Hybrid energy harvester based on radio frequency and solar energy

Abstract

The present application belongs to the energy collection and energy conversion technology, and relates to a mixed energy collector of radio frequency and solar energy cooperation, comprising: a rectifier circuit (1) and a receiving antenna (2), characterized in that the rectifier circuit (1) is composed of a first dielectric substrate (3), a first metal ground plate (4), a matching circuit (5), a bias circuit (6), a rectification topology structure (7) and a grounding column (8). It improves the working state of the rectifier diode, and realizes the collection of solar energy and radio frequency energy. The present application can collect radio frequency and solar energy at the same time, the two energy sources can complement each other, the rectification efficiency can be improved, and the stability and continuity of the energy collection system can be greatly improved while more energy is obtained.

Description

Technical Field

[0001] This invention pertains to energy harvesting and energy conversion technologies, and relates to a hybrid energy harvester that combines radio frequency and solar energy, which can be used in self-powered systems and multi-node wireless sensor networks. Background Technology

[0002] Technologies for harvesting ambient energy are crucial for self-powered and battery-free systems. Energy harvesting systems use highly sensitive front-end energy harvesters to collect small amounts of energy from the environment or specific energy sources, then convert this energy into electrical energy using low-power back-end rectifier circuits to power related electronic devices. Commonly used energy sources include radio frequency energy, thermal energy, kinetic energy, and solar energy.

[0003] Current energy harvesting systems target single energy sources, such as environmental radio frequency signals, but their low energy density hinders energy harvesting. Y. Huang's paper published in IEEE, "Novel Compact and Broadband Frequency-Selectable Rectennas for a Wide Input-Power and LoadImpedance Range," proposes a rectifier antenna suitable for different frequency bands, input powers, and loads, implemented using a relatively simple matching network, offering certain advantages. However, its rectification efficiency is less than 30% when the input radio frequency power ranges from -20dBm to -10dBm, indicating a need for further improvement at low input power.

[0004] On the other hand, K. Wu's paper "Collaboratively Harvesting Ambient Radiofrequency and Thermal Energy" published in IEEE demonstrates how the energy generated by the temperature difference can be used to provide a certain bias voltage for the rectifier diodes, thereby enabling the rectifier circuit to have high rectification efficiency at low input power. This design idea is inspiring. Summary of the Invention

[0005] The purpose of this invention is to address the shortcomings of the existing technology by providing a hybrid energy harvester based on radio frequency and solar energy, which aims to achieve the characteristics of radio frequency energy harvesting and improved rectification efficiency while ensuring solar energy harvesting in a normal environment.

[0006] This invention is achieved through the following technical solution: a hybrid energy harvester based on radio frequency and solar energy, comprising: a rectifier circuit (1) and a receiving antenna (2), characterized in that the rectifier circuit (1) is composed of a first dielectric substrate (3), a first metal ground plane (4), a matching circuit (5), a bias circuit (6), a rectifier topology (7), and a grounding post (8). The upper surface of the first dielectric substrate (3) is printed with a microstrip portion of the rectifier circuit (1), and the lower surface is printed with a first metal ground plane (4), both made of copper. The matching circuit (5) is composed of a rectangular microstrip line (51) connected in parallel and short-circuited. The stub (52) is formed by connecting the end of the rectangular microstrip line (51) in series with a tapered microstrip line (53). The short-circuit stub (52) is connected to the first metal ground plane (4) through the first grounding post (81). The matching circuit (5), the bias circuit (6) and the rectifier topology (7) are connected by a microstrip line. The components contained in the bias circuit (6) and the rectifier topology (7) are also connected by a microstrip line. The grounding post (8) includes the first grounding post (81), the second grounding post (82), the third grounding post (83), the fourth grounding post (84) and the fifth grounding post (85).

[0007] The receiving antenna (2) includes a second dielectric substrate (9), an L-shaped feed (10), a second metal ground plane (11), and a radiating patch (12). The L-shaped feed (10), the second metal ground plane (11), and the radiating patch (12) of the receiving antenna (2) are printed on the upper surface of the second dielectric substrate (9). All of them are made of copper. The L-shaped feed (10) and the second metal ground plane (11) form a coplanar waveguide structure.

[0008] In the matching circuit (5), the width wa of the wider end of the rectangular microstrip line (51), the short-circuit stub (52) and the tapered microstrip line (53) is 2mm-3mm, and the width wb of the narrower end of the tapered microstrip line (53) is 0.3mm-0.7mm; the length la of the rectangular microstrip line (51) is 15mm-18mm, the length lb of the short-circuit stub (52) is 6mm-9mm, and the length lc of the tapered microstrip line (53) is 4mm-6mm.

