing a reliable impedance basis for the design of the dual-band impedance transformation unit. This facilitates impedance matching at both frequencies and provides crucial boundary conditions for the accurate design of the subsequent matching network.

[0031] Step 102: Construct a dual-band impedance transformation unit to convert the dynamic input impedance into the standard system impedance.

[0032] In some embodiments, constructing a dual-band impedance transformation unit includes: constructing a dual-band impedance transformation unit comprising series microstrip line segments and parallel open-circuit stubs. This dual-band impedance transformation unit is based on a microstrip line structure, and through the combination of series microstrip line segments and parallel open-circuit stubs, forms a compact circuit topology, which helps reduce circuit parasitic losses and adapts to the integrated design requirements of microwave circuits.

[0033] In some embodiments, the dynamic input impedance is converted to a standard system impedance using a dual-band impedance transformation unit, including: converting the dynamic input impedance to a 50Ω standard system impedance based on the stepped impedance transformation principle. Impedance transformation based on the stepped impedance transformation principle can adjust the dynamic input impedance of the rectifier at the target frequency to match the standard system impedance, helping to reduce signal reflection at the target frequency.

[0034] Please see Figure 3 , Figure 3 This is a schematic diagram of the circuit structure of a dual-band impedance transformation unit. Figure 3It is a four-segment dual-band microstrip impedance matching network used to connect the receiving antenna and the rectifier module. This network can simultaneously perform impedance transformation at 2.45GHz and 5.8GHz, matching the complex impedance of the rectifier end to the standard 50Ω port of the antenna, effectively reducing port return loss, reducing microwave energy reflection loss, and ensuring that all the RF energy collected by the antenna is sent to the rectifier unit.

[0035] The backbone of this dual-band impedance transformation unit is a series microstrip line. Two parallel open-circuit microstrip stubs are vertically led out from the backbone at different electrical lengths from the rectifier. By finely adjusting the physical position and characteristic impedance of the parallel stubs, the circuit can simultaneously excite deep low-reflection resonant points at two target frequencies. On the Smith chart, the impedance points at 2.45 GHz and 5.8 GHz are simultaneously drawn to the matching center, ensuring optimal return loss at the input across both frequency bands. During operation, the impedance values ​​corresponding to two specific frequencies are converted into a pair of conjugate impedances. These conjugate impedances are then adjusted to a standard 50Ω impedance through the matching network, allowing microwave energy to be injected into the rectifier branch with high transmittance. This matching method is similar to the strategy used in power amplifier circuits, employing four microstrip lines to achieve effective impedance matching between different frequency bands, achieving high-efficiency transmission across multiple frequency bands while maintaining overall system stability and performance. The overall circuit topology is compact, effectively avoiding parasitic losses caused by traditional discrete components.

[0036] Step 103: Install a DC filter and harmonic suppression unit at the output of the rectifier. This DC filter and harmonic suppression unit, through a specific microstrip structure combination, can reflect energy in the microwave frequency band, reduce microwave energy leakage to the DC side, and help improve the energy conversion efficiency of the rectifier.

[0037] In some embodiments, a DC filtering and harmonic suppression unit is provided at the output end of the rectifier, including: providing a DC filtering and harmonic suppression unit comprising multiple microstrip lines and fan-shaped stubs at the output end of the rectifier.

[0038] like Figure 4 As shown, Figure 4 This is a schematic diagram of a harmonic suppression circuit. Figure 4 To accommodate Class F harmonic suppression microstrip circuits at 2.45GHz and 5.8GHz, it consists of six microstrip transmission lines (TL5 to TL10) with different parameters. Two sets of branches provide resonant constraints for the second and third harmonics, reflecting outward-leaking harmonics back into the diode circuit to participate in energy conversion. This optimizes the overlap range of diode voltage and current waveforms, reduces conduction losses, and improves dual-frequency rectification efficiency. The overall structure employs a distributed microstrip design, facilitating integration with the rectifier circuit.

