Passive audio receiving method and system based on pixelated microwave thermoacoustic phased array

Abstract

The application discloses a kind of passive audio receiving method and system based on pixelated microwave thermoacoustic phased array, belong to passive receiving technical field.The system of the present application includes active audio transmission module and passive audio receiving module;Method includes: transmitting end loads audio signal on high-frequency carrier, obtains audio high-frequency signal;Transmitting end carries out power amplification to audio high-frequency signal and carries out wireless transmission;Passive audio receiving device built-in pixelated microwave thermoacoustic receiving array receives audio high-frequency signal, each pixel unit generates transient thermal change synchronous with audio envelope under the excitation of audio high-frequency signal, and converts it into thermoacoustic sound pressure wave by microwave thermal sound effect;Finally, thermoacoustic sound pressure wave is guided to user ear portion and restored as audio signal play.The receiving end of the present application does not need active component, has the advantages of light and thin structure, fast response speed, maintenance-free, can realize directional private sound, adapts to a variety of near-ear wearing forms.

Description

Technical Field

[0001] This invention belongs to the field of passive receiving technology, and particularly relates to a passive audio receiving method and system based on a pixelated microwave thermoacoustic receiving phased array. Background Technology

[0002] Existing wireless audio receivers typically take the form of Bluetooth headsets, bone conduction headphones, or hearing aid receivers. These devices usually require built-in batteries, charging ports, active receiving circuits, and active power amplifier circuits, which limit their suitability for long-term wear, lightweight design, maintenance costs, and continuous standby time. Traditional bone conduction headphones, in particular, rely on mechanical diaphragms vibrating against the skin or skull to transmit sound, requiring power and still having drawbacks in terms of size, wearing comfort, and structural complexity.

[0003] On the other hand, pixelated microwave thermoacoustic structures have advantages such as high operating signal frequency, no mechanical diaphragm, fast transient response, and ease of micro / nano fabrication. Existing technologies use this type of microwave thermoacoustic structure for active sound generation or directional sound radiation, but systematic solutions for placing it near the ear as a passive audio receiving device or for directly utilizing the energy of distant incident high-frequency signals to achieve sound reproduction are still rare.

[0004] Therefore, it is necessary to propose a passive audio receiving solution that enables the receiver to complete audio reception and sound output in an active audio transmission system without the need for a battery and charging module, in order to meet application requirements such as lightweight wear, charging-free use, and simple maintenance. Summary of the Invention

[0005] This invention aims to overcome the shortcomings of existing wireless audio receiving devices that rely on battery power and charging maintenance, and traditional bone conduction headphones that rely on mechanical vibrators and have a high wearing burden. It provides a passive audio receiving method and system based on a pixelated microwave thermoacoustic receiving array, so as to achieve audio reception and sound reproduction without the need for local power supply.

[0006] The technical solution adopted in this invention is as follows:

[0007] In a first aspect, the present invention provides a passive audio receiving method based on a pixelated microwave thermoacoustic phased array, comprising:

[0008] S1. The transmitting end loads the audio signal to be transmitted onto a high-frequency carrier wave to obtain a high-frequency audio signal;

[0009] S2. The transmitter amplifies the power of the high-frequency audio signal and wirelessly transmits it to the passive audio receiver.

[0010] S3. The pixelated microwave thermoacoustic receiving array built into the passive audio receiving device receives the high-frequency sound carrier signal, causing each pixel unit to generate transient thermal changes synchronized with the audio envelope under the excitation of the high-frequency sound carrier signal, and converting the high-frequency sound carrier signal into a thermoacoustic pressure wave through the microwave thermoacoustic effect.

[0011] S4. The thermo-induced acoustic pressure wave is guided to the user's ear through an acoustic coupling cavity, a sound guiding channel, or a sound outlet, and the generated sound intensity is restored as an audio signal for playback.

[0012] Preferably, in step S2, the transmission power of the carrier high-frequency signal is... Calibration is performed based on the target output sound intensity matching the following thermoacoustic conversion sound intensity formula:

[0013]

[0014] in, Indicates the target output sound intensity. For the speed of sound in air, () represents the thermal expansion coefficient of the thermoacoustic conversion layer. The specific heat capacity at constant pressure of the thermoacoustic conversion layer, The equivalent conductivity of the microwave absorption structure of the pixel unit. This represents the real part of the intrinsic impedance of the microwave absorbing medium. This represents the pulse width.

