A multi-axis helical antenna array for RF energy harvesting

Abstract

The present invention belongs to the field of radio frequency energy collection, and specifically is a multi-axis helical antenna array for radio frequency energy collection, which is used to realize wide-band radio frequency signal reception, including: a dielectric substrate, a feed line, a radiation patch, a ground plate and an impedance matching adjustment section. The feeding method adopts multi-coaxial line coaxial feeding, the radiation patch adopts four coaxial double helical shapes, and the four coaxial double helical shapes are symmetrically distributed on the dielectric substrate on the front of the antenna, the impedance matching adjustment section is arranged on the upper and lower edges of the dielectric substrate, and the ground plate on the back of the antenna adopts a metal plate of the same size as the dielectric substrate and with a slit in the middle. The antenna is designed based on the helical antenna, with a relatively simple structure and moderate size. It can work in a wide frequency band of 0.7GHz-2.6GHz, has good frequency characteristics, is easy to use and has low cost.

Description

Technical Field

[0001] The invention belongs to the technical field of radio frequency energy collection and relates to a multi-axis helical antenna array for radio frequency energy collection. Background Art

[0002] With the continuous development of wireless communication technology, there are more and more RF transmission sources, including communication base stations, TV and radio signal transmission stations, wireless routers, etc. It has become a trend to use RF energy to power some low-power circuits. Using the collected RF energy to power devices can reduce the demand for batteries, and can also charge devices with batteries to extend the working time of the devices.

[0003] The receiving antenna is one of the core parts of the RF energy harvesting system. It is used to receive RF signals from the surrounding environment, convert the RF signals into DC through the rectifier circuit and boost it, and store energy to power the load. The current problems with the design of the receiving antenna of the RF energy harvesting system are:

[0004] (1) The receiving antenna has poor effect and a single operating frequency band. The antenna working in the low frequency band is large in size, and the high frequency antenna has a short receiving distance.

[0005] (2) Different antennas operate in different frequency bands and require different impedance matching circuits, which causes all matching circuits in the multi-frequency antenna system to operate simultaneously. The circuits affect each other, resulting in a decrease in reception effect. Summary of the invention

[0006] The purpose of the present invention is to design a multi-axis helical antenna array for radio frequency energy collection to achieve wide-band radio frequency signal reception.

[0007] The present invention is realized by the following technical scheme: a multi-axis helical antenna array for radio frequency energy collection, comprising a dielectric substrate, a feed line, a radiation patch, a ground plate and an impedance matching adjustment section, wherein the feeding method adopts multi-coaxial line coaxial feeding, the radiation patch adopts four coaxial double helical shapes, and the four coaxial double helical shapes are symmetrically distributed on the dielectric substrate on the front side of the antenna, the impedance matching adjustment section is arranged at the upper and lower edges of the dielectric substrate, and the ground plate on the back side of the antenna adopts a metal plate of the same size as the dielectric substrate and with a slit in the middle.

[0008] Preferably, the impedance matching adjustment section is four metal patches located above and below the dielectric substrate and extending to the edge.

[0009] Preferably, the four metal patches are symmetrically distributed about the dielectric substrate.

[0010] Preferably, the center of each coaxial double-helix-shaped radiation patch is a metal axis that penetrates the dielectric substrate and connects to the ground plate.

[0011] Preferably, the center of the dielectric substrate is a coaxial feed line, and the coaxial feed line is located at the center of a square formed by four metal axes as vertices.

[0012] Preferably, the middle portion of the grounding plate is an open concave slot with four metal axes as vertices.

[0013] Preferably, the center position of the ground plate is a lumped port.

[0014] The beneficial effects of the present invention are:

[0015] The present invention designs a multi-axis helical antenna array for radio frequency energy collection. The antenna is designed based on a helical antenna, has a relatively simple structure, and a moderate size. It can operate in a wide frequency band of 0.7GHz-2.6GHz, has good frequency characteristics, is easy to use, and has low cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 A schematic diagram showing the front structure of a multi-axis helical antenna array for radio frequency energy harvesting;

[0017] Figure 2 A schematic diagram of the back structure of a multi-axis helical antenna array for radio frequency energy harvesting;

[0018] Figure 3 A schematic diagram showing the side structure of a multi-axis helical antenna array for radio frequency energy harvesting;

[0019] Figure 4 A graph showing the relationship between S11 return loss and frequency for a multi-axis helical antenna array used for RF energy harvesting. DETAILED DESCRIPTION

[0020] The present invention will be further described below using the accompanying drawings and specific implementation methods.

[0021] The present invention provides a technical solution: a multi-axis helical antenna array for radio frequency energy collection, comprising a dielectric substrate, a feed line, a radiation patch, a ground plate and an impedance matching adjustment section, wherein a feeding method adopts multi-coaxial line coaxial feeding, the radiation patch adopts four coaxial double helical shapes, and the four coaxial double helical shapes are symmetrically distributed on the dielectric substrate on the front side of the antenna, the impedance matching adjustment section is arranged at the upper and lower edges of the dielectric substrate, and the ground plate on the back side of the antenna adopts a metal plate which is the same size as the dielectric substrate and has a slit in the middle.

