A liquid metal based frequency adaptive radio frequency energy harvester

Abstract

The application discloses a frequency adaptive radio frequency energy collector based on liquid metal, which comprises a frequency reconfigurable antenna connected with a broadband rectifier circuit and a stretching device, a microcontroller connected with the broadband rectifier circuit and a motor, and the motor connected with the stretching device to drive the stretching device and further drive the frequency reconfigurable antenna to stretch; wherein the broadband rectifier circuit is used for converting radio frequency energy output by the frequency reconfigurable antenna into direct current energy; the microcontroller is used for detecting output voltage of the broadband rectifier circuit in real time; the microcontroller is also used for providing a signal to the motor to control rotation of the motor; the stretching device is used for changing the length of the frequency reconfigurable antenna by stretching; the frequency reconfigurable antenna is composed of liquid metal and is stretchable, and is used for changing the working frequency of the frequency reconfigurable antenna according to the change of the length of the frequency reconfigurable antenna, so as to change the working frequency of the radio frequency energy collector. The application can change the working frequency according to the change of the frequency in the external environment, and realizes efficient radio frequency-direct current conversion.

Description

Technical Field

[0001] This invention belongs to the field of microwave technology, specifically relating to a frequency-adaptive radio frequency energy harvester based on liquid metal. Background Technology

[0002] Radio frequency (RF) energy harvesting technology has attracted considerable attention because it captures radio frequency energy from the surrounding environment and converts it into direct current (DC) to power low-power sensors in the Internet of Things (IoT). Unlike other environmental energy harvesting technologies such as wind and solar power, RF energy harvesting relies on specific frequency bands because RF energy primarily originates from communication and local area network (LAN) bands, such as LTE, Wi-Fi, and 5G. For effective harvesting of electromagnetic energy from the environment, the operating frequency of the RF energy harvester must match the frequency of the RF energy in the environment. Unfortunately, in a given environment, RF energy relying on external RF sources (such as Wi-Fi, 5G, and LTE base stations) is often distributed across one or two frequency bands. This means that RF energy harvesters operating at fixed frequencies may fail to function properly after environmental changes. Summary of the Invention

[0003] The purpose of this invention is to provide a frequency-adaptive radio frequency energy harvester based on liquid metal, which can change its operating frequency according to changes in the frequency of the external environment, thereby achieving efficient radio frequency-to-DC conversion.

[0004] To solve the above-mentioned technical problems, the technical solution of the present invention is as follows: a frequency-adaptive radio frequency energy harvester based on liquid metal, comprising a frequency-reconfigurable antenna, a broadband rectifier circuit, a microcontroller, a motor, and a stretching device. The frequency-reconfigurable antenna is connected to both the broadband rectifier circuit and the stretching device. The microcontroller is connected to both the broadband rectifier circuit and the motor. The motor is connected to the stretching device to drive the stretching device, thereby stretching the frequency-reconfigurable antenna.

[0005] A broadband rectifier circuit is used to convert the radio frequency energy output from a frequency-reconfigurable antenna into DC energy.

[0006] The microcontroller is used to detect the output voltage of the broadband rectifier circuit in real time; it is also used to provide signals to the motor and control the motor rotation.

[0007] A stretching device for changing the length of a frequency-reconfigurable antenna by stretching it.

[0008] A frequency-reconfigurable antenna, made of liquid metal, is stretchable and can change its operating frequency according to changes in its length, thereby changing the operating frequency of the radio frequency energy harvester.

[0009] The operating frequency of the broadband rectifier circuit covers the operating frequency of the reconfigurable antenna.

[0010] The stretching device is equipped with a clamp that holds the frequency reconfigurable antenna. Driven by a motor, the clamp stretches the frequency reconfigurable antenna to change its length.

[0011] The motor is a stepper motor. The microcontroller provides a square wave signal to the stepper motor to control its rotation.

[0012] When the input frequency of the external environment changes to a point where it no longer matches the current operating frequency of the frequency reconfigurable antenna, the microcontroller detects a decrease in the output voltage of the broadband rectifier circuit. The microcontroller then controls the motor to drive the stretching device, causing the frequency reconfigurable antenna to return to its original length and gradually stretch from the original length to a preset length, thereby changing the operating frequency of the radio frequency energy harvester.

[0013] When the length of the frequency-reconfigurable antenna changes, the microcontroller detects and compares the output voltage of the broadband rectifier circuit in real time and records the changed length of the frequency-reconfigurable antenna. After one cycle of stretching the frequency-reconfigurable antenna, the microcontroller obtains the length of the frequency-reconfigurable antenna corresponding to the maximum value of the output voltage of the broadband rectifier circuit, and controls the motor to stretch the frequency-reconfigurable antenna to the length corresponding to the maximum value of the output voltage, thereby realizing the adaptive adjustment of the operating frequency of the radio frequency energy harvester. When the frequency-reconfigurable antenna is stretched from its original length to the preset length, it is considered that one cycle is completed.

