An ultra-wideband compact rectifier circuit

Abstract

The application discloses a kind of ultra-wideband compact rectifier circuits, including top layer microstrip circuit, dielectric substrate and ground plane, wherein top layer microstrip circuit is located on the upper surface of dielectric substrate, ground plane is printed on the lower surface of dielectric substrate;The top layer microstrip circuit includes radio frequency energy input end, ultra-wideband impedance matching network, second-order voltage doubler rectifier circuit, low-pass filter and load end;The input end of the ultra-wideband impedance matching network is connected with the radio frequency energy input end, the output end of the ultra-wideband impedance matching network and the input end of the second-order voltage doubler rectifier circuit are connected, the output end of the second-order voltage doubler rectifier circuit and the input end of the low-pass filter are connected, the output end of the low-pass filter is connected with the load end;Ultra-wideband miniaturization rectifier circuit proposed in the application not only has the function of wide frequency rectification, ensure that the overall area of circuit is small, improve the power capacity of rectifier circuit and the efficiency in rectification wideband.

Description

Technical Field

[0001] This invention relates to the field of wireless radio frequency power transmission and harvesting technology, and in particular to an ultra-wideband compact rectifier circuit. Background Technology

[0002] With the rapid development of wireless communication technology, the number of radio frequency (RF) signals in the environment has increased dramatically. RF energy harvesting systems can collect RF signal energy from different frequency bands in the environment and convert it into DC power to power low-power wireless electronic devices. This power supply method, which requires no physical connection, provides an important solution to the energy supply problem of IoT sensors, implantable medical devices, and other devices in complex environments.

[0003] As a crucial component of radio frequency (RF) energy harvesting systems, the rectifier circuit is responsible for converting the harvested RF signals into DC energy. The conversion efficiency, operating bandwidth, and physical size of the rectifier circuit directly affect the overall system efficiency and level of integration. Designing a rectifier circuit with wide bandwidth and a compact structure is of significant application value in order to fully harvest energy distributed across multiple frequency bands in the environment.

[0004] In the ultra-wideband range, the input impedance of a Schottky diode varies drastically with frequency, making it difficult for the matching network to maintain consistently low reflection loss across the entire frequency band. To achieve ultra-wideband matching, existing technologies often require the introduction of multi-section impedance transformers or complex stub structures. This not only significantly increases the physical size of the rectifier circuit but also limits its engineering applications in miniaturized, embedded electronic devices. Therefore, smaller device size and higher space efficiency are necessary to meet the high-performance requirements of modern integrated systems for rectifier circuits. Summary of the Invention

[0005] The main objective of this invention is to provide an ultra-wideband compact rectifier circuit, which aims to solve the existing technical problems.

[0006] To achieve the above objectives, the present invention provides an ultra-wideband compact rectifier circuit, comprising a top microstrip circuit, a dielectric substrate, and a ground plane, wherein the top microstrip circuit is located on the upper surface of the dielectric substrate, and the ground plane is printed on the lower surface of the dielectric substrate. The top-level microstrip circuit includes an RF energy input terminal, an ultra-wideband impedance matching network, a second-order voltage doubler rectifier circuit, a low-pass filter, and a load terminal. The input terminal of the ultra-wideband impedance matching network is connected to the radio frequency energy input terminal, the output terminal of the ultra-wideband impedance matching network is connected to the input terminal of the second-order voltage doubler rectifier circuit, the output terminal of the second-order voltage doubler rectifier circuit is connected to the input terminal of the low-pass filter, and the output terminal of the low-pass filter is connected to the load terminal.

[0007] Furthermore, the radio frequency energy input terminal includes a 50-ohm impedance microstrip line, a first metal pad, and a second metal pad; The first metal pad and the second metal pad are symmetrically distributed on the upper and lower sides of the 50-ohm impedance microstrip line. The first metal pad is connected to the ground plane through the first metallized via, and the second metal pad is connected to the ground plane through the second metallized via. The 50-ohm impedance microstrip line is connected to the input terminal of the DC blocking capacitor.

