Miniaturized broadband rectifier circuit

Abstract

The application discloses a miniaturized wideband rectifier circuit, which comprises a direct-current isolation capacitor; an output end of the direct-current isolation capacitor is connected with an input end of a T-shaped impedance matching network, an output end of the T-shaped impedance matching network is connected with an input end of a voltage doubling rectifier structure, and output ends of the voltage doubling rectifier structure are connected with input ends of filter capacitors and an input end of a direct-current load respectively. The voltage doubling rectifier structure is adopted, so that the output voltage amplitude of the rectifier circuit is improved, the impedance change of the circuit in a wide frequency band is relatively flat, and the wideband characteristic is beneficial to be realized.

Description

Technical Field

[0001] This invention belongs to the field of radio frequency circuit technology, and specifically relates to a miniaturized broadband 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. While these signals perform normal communication and detection tasks, they can also cause electromagnetic interference to other devices. However, from another perspective, these ubiquitous RF signals create conditions for RF energy harvesting. RF energy harvesting systems can collect energy from environmental RF signals and convert it into DC power to power low-power wireless electronic devices. Therefore, the emergence of environmental RF energy harvesting offers a possible solution to the energy supply problem for a large number of wireless devices in various application scenarios, and has thus attracted widespread attention.

[0003] As a crucial component of a radio frequency (RF) energy harvesting system, the rectifier circuit is responsible for converting the harvested RF energy into DC energy to power devices or store it. Therefore, the conversion efficiency of the rectifier circuit directly affects the overall efficiency of the RF energy harvesting system and has a significant impact on the overall system performance.

[0004] Radio frequency (RF) energy in the environment is typically distributed across multiple frequency bands. To fully collect this RF energy, a broadband rectifier circuit covering multiple frequency bands needs to be designed. Existing rectifier circuits usually only operate in a single frequency band, and existing broadband rectifier circuits suffer from low rectification efficiency and large circuit size, which are detrimental to large-scale applications and the trend towards device miniaturization. Therefore, designing a broadband rectifier circuit that simultaneously features small size and high efficiency is of great significance. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a miniaturized broadband rectifier circuit, the purpose of which is to solve the problems in the background technology.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a miniaturized broadband rectifier circuit, including a DC blocking capacitor; the output terminal of the DC blocking capacitor is connected to the input terminal of a T-type impedance matching network, the output terminal of the T-type impedance matching network is connected to the input terminal of a voltage doubler rectifier structure, and the output terminal of the voltage doubler rectifier structure is connected to the input terminal of a filter capacitor and the input terminal of a DC load, respectively.

[0007] Furthermore, the T-type impedance matching network includes a first inductor, a second inductor, and a first capacitor; the input terminal of the first inductor is connected to the DC blocking capacitor via a second microstrip line, and the output terminal of the first inductor is connected to the input terminals of the second inductor and the first capacitor via a third microstrip line; the other end of the first capacitor is connected to the input terminal of a fourth microstrip line, and the other end of the fourth microstrip line is open-circuited; the output terminal of the second inductor is connected to the input terminal of the voltage doubler rectifier structure via a fifth microstrip line.

[0008] Furthermore, the voltage doubler rectifier structure uses diodes in an SMS7630-005LF package, including a first Schottky diode and a second Schottky diode; the cathode of the first Schottky diode and the anode of the second Schottky diode are connected to the output terminal of the second inductor via a fifth microstrip line; the anode of the first Schottky diode is connected to the input terminal of a sixth microstrip line, the sixth microstrip line including a first microstrip grounding hole, the first microstrip grounding hole being connected to ground; the cathode of the second Schottky diode is connected to the input terminal of the filter capacitor and the input terminal of the DC load via a seventh microstrip line.

[0009] Furthermore, the other end of the filter capacitor is connected to the input end of the eighth microstrip line, which includes a second microstrip grounding hole connected to ground.