[0009] The bias circuit (6) consists of a photodiode (61) connected in parallel with a bypass capacitor (62) and a choke inductor (63). The other end of the photodiode (61) is connected to the first metal ground plane (4) through the second grounding post (82), and the bypass capacitor (62) is connected to the first metal ground plane (4) through the third grounding post (83).

[0010] The rectifier topology (7) consists of a first filter capacitor (71), a rectifier diode (72), a second filter capacitor (73), and an output load (74). The second filter capacitor (73) is connected to the first metal ground plane (4) via a fourth grounding post (84), and the output load (74) is connected to the first metal ground plane (4) via a fifth grounding post (85). The capacitance value C2 of the first filter capacitor (71) can be 10pF-100pF, packaged as 0201. The capacitance value C3 of the second filter capacitor (73) can also be 10pF-100pF, packaged as 0201. The rectifier diode (72) can be a Schottky diode or a varactor diode. The output load (74) can use a lumped resistor with a 0201 package and a resistance value R. load It can range from 2000Ω to 10000Ω.

[0011] The length L of the rectifier circuit (1) is 28mm-35mm and the width W is 14mm-18mm.

[0012] The diameter d1 of the first grounding post (81) is 0.7mm-1.5mm, and the diameter d2 of the second grounding post (82), third grounding post (83), fourth grounding post (84) and fifth grounding post (85) is between 0.2mm-0.4mm.

[0013] A groove structure is provided between the L-shaped feed (10) and the metal floor (11), with a groove width s of 0.1mm-0.5mm. A radiating patch (12) is fed into the end of the L-shaped feed (10). The radiating patch (12) is a square patch with a pair of branches (121) and a pair of chamfers (122). The length l1 of the L-shaped feed (10) is 20mm-24mm, the width w1 of the L-shaped feed (10) is 2.2mm-2.8mm, and the length l2 where the L-shaped feed (10) connects to the radiating patch (12) is 8.5mm-11.5m. The distance w2 between the L-shaped feed (10) and the radiating patch (12) is 4mm-5mm; the width g of the radiating patch (12) is 24mm-28mm; the length m of a pair of branches (121) on the radiating patch (12) is 2mm-4mm; the width n is 0.5mm-1.5mm; the isosceles right-angled side length ws of a pair of chamfered corners (122) on the radiating patch (12) is 2mm-4mm; the second metal floor (11) is a ring structure with a width w3 of 9mm-11mm and an outer side length G of 58mm-62mm.

[0014] The thickness h1 of the first dielectric substrate (3) is 0.6mm-1.2mm, the thickness h2 of the second dielectric substrate (9) is 0.6mm-1.2mm, the material of the first dielectric substrate (3) and the second dielectric substrate (9) is F4B, the dielectric constant is 2.2, and the loss tangent is 0.001.

[0015] The photodiode (61) is model BPW 34S_EN, the bypass capacitor (62) has a capacitance value C1 of 10pF-20pF and a package of 0201, and the choke inductor (63) has an inductance value L1 of 30nH-60nH and a package of 0201.

[0016] The rectifier circuit 1 and the receiving antenna 2 are connected by an SMA connector to form a system.

[0017] Furthermore, the RF power in the input rectifier circuit 1 is defined as P. RF The solar power input to rectifier circuit 1 is defined as P. solar The output power at the output load 74 is defined as P. DC Its rectification efficiency is PCE:

[0018]

[0019] The present invention has the following beneficial effects:

[0020] 1. This invention improves the operating state of the rectifier diode by using the solar energy collected by the photodiode as the bias voltage of the rectifier diode, thereby realizing the collection of solar energy and radio frequency energy.

[0021] 2. The present invention improves matching performance and maintains high rectification efficiency under different RF input power and different bias voltage through the designed matching circuit, enabling the rectifier circuit to achieve high-efficiency energy harvesting under wide input power and wide bias voltage.

[0022] 3. This invention is applicable to multi-source hybrid energy harvesting. The solar energy density in the environment is high, and both radio frequency and solar energy are harvested simultaneously. The two energy sources can complement each other, which can improve rectification efficiency. While obtaining more energy, the stability and continuity of the energy harvesting system will also be greatly improved. Attached Figure Description

[0023] Figure 1A This is a schematic diagram of the rectifier circuit structure according to an embodiment of the present invention;

[0024] Figure 1B This is a magnified view of a portion of Figure 1;

[0025] Figure 2 This is a schematic diagram of the receiving antenna structure according to an embodiment of the present invention;

[0026] Figure 3 The S-parameter curves of the rectifier circuit under different illumination voltages are shown in the embodiments of the present invention.

