Door aperture electromagnetic metasurface and electromagnetic metasurface intelligent door

Abstract

The invention discloses a door aperture electromagnetic metasurface and an electromagnetic metasurface intelligent door. The electromagnetic metasurface intelligent door comprises an electromagnetic metasurface regulation and control layer, an intelligent sensing and interaction layer, a communication and energy management layer and a safety and structure layer. Wherein the safety and structure layer is located on the outermost side, the electromagnetic metasurface regulation and control layer is embedded into the inner side of the safety and structure layer, the intelligent sensing and interaction layer is located on the inner side of the metasurface layer and is close to the middle layer of the door body, and the communication and energy management layer is distributed in a scattered mode. The intelligent sensing and interaction layer connects a signal flow to the electromagnetic metasurface regulation and control layer, the communication and energy management layer transmits the signal flow to the electromagnetic metasurface regulation and control layer, and the metasurface regulation and control communication and energy management layer is in wireless power supply connection with an energy storage system. According to the invention, main functions of the door lock are realized through the metasurface; the system has the characteristics of high integration, dynamic programmable safety and passive low-power-consumption operation.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of intelligent electrical appliances controlled by electromagnetic metasurfaces, and particularly relates to a door aperture electromagnetic metasurface and an electromagnetic metasurface intelligent door. BACKGROUND

[0002] The existing intelligent door lock mainly relies on fingerprint, face recognition, password or physical key and the like. Although these technologies can provide convenience to a certain extent, there are still security limitations such as brute force cracking, fingerprint copying and secret leakage. For example, fingerprint recognition may be threatened by fingerprint forgery or breakthrough of biometric technology, and password input is at risk of password leakage or brute force cracking.

[0003] At the same time, the existing intelligent door lock has weak anti-interference ability, and the wireless communication module is prone to malfunction due to electromagnetic interference. In addition, the traditional intelligent door function is relatively single, only having the basic functions of locking and unlocking. In addition, the energy consumption and endurance of the traditional intelligent door are also problems, and the battery needs to be replaced regularly, and low power may cause failure. SUMMARY

[0004] In order to overcome the deficiencies of the prior art, the purpose of the present application is to provide a door aperture electromagnetic metasurface and an electromagnetic metasurface intelligent door, which realizes the main functions of the door lock through the metasurface; and has the characteristics of high integration, dynamic programmable security and passive low-power operation.

[0005] In order to achieve the above purpose, the technical scheme adopted by the present application is:

[0006] A door aperture electromagnetic metasurface, comprising a transmitting coil and a receiving device, the transmitting coil is arranged inside the transmitting device and used for generating an alternating magnetic field;

[0007] The receiving device comprises a receiving coil and a rectifier circuit, the receiving coil is arranged opposite to the transmitting coil and closely attached to both sides of the door aperture electromagnetic field surface, so that the two are arranged opposite to each other to form magnetic coupling; and is used for receiving the alternating magnetic field and inducing a voltage signal;

[0008] The rectifier circuit converts the induced alternating current into direct current for use by the load;

[0009] When a person approaches the door aperture area, the door aperture electromagnetic metasurface structure embedded in both sides of the door frame starts a low-power monitoring mode and triggers transmission.

[0010] The transmitting coil has a spiral structure, and the transmitting coil is connected to a driving circuit; the driving circuit is arranged inside the transmitting device and is electrically connected to the receiving coil in a PCB or modular arrangement form to receive an alternating current signal and generate a high-frequency alternating magnetic field in space;

[0011] The driving circuit comprises a high-frequency oscillation module, a power amplification module and a resonance matching network.

[0012] The high-frequency oscillation module is used to generate a high-frequency alternating electric signal of a preset frequency, the power amplification module amplifies the signal and outputs the amplified signal to the transmitting coil, and the resonance matching network is used to realize impedance matching between the driving circuit and the transmitting coil.

[0013] An electromagnetic metasurface intelligent door comprises an electromagnetic metasurface regulation and control layer, an intelligent sensing and interaction layer, a communication and energy management layer and a safety and structure layer.

[0014] The electromagnetic metasurface regulation and control layer is located at the innermost layer, the intelligent sensing and interaction layer and the communication and energy management layer are sequentially arranged at the upper and lower ends of the electromagnetic metasurface regulation and control layer, and the safety and structure layer is arranged around the outer sides of the layers.

[0015] The intelligent sensing and interaction layer connects a signal stream to the electromagnetic metasurface regulation and control layer, the communication and energy management layer transmits a signal stream to the electromagnetic metasurface regulation and control layer, and the metasurface regulation and control communication and energy management layer is connected to an energy storage system through wireless power supply.

[0016] The door body itself has a relatively small width, the safety and structure layer surrounds the core module, the intelligent sensing and interaction layer is located at the position of the door body and has little influence on the function, and a signal acquisition end is located at a millimeter wave radar module.

[0017] The electromagnetic metasurface regulation and control layer, the intelligent sensing and interaction layer and the communication and energy management layer are arranged based on a door aperture electromagnetic metasurface; and the safety and structure layer is used to provide mechanical strength of the door body and plays a supporting and protecting role, and the safety and structure layer is a metal material shell.

[0018] The electromagnetic metasurface regulation and control layer is applied to reflection, absorption, transmission, reconstruction and beam forming of incident electromagnetic waves.

[0019] The electromagnetic metasurface regulation and control layer comprises a door aperture electromagnetic metasurface and a signal processing and identity recognition module; the door aperture electromagnetic metasurface comprises a transmitting device and a receiving device of reflected signals.