[0010] Furthermore, the output terminal of the DC load is connected to the input terminal of the ninth microstrip line, which includes a third microstrip grounding hole connected to ground.

[0011] Furthermore, the input terminal of the DC blocking capacitor is connected to the microwave signal source via a first microstrip line.

[0012] Compared with existing technologies, the present invention has the following advantages:

[0013] (1) The present invention adopts a T-type impedance matching network composed of lumped elements (i.e., two inductors and one capacitor) to realize a miniaturized rectifier circuit design with an overall size of only 20.56mm×12.72mm×1mm.

[0014] (2) The present invention adopts a voltage doubler rectifier structure, which not only improves the output voltage amplitude of the rectifier circuit, but also makes the impedance of the circuit change more smoothly in a wider frequency band, which is conducive to achieving broadband characteristics. Under the input power of 0dBm, the measured energy conversion efficiency of the rectifier circuit in the broadband range of 0.4-1.7GHz all exceeded 50%. Attached Figure Description

[0015] Figure 1 This is the circuit layout of the miniaturized broadband rectifier circuit of the present invention.

[0016] Figure 2The graph shows the conversion efficiency versus frequency of the miniaturized broadband rectifier circuit of this invention, as tested and simulated.

[0017] Figure 3 This is a graph showing the energy conversion efficiency versus input power of the miniaturized broadband rectifier circuit of the present invention at different frequencies.

[0018] In the diagram: 1. DC blocking capacitor; 2. T-type impedance matching network; 21. First inductor; 22. Second inductor; 23. First capacitor; 3. Voltage doubler rectifier structure; 31. First Schottky diode; 32. Second Schottky diode; 4. Filter capacitor; 5. DC load; 101. First microstrip line; 102. Second microstrip line; 201. Third microstrip line; 202. Fourth microstrip line; 301. Fifth microstrip line; 302. Sixth microstrip line; 303. Seventh microstrip line; 401. Eighth microstrip line; 501. Ninth microstrip line; V1. First microstrip grounding hole; V2. Second microstrip grounding hole; V3. Third microstrip grounding hole; 6. Microwave signal source. Detailed Implementation

[0019] like Figure 1 As shown, the present invention provides a technical solution: a miniaturized broadband rectifier circuit, comprising: a DC blocking capacitor 1, a T-type impedance matching network 2, a voltage doubler rectifier structure 3, a filter capacitor 4, and a DC load 5;

[0020] The input terminal of the DC blocking capacitor 1 is connected to the microwave signal source 6 via a first microstrip line 101, and the impedance of the microwave signal source 6 is 50 ohms. The other end of the DC blocking capacitor 1 is connected to the input terminal of the T-type impedance matching network 2 via a second microstrip line 102. The other end of the T-type impedance matching network 2 is connected to the input terminal of the voltage doubler rectifier structure 3 via a fifth microstrip line 301. The other end of the voltage doubler rectifier structure 3 is connected to the filter capacitor 4 and the DC load 5 via a seventh microstrip line 303. In this embodiment, the DC blocking capacitor 1 is used to isolate the DC energy generated by the voltage doubler rectifier structure 3 from the microwave signal source 6, preventing the DC energy from flowing back to the microwave signal source 6.

[0021] The T-type impedance matching network 2 includes a first inductor 21, a second inductor 22, and a first capacitor 23. The input terminal of the first inductor 21 is connected to the DC blocking capacitor 1 via a second microstrip line 102, and the output terminal of the first inductor 21 is connected to the input terminals of the second inductor 22 and the first capacitor 23 via a third microstrip line 201. The other end of the first capacitor 23 is connected to the input terminal of the fourth microstrip line 202, and the other end of the fourth microstrip line 202 is open. The output terminal of the second inductor 22 is connected to the input terminal of the voltage doubler rectifier structure 3 via a fifth microstrip line 301. In this embodiment, the T-type impedance matching network 2 is used to adjust the input impedance of the rectifier circuit, which is the same as the output impedance of the microwave signal source 6, so that the input impedance of the rectifier circuit is well matched with the output impedance of the microwave signal source 6 within a wide frequency range.