[0027] Figure 4 This is a conversion efficiency curve of the rectifier circuit under the condition that the radio frequency input power and the light illumination input power are the same in an embodiment of the present invention;

[0028] Figure 5 This is a graph showing the S-parameters of the receiving antenna in an embodiment of the present invention.

[0029] Figure 6a , Figure 6a This is the radiation pattern of the receiving antenna in an embodiment of the present invention. Figure 6a The radiation pattern of the XOZ plane of the receiving antenna. Figure 6b The radiation pattern of the YOZ plane of the receiving antenna;

[0030] Figure 7 This is a graph showing the axial ratio bandwidth of the receiving antenna in an embodiment of the present invention.

[0031] In the attached figures: 1. Rectifier circuit; 2. Receiving antenna; 3. First dielectric substrate; 4. First metal ground plane; 5. Matching circuit; 51. Rectangular microstrip line; 52. Short-circuit stub; 53. Tapered microstrip line; 6. Bias circuit; 61. Photodiode; 62. Bypass capacitor; 63. Choke inductor; 7. Rectifier topology; 71. First filter capacitor; 72. Rectifier diode; 73. Second filter capacitor; 74. Output load; 8. Grounding post; 81. First grounding post; 82. Second grounding post; 83. Third grounding post; 84. Fourth grounding post; 85. Fifth grounding post; 9. Second dielectric substrate; 10. L-shaped feed section; 11. Second metal ground plane; 12. Radiating patch; 121. A pair of rectangular stubs; 122. A pair of chamfered corners. Detailed Implementation

[0032] To illustrate the technical content, structural features, and achieved objectives and effects of this invention in detail, the implementation methods are described in conjunction with specific illustrations:

[0033] Example 1

[0034] Reference Figure 1A , Figure 1B , Figure 2As shown, a hybrid energy harvester based on radio frequency and solar energy includes: a rectifier circuit 1 and a receiving antenna 2. The rectifier circuit 1 is composed of a first dielectric substrate 3, a first metal ground plane 4, a matching circuit 5, a bias circuit 6, a rectifier topology 7, and a grounding post 8. The upper surface of the first dielectric substrate 3 is printed with the microstrip portion of the rectifier circuit 1, and the lower surface is printed with the first metal ground plane 4, both made of copper. The grounding post 8 includes a first grounding post 81, a second grounding post 82, a third grounding post 83, a fourth grounding post 84, and a fifth grounding post 85. The matching circuit 5 is composed of a rectangular microstrip line 51 connected in parallel with a short-circuit stub 52, and the end of the rectangular microstrip line 51 is connected in series with a tapered microstrip line 53. The short-circuit stub 52 is connected to the first metal ground plane 4 through the first grounding post 81. The matching circuit 5, the bias circuit 6, and the rectifier topology 7 are connected by a microstrip line, and the components contained in the bias circuit 6 and the rectifier topology 7 are also connected by a microstrip line. In this embodiment, the diameter d1 of the first grounding post 81 is 0.7 mm, and the diameters d2 of the second grounding post 82, the third grounding post 83, the fourth grounding post 84, and the fifth grounding post 85 are 0.2 mm. The rectifier circuit 1 has a length L = 28 mm and a width W = 14 mm. The thickness h1 of the first dielectric substrate 3 is 0.6 mm, and the thickness h2 of the second dielectric substrate 9 is 0.6 mm. The first dielectric substrate 3 and the second dielectric substrate 9 are made of F4B material with a dielectric constant of 2.2 and a loss tangent of 0.001.

[0035] In the matching circuit 5, the width of the wider end of the rectangular microstrip line 51, the short-circuit stub 52, and the tapered microstrip line 53 is wa = 2 mm, and the width of the narrower end of the tapered microstrip line 53 is wb = 0.3 mm; the length of the rectangular microstrip line 51 is la = 15 mm, the length of the short-circuit stub 52 is lb = 6 mm, and the length of the tapered microstrip line 53 is lc = 4 mm.

[0036] The bias circuit 6 consists of a photodiode 61 connected in parallel with a bypass capacitor 62, and then connected in series with a choke inductor 63. The other end of the photodiode 61 is connected to the first metal ground plane 4 through a second grounding post 82, and the bypass capacitor 62 is connected to the first metal ground plane 4 through a third grounding post 83. The bypass capacitor 62 has a capacitance of C1 = 10pF and is packaged as a 0201, while the choke inductor 63 has an inductance of L1 = 30nH and is also packaged as a 0201.