[0020] When the transmitting signal reaches a human body, reflected electromagnetic waves are generated and returned to the door aperture electromagnetic metasurface, which is incident electromagnetic waves relative to the door aperture electromagnetic metasurface.

[0021] Through the door aperture electromagnetic metasurface in the electromagnetic metasurface regulation and control layer, electromagnetic waves of specific frequency and waveform are transmitted to the human body, and the electromagnetic waves produce physical interaction effects with human tissues, organs and body fluids.

[0022] At this time, reflected signals are generated, which are incident electromagnetic waves.

[0023] The receiving device of the reflected signal is also arranged in the door frame, and the receiving device has an array type electromagnetic metasurface receiving antenna structure for collecting electromagnetic waves reflected from each tissue of the human body; the signal processing and identity recognition module realizes non-contact identity recognition by pre-processing, feature extraction and pattern recognition of the target reflected echo signal; the signal processing and identity recognition module includes an FPGA or an embedded processor, and target feature information is obtained by filtering, denoising and normalizing the original echo signal, the extracted multi-dimensional biological feature vector is compared with the registered identity template in the preset database, and pattern recognition is completed.

[0024] The door frame is embedded with a door aperture electromagnetic metasurface on both sides, and the door aperture electromagnetic metasurface further includes a plurality of electromagnetic unit arrays, and each electromagnetic unit array includes a plurality of periodically arranged metal resonance units, and each metal resonance unit includes an adjustable charge carrier component (such as a PIN diode, a varactor diode), a bias circuit network, an antenna unit and an electromagnetic response control;

[0025] By combining the antenna unit with the bias circuit network, the adjustable charge carrier component and the electromagnetic response control, the electromagnetic metasurface control layer dynamically controls the phase of the metasurface; based on the electromagnetic metasurface control layer, the electromagnetic metasurface control layer is applied to the health sensing door aperture metasurface to emit electromagnetic waves, which are reflected by the human body and received by the millimeter wave radar of the intelligent sensing and interaction layer, and by dynamically controlling the phase of the metasurface, multi-angle scanning is realized to complete signal transmission and modulation.

[0026] The method steps include:

[0027] (1) The reflected signal receiving module collects the I / Q signal reflected by the target;

[0028] (2) Band-pass filtering and time-frequency transformation are performed to obtain a micro-Doppler spectrum diagram;

[0029] (3) The signal processing and identity recognition module models and recognizes the physiological characteristics of the target based on a support vector machine or a convolutional neural network;

[0030] (4) The recognition is output, and physiological characteristic parameters such as heart rate micro-vibration frequency, respiration frequency and body surface water content are extracted; if the physiological parameters of the target individual are abnormal, the system will issue a prompt on the display end, or send the abnormal data to the background system for remote health management.

[0031] The intelligent sensing and interaction layer is used for identifying user behavior and realizing intelligent interaction with the user; the intelligent sensing and interaction layer detects respiration by analyzing the Doppler shift caused by chest cavity micro-movement, and detects heart rate by analyzing the phase change caused by the pulsation of skin surface micro-vessels; the edge computing unit processes data in real time, and abnormal values are uploaded to a medical platform through 5G to complete analysis and early warning of human body data.

[0032] The intelligent sensing and interaction layer includes a millimeter wave radar module, a multispectral imaging, an infrared sensor, an electromagnetic wave echo feature analysis unit, and an interactive display screen;

[0033] Based on the door aperture electromagnetic metasurface in the intelligent sensing and interaction layer, when a person approaches the door aperture area, the door aperture electromagnetic metasurface structure embedded on both sides of the door frame starts a low-power monitoring mode; the system realizes target heat source and contour pre-detection through the cooperation of the infrared sensor and the multispectral imaging, and once a potential target is identified, the control unit (FPGA / MCU) changes the response state of the electromagnetic metasurface structure through the bias network to switch from the original standby mode to the authentication mode; the millimeter wave radar module starts high-frequency detection, continuously collects human micro-Doppler signals, and accurately captures micro-vibrations of more than 0.1 mm caused by breathing and heartbeat within a distance of 1.5 meters; the electromagnetic wave echo feature analysis unit performs edge AI processing on the echo signal to extract high-dimensional features such as the heartbeat frequency (0.8-2 Hz), micro-vibration amplitude, and phase trajectory of the target; at the same time, the multispectral imaging collects image information such as finger veins and facial micro-features based on near-infrared and visible light channels for cross-verification of identity; the infrared sensor assists in detecting the body surface temperature distribution for screening abnormal conditions, and the interactive display screen displays the results; if the authentication result is correct, the door lock is unlocked and a green light is prompted, and if the authentication is incorrect, an audible and visual alarm is sounded and the event is recorded;

[0034] When the user stands in front of the door, the human tissue produces multi-path reflection of electromagnetic waves, and after the receiving array obtains the reflected signal, the signal processing module extracts electromagnetic characteristic parameters such as the amplitude change, phase shift, and reflection distribution map of the reflected wave through fast Fourier transform (FFT), phase demodulation, and time delay analysis;

[0035] (1) The millimeter wave radar module and the electromagnetic wave echo feature analysis unit in the intelligent sensing and interaction layer cooperatively collect the I / Q signal data of the target reflection, and the infrared sensor monitors the approach of the person in real time to trigger the identification process;

[0036] (2) The collected original signal data is pre-processed through band-pass filtering, window function weighting, and noise suppression to improve the signal-to-noise ratio and system stability;

[0037] (3) Fast Fourier transform (FFT) is used to extract the reflection spectrum features from the pre-processed signal to analyze the response mode of the human tissue structure to electromagnetic waves of different frequencies;

[0038] (4) Phase demodulation processing is performed to extract the phase micro-variation of the reflected signal caused by heartbeat, breathing, and other small physiological movements to realize millimeter-level micro-displacement sensing;

[0039] (5) Combining time delay (ToA) and phase difference analysis techniques, the target is located with high precision, and the multi-path propagation path is reconstructed to realize behavior trajectory extraction and dynamic recognition.