[0008] Furthermore, the ultra-wideband impedance matching network includes a DC blocking capacitor, a first high-impedance microstrip line, a first low-impedance microstrip line, a first sector open-circuit stub, a second sector open-circuit stub, and a second high-impedance microstrip line. The output terminal of the DC blocking capacitor is connected to the input terminal of the first high-impedance microstrip line. The first high-impedance microstrip line, the first low-impedance microstrip line, and the second high-impedance microstrip line are cascaded and connected to the input terminal of the second-order voltage doubler rectifier circuit. The first sector open-circuit stub and the second sector open-circuit stub are symmetrically distributed on the upper and lower sides of the first low-impedance microstrip line.

[0009] Furthermore, the second-order voltage doubler rectifier circuit includes a first Schottky diode, a second Schottky diode, and a third metal pad; The anode of the first Schottky diode is connected to the output terminal of the second high-impedance microstrip line, and the cathode is connected to the third metal pad and connected to the ground plane through the third metallized via. The anode of the first Schottky diode is connected to the cathode of the second Schottky diode, and the anode of the second Schottky diode is connected to the input terminal of the low-pass filter.

[0010] Furthermore, the low-pass filter includes a third high-impedance microstrip line, a second low-impedance microstrip line, a third open-circuit stub, and a fourth open-circuit stub; The third high-resistance microstrip line and the second low-resistance microstrip line are cascaded and connected to the load resistor. The third sector open-circuit stub and the fourth sector open-circuit stub are symmetrically distributed on the upper and lower sides of the second low-resistance microstrip line. Furthermore, the load terminal includes a load resistor and a fourth metal pad; The load resistor is connected to the fourth metal pad and to the ground plane through the fourth metallized via.

[0011] The beneficial effects of this invention are reflected in: This invention employs an ultra-wideband impedance matching network consisting of a DC blocking capacitor, a first high-impedance microstrip line, a first low-impedance microstrip line, symmetrically distributed first and second sector-shaped open-circuit stubs, and a second high-impedance microstrip line. By utilizing the multi-stage reactance slope compensation mechanism of the high and low impedance microstrip lines and the multi-mode resonance characteristics of the sector-shaped open-circuit stubs, the quality factor Q of the circuit is effectively reduced, achieving wideband compensation for the drastic changes in diode input impedance with frequency.

[0012] This invention uses high-impedance microstrip lines to replace traditional multi-section impedance transformers, and replaces multiple rectangular microstrip line open-circuit stubs with fan-shaped open-circuit stubs, which greatly reduces the circuit size.

[0013] This invention achieves an RF-DC rectification efficiency of over 50% in the ultra-wideband range. This high efficiency is attributed to three aspects: First, the ultra-wideband impedance matching network ensures efficient transmission of the RF signal to the rectifier diodes; second, the second-order voltage doubler rectifier circuit topology effectively improves the output voltage; third, the low-pass filter, composed of a third high-impedance microstrip line, a second low-impedance microstrip line, and symmetrically distributed third and fourth sector open-circuit stubs, effectively suppresses the backflow of harmonic signals of each order, reflecting the harmonic energy back to the rectifier circuit for secondary rectification, further improving the overall conversion efficiency. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the layer structure of an ultra-wideband compact rectifier circuit according to the present invention; Figure 2 This is a schematic diagram of the various structures of the top-level microstrip circuit of an ultra-wideband compact rectifier circuit according to the present invention. Figure 3 This is an illustration of the microstrip lines and lumped elements of the top-level microstrip circuit of an ultra-wideband compact rectifier circuit according to the present invention; Figure 4 This is an illustration of the metal vias in the intermediate dielectric substrate of an ultra-wideband compact rectifier circuit according to the present invention. Figure 5 The figures show the simulation and test performance of an ultra-wideband compact rectifier circuit according to the present invention.