[0037] The rectifier topology 7 consists of a first filter capacitor 71, a rectifier diode 72, a second filter capacitor 73, and an output load 74. The second filter capacitor 73 is connected to the first metal ground plane 4 via a fourth grounding post 84, and the output load 74 is connected to the first metal ground plane 4 via a fifth grounding post 85. The first filter capacitor 71 has a capacitance of C2 = 10pF and is packaged as a 0201. The rectifier diode 72 is a Schottky diode from Skyworks, model SMS7630, packaged as SOD-882. The second filter capacitor 73 has a capacitance of C3 = 10pF and is packaged as a 0201. The output load 74 can use a lumped resistor in a 0201 package with a resistance value R. load =2000Ω.

[0038] Reference Figure 2 The receiving antenna 2 includes a second dielectric substrate 9, an L-shaped feed 10, a second metal ground plane 11, and a radiating patch 12. The L-shaped feed 10, the second metal ground plane 11, and the radiating patch 12 of the receiving antenna 2 are printed on the upper surface of the second dielectric substrate 9. All of them are made of copper. The L-shaped feed 10 and the second metal ground plane 11 form a coplanar waveguide structure. A groove structure is provided between the L-shaped feeder 10 and the metal floor 11. The width of the groove is s = 0.1 mm. A radiating patch 12 is fed into the end of the L-shaped feeder 10. The radiating patch 12 is a square patch with a pair of branches 121 and a pair of chamfers 122. The length of the L-shaped feeder 10 is 11 = 20 mm, the width of the L-shaped feeder 10 is wl = 2.2 mm, the length l2 = 8.5 mm at which the L-shaped feeder 10 connects with the radiating patch 12, and the distance w2 = 4 mm between the L-shaped feeder 10 and the radiating patch 12. The width of the radiating patch 12 is g = 24 mm, the length m = 2 mm and the width n = 0.5 mm of the pair of branches 121 on the radiating patch 12, and the length ws = 2 mm of the isosceles right-angled side of the pair of chamfers 122 on the radiating patch 12. The second metal floor 11 is a ring structure with a width w3 = 9 mm and an outer side length G = 58 mm.

[0039] Table 1. List of parameters in Example 1 (mm)

[0040] la lb lc wa wb h1 h2 15 6 4 2 0.3 0.6 0.6 l1 l2 w1 w2 w3 ws s 20 8.5 2.2 4 9 2 0.1 m n g G L W 2 0.5 24 58 28 14

[0041] Example 2

[0042] Reference Figure 1A , Figure 1B , Figure 2As shown, a hybrid energy harvester based on radio frequency and solar energy includes: a rectifier circuit 1 and a receiving antenna 2. The rectifier circuit 1 is composed of a first dielectric substrate 3, a first metal ground plane 4, a matching circuit 5, a bias circuit 6, a rectifier topology 7, and a grounding post 8. The upper surface of the first dielectric substrate 3 is printed with the microstrip portion of the rectifier circuit 1, and the lower surface is printed with the first metal ground plane 4, both made of copper. The grounding post 8 includes a first grounding post 81, a second grounding post 82, a third grounding post 83, a fourth grounding post 84, and a fifth grounding post 85. The matching circuit 5 is composed of a rectangular microstrip line 51 connected in parallel with a short-circuit stub 52, and the end of the rectangular microstrip line 51 is connected in series with a tapered microstrip line 53. The short-circuit stub 52 is connected to the first metal ground plane 4 through the first grounding post 81. The matching circuit 5, the bias circuit 6, and the rectifier topology 7 are connected by a microstrip line, and the components contained in the bias circuit 6 and the rectifier topology 7 are also connected by a microstrip line. In this embodiment, the diameter d1 of the first grounding post 81 is 1 mm, and the diameters d2 of the second grounding post 82, the third grounding post 83, the fourth grounding post 84, and the fifth grounding post 85 are 0.3 mm. The length L of the rectifier circuit 1 is 30 mm, and the width W is 16 mm. The thickness h1 of the first dielectric substrate 3 is 0.8 mm, and the thickness h2 of the second dielectric substrate 9 is 0.8 mm. The first dielectric substrate 3 and the second dielectric substrate 9 are made of F4B material, with a dielectric constant of 2.2 and a loss tangent of 0.001.