[0040] (6) The obtained amplitude change map, phase shift map and spectrum map are combined into a reflectance map; in addition, the system can simultaneously acquire image data from the multispectral imaging module and infrared sensor to further enhance the recognition dimension and anti-interference capability, and can display the current recognition status and processing feedback in real time through the interactive display screen.

[0041] The system has a built-in human electromagnetic reflection model database. Each registered user needs to complete an "electromagnetic feature registration" at a standard location when using it for the first time. This means that the system records the comprehensive reflection feature template of the user under multi-frequency electromagnetic wave irradiation, including the corresponding reflection spectrum distribution, phase characteristics and physiological micro-motion information.

[0042] During the actual identification process, the system matches the multimodal sensing features of the current target with the templates in the database and determines whether it is an authorized user based on the set similarity threshold. If the comparison is successful, the system sends an unlocking control signal to the electronic door lock (which can be an electronic magnetic lock, electric tongue lock, or smart mechanical lock) through the GPIO interface, and the door lock unlocks automatically. If the comparison fails, the system does not send a control signal, the door lock remains closed, and the system automatically records the timestamp and relevant feature data of the identification failure event and records the identification log.

[0043] The communication and energy management layer is used to realize the system's wireless communication, power supply and energy dispatch; the communication and energy management layer includes a main control communication module, a radio frequency identification (RFID) read and write unit, a wireless power supply module, a battery pack and an energy storage module;

[0044] The aforementioned aperture electromagnetic metasurface is applied to the wireless power transmission transmitter. The aperture electromagnetic metasurface replaces the traditional fixed antenna array and has real-time adjustable radiation characteristics. It can dynamically optimize the beam direction and energy distribution according to environmental changes. The receiver is a reconfigurable reflective surface structure. The reflection parameters are adaptively adjusted by the control unit, thereby enhancing the energy harvesting efficiency under multipath paths.

[0045] When the terminal device is in standby mode, the receiver actively activates and sends a low-power beacon signal. The main control communication module receives and parses the positioning and identification information in the beacon, and drives the aperture electromagnetic metasurface to dynamically adjust the phase state of each unit according to the feedback signal, thereby realizing spatial positioning and directional beamforming of the target.

[0046] RFID reader / writer units can be used to verify the identity of receiving devices or identify access permissions, serving as one of the triggering criteria for energy transfer tasks;

[0047] The phase-regulated door aperture electromagnetic super surface emits a directional radio frequency beam to accurately project energy to a target receiving end; the receiving end converts the received electromagnetic wave energy into direct current through an integrated rectifier antenna structure to provide stable power support for local intelligent identification equipment, sensor nodes, etc.

[0048] This mechanism significantly improves the intelligence level and passive operation capability of the system, and reduces the dependence on traditional power supply lines and battery replacement.

[0049] In terms of energy management, the built-in wireless power supply module of the system is responsible for controlling the transmission power and frequency in conjunction with the door aperture electromagnetic super surface; the supporting battery pack and energy storage module are used to store excess energy, and in the case of unavailable or unstable wireless power supply, they serve as redundant power supply for identification and communication equipment to ensure system continuity and safety.

[0050] At the system scheduling level, the main control communication module alternately executes communication tasks and energy transmission tasks in the same frequency band by dividing microsecond or millisecond time slots, building a time division multiplexing full-duplex mechanism to effectively avoid frequency band interference and improve overall system operation efficiency. This mechanism further combines an adaptive time slot scheduling algorithm to dynamically adjust the time proportion of each task according to real-time communication load and energy demand, achieving fine allocation and maximum utilization of communication and power supply resources.

[0051] The beneficial effects of the present application are:

[0052] 1. The present application adopts a scheme combining millimeter wave communication and backscatter technology to simultaneously achieve energy transmission and data communication on a single radio frequency link; it realizes integrated energy communication, improves energy efficiency and data transmission efficiency.

[0053] The present application uses an intelligent beam forming algorithm to first establish an antenna array model, estimate the user positioning and beam through RFID and millimeter wave radar, predict the optimal beam direction and pitch angle, calculate the beam forming weight through the maximum signal-to-noise ratio, and real-time issue the weight vector calculated by the algorithm to the radio frequency front-end controller of the antenna array to dynamically adjust the phase and gain of the transmitted signal, achieving beam directivity control. The system can achieve an energy conversion efficiency of more than 85% within a range of 10 meters, while supporting 1Gbps level high-speed data transmission. Compared with the traditional intelligent door scheme that requires independent deployment of power supply and communication modules, the present application significantly reduces system complexity and solves the long-term power supply problem of Internet of Things terminal devices, enabling them to work stably in a battery-free or low-power state.