[0015] Explanation of reference numerals in the attached figures: Ⅰ. Top layer microstrip circuit; Ⅱ. Dielectric substrate; Ⅲ. Ground plane; 1. RF power input terminal; 2. Ultra-wideband impedance matching network; 3. Second-order voltage doubler rectifier circuit; 4. Low-pass filter; 5. Load terminal; 1-1, 50-ohm impedance microstrip line; 1-2, First metal pad; 1-3, Second metal pad; 1-4, First metallized via; 1-5, Second metallized via; 2-1, DC blocking capacitor; 2-2, First high-resistance microstrip line; 2-3, First low-resistance microstrip line; 2-4, First open-circuit stub; 2-5, Second open-circuit stub; 2-6, Second high-resistance microstrip line; 3-1, First Schottky diode; 3-2, Second Schottky diode; 3-3, Third metal pad; 3-4, Third metallized via; 4-1, Third high-resistance microstrip line; 4-2, Second low-resistance microstrip line; 4-3, Third open-circuit stub; 4-4, Fourth open-circuit stub; 5-1, Load resistor; 5-2, Fourth metal pad; 5-3, Fourth metallized via. Detailed Implementation

[0016] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Unless otherwise specified, the embodiments and features in the embodiments of this application can be combined with each other. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0017] Please see Figure 1 and 2 The present invention provides an ultra-wideband compact rectifier circuit, comprising a top microstrip circuit I, a dielectric substrate II, and a ground plane III, wherein the top microstrip circuit I is located on the upper surface of the dielectric substrate II, and the ground plane III is printed on the lower surface of the dielectric substrate II.

[0018] The top-level microstrip circuit I consists of an RF energy input terminal 1, an ultra-wideband impedance matching network 2, a second-order voltage doubler rectifier circuit 3, a low-pass filter 4, and a load terminal 5; The RF power input terminal 1 is composed of a 50-ohm impedance microstrip line 1-1, a first metal pad 1-2, and a second metal pad 1-3. The first metal pad 1-2 and the second metal pad 1-3 are symmetrically distributed on the upper and lower sides of the 50-ohm impedance microstrip line. The first metal pad 1-2 is connected to the ground plane III through a first metallized via 1-4, and the second metal pad 1-3 is connected to the ground plane III through a second metallized via 1-5. The 50-ohm impedance microstrip line 1-1 is connected to the input terminal of the DC blocking capacitor 2-1. For details, please refer to Figure 3 and Figure 4 The ultra-wideband impedance matching network 2 consists of a DC blocking capacitor 2-1, a first high-impedance microstrip line 2-2, a first low-impedance microstrip line 2-3, a first open-circuit stub 2-4, a second open-circuit stub 2-5, and a second high-impedance microstrip line 2-6. The output terminal of the DC blocking capacitor 2-1 is connected to the input terminal of the first high-impedance microstrip line 2-2. The first high-impedance microstrip line 2-2, the first low-impedance microstrip line 2-3, and the second high-impedance microstrip line 2-6 are cascaded and connected to the input terminal of the second-order voltage doubler rectifier circuit 3. The first open-circuit stub 2-4 and the second open-circuit stub 2-5 are symmetrically distributed on the upper and lower sides of the first low-impedance microstrip line 2-3. The second-order voltage multiplier rectifier circuit 3 consists of a first Schottky diode 3-1, a second Schottky diode 3-2, and a third metal pad 3-3. The anode of the first Schottky diode 3-1 is connected to the output terminal of the second high-impedance microstrip line 2-6, and the cathode is connected to the third metal pad 3-3 and connected to the ground plane Ⅲ through the third metallized via 3-4. The anode of the first Schottky diode 3-1 is connected to the cathode of the second Schottky diode 3-2, and the anode of the second Schottky diode 3-2 is connected to the input terminal of the low-pass filter 4. The input impedances of the first Schottky diode 3-1 and the second Schottky diode 3-2 can be obtained from the SPICE model, and the expression for calculating the input impedance is as follows: ; in, Z D The input impedance of the diode. ω Angular frequency, R in This is the large-signal equivalent input resistance of the diode. j The imaginary unit, L p Package parasitic inductance, C j,avg Diode junction capacitance; The equivalent impedance calculation expression after designing a second high-impedance microstrip line 2-6 and cascading it with a second-order voltage doubler rectifier circuit 3 is as follows: ; in, Z 03 This is the characteristic impedance of the second high-resistivity microstrip line. L 3 represents the physical length of the microstrip line. β Let be the phase propagation constant; The characteristic impedance and physical length of the second high-impedance microstrip line 2-6 can generate a phase-shifted rotating impedance trajectory, which cancels out the package parasitic inductance. L p The influence of this causes the transformed admittance virtual branch to fall into the compensable range of the subsequent fan-shaped branch.