[0043] In the matching circuit 5, the width of the wider end of the rectangular microstrip line 51, the short-circuit stub 52, and the tapered microstrip line 53 is wa = 2.5 mm, and the width of the narrower end of the tapered microstrip line 53 is wb = 0.5 mm; the length of the rectangular microstrip line 51 is la = 16 mm, the length of the short-circuit stub 52 is lb = 7.5 mm, and the length of the tapered microstrip line 53 is lc = 5 mm.

[0044] The bias circuit 6 consists of a photodiode 61 connected in parallel with a bypass capacitor 62, and then connected in series with a choke inductor 63. The other end of the photodiode 61 is connected to the first metal ground plane 4 through a second grounding post 82, and the bypass capacitor 62 is connected to the first metal ground plane 4 through a third grounding post 83. The bypass capacitor 62 has a capacitance value C1 of 15pF and a 0201 package, and the choke inductor 63 has an inductance value L1 of 50nH and a 0201 package.

[0045] The rectifier topology 7 consists of a first filter capacitor 71, a rectifier diode 72, a second filter capacitor 73, and an output load 74. The second filter capacitor 73 is connected to the first metal ground plane 4 via a fourth grounding post 84. The output load 74 is connected to the first metal ground plane 4 via a fifth grounding post 85. The first filter capacitor 71 has a capacitance of C2 = 60pF and is packaged as a 0201. The rectifier diode 72 is a Schottky diode from Skyworks, model SMS7630, packaged as SOD-882. The second filter capacitor 73 has a capacitance of C3 = 60pF and is packaged as a 0201. The output load 74 can use a lumped resistor in a 0201 package with a resistance value R. load =3000Ω.

[0046] Reference Figure 2 The receiving antenna 2 includes a second dielectric substrate 9, an L-shaped feed 10, a second metal ground plane 11, and a radiating patch 12. The L-shaped feed 10, the second metal ground plane 11, and the radiating patch 12 of the receiving antenna 2 are printed on the upper surface of the second dielectric substrate 9. All of them are made of copper. The L-shaped feed 10 and the second metal ground plane 11 form a coplanar waveguide structure. A groove structure is provided between the L-shaped feeder 10 and the metal floor 11. The width of the groove is s = 0.25 mm. A radiating patch 12 is fed into the end of the L-shaped feeder 10. The radiating patch 12 is a square patch with a pair of branches 121 and a pair of chamfers 122. The length of the L-shaped feeder 10 is ll = 22 mm, the width of the L-shaped feeder 10 is wl = 2.5 mm, the length l2 where the L-shaped feeder 10 connects to the radiating patch 12 is 10 mm, and the distance between the L-shaped feeder 10 and the radiating patch 12 is w2 = 4.5 mm. The width of the radiating patch 12 is g = 25 mm, the length of the pair of branches 121 on the radiating patch 12 is m = 3 mm, the width is n = 1 mm, and the isosceles right-angled side length of the pair of chamfers 122 on the radiating patch 12 is wt = 3 mm. The second metal floor 11 is a ring structure with a width w3 = 10 mm and an outer side length G = 60 mm.

[0047] Table 2 Parameter list in Example 2 (mm)

[0048] la lb lc wa wb h1 h2 16 7.5 5 2.5 0.5 0.8 0.8 l1 l2 w1 w2 w3 ws s 22 10 2.5 4.5 10.5 3 0.25 m n g G L W 3 1 25 60 30 16

[0049] Example 3

[0050] Reference Figure 1A , Figure 1B , Figure 2As shown, a hybrid energy harvester based on radio frequency and solar energy includes: a rectifier circuit 1 and a receiving antenna 2. The rectifier circuit 1 is composed of a first dielectric substrate 3, a first metal ground plane 4, a matching circuit 5, a bias circuit 6, a rectifier topology 7, and a grounding post 8. The upper surface of the first dielectric substrate 3 is printed with the microstrip portion of the rectifier circuit 1, and the lower surface is printed with the first metal ground plane 4, both made of copper. The grounding post 8 includes a first grounding post 81, a second grounding post 82, a third grounding post 83, a fourth grounding post 84, and a fifth grounding post 85. The matching circuit 5 is composed of a rectangular microstrip line 51 connected in parallel with a short-circuit stub 52, and the end of the rectangular microstrip line 51 is connected in series with a tapered microstrip line 53. The short-circuit stub 52 is connected to the first metal ground plane 4 through the first grounding post 81. The matching circuit 5, the bias circuit 6, and the rectifier topology 7 are connected by a microstrip line, and the components contained in the bias circuit 6 and the rectifier topology 7 are also connected by a microstrip line. In this embodiment, the diameter d1 of the first grounding post 81 is 1.5 mm, and the diameters d2 of the second grounding post 82, the third grounding post 83, the fourth grounding post 84, and the fifth grounding post 85 are 0.4 mm. The length L of the rectifier circuit 1 is 35 mm, and the width W is 18 mm. The thickness h1 of the first dielectric substrate 3 is 1.2 mm, and the thickness h2 of the second dielectric substrate 9 is 1.2 mm. The first dielectric substrate 3 and the second dielectric substrate 9 are made of F4B material, with a dielectric constant of 2.2 and a loss tangent of 0.001.