[0022] In this embodiment, the voltage doubler rectifier structure 3 uses diodes in an SMS7630-005LF package, namely a first Schottky diode 31 and a second Schottky diode 32. The cathode of the first Schottky diode 31 and the anode of the second Schottky diode 32 are connected to the output terminal of the second inductor 22 via a fifth microstrip line 301. The anode of the first Schottky diode 31 is connected to ground via a sixth microstrip line 302 (containing a first microstrip grounding hole V1). The cathode of the second Schottky diode 32 is connected to the input terminal of the filter capacitor 4 and the input terminal of the DC load 5 via a seventh microstrip line 303. This embodiment uses a voltage doubler rectifier structure 3, which can not only reduce the input impedance variation of the diode in the frequency band, making it easier for the voltage doubler rectifier structure 3 to match the input impedance of the microwave signal source 6 in the frequency band to achieve broadband operation, but also effectively improve the DC output voltage of the rectifier circuit.

[0023] The other end of the filter capacitor 4 is connected to ground through the eighth microstrip line 401 (containing the second microstrip grounding hole V2); in this embodiment, the filter capacitor 4 is used to ensure the smoothness of the output DC energy.

[0024] The output terminal of the DC load 5 is connected to ground through the ninth microstrip line 501 (containing the third microstrip grounding hole V3) to absorb the generated DC energy.

[0025] The dielectric substrate of the rectifier circuit is a polytetrafluoroethylene glass fiber board F4BM-2 with a relative permittivity of 2.2 and a thickness of 1 mm.

[0026] The capacitance of the DC blocking capacitor 1 is 100pF. The length of the first microstrip line 101 on the left side of the DC blocking capacitor 1 is 4mm and the width is 2mm. The length of the second microstrip line 102 on the right side of the DC blocking capacitor 1 is 3mm and the width is 2mm.

[0027] In the T-type impedance matching network 2 to the right of the second microstrip line 102, the inductance values ​​of the first inductor 21 and the second inductor 22 are both 1.6nH, and the capacitance value of the first capacitor 23 is 5pF; the length of the third microstrip line 201 located between the first inductor 21 and the second inductor 22 is 3mm and the width is 2mm.

[0028] The fourth microstrip line 202 below the first capacitor 23 has a length of 3mm and a width of 2mm, and the fifth microstrip line 301 located between the second inductor 22 and the second Schottky diode 32 has a length of 3mm and a width of 2mm.

[0029] The length of the sixth microstrip line 302 below the first Schottky diode 31 is 3mm and the width is 2mm; the radius of the first microstrip grounding hole V1 is 0.3mm;

[0030] The seventh microstrip line 303 to the right of the second Schottky diode 32 has a length of 4 mm and a width of 2 mm. The filter capacitor 4 has a capacitance of 100 pF. The eighth microstrip line 401 to the left of the filter capacitor 4 has a length of 3 mm and a width of 2 mm. The radius of the second microstrip grounding hole V2 is 0.3 mm. The optimal resistance of the DC load 5 is 1200 Ω. The ninth microstrip line 501 on the upper side of the DC load 5 has a length of 3 mm and a width of 2 mm. The radius of the third microstrip grounding hole V3 is 0.3 mm.

[0031] in, Figure 2 This embodiment demonstrates how the energy conversion efficiency changes with frequency for both 0 dBm input power testing and 0 dBm simulation.

[0032] from Figure 2 As can be seen, at 0 dBm input power, the rectifier circuit's energy conversion efficiency is greater than 50% in both the test and simulation in the frequency range of 0.4-1.7 GHz (0.1-1.7 GHz in simulation), with corresponding fractional bandwidths of 123.8% (test) and 177.8% (simulation).