[0019] The equivalent input admittance calculation expression for the cascaded first low-impedance microstrip line 2-3, first sector open-circuit stub 2-4, and second sector open-circuit stub 2-5 is as follows: ; in, j The imaginary unit, B fan1 The susceptance of the fan-shaped open-circuit branch, Y fan1 The characteristic admittance of the fan-shaped open branch is given. β Phase propagation constant, R1 represents the radius of the sector; The equivalent input impedance of the second stage, after being cascaded with the first low-impedance microstrip line 2-3, the first sector open-circuit stub 2-4, and the second sector open-circuit stub 2-5, and then cascaded with the second high-impedance microstrip line 2-6, and finally cascaded with the second-order voltage doubler rectifier circuit, is calculated as follows: ; In this example, the imaginary part of the second-stage input impedance needs to be zero, that is: ; The real impedance transformation is achieved in the first high-impedance microstrip line 2-2, and the calculation expression is as follows: ; The purpose of DC blocking capacitor 2-1 is to prevent DC leakage. The final circuit input impedance calculation expression is as follows: To achieve impedance matching in ultra-wideband applications; The low-pass filter 4 is composed of a third high-impedance microstrip line 4-1, a second low-impedance microstrip line 4-2, a third sector open-circuit stub 4-3, and a fourth sector open-circuit stub 4-4. The third high-impedance microstrip line 4-1 and the second low-impedance microstrip line 4-2 are cascaded and connected to the load resistor 5-1. The third sector open-circuit stub 4-3 and the fourth sector open-circuit stub 4-4 are symmetrically distributed on the upper and lower sides of the second low-impedance microstrip line 4-2. The third high-impedance microstrip line 4-1 is in an open-circuit state for broadband RF signals, and its equivalent input impedance is calculated as follows: ; in, Z high The characteristic impedance of the third high-resistivity microstrip line 4-1 is... β Phase propagation constant, L f1 The physical length of the microstrip line; The cascaded low-impedance microstrip line 4-2, the third sector open-circuit stub 4-3, and the fourth sector open-circuit stub 4-4 act as a short circuit for broadband radio frequency signals. The equivalent input admittance is calculated as follows: ; in G L For load conductance, j The imaginary unit, B fan2 The susceptance of the fan-shaped open-circuit branch, Y fan2 The characteristic admittance of the fan-shaped open branch is given. β Phase propagation constant, R 2 represents the radius of the sector; The combination of the third high-impedance microstrip line 4-1, the second low-impedance microstrip line 4-2, the third sector open-circuit stub 4-3, and the fourth sector open-circuit stub 4-4 realizes the function of a low-pass filter. Based on the above calculation formulas, the specific physical parameters of the DC blocking capacitor 2-1, the first high-resistivity microstrip line 2-2, the first low-resistivity microstrip line 2-3, the first sector open-circuit stub 2-4, the second sector open-circuit stub 2-5, the second high-resistivity microstrip line 2-6, the third high-resistivity microstrip line 4-1, the second low-resistivity microstrip line 4-2, the third sector open-circuit stub 4-3, and the fourth sector open-circuit stub 4-4 can be designed. The load terminal 5 consists of a load resistor 5-1 and a fourth metal pad 5-2. The load resistor 5-1 is connected to the fourth metal pad 5-2 and is connected to the ground plane Ⅲ through the fourth metallized through-hole 5-3.