[0015] Preferably, the pixelated microwave thermoacoustic receiving array is composed of multiple pixel units arranged in such a way that the thermoacoustic pressure waves generated by each pixel unit are coherently superimposed in the direction of the ear canal to form sound intensity, and partially canceled out in the non-target direction.

[0016] The following are the possible array configurations:

[0017] 1) Multiple pixel units are arranged in an M×N matrix, where M and N are both integers greater than or equal to 2; the center distance between adjacent pixel units is determined according to the target audio wavelength, the position of the ear canal entrance and the shape of the receiving device, so that the heat-induced acoustic pressure waves generated by each pixel unit have a predetermined phase relationship at the ear canal entrance.

[0018] 2) Multiple pixel units are arranged along the extension direction of the auricle, ear hook or temple of glasses, and preset phase compensation is achieved through the geometric distance difference between each pixel unit and the ear canal entrance, so that the sound pressure wave is superimposed in the direction of the user's ear.

[0019] 3) The pixel unit is set on a curved substrate that conforms to the contour of the ear. The curved substrate can be a flexible dielectric layer, an insulating support layer or a microstructure support layer. This array method can improve the receiving area and the fit of the ear, while reducing sound leakage in non-target directions.

[0020] 3) Divide the pixelated microwave thermoacoustic receiver array into multiple subarrays, each subarray corresponding to a different matching branch, absorption region or acoustic coupling cavity; each subarray forms different equivalent phase and amplitude weights through the feed path length, impedance matching parameters, absorption layer size or thermoacoustic conversion layer thickness, so as to achieve near-ear sound field focusing.

[0021] The aforementioned phase and amplitude adjustments are pre-set structurally or passively matched, requiring no battery, digital processor, or active power amplifier at the receiver.

[0022] Preferably, the pixel unit includes at least one microwave thermoacoustic receiving unit, which is a passive microstructure device capable of converting incident high-frequency acoustic signals into thermo-induced acoustic pressure waves.

[0023] The microwave thermoacoustic receiving unit includes a microwave absorbing structure, a thermoacoustic conversion layer, and an acoustic coupling cavity.

[0024] When a high-frequency audio signal is incident on a microwave absorption structure, the microwave loss generated by the microwave absorption structure causes the thermoacoustic conversion layer to generate transient thermal deposits that change synchronously with the audio envelope. The transient thermal deposits drive the acoustic coupling cavity to undergo thermal expansion and contraction, thereby forming pressure disturbances and outputting thermoacoustic pressure waves.

[0025] Preferably, the pixelated microwave thermoacoustic receiving array is provided with a heat-insulating support structure, a temperature-limiting gap, or a thermally conductive isolation layer on its exterior to reduce the transfer of heat to the user's ear side and to ensure that the heat mainly participates in sound pressure conversion between the thermoacoustic conversion layer and the acoustic coupling cavity, thereby improving safety and energy conversion efficiency.

[0026] Preferably, in step S1, the high-frequency carrier signal is a microwave signal; the audio signal to be transmitted is loaded onto the microwave signal through one or more of the following methods: amplitude modulation, pulse modulation, envelope modulation, double-sideband modulation, or single-sideband modulation.

[0027] Preferably, the passive audio receiving device is a wearable near-ear device, such as an in-ear receiving device, an ear-hook receiving device, an ear clip receiving device, an attached receiving device, or a near-ear receiving device integrated with the temple of glasses.

[0028] Preferably, the original audio signal includes at least one of voice, music, and device prompts.

[0029] Secondly, the present invention provides a passive audio receiving system based on a pixelated microwave thermoacoustic phased array, the system comprising an active audio transmitting module and a passive audio receiving module;

[0030] The active audio transmission module includes an audio input unit, a mixer, a high-frequency signal generation unit, and a radio frequency (RF) transmission unit. The audio input unit transmits the audio signal to be transmitted to the mixer. The high-frequency signal generation unit generates a high-frequency carrier wave and transmits it to the mixer. The mixer loads the input audio signal onto the high-frequency carrier wave to generate a high-frequency carrier signal and transmits it to the RF transmission unit. The RF transmission unit amplifies the high-frequency carrier signal and radiates it outwards.

[0031] A passive audio receiving module includes a housing and a pixelated microwave thermoacoustic receiving array built into the housing; the housing is a wearable near-ear device (ear-hook, ear clip, auricle-attached, or integrated with eyeglass temples); the pixelated microwave thermoacoustic receiving array is used to receive the high-frequency audio signal and convert it into sound intensity output.