[0039] This DC filtering and harmonic suppression unit introduces a Class F harmonic suppression mechanism, utilizing a combination of multiple microstrip lines of specific electrical lengths (such as TL5 to TL10). These microstrip lines are transparent in the DC path, allowing the rectified power to flow smoothly to the load resistor; while in the microwave frequency band, they produce a more accurate equivalent open-circuit or short-circuit effect at the operating frequencies f1, f2 and the corresponding second and third harmonic frequencies.

[0040] Two open-circuit stubs with different radii and a 90-degree angle are connected in series along the DC output microstrip line path. The radius parameters of the first stub are designed for notch filtering at the 5.8 GHz fundamental frequency and its harmonics; the radius parameters of the second stub are designed for notch filtering at the 2.45 GHz fundamental frequency and its harmonics. The two stubs work together with the high-impedance transmission line to create deep short-circuit reflections in the microwave band, reducing the channels for RF energy leakage to the load.

[0041] This multi-stage notch filter mechanism creates a high input reflection impedance at the output end, which can effectively block the path of microwave energy leakage to the DC side and confine the energy to the two ends of the rectifier device for secondary rectification and conversion, thereby helping to improve the overall power conversion efficiency.

[0042] This invention also provides a dual-frequency microwave rectifier circuit design system with harmonic suppression characteristics, comprising: a modeling and impedance extraction module for constructing a nonlinear equivalent impedance model of the rectifier device and extracting the dynamic input impedance of the rectifier device at two target frequency points; an impedance transformation unit construction module for constructing a dual-band impedance transformation unit to convert the dynamic input impedance into a standard system impedance; and a filtering and harmonic suppression unit setting module for setting DC filtering and harmonic suppression units at the output of the rectifier device.

[0043] This invention also provides a computer device, including a memory, a processor, and a computer program stored in the memory and executable on the processor. The feature is that when the processor executes the computer program, it implements a dual-frequency microwave rectifier circuit design method with harmonic suppression characteristics.

[0044] This invention also provides a computer-readable storage medium storing a computer program, characterized in that the computer program, when executed by a processor, implements a design method for a dual-frequency microwave rectifier circuit with harmonic suppression characteristics.

[0045] The same or similar parts between the various embodiments in this specification can be referred to each other, and will not be repeated here.

[0046] Please see Figure 5 , Figure 5This is a comparison chart of simulation and test results for the return loss of a dual-frequency rectifier circuit.

[0047] When the input power is set to 11dBm, from Figure 5 The simulation results shown in (a) indicate that the diode rectification efficiency of this circuit can reach 72.59%; under the conditions of microwave input power of 11dBm and load set to 500Ω, from Figure 5 The test results in (b) show that the rectifier circuit achieves a rectification efficiency of 66.46% at 2.45 GHz and 70.71% at 5.8 GHz, and its overall performance meets the design requirements of this system.

[0048] Please see Figure 6 , Figure 6 The graph shows the relationship between rectification efficiency and input power at different operating frequencies.

[0049] Figure 6 The time-domain simulation voltage and current waveforms of the rectifier device designed in this invention at 2.45 GHz and 5.8 GHz are shown, demonstrating that the designed rectifier device has good Class F operating performance. By setting an Class F harmonic suppression network at the front end of the rectifier device, even-order harmonics generated by the rectifier device are short-circuited, while odd-order harmonics are open-circuited. In this way, the voltage distribution on the rectifier device forms a square wave pattern, while the current remains sinusoidal. The overlap between the voltage and current waveforms is significantly reduced, and the internal losses of the rectifier device are effectively controlled, thereby contributing to higher rectification efficiency.

[0050] This invention constructs a suitable dual-band impedance transformation unit by performing nonlinear impedance modeling on rectifier devices and extracting dynamic input impedance, which helps improve the stability of dual-band matching. At the same time, by setting up DC filtering and harmonic suppression units, corresponding reflection effects are formed on the target frequency and its harmonics, which can reduce microwave energy leakage to the DC side and improve the harmonic suppression effect. The overall compact topology of microstrip lines and stubs also helps to simplify the circuit structure, reduce parasitic losses, and adapt to the requirements of integrated design.