[0020] The above design yields an ultra-wideband compact rectifier circuit. During normal operation, the RF power signal enters the ultra-wideband impedance matching network 2 through input terminal 1 to obtain a "clean" AC signal. Then, it enters the second-order voltage doubler rectifier circuit 3 to be converted into DC energy. The residual harmonic signals are then suppressed by the low-pass filter 4, and the harmonic signals are returned to improve the rectification efficiency. Finally, the DC power is provided to the load.

[0021] According to the design principle, the first high-resistivity microstrip line 2-2 used in this embodiment has a width of 0.35mm and a length of 0.85mm, the first low-resistivity microstrip line 2-3 has a width of 3.1mm and a length of 1.3mm, the first fan-shaped open-circuit stub 2-4 and the second fan-shaped open-circuit stub 2-5 both have a fan radius of 2.1mm and an angle of 39°, the second high-resistivity microstrip line 2-6 has a width of 0.65mm and a length of 0.6mm, the third high-resistivity microstrip line 4-1 has a line width of 0.18mm and a length of 1.7mm, the second low-resistivity microstrip line 4-2 has a width of 1.7mm and a length of 1.5mm, the third fan-shaped open-circuit stub 4-3 and the fourth fan-shaped open-circuit stub 4-4 both have a radius of 6.3mm and an angle of 57°. The first Schottky diode 3-1 and the second Schottky diode 3-2 used in this embodiment are HSMS2862 manufactured by Agilent Technologies, which have low forward voltage, low series resistance and good radio frequency characteristics. In this embodiment, DC blocking capacitor 2-1 is a high-frequency lumped capacitor with a capacitance value of 22pF. In this embodiment, the load resistor is 5-1, and the optimal resistance value is obtained through load pulling, with a resistance value of 360Ω. In this embodiment, the dielectric substrate material of the ultra-wideband miniaturized rectifier circuit is selected as FR4 with a thickness of 1.6mm; In this embodiment, the rectifier circuit layout was simulated, fabricated, and tested. The simulation and test results are as follows: Figure 5The results show that, with an input power of 11 dBm, the rectifier circuit exhibits high power conversion efficiency within the 0.8-7.8 GHz frequency range, with an absolute bandwidth of 7 GHz. Therefore, the ultra-wideband rectifier circuit in this embodiment can cover the Sub-6 GHz band and the C-band, demonstrating broad application prospects in WPT (Wideband Transformer).

[0022] The broadband matching network is the core module for rectifier circuits to achieve wide bandwidth. It is usually implemented by multiple microstrip lines with series and parallel structures or multiple lumped capacitors and inductors. This invention uses only three small microstrip lines to achieve broadband matching, which avoids the disadvantage of excessive area caused by the need for multiple stub microstrip lines in traditional microstrip wide bandwidth matching, and also avoids the process inconsistency problem in lumped element matching, thus realizing an ultra-wideband miniaturized rectifier circuit.

[0023] The various embodiments in this specification are described in a related manner. Similar or identical parts between embodiments can be referred to mutually. Each embodiment focuses on describing the differences from other embodiments. In particular, the system embodiments are basically similar to the method embodiments, so the description is relatively simple; relevant parts can be referred to the descriptions of the method embodiments.