[0054] 2.The application adopts time division multiplexing full duplex architecture to realize dynamic adjustable wireless power transmission in 5.8GHz ISM frequency band.The system can automatically adjust the transmission power (10mW-1W adjustable) according to the device type (such as smart door lock, camera, sensor, etc.), and provide efficient power supply for different loads under the premise of meeting FCC / CE radio frequency radiation safety standards. Experiments show that this technology can extend the battery life of traditional smart door devices by 8-10 times, and support energy harvesting mode, which can still run continuously in the absence of external power supply.

[0055] 3.The application integrates millimeter wave radar and multi-spectral imaging system, which can complete high-precision biometric recognition in a non-contact range of 0.5-1.2 meters, including: three-dimensional face reconstruction (accuracy up to 0.1mm, anti-photo / mask attack), finger vein / palm vein recognition (based on near-infrared spectrum analysis), dynamic micro-expression living body detection (200fps high-speed sampling, anti-video fraud), through multi-modal fusion algorithm, the system reduces the false acceptance rate (FAR) to 10 -7 orders of magnitude, while supporting identity verification in complex scenarios such as wearing masks and glasses, and balancing high security and user experience.

[0056] 4.The application is equipped with a millimeter wave radar, which can non-invasively monitor multiple physiological indicators when the user is passing naturally, including: respiratory rate (±0.5 times / minute error), heart rate and variability (HRV) (medical-grade accuracy), body temperature anomaly detection (infrared thermal imaging assisted), the system built-in AI analysis engine can identify 7 types of health risks such as arrhythmia and apnea, and trigger a three-level early warning mechanism (automatically notify the user or medical institution through 5G / Bluetooth) according to the severity. This function is particularly suitable for scenarios such as elderly communities and hospital isolation areas, and realizes health management and security linkage. BRIEF DESCRIPTION OF DRAWINGS

[0057] Figure 1 It is a schematic diagram of the aperture size metasurface door structure of the application.

[0058] Among them, light blue is the safety and structure layer, orange is the metasurface regulation layer, dark blue is the communication and energy management layer, and red is the intelligent sensing and interaction layer.

[0059] Figure 2 It is a schematic diagram of the aperture size metasurface of the application.

[0060] Figure 3 It is a flow chart of wireless power transmission of electromagnetic metasurface of the application.

[0061] Figure 4 It is a flow chart of health sensing of electromagnetic metasurface of the application.

[0062] Figure 5 It is a flow chart of authentication of electromagnetic metasurface of the application. DETAILED DESCRIPTION

[0063] The application will be described in further detail below with reference to the drawings.

[0064] Unlike traditional door locks, the application introduces electromagnetic metasurfaces. Electromagnetic metasurfaces are artificially designed ultra-thin material structures that can manipulate the propagation characteristics of electromagnetic waves through precise microstructure arrangement and control. They can achieve reflection, refraction, and transmission of electromagnetic waves, and usually interact with incident electromagnetic waves to change their propagation direction and polarization state. In addition, electromagnetic metasurfaces can automatically adjust the propagation direction and intensity of signals according to environmental changes to achieve optimal signal transmission. When electromagnetic waves come into contact with biological bodies (such as skin or blood vessels), the electromagnetic properties of the biological bodies will cause changes in the propagation of electromagnetic waves. By monitoring changes in the reflection, transmission, and scattering of electromagnetic waves, the electromagnetic characteristics of the biological body can be inferred. Unlike existing contact verification methods, electromagnetic metasurface sensing technology works in a non-contact manner, and users do not need to actively touch any sensors or devices. The door lock will automatically sense the user's bioelectromagnetic characteristics and unlock.

[0065] Electromagnetic biometrics have high personalization because the bioelectromagnetic properties of each individual (such as skin, blood flow, etc.) are unique. The reflection and transmission characteristics of electromagnetic waves are closely related to the electromagnetic characteristics of each individual, making it difficult to fake or copy, greatly improving accuracy and security. Electromagnetic metasurfaces can also transmit data and energy simultaneously, supporting seamless wireless communication and energy supply. In particular, in Internet of Things devices that require high energy efficiency, electromagnetic metasurface technology can achieve simultaneous data communication and energy supply, optimizing resource usage. At the same time, electromagnetic metasurfaces can work stably in complex electromagnetic environments and even actively suppress interference. The above characteristics provide a preliminary theoretical basis for the application of electromagnetic metasurfaces in intelligent door locks.

[0066] As shown in Figure 1 , the electromagnetic metasurface intelligent door specifically includes:

[0067] 1. The metasurface-enabled communication module relies on the metasurface antenna's ability to control the propagation direction, polarization state, and amplitude of electromagnetic waves. This characteristic allows the metasurface antenna to concentrate energy in a specific receiving area, thereby improving the efficiency of energy harvesting. In energy-carrying communication, information and energy are usually transmitted within the same frequency band through time multiplexing, frequency multiplexing, or spatial multiplexing. It can also dynamically adjust the beam direction, frequency, or polarization mode of transmission according to changes in the environment and communication requirements to optimize energy transmission and information transmission performance. Therefore, the metasurface antenna can simultaneously control the transmission of information signals and energy signals, greatly achieving signal de-blinding, enhancing signal coverage, effectively reducing signal attenuation in complex urban environments or building interiors, overcoming environmental and terrain difficulties, quickly responding to environmental changes, and thus improving the security and response efficiency of the access control system.