[0022] The four coaxial double-helix-shaped radiation patches on the front are symmetrically distributed on the dielectric substrate. The four metal patches on the upper and lower sides of the front extending to the edge of the dielectric substrate serve as the impedance matching adjustment section of the antenna to broaden the frequency band of the antenna. When the impedance characteristics change due to factors such as processing errors during the antenna design process and after processing, appropriate adjustments can be made. Preferably, the four metal patches are symmetrically distributed about the dielectric substrate. The center of each coaxial double-helix-shaped radiation patch is a metal axis that runs through the dielectric substrate and connects to the ground plate. The center of the dielectric substrate is a coaxial feed line, and at the center position of the square formed by the four metal axes as vertices, the upper and lower surfaces have good feeding and are conducive to the realization of electromagnetic weak coupling with broadband characteristics. The back of the antenna is the antenna ground plate. In the middle of the ground plate is an open concave slit with four metal axes as vertices, which gives the antenna a higher degree of freedom and can form resonant excitation modes of different directions and sizes within a wide frequency band, thereby facilitating the realization of broadband excitation.

[0023] Example: Refer to Figure 1 A multi-axis helical antenna array for radio frequency energy collection of the present invention includes: a dielectric substrate 1, four coaxial double-helix-shaped radiation patches 2, 5, 9, 14 on the front of the antenna, four metal shafts 4, 6, 11, 12 passing through the dielectric substrate, impedance matching adjustment sections 3, 7, 10, 13 and a coaxial feed line 8 in the center of the dielectric substrate.

[0024] Reference Figure 2 The back of the antenna includes a ground plate 15, a concave slot 16 in the middle of the ground plate, and a lumped port 17.

[0025] Reference Figure 1 , Figure 2 , Figure 3The dielectric substrate 1 is FR4 with a thickness of 1.6mm, a length of 10cm, and a width of 9.1cm. The four coaxial double-helix-shaped radiation patches 2, 5, 9, and 14 on the front are symmetrically distributed on the dielectric substrate. The patch spacing of the coaxial double-helix-shaped radiation patches 2, 5, 9, and 14 is L1 = 4mm, the patch width K1 = 0.5mm, and the number of rotations is 4. The four metal shafts 4, 6, 11, and 12 that penetrate the dielectric substrate are cylinders with a radius r = 1mm and a height h = 1.635mm. The impedance matching adjustment sections 3, 7, 10, and 13 have a length L2 = 19mm and a width K2 = 0.5mm of the metal patch. The coaxial feed line 8 at the center of the dielectric substrate is located at the center of the square formed by the four metal shafts 4, 6, 11, and 12 that penetrate the dielectric substrate, so that the upper and lower surfaces have good feeding and are conducive to achieving electromagnetic weak coupling with broadband characteristics. The ground plane 15 on the back of the antenna is the same size as the dielectric substrate 1. It is an open concave slit 16 composed of four square patches with metal shafts 4, 6, 11, and 12 that penetrate the substrate as vertices. The slit width K3 of the concave structure 16 is 1mm. The center is the lumped port 17 of the antenna, which is a square with a side length of 7mm. This structure gives the antenna a higher degree of freedom and can form resonant excitation modes of different directions and sizes in a wide frequency band, which is conducive to the realization of broadband excitation. The copper coating thickness of all patches is 0.035mm.

[0026] Reference Figure 4 The antenna in this embodiment is simulated using Ansoft HFSS simulation software. The simulation results show that the broadband antenna can effectively collect wide-band RF energy from 0.7 GHz to 2.6 GHz, covering RF signals in lower frequency bands. It has the advantages of high bandwidth, simple structure, strong operability, and low production cost.

[0027] The above only expresses the preferred embodiments of the present invention, and the description is relatively specific and detailed, but it cannot be understood as limiting the scope of the patent of the present invention. It should be pointed out that for ordinary technicians in this field, several modifications, improvements and substitutions can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be based on the attached claims.

Claims

1. A multi-axis helical antenna array for radio frequency energy harvesting, characterized in that: The antenna comprises a dielectric substrate, a feed line, a radiation patch, a grounding plate and an impedance matching adjustment section. The feeding method adopts multi-coaxial coaxial feeding. The radiation patch adopts four coaxial double helical shapes, and the four coaxial double helical shapes are symmetrically distributed on the dielectric substrate on the front of the antenna. The impedance matching adjustment section is arranged on the upper and lower edges of the dielectric substrate. The grounding plate on the back of the antenna adopts a metal plate of the same size as the dielectric substrate and with a slit in the middle. The center of each coaxial double-helix-shaped radiation patch is a metal axis that penetrates the dielectric substrate and connects to the ground plate; The center of the dielectric substrate is a coaxial feed line, and the coaxial feed line is located at the center of a square formed by four metal axes as vertices; The middle part of the grounding plate is an open concave slot with four metal axes as vertices.

2. The antenna array according to claim 1, characterized in that: The impedance matching adjustment section is four metal patches located above and below the dielectric substrate and extending to the edge.

3. The antenna array according to claim 2, characterized in that: The four metal patches are symmetrically distributed with respect to the dielectric substrate.

4. The antenna array according to claim 1, characterized in that: The center position of the ground plate is a lumped port.

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