[0051] In the matching circuit 5, the width of the wider end of the rectangular microstrip line 51, the short-circuit stub 52, and the tapered microstrip line 53 is wa = 3 mm, and the width of the narrower end of the tapered microstrip line 53 is wb = 0.7 mm; the length of the rectangular microstrip line 51 is la = 18 mm, the length of the short-circuit stub 52 is lb = 9 mm, and the length of the tapered microstrip line 53 is lc = 6 mm.

[0052] The bias circuit consists of a photodiode 61 connected in parallel with a bypass capacitor 62, and then connected in series with a choke inductor 63. The other end of the photodiode 61 is connected to the first metal ground plane 4 through a second grounding post 82, and the bypass capacitor 62 is connected to the first metal ground plane 4 through a third grounding post 83. The bypass capacitor 62 has a capacitance of C1 = 20pF and is packaged in a 0201 package. The choke inductor 63 has an inductance of L1 = 60nH and is also packaged in a 0201 package.

[0053] The rectifier topology 7 consists of a first filter capacitor 71, a rectifier diode 72, a second filter capacitor 73, and an output load 74. The second filter capacitor 73 is connected to the first metal ground plane 4 via a fourth grounding post 84. The output load 74 is connected to the first metal ground plane 4 via a fifth grounding post 85. The first filter capacitor 71 has a capacitance of C2 = 100pF and is packaged as a 0201. The rectifier diode 72 is a Schottky diode from Skyworks, model SMS7630, packaged as SOD-882. The second filter capacitor 73 has a capacitance of C3 = 100pF and is packaged as a 0201. The output load 74 can use a lumped resistor in a 0201 package with a resistance value R. load =10000Ω.

[0054] Reference Figure 2 The receiving antenna 2 includes a second dielectric substrate 9, an L-shaped feed 10, a second metal ground plane 11, and a radiating patch 12. The L-shaped feed 10, the second metal ground plane 11, and the radiating patch 12 of the receiving antenna 2 are printed on the upper surface of the second dielectric substrate 9. All of them are made of copper. The L-shaped feed 10 and the second metal ground plane 11 form a coplanar waveguide structure. A groove structure is provided between the L-shaped feeder 10 and the metal floor 11. The width of the groove is s = 0.5 mm. A radiating patch 12 is fed into the end of the L-shaped feeder 10. The radiating patch 12 is a square patch with a pair of branches 121 and a pair of chamfers 122. The length of the L-shaped feeder 10 is 11 = 24 mm, the width of the L-shaped feeder 10 is wl = 2.8 mm, the length l2 where the L-shaped feeder 10 connects to the radiating patch 12 is 11.5 mm, and the distance w2 between the L-shaped feeder 10 and the radiating patch 12 is 5 mm. The width of the radiating patch 12 is g = 28 mm, the length m of the pair of branches 121 on the radiating patch 12 is 4 mm, the width n = 1.5 mm, and the isosceles right-angled side length ws = 4 mm of the pair of chamfers 122 on the radiating patch 12. The second metal floor 11 is a ring structure with a width w3 = 11 mm and an outer side length G = 62 mm.

[0055] The rectifier circuit 1 and the receiving antenna 2 are connected by an SMA connector to form a system.

[0056] The parameters used in this embodiment are shown in Table 3.

[0057] Table 3. Parameter list in Example 3 (mm)

[0058] la lb lc wa wb h1 h2 18 9 6 3 0.7 1.2 1.2 l1 l2 w1 w2 w3 ws s 24 11.5 2.8 5 11 4 0.5 m n g G L W 4 1.5 28 62 35 18

[0059] This invention defines the radio frequency power in the input rectifier circuit 1 as P. RF The solar power input to rectifier circuit 1 is defined as P. solar The output power at the output load 74 is defined as P.DC Its rectification efficiency is PCE:

[0060]

[0061] The technical effects of the present invention will be further explained below with reference to simulation experiments:

[0062] 1. Simulation conditions and content:

[0063] 1.1 The rectifier circuit in Example 2 was simulated using the commercial simulation software ADS2020 at an RF input power of -15dBm and different illumination voltages. The S-parameter curves of the rectifier circuit are shown below. Figure 3 As shown.