[0068] 2. The metasurface wireless power transmission technology (WPT) converts electrical energy into electromagnetic waves through the transmitting end of the energy source (such as a charger) and transmits it to the receiving end through the air. It utilizes the principle of magnetic resonance, and the transmitting end and the receiving end exchange energy through the same frequency of resonant electromagnetic fields. The receiving end receives these electromagnetic waves and then converts them into electrical energy, which can be stored in a battery to support long-term operation of the device.

[0069] Meanwhile, the wireless information and power transmission technology (SWIPT) can concentrate radio frequency signals to the energy harvesting unit of the receiving end through a specially designed metasurface structure, thereby achieving efficient energy transmission. In another frequency band or using different modulation techniques, the antenna can modulate the signal into data form and transmit it to the receiving end. The metasurface structure of the receiving end antenna can optimize the efficiency of energy harvesting, converting the received radio frequency signals into electrical energy for storage. The information decoding receiving unit can extract data from the radio frequency signals and convert it into original information through appropriate demodulation techniques, reducing the antenna size while maintaining high efficiency, supporting the implementation of metasurfaces with a gate diameter size, and achieving efficient sharing of information and energy.

[0070] 3. The metasurface health sensing function relies on the metasurface antenna emitting electromagnetic waves in a specific frequency range. These electromagnetic waves can penetrate the skin and other tissues and enter the human body. According to different health monitoring requirements, the frequency and wavelength of electromagnetic waves can be adjusted according to the design to ensure that the signal can effectively penetrate and interact with the human physiological parameters.

[0071] When electromagnetic waves penetrate the human body, each tissue and organ of the human body (such as blood, muscle, bone, etc.) will have different reflection, refraction or absorption effects on electromagnetic waves. For example, the reflection characteristics of water, fat, muscle and other different tissues in the blood are different. With the change of time, the physiological state inside the human body (such as heartbeat, breathing, blood flow, etc.) will affect these interactions. The metasurface antenna receives the reflected signals from the human body. Due to the different interactions of electromagnetic waves with human tissues, these returned signals contain useful health information, such as heart rate, respiratory rate, blood oxygen level, etc. Through signal processing techniques (such as Fourier transform, filtering and denoising methods), these information will be extracted and converted into usable health data. After analyzing the returned signals, the system will use algorithms (such as machine learning, artificial intelligence algorithms, etc.) to interpret the signals, compare these data with normal physiological data, and identify the health status of the human body. The application of electromagnetic metasurface on the smart door is that it can interact with the biometric signals. When the user approaches the door lock, the metasurface structure will interact with the user's biometric characteristics to generate a unique electromagnetic signal pattern. Therefore, by designing the electromagnetic metasurface to be highly sensitive to electromagnetic waves in a specific frequency range, the sensing technology of the electromagnetic metasurface captures the changes in the biometric characteristics, and the system further analyzes the changes in the phase and amplitude of the electromagnetic waves to identify whether it is a human characteristic, and further compares it with the pre-stored electromagnetic characteristics of the user to determine whether it matches. If it matches successfully, the electromagnetic metasurface can transmit electromagnetic energy to drive the door lock to unlock.

[0072] 4. The metasurface authentication function can be achieved by designing different structural units to encrypt and decrypt electromagnetic waves. By using a specific encryption algorithm during the authentication process, the identity information is transmitted in the form of electromagnetic waves, and the receiving end metasurface antenna judges whether the received signal is consistent with the predetermined authentication data by accurately controlling the polarization or reflection characteristics of the signal. During the authentication process, malicious attackers may try to bypass the authentication by interfering with the signal or tampering with the authentication information. The design of the metasurface antenna can reduce the loss of the signal during transmission and increase the anti-interference ability of the system, and can also enhance the security of the authentication through multi-layer authentication, each layer using different signal processing methods, dynamically changing the authentication information at each communication, so that each communication has a different identity identifier. Further enhance security.

[0073] As shown in Figure 2 The present application relates to a door aperture metasurface based on the principle of electromagnetic induction, and the present application comprises the following main structures:

[0074] Transmit coil (left spiral structure in the figure): provided in the transmitting device, for generating an alternating magnetic field. The transmit coil is driven by a drive circuit including a high-frequency oscillation module, a power amplification module, and a resonance matching network. The high-frequency oscillation module is used to generate a high-frequency alternating electric signal of a preset frequency, the power amplification module amplifies the signal and outputs it to the transmit coil, and the resonance matching network is used to realize impedance matching between the drive circuit and the coil, thereby improving the transmission efficiency of the system. The drive circuit is arranged inside the transmitting device shell and is electrically connected to the transmit coil through PCB or modular arrangement to receive the alternating current signal and generate a high-frequency alternating magnetic field in space.

[0075] Receiving device (right rectangular structure with small circular structure in the figure): including a receiving coil and a rectifier circuit, the receiving coil is arranged at a spatial position opposite to the transmit coil, for receiving an alternating magnetic field and inducing a voltage signal; the rectifier circuit converts the induced alternating current into direct current for use by the load. Compared with the traditional contact power supply method, the present application has the advantages of simple structure, no electrical contact, and being suitable for closed or mobile devices.

[0076] As shown in Figure 3 , the present application provides a wireless energy harvesting and transmission system based on a gate aperture electromagnetic super surface antenna; including an electromagnetic super surface control layer, an intelligent sensing and interaction layer, a communication and energy management layer, and a safety and structure layer;

[0077] The gate aperture electromagnetic super surface has three functions of wireless energy harvesting module, signal processing and control module, and energy management and supply module.