[0024] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. 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 of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. An ultra-wideband compact rectifier circuit, characterized in that: It includes a top microstrip circuit (Ⅰ), a dielectric substrate (Ⅱ), and a ground plane (Ⅲ), wherein the top microstrip circuit (Ⅰ) is located on the upper surface of the dielectric substrate (Ⅱ), and the ground plane (Ⅲ) is printed on the lower surface of the dielectric substrate (Ⅱ); The top-level microstrip circuit (Ⅰ) includes an RF energy input terminal (1), an ultra-wideband impedance matching network (2), a second-order voltage doubler rectifier circuit (3), a low-pass filter (4), and a load terminal (5). The input terminal of the ultra-wideband impedance matching network (2) is connected to the radio frequency energy input terminal (1), the output terminal of the ultra-wideband impedance matching network (2) is connected to the input terminal of the second-order voltage doubler rectifier circuit (3), the output terminal of the second-order voltage doubler rectifier circuit (3) is connected to the input terminal of the low-pass filter (4), and the output terminal of the low-pass filter (4) is connected to the load terminal (5).

2. The ultra-wideband compact rectifier circuit as described in claim 1, characterized in that: The radio frequency energy input terminal (1) includes a 50-ohm impedance microstrip line (1-1), a first metal pad (1-2), and a second metal pad (1-3). The first metal pad (1-2) and the second metal pad (1-3) are symmetrically distributed on the upper and lower sides of the 50-ohm impedance microstrip line. The first metal pad (1-2) is connected to the ground plane (Ⅲ) through the first metallized via (1-4), and the second metal pad (1-3) is connected to the ground plane (Ⅲ) through the second metallized via (1-5). The 50-ohm impedance microstrip line (1-1) is connected to the input terminal of the DC blocking capacitor (2-1).

3. The ultra-wideband compact rectifier circuit as described in claim 1, characterized in that: The ultra-wideband impedance matching network (2) includes a DC blocking capacitor (2-1), a first high-impedance microstrip line (2-2), a first low-impedance microstrip line (2-3), a first sector open-circuit stub (2-4), a second sector open-circuit stub (2-5), and a second high-impedance microstrip line (2-6). The output terminal of the DC blocking capacitor (2-1) is connected to the input terminal of the first high-impedance microstrip line (2-2). The first high-impedance microstrip line (2-2), the first low-impedance microstrip line (2-3), and the second high-impedance microstrip line (2-6) are cascaded and connected to the input terminal of the second-order voltage doubler rectifier circuit (3). The first sector open-circuit stub (2-4) and the second sector open-circuit stub (2-5) are symmetrically distributed on the upper and lower sides of the first low-impedance microstrip line (2-3).

4. The ultra-wideband compact rectifier circuit as described in claim 1, characterized in that: The second-order voltage multiplier rectifier circuit (3) includes a first Schottky diode (3-1), a second Schottky diode (3-2), and a third metal pad (3-3). The positive terminal of the first Schottky diode (3-1) is connected to the output terminal of the second high-impedance microstrip line (2-6), and the negative terminal is connected to the third metal pad (3-3) and connected to the ground plane (Ⅲ) through the third metallized via (3-4); the positive terminal of the first Schottky diode (3-1) is connected to the negative terminal of the second Schottky diode (3-2), and the positive terminal of the second Schottky diode (3-2) is connected to the input terminal of the low-pass filter (4).

5. The ultra-wideband compact rectifier circuit as described in claim 1, characterized in that: The low-pass filter (4) includes a third high-impedance microstrip line (4-1), a second low-impedance microstrip line (4-2), a third open-circuit stub (4-3), and a fourth open-circuit stub (4-4). The third high-resistivity microstrip line (4-1) and the second low-resistivity microstrip line (4-2) are cascaded and connected to the load resistor (5-1). The third sector open-circuit stub (4-3) and the fourth sector open-circuit stub (4-4) are symmetrically distributed on the upper and lower sides of the second low-resistivity microstrip line (4-2).

6. The ultra-wideband compact rectifier circuit as described in claim 1, characterized in that: The load terminal (5) includes a load resistor (5-1) and a fourth metal pad (5-2). The load resistor (5-1) is connected to the fourth metal pad (5-2) and to the ground plane (Ⅲ) through the fourth metallized via (5-3).

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