[0064] 1.2 The rectifier circuit in Example 2 was simulated using the commercial simulation software ADS2020 when the RF input energy and the light input energy were the same. The conversion efficiency curve of the rectifier circuit is shown in the figure below. Figure 4 As shown;

[0065] 1.3 The S-parameters of the receiving antenna in Example 2 were simulated and calculated using the commercial simulation software HFSS19.0, such as... Figure 5 As shown.

[0066] 1.4 The far-field radiation pattern of the receiving antenna in Example 2 was simulated and calculated using the commercial simulation software HFSS19.0. The XOZ plane radiation pattern of the receiving antenna is shown below. Figure 6a As shown, the YOZ plane radiation pattern of the receiving antenna is as follows. Figure 6b As shown.

[0067] 1.5 The axial ratio bandwidth of the receiving antenna in Example 2 was simulated and calculated using the commercial simulation software HFSS19.0. The axial ratio bandwidth diagram of the receiving antenna is shown below. Figure 7 As shown.

[0068] 2. Simulation results:

[0069] Reference Figure 3 The horizontal axis represents frequency, and the vertical axis represents reflection coefficient S11. With S11≤-10dB as the standard, the rectifier circuit in this embodiment can achieve impedance matching under different light voltage conditions, indicating that the rectifier circuit works in a state of impedance matching with the 50Ω port and can achieve maximum power transmission.

[0070] Reference Figure 4 The horizontal axis represents the simultaneous injection of the same power into the rectifier circuit by solar energy and radio frequency energy, with the power varying within the range of -20dBm to 0dBm. The rectification efficiency PCE ≥ 50% indicates that the rectifier circuit still has high rectification efficiency characteristics under low input power.

[0071] Reference Figure 5 The horizontal axis represents frequency, and the vertical axis represents reflection coefficient S11. With S11≤-10dB as the standard, the impedance bandwidth of the receiving antenna in this embodiment is 1.84-2.81GHz, which has good port matching characteristics.

[0072] Reference Figure 6a and Figure 6b The maximum radiation direction gain of the receiving antenna in Example 2 is 4.0 dBi, and the radiation is bidirectional, indicating that the receiving antenna has the ability to receive bidirectional incoming waves in space.

[0073] Reference Figure 7 The horizontal axis represents frequency, and the vertical axis represents axial ratio. With an axial ratio ≤ -3dB as the standard, the axial ratio bandwidth of the receiving antenna in this embodiment is 2.33-2.78GHz.

[0074] The above description is merely a specific example of the present invention and does not constitute any limitation on the present invention. Obviously, those skilled in the art, after understanding the content and principles of the present invention, may make various modifications and changes in form and detail without departing from the principles and structure of the present invention. However, these modifications and changes based on the ideas of the present invention are still within the scope of protection of the claims of the present invention.

Claims

1. A hybrid energy harvester based on radio frequency and solar energy, comprising: The rectifier circuit (1) and the receiving antenna (2) are composed of a first dielectric substrate (3), a first metal ground plane (4), a matching circuit (5), a bias circuit (6), a rectifier topology (7), and a grounding post (8). The microstrip portion of the rectifier circuit (1) is printed on the upper surface of the first dielectric substrate (3), and the first metal ground plane (4) is printed on the lower surface. Both are made of copper. The matching circuit (5) is composed of a rectangular microstrip line (51) connected in parallel with a short-circuit stub (52), and the end of the rectangular microstrip line (51) is connected in series with a tapered microstrip line (53). The short-circuit stub (52) is connected to the first metal ground plane (4) through the first grounding post (81). The matching circuit (5), the bias circuit (6), the rectifier topology (7), and the grounding post (8) are all made of copper. The circuit (6) and the rectifier topology (7) are connected by a microstrip line, and the components contained in the bias circuit (6) and the rectifier topology (7) are also connected by a microstrip line; the grounding post (8) includes a first grounding post (81), a second grounding post (82), a third grounding post (83), a fourth grounding post (84) and a fifth grounding post (85); the bias circuit (6) is composed of a photodiode (61) connected in parallel with a bypass capacitor (62) and then connected in series with a choke inductor (63), the other end of the photodiode (61) is connected to the first metal ground (4) through the second grounding post (82), and the bypass capacitor (62) is connected to the first metal ground (4) through the third grounding post (83).