[0078] Wireless energy harvesting module: the present application uses the electromagnetic super surface antenna deployed in the gate area to harvest the electromagnetic energy carried by the existing radio waves (such as WiFi, Bluetooth, 5G, RFID signals, etc.) in the surrounding environment. The focused energy is received by the embedded antenna unit and converted into radio frequency alternating current, and the radio frequency signal is efficiently converted into direct current by the rectifier module and stored in the energy unit. The whole system has the ability of energy harvesting, integration, conversion and state monitoring, providing auxiliary or main power support for the intelligent door control system, realizing efficient harvesting, integration and energy conversion of wireless electric energy, providing power source for the subsequent system, and performing energy metering and energy state monitoring.

[0079] Signal processing and control module: the super surface antenna not only has energy harvesting capability, but also can process the received wireless signal. The system realizes signal demodulation, discrimination, control and forwarding by extracting and analyzing the characteristic parameters such as phase, frequency and amplitude of the signal. The built-in control unit in this module can perform protocol identification, data decoding, feedback control instruction output and other operations, so that the system has the preliminary information interaction function.

[0080] Energy management and anti-supply module: the collected wireless energy is stored in the internal battery or super capacitor after rectification, filtering and voltage stabilization. When other devices are connected, the energy can be output wirelessly or wired through the interface to power other devices, ensuring the cooperative operation and emergency work capacity of the surrounding devices. The system also supports energy state feedback, realizing remote energy monitoring and scheduling.

[0081] As shown in Figure 4 The system emits electromagnetic waves (such as millimeter waves, microwaves, etc.) of specific frequency and waveform to the human body through the door electromagnetic super surface antenna. The electromagnetic waves can penetrate the surface skin of the human body and interact with the human tissues, organs, and body fluids. The transmitting module is arranged on the side of the door frame and integrates the electromagnetic super surface structure of the transmitting unit. The transmitting module emits electromagnetic waves of specific frequency (such as 24GHz millimeter wave signals), forming a directional propagation area, which can scan the personnel in contactless manner when they approach the door. The reflection signal receiving module is also arranged in the door frame and has an array electromagnetic super surface receiving antenna structure for collecting electromagnetic wave signals reflected from the human tissues. The characteristics (phase difference, spectral characteristics, amplitude attenuation, etc.) of the collected signals have individual differences. The signal processing and identity recognition module includes FPGA or embedded processor, which realizes contactless identity recognition by pre-processing, feature extraction and pattern recognition of the target reflection echo signal. The method steps include:

[0082] (1) Collect the I / Q signal of the target reflection;

[0083] (2) Perform band-pass filtering and time-frequency transformation to obtain the micro-Doppler spectrum diagram;

[0084] (3) Model and identify the target physiological characteristics based on support vector machine or convolutional neural network;

[0085] (4) Output the identification. At the same time, physiological characteristic parameters such as heart rate micro-shock frequency, breathing frequency, and body surface water content can be extracted. If the physiological parameters of the target individual are abnormal (such as heart rate higher than the normal range, rapid breathing, etc.), the system will issue a prompt on the display end (such as the screen on the door or the mobile phone App), or send the abnormal data to the background system for remote health management.

[0086] As shown in Figure 5As shown, electromagnetic metasurface structures are embedded on both sides of the door frame. The structure contains multiple electromagnetic unit arrays, which include multiple periodically arranged metal resonant units. Each unit structure includes a metal pattern structure, a controllable device, a dielectric substrate, a bias circuit, and a control interface. The metal pattern is used to achieve resonance response in the target frequency band. The controller (such as a PIN diode or a varactor diode) is controlled by an FPGA or microcontroller, and the state of each unit is dynamically adjusted through the bias circuit. Part of the electromagnetic units are integrated with a micro antenna structure, which is used to realize directional transmission and reception of the beam during system operation, thereby constructing an intelligent metasurface antenna array with real-time regulation capability, capable of transmitting and receiving electromagnetic wave signals at a specified frequency band (such as 24 GHz or 60 GHz). The transmitting antenna periodically emits a detection beam through the control unit or when an object is detected to be close.

[0087] When the user stands in front of the door, the human body tissue produces multiple path reflections on the electromagnetic waves. After the receiving array acquires the reflected signal, the signal processing module extracts the amplitude variation, phase shift, and reflection distribution map of the reflected wave through fast Fourier transform (FFT), phase demodulation, time delay analysis, and other methods;

[0088] (1) Collect the I / Q signal data of the target reflection;

[0089] (2) Perform band-pass filtering, window function weighting, and denoising preprocessing;

[0090] (3) Extract the reflection spectrum characteristics using fast Fourier transform (FFT);

[0091] (4) Perform phase demodulation analysis of the micro displacement characteristics;

[0092] (5) Perform target positioning and path extraction based on time delay (ToA) and phase difference analysis;

[0093] (6) Combine the amplitude variation map, phase shift map, and spectrum map into a reflection map for subsequent behavior recognition and identity authentication.

[0094] The system has a built-in human electromagnetic reflection model database. Each registered user completes an "electromagnetic feature registration" at the first use, that is, the system records their reflection characteristic template under the standard station. In the actual identification process, the system compares the current target characteristics with the templates in the database, and determines whether it is an authorized user through a set matching threshold (such as a similarity of more than 85%). If the comparison is successful, the system sends an unlocking control signal to the electronic door lock through the GPIO interface. The door lock can be an electronic magnetic lock, an electric tongue lock, or a smart mechanical lock, which completes the unlocking action after receiving the instruction; if the comparison fails, the system does not send a control signal, and the door lock remains closed, and records the identification log of this time.