[0033] When the input frequency is 1.3GHz (test) or 1.2GHz (simulation), the conversion efficiency reaches its peak, with energy conversion efficiencies of 74.3% and 74.6% respectively. It can be seen that the test result of 74.3% and the simulation result of 74.6% are basically consistent. It can be seen that the rectifier circuit of this embodiment has good energy conversion efficiency over a wide frequency band.

[0034] Among them, the appendix Figure 3 This embodiment demonstrates how the energy conversion efficiency varies with input power at different frequencies. Figure 3As can be seen, within the input power range of -10dBm to 10dBm, the maximum conversion efficiencies of the rectifier circuit at the three frequency points of 0.9GHz, 1.1GHz, and 1.8GHz are 79.9%, 83.2%, and 56.2%, respectively; this further demonstrates that the rectifier circuit has high energy conversion efficiency over a wide frequency band.

[0035] A broadband matching network is the core module for achieving wide bandwidth in a rectifier circuit. It is typically implemented using microstrip lines with a series-parallel structure. Good impedance matching over a wide frequency band is achieved by adjusting the size and layout of the microstrip lines. However, matching networks based on microstrip line structures are relatively large. Although the size can be reduced through design and layout optimization, it is still generally still quite large. This invention proposes a miniaturized broadband rectifier circuit using a T-type impedance matching network 2 composed of lumped elements (i.e., two inductors and one capacitor). This achieves a miniaturized rectifier circuit design with an overall size of only 20.56mm × 12.72mm × 1mm (0.072λ0 × 0.045λ0 × 0.003λ0). λ 0 represents the wavelength corresponding to the rectifier circuit's operating center frequency of 1.05 GHz. The T-type impedance matching network 2 achieves wideband impedance matching while also featuring miniaturized structural size.

[0036] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A miniaturized broadband rectifier circuit, characterized in that, It includes a DC blocking capacitor; the output terminal of the DC blocking capacitor is connected to the input terminal of a T-type impedance matching network, the output terminal of the T-type impedance matching network is connected to the input terminal of a voltage doubler rectifier structure, and the output terminal of the voltage doubler rectifier structure is connected to the input terminal of a filter capacitor and the input terminal of a DC load, respectively. The T-type impedance matching network includes a first inductor, a second inductor, and a first capacitor; the input terminal of the first inductor is connected to the DC blocking capacitor via a second microstrip line, and the output terminal of the first inductor is connected to the input terminals of the second inductor and the first capacitor via a third microstrip line; the other end of the first capacitor is connected to the input terminal of a fourth microstrip line, and the other end of the fourth microstrip line is open-circuited. The output terminal of the second inductor is connected to the input terminal of the voltage doubler rectifier structure via the fifth microstrip line; The voltage doubler rectifier structure uses a diode in an SMS7630-005LF package. The diode includes a first Schottky diode and a second Schottky diode. The cathode of the first Schottky diode and the anode of the second Schottky diode are connected to the output terminal of the second inductor through a fifth microstrip line. The anode of the first Schottky diode is connected to the input terminal of a sixth microstrip line. The sixth microstrip line includes a first microstrip grounding hole, which is connected to ground. The cathode of the second Schottky diode is connected to the input terminal of the filter capacitor and the input terminal of the DC load via the seventh microstrip line.

2. The miniaturized broadband rectifier circuit according to claim 1, characterized in that: The other end of the filter capacitor is connected to the input end of the eighth microstrip line, which includes a second microstrip grounding hole connected to ground.

3. The miniaturized broadband rectifier circuit according to claim 2, characterized in that: The output terminal of the DC load is connected to the input terminal of the ninth microstrip line, which includes a third microstrip grounding hole connected to ground.

4. The miniaturized broadband rectifier circuit according to claim 3, characterized in that: The input terminal of the DC blocking capacitor is connected to the microwave signal source via a first microstrip line.

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