2. The hybrid energy harvester based on radio frequency and solar energy according to claim 1, characterized in that: The receiving antenna (2) includes a second dielectric substrate (9), an L-shaped feed (10), a second metal ground plane (11), and a radiating patch (12). The L-shaped feed (10), the second metal ground plane (11), and the radiating patch (12) of the receiving antenna (2) are printed on the upper surface of the second dielectric substrate (9). All of them are made of copper. The L-shaped feed (10) and the second metal ground plane (11) form a coplanar waveguide structure. The radiating patch (12) is a square patch with a pair of stubs (121) and a pair of chamfers (122) on it.

3. A hybrid energy harvester based on radio frequency and solar energy according to claim 1, characterized in that: In the matching circuit (5), the width wa of the wider end of the rectangular microstrip line (51), the short-circuit stub (52) and the tapered microstrip line (53) is 2mm-3mm, and the width wb of the narrower end of the tapered microstrip line (53) is 0.3mm-0.7mm; the length la of the rectangular microstrip line (51) is 15mm-18mm, the length lb of the short-circuit stub (52) is 6mm-9mm, and the length lc of the tapered microstrip line (53) is 4mm-6mm.

4. A hybrid energy harvester based on radio frequency and solar energy according to claim 1, characterized in that: The rectifier topology (7) consists of a first filter capacitor (71), a rectifier diode (72), a second filter capacitor (73), and an output load (74). The second filter capacitor (73) is connected to the first metal ground plane (4) via a fourth grounding post (84), and the output load (74) is connected to the first metal ground plane (4) via a fifth grounding post (85). The capacitance value C2 of the first filter capacitor (71) is 10pF-100pF, and the package is 0201. The capacitance value C3 of the second filter capacitor (73) is 10pF-100pF, and the package is 0201. The rectifier diode (72) is a Schottky diode or a varactor diode. The output load (74) uses an integrated resistor with a 0201 package and a resistance value R. load The range is 2000Ω-10000Ω.

5. A hybrid energy harvester based on radio frequency and solar energy according to claim 1, characterized in that: The length L of the rectifier circuit (1) is 28mm-35mm and the width W is 14mm-18mm.

6. A hybrid energy harvester based on radio frequency and solar energy according to claim 1, characterized in that: The diameter d1 of the first grounding post (81) is 0.7mm-1.5mm, and the diameter d2 of the second grounding post (82), third grounding post (83), fourth grounding post (84) and fifth grounding post (85) is between 0.2mm-0.4mm.

7. A hybrid energy harvester based on radio frequency and solar energy according to claim 2, characterized in that: A groove structure is provided between the L-shaped feeder (10) and the metal floor (11), with a groove width s of 0.1mm-0.5mm. A radiating patch (12) is fed into the end of the L-shaped feeder (10). The radiating patch (12) is a square patch with a pair of branches (121) and a pair of chamfers (122). The length l1 of the L-shaped feeder (10) is 20mm-24mm, the width w1 of the L-shaped feeder (10) is 2.2mm-2.8mm, and the length l2 where the L-shaped feeder (10) connects to the radiating patch (12) is 8.5mm-11.5m. The distance w2 between the L-shaped feed (10) and the radiating patch (12) is 4mm-5mm; the width g of the radiating patch (12) is 24mm-28mm; the length m of a pair of branches (121) on the radiating patch (12) is 2mm-4mm; the width n is 0.5mm-1.5mm; the isosceles right-angled side length ws of a pair of chamfered corners (122) on the radiating patch (12) is 2mm-4mm; the second metal floor (11) is a ring structure with a width w3 of 9mm-11mm and an outer side length G of 58mm-62mm.

8. A hybrid energy harvester based on radio frequency and solar energy according to claim 1, characterized in that: The thickness h1 of the first dielectric substrate (3) is 0.6mm-1.2mm, the thickness h2 of the second dielectric substrate (9) is 0.6mm-1.2mm, the material of the first dielectric substrate (3) and the second dielectric substrate (9) is F4B, the dielectric constant is 2.2, and the loss tangent is 0.

001.

9. A hybrid energy harvester based on radio frequency and solar energy according to claim 1, characterized in that: The photodiode (61) is model BPW 34 S_EN, the bypass capacitor (62) has a capacitance value C1 of 10pF-20pF and a package of 0201, and the choke inductor (63) has an inductance value L1 of 30nH-60nH and a package of 0201.

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