Claims

1. A doorway electromagnetic metasurface, characterized in that, The transmitting coil is arranged inside the transmitting device and used to generate an alternating magnetic field. The receiving device includes a receiving coil and a rectifier circuit. The receiving coil is arranged opposite to the transmitting coil and closely attached to both sides of the door aperture electromagnetic surface.

2. The doorway electromagnetic metasurface according to claim 1, characterized in that, The rectifier circuit converts the induced alternating current into direct current for use by the load. When a person approaches the door aperture area, the door aperture electromagnetic metasurface structure embedded in both sides of the door frame starts a low-power monitoring mode and triggers the transmission. The transmitting coil has a spiral structure and is connected to a driving circuit.

3. An electromagnetic metasurface smart door characterized by, The driving circuit is arranged inside the transmitting device and electrically connected to the receiving coil through PCB or modular arrangement to receive an alternating current signal and generate a high-frequency alternating magnetic field in space. The driving circuit includes a high-frequency oscillation module, a power amplification module, and a resonance matching network. The high-frequency oscillation module is used to generate a high-frequency alternating electric signal at a preset frequency. The power amplification module amplifies the signal and outputs it to the transmitting coil.

4. The electromagnetic metasurface smart door of claim 3, wherein, The resonance matching network is used to achieve impedance matching between the driving circuit and the transmitting coil. The electromagnetic metasurface intelligent door includes an electromagnetic metasurface regulation layer, an intelligent sensing and interaction layer, a communication and energy management layer, and a safety and structure layer. The electromagnetic metasurface regulation layer, the intelligent sensing and interaction layer, and the communication and energy management layer are based on the door aperture electromagnetic metasurface. The safety and structure layer is a metal material shell that provides mechanical strength to the door body and serves as support and protection. The electromagnetic metasurface regulation layer is located in the innermost layer. The intelligent sensing and interaction layer and the communication and energy management layer are arranged on the upper and lower ends of the electromagnetic metasurface regulation layer, respectively. The intelligent sensing and interaction layer connects the signal stream to the electromagnetic metasurface regulation layer. The communication and energy management layer transmits the signal stream to the electromagnetic metasurface regulation layer. The electromagnetic metasurface regulation layer is used to reflect, absorb, transmit, reconstruct, and beamform incident electromagnetic waves. The electromagnetic metasurface regulation layer includes a door aperture electromagnetic metasurface and a signal processing and identity recognition module. When the transmitting signal reaches the human body, a reflected electromagnetic wave returns to the door aperture electromagnetic metasurface, which is the incident electromagnetic wave relative to the door aperture electromagnetic metasurface. The electromagnetic metasurface regulation layer emits electromagnetic waves with specific frequency and waveform to the human body, which produces physical interaction effects with human tissues, organs, and body fluids. The receiving device also has an array-type electromagnetic metasurface receiving antenna structure for collecting electromagnetic waves reflected from the human body tissues. The signal processing and identity recognition module realizes non-contact identity recognition by pre-processing, feature extraction and pattern recognition of the target reflected echo signal; the signal processing and identity recognition module includes an FPGA or an embedded processor, and target feature information is obtained by filtering, denoising and normalizing operation on the original echo signal; the extracted multi-dimensional biological feature vector is compared with the registered identity template in the preset database to complete pattern recognition.

5. The electromagnetic metasurface smart door according to claim 4, wherein, The door frame is embedded with a door aperture electromagnetic super surface, and the door aperture electromagnetic super surface further includes a plurality of electromagnetic unit arrays, and each electromagnetic unit array includes a plurality of periodically arranged metal resonant units, and each metal resonant unit includes an adjustable charge carrier assembly, a bias circuit network, an antenna unit and an electromagnetic response control; By combining the antenna unit with the bias circuit network, the adjustable charge carrier assembly and the electromagnetic response control, the electromagnetic super surface regulation layer dynamically regulates the super surface phase; The electromagnetic super surface regulation layer is applied to a health sensing door aperture super surface to emit electromagnetic waves, which are reflected by the human body and received by the millimeter wave radar of the intelligent sensing and interaction layer; by dynamically regulating the super surface phase, multi-angle scanning is realized to complete signal transmission and modulation.

6. The electromagnetic metasurface smart door of claim 3, wherein, The intelligent sensing and interaction layer is used for identifying user behavior and realizing intelligent interaction with the user; the intelligent sensing and interaction layer detects respiration by analyzing the Doppler shift caused by chest cavity micro-movement, and detects heart rate by analyzing the phase change caused by the pulsation of skin surface micro-vessels; abnormal values are uploaded to a medical platform through 5G for human data analysis and early warning through real-time data processing by an edge computing unit.