[0051] The sequence numbers of the above embodiments of the present invention are for descriptive purposes only and do not represent the superiority or inferiority of the embodiments.

[0052] In the above embodiments of the present invention, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions of other embodiments.

[0053] In the several embodiments provided in this application, it should be understood that the disclosed technical content can be implemented in other ways. The device embodiments described above are merely illustrative; for example, the division of units can be a logical functional division, and in actual implementation, there may be other division methods. For instance, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the displayed or discussed mutual coupling, direct coupling, or communication connection may be through some interfaces; the indirect coupling or communication connection between units or modules may be electrical or other forms.

[0054] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0055] Furthermore, the functional units in the various embodiments of the present invention can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit.

[0056] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A design method for a dual-frequency microwave rectifier circuit with harmonic suppression characteristics, characterized in that, include: A nonlinear equivalent impedance model of the rectifier is constructed, and the dynamic input impedance of the rectifier at two target frequency points is extracted. A dual-band impedance transformation unit is constructed to convert the dynamic input impedance into a standard system impedance. A DC filter and harmonic suppression unit is provided at the output end of the rectifier.

2. The design method for a dual-frequency microwave rectifier circuit with harmonic suppression characteristics according to claim 1, characterized in that, The nonlinear equivalent impedance modeling of the rectifier includes: constructing a diode equivalent parallel circuit model that includes junction capacitance, series resistance, and package parasitic parameters.

3. The design method for a dual-frequency microwave rectifier circuit with harmonic suppression characteristics according to claim 1, characterized in that, The step of extracting the dynamic input impedance of the rectifier at two target frequency points includes: extracting the dynamic input impedance of the rectifier at 2.45 GHz and 5.8 GHz frequency points.

4. The design method for a dual-frequency microwave rectifier circuit with harmonic suppression characteristics according to claim 1, characterized in that, The construction of the dual-band impedance transformation unit includes: constructing a dual-band impedance transformation unit comprising a series microstrip line segment and a parallel open-circuit stub.

5. The design method for a dual-frequency microwave rectifier circuit with harmonic suppression characteristics according to claim 1, characterized in that, The dual-band impedance transformation unit converts the dynamic input impedance into a standard system impedance, including: based on the step impedance transformation principle, converting the dynamic input impedance into a 50Ω standard system impedance.

6. The design method for a dual-frequency microwave rectifier circuit with harmonic suppression characteristics according to claim 1, characterized in that, The provision of a DC filter and harmonic suppression unit at the output end of the rectifier includes: providing a DC filter and harmonic suppression unit at the output end of the rectifier, comprising multiple microstrip lines and fan-shaped stubs.

7. The design method for a dual-frequency microwave rectifier circuit with harmonic suppression characteristics according to claim 1, characterized in that, The rectifier is a Schottky diode.

8. A dual-frequency microwave rectifier circuit design system with harmonic suppression characteristics, characterized in that, include: The modeling and impedance extraction module is used to construct a nonlinear equivalent impedance model of the rectifier and extract the dynamic input impedance of the rectifier at two target frequency points. An impedance transformation unit construction module is used to construct a dual-band impedance transformation unit, which converts the dynamic input impedance into a standard system impedance. The filtering and harmonic suppression unit setting module is used to set a DC filtering and harmonic suppression unit at the output end of the rectifier.

9. A computer device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the computer program, it implements a dual-frequency microwave rectifier circuit design method with harmonic suppression characteristics according to any one of claims 1 to 7.

10. A computer-readable storage medium storing a computer program, characterized in that, When the computer program is executed by the processor, it implements a design method for a dual-frequency microwave rectifier circuit with harmonic suppression characteristics according to any one of claims 1 to 7.

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