[0014] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0015] This invention can change its operating frequency according to changes in the frequency of the external environment, thereby achieving efficient radio frequency to DC conversion. Attached Figure Description

[0016] Figure 1 This is a schematic diagram illustrating signal transmission and function according to an embodiment of the present invention;

[0017] Figure 2 This is a schematic diagram of the rectifier circuit structure in an embodiment of the present invention. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0019] The technical solution of the present invention is a frequency adaptive radio frequency energy harvester based on liquid metal, including a stretchable frequency reconfigurable antenna, a broadband rectifier circuit, a microcontroller, a stepper motor, and a stretching device.

[0020] The stretchable frequency-reconfigurable antenna is made of liquid metal as a conductor, and its operating frequency can be changed by controlling the length of the antenna.

[0021] The operating frequency band of the broadband rectifier circuit basically matches the operating frequency band of the antenna, and its function is to convert the radio frequency energy received by the antenna into DC energy.

[0022] The microcontroller has two functions: first, to detect the output voltage of the rectifier circuit in real time; and second, to provide a square wave signal to the stepper motor to control its rotation.

[0023] The stretching device has clamps that can hold the antenna in place. By controlling the movement of the stretching device, the length of the antenna can be changed, thereby changing the antenna's operating frequency.

[0024] like Figure 1 The diagram illustrates the signal transmission and function of an embodiment of the present invention. When the external frequency changes, it no longer matches the antenna's operating frequency, causing a decrease in the output voltage of the rectifier circuit. The microcontroller detects this decrease in the rectifier circuit's output voltage and indirectly controls the stretching device by controlling the stepper motor, causing the antenna to stretch from its initial state, thereby changing the antenna's operating frequency. Simultaneously, the microcontroller continuously monitors and compares the rectifier circuit's output voltage and records the antenna's position. After one cycle of antenna stretching, the microcontroller obtains the antenna position corresponding to the maximum value of the rectifier circuit's output voltage and controls the stepper motor to bring the antenna to that position, thus achieving the frequency adaptive function of this RF energy harvester.

[0025] like Figure 2 The diagram shows a broadband rectifier circuit according to the present invention, which converts radio frequency (RF) energy received by the antenna into DC energy. The rectifier circuit includes two rectifier diodes D1 and D2 for converting RF energy into DC energy; two inductors L1 and L2 and a capacitor C for preventing RF energy from passing through the load R; and six fan-shaped stubs for impedance matching, the operating frequency of the circuit can be changed by adjusting the length of the fan-shaped stubs.

[0026] This invention can change its operating frequency according to changes in the frequency of the external environment, thereby achieving efficient radio frequency to DC conversion.

[0027] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A frequency-adaptive radio frequency energy harvester based on liquid metal, characterized in that, The system includes a frequency-reconfigurable antenna, a broadband rectifier circuit, a microcontroller, a motor, and a stretching device. The frequency-reconfigurable antenna is connected to both the broadband rectifier circuit and the stretching device. The microcontroller is connected to both the broadband rectifier circuit and the motor. The motor is connected to the stretching device to drive the stretching device, thereby stretching the frequency-reconfigurable antenna. A broadband rectifier circuit is used to convert the radio frequency energy output from a frequency-reconfigurable antenna into DC energy. The microcontroller is used to detect the output voltage of the broadband rectifier circuit in real time; it is also used to provide signals to the motor and control the motor rotation. A stretching device for changing the length of a frequency-reconfigurable antenna by stretching it. A frequency-reconfigurable antenna, made of liquid metal, is stretchable and can change its operating frequency according to changes in its length, thereby changing the operating frequency of the radio frequency energy harvester. When the input frequency of the external environment changes to the point that it no longer matches the current operating frequency of the frequency reconfigurable antenna, the microcontroller detects the decrease in the output voltage of the broadband rectifier circuit. The microcontroller then controls the motor to drive the stretching device, causing the frequency reconfigurable antenna to return from its current length to its original length and gradually stretch from its original length to a preset length, thereby changing the operating frequency of the radio frequency energy harvester. When the length of the frequency-reconfigurable antenna changes, the microcontroller detects and compares the output voltage of the broadband rectifier circuit in real time and records the changed length of the frequency-reconfigurable antenna. After one cycle of stretching the frequency-reconfigurable antenna, the microcontroller obtains the length of the frequency-reconfigurable antenna corresponding to the maximum value of the output voltage of the broadband rectifier circuit, and controls the motor to stretch the frequency-reconfigurable antenna to the length corresponding to the maximum value of the output voltage, thereby realizing the adaptive adjustment of the operating frequency of the radio frequency energy harvester. When the frequency-reconfigurable antenna is stretched from its original length to the preset length, it is considered that one cycle is completed.

2. The frequency-adaptive radio frequency energy harvester based on liquid metal according to claim 1, characterized in that, The operating frequency of the broadband rectifier circuit covers the operating frequency of the reconfigurable antenna.

3. A frequency-adaptive radio frequency energy harvester based on liquid metal according to claim 1, characterized in that, The stretching device is equipped with a clamp that holds the frequency reconfigurable antenna. Driven by a motor, the clamp stretches the frequency reconfigurable antenna to change its length.

4. A frequency-adaptive radio frequency energy harvester based on liquid metal according to claim 1, characterized in that, The motor is a stepper motor. The microcontroller provides a square wave signal to the stepper motor to control its rotation.

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