7. The electromagnetic metasurface smart door according to claim 6, wherein, The intelligent sensing and interaction layer includes a millimeter wave radar module, a multi-spectral imaging module, an infrared sensor, an electromagnetic wave echo feature analysis unit and an interactive display screen; Based on the door aperture electromagnetic super surface in the intelligent sensing and interaction layer, the door aperture electromagnetic super surface structure embedded in the door frame is started in a low-power monitoring mode when a person approaches the door aperture area; target heat source and contour pre-detection are realized by the infrared sensor and the multi-spectral imaging module; once a potential target is identified, the control unit drives the electromagnetic super surface structure to change its response state through the bias network, switching from the original standby mode to the authentication mode; The millimeter wave radar module starts high-frequency detection to continuously collect human micro-Doppler signals, accurately capturing micro-vibrations of more than 0.1mm caused by respiration and heartbeat within a distance of 1.5 meters; the electromagnetic wave echo feature analysis unit performs edge AI processing on the echo signal to extract high-dimensional features such as the target's 0.8-2Hz heartbeat frequency, micro-vibration amplitude and phase trajectory; The multi-spectral imaging module collects image information of finger veins and facial micro-features based on near-infrared and visible light channels for cross-identity verification; The infrared sensor assists in detecting body surface temperature distribution for screening abnormal conditions, and the interactive display screen displays the results; If the authentication result is correct, the door lock is unlocked and a green light is displayed; if the authentication is incorrect, an audible and visual alarm is sounded and the event is recorded.

8. The electromagnetic metasurface smart door according to claim 7, wherein, When a user stands in front of the door, the human body tissue reflects electromagnetic waves through multiple paths. After the receiving array acquires the reflected signal, the signal processing module extracts electromagnetic characteristic parameters such as amplitude change, phase shift, and reflection distribution spectrum of the reflected wave through Fast Fourier Transform (FFT), phase demodulation, and time delay analysis. (1) The millimeter-wave radar module and the electromagnetic wave echo feature analysis unit in the intelligent sensing and interaction layer jointly collect the I / Q signal data reflected by the target, that is, the raw signal data, and combine it with the infrared sensor to monitor the approach of personnel in real time to trigger the identification process. (2) Perform bandpass filtering, window function weighting and noise suppression preprocessing on the acquired raw signal data to improve the signal-to-noise ratio and system stability; (3) The Fast Fourier Transform (FFT) is used to extract the reflection spectrum features from the preprocessed signal and analyze the response mode of human tissue structure to electromagnetic waves of different frequencies. (4) Perform phase demodulation processing to extract the phase change of the reflected signal caused by the small physiological movements of heartbeat and breathing, and realize millimeter-level micro-displacement sensing; (5) Combining time delay (ToA) and phase difference analysis techniques, the target is located with high precision, and the multi-path propagation path is reconstructed to achieve behavior trajectory extraction and dynamic recognition. (6) Combine the obtained amplitude change map, phase shift map and spectrum map into a reflectance map; simultaneously acquire image data from the multispectral imaging module and infrared sensor to obtain multimodal perception features, and display the current recognition status and processing feedback in real time through the interactive display screen.

9. The electromagnetic metasurface smart door of claim 8, wherein, The system has a built-in human electromagnetic reflection model database. Each registered user needs to complete an "electromagnetic feature registration" at a standard position when using it for the first time. That is, the system records the comprehensive reflection feature template of the user under multi-frequency electromagnetic wave irradiation, including the corresponding reflection spectrum distribution, phase characteristics and physiological micro-motion information. In the actual recognition process, the system matches the multimodal perception features of the current target with the templates in the database and determines whether it is an authorized user based on the set similarity threshold. If the comparison is successful, the system sends an unlocking control signal to the electronic door lock through the GPIO interface, and the door lock unlocks automatically. If the comparison fails, the system does not send a control signal, the door lock remains closed, and the timestamp and relevant feature data of the recognition failure event are automatically recorded, and the recognition log is recorded.

10. The electromagnetic metasurface smart door of claim 3, wherein, The communication and energy management layer is used to realize the system's wireless communication, power supply and energy dispatch; the communication and energy management layer includes a main control communication module, an RFID reader / writer unit, a wireless power supply module, a battery pack and an energy storage module. The aforementioned aperture electromagnetic metasurface is applied to the wireless power transmission transmitter. The aperture electromagnetic metasurface has real-time adjustable radiation characteristics and dynamically optimizes the beam direction and energy distribution according to environmental changes. The receiver is a reconfigurable reflector structure. The reflection parameters are adaptively adjusted by the control unit to enhance the energy harvesting efficiency under multipath paths. When the terminal device is in the standby power state, the receiving end actively activates and sends a low-power beacon signal, which is received and analyzed by the master communication module for positioning and identification information. The door aperture electromagnetic metasurface dynamically adjusts the phase state of each unit according to the feedback signal, realizing spatial positioning and directional beam forming of the target. The radio frequency identification (RFID) read-write unit can be used for identity confirmation or access permission identification of the receiving end device, serving as one of the triggers for energy transmission tasks. The phase-controlled door aperture electromagnetic metasurface forms a directional radio frequency beam, accurately projecting energy to the target receiving end. The receiving end converts the received electromagnetic wave energy into direct current through the integrated rectifier antenna structure, providing stable power support for local intelligent identification devices, sensor nodes, etc. The wireless power supply module is responsible for controlling the transmission power and frequency in conjunction with the door aperture electromagnetic metasurface. The supporting battery pack and energy storage module are used to store excess energy and serve as a redundant power supply for identification and communication devices when wireless power supply is unavailable or unstable, ensuring system continuity and security. The master communication module divides the time into microsecond or millisecond slots and alternately executes communication tasks and energy transmission tasks in the same frequency band, constructing a time division multiplexing full-duplex mechanism. The time division multiplexing full-duplex mechanism combines with an adaptive time slot scheduling algorithm to dynamically adjust the time proportion of each task according to real-time communication load and energy demand, realizing fine allocation and maximum utilization of communication and power supply resources.

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