[0032] The specific sound intensity restoration process of this invention is as follows: the envelope of the high-frequency carrier signal is converted into synchronous thermal waves in a pixelated microwave thermoacoustic receiving array. These thermal waves are then converted into sound pressure waves with the same envelope through the microwave thermoacoustic effect. After the sound pressure waves are output to the user's ear via an acoustic coupling cavity, the ear canal and auditory system receive audible sound pressure changes corresponding to the original audio signal, thus restoring it as speech, music, or prompts. This process differs from traditional bone conduction or loudspeaker solutions, as it does not rely on mechanical oscillators or electroacoustic transducers for active amplification. Instead, it utilizes the high-frequency carrier signal itself incident at the far end to provide conversion energy for the passive receiver.

[0033] The beneficial effects of this invention are as follows:

[0034] (1) Using a passive audio receiver as the audio playback end, there is no need for a battery, charging module or active power amplifier module, which can reduce the burden of wearing and reduce maintenance costs.

[0035] (2) Sound is reproduced by a pixelated microwave thermoacoustic receiver array. It has no mechanical diaphragm, a thin and light structure, and a fast response speed.

[0036] (3) Unlike traditional bone conduction headphones that rely on mechanical vibrators to produce sound by touching the skin or skull, this invention directly converts the received signal into sound intensity through microwave thermoacoustic effect, which can reduce mechanical parts while maintaining the fit to the ear.

[0037] (4) The active audio transmitting module and passive audio receiving module in the system are flexible in form and can be adapted to various application scenarios such as mobile terminals, dedicated transmitters and lightweight receiving terminals.

[0038] (5) The pixelated microwave thermoacoustic receiver array has the combined capabilities of phased array energy reception, thermoacoustic transduction and near-ear directional sound field formation. It can improve sound intensity restoration efficiency, reduce mechanical structure and enhance directional privacy output effect under passive reception conditions. Attached Figure Description

[0039] Figure 1 This is a schematic diagram of a passive audio receiving system and control process based on a pixelated microwave thermoacoustic phased array.

[0040] 101—Audio Input Unit;

[0041] 102—Mixer;

[0042] 103—High-frequency signal generation unit;

[0043] 104—Radio Frequency Transmitter Unit;

[0044] 105—Passive audio receiver module;

[0045] 106—Sound output module. Detailed Implementation

[0046] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0047] like Figure 1 As shown, this embodiment of a passive audio receiving system based on a pixelated microwave thermoacoustic phased array includes an active audio transmitting module and a passive audio receiving module.

[0048] The active audio transmitting module includes an audio input unit, a mixer, a high-frequency signal generating unit, and a radio frequency transmitting unit. The audio input unit transmits the audio signal to be transmitted to the mixer. The high-frequency signal generating unit generates a high-frequency carrier wave and transmits it to the mixer. The mixer loads the input audio signal onto the high-frequency carrier wave to generate a high-frequency carrier signal and transmits it to the radio frequency transmitting unit. The radio frequency transmitting unit amplifies the high-frequency carrier signal and radiates it outwards.

[0049] A passive audio receiving module includes a housing and a pixelated microwave thermoacoustic receiving array built into the housing; the housing is a wearable near-ear device; the pixelated microwave thermoacoustic receiving array is composed of multiple pixel units arranged to receive the high-frequency sound carrier signal, and the generated thermo-induced acoustic pressure waves coherently superimpose in the direction of the ear canal to form a sound intensity output, and partially cancel out in the non-target direction.

[0050] The pixel unit includes at least one microwave thermoacoustic receiving unit, which is a passive microstructure device capable of converting incident high-frequency acoustic signals into thermo-induced acoustic pressure waves.

[0051] The microwave thermoacoustic receiving unit includes a microwave absorbing structure, a thermoacoustic conversion layer, and an acoustic coupling cavity. When a high-frequency audio signal is incident on the microwave absorbing structure, the microwave loss generated by the absorbing structure causes the thermoacoustic conversion layer to generate transient thermal deposition that changes synchronously with the audio envelope. This transient thermal deposition drives the acoustic coupling cavity to undergo thermal expansion and contraction, thereby forming a pressure disturbance and outputting a thermoacoustic pressure wave. Due to the low heat capacity and high heat diffusion efficiency of the thermoacoustic conversion layer, its temperature fluctuates rapidly with the high-frequency audio signal, driving the adjacent air or acoustic coupling region to undergo periodic thermal expansion and contraction, thus forming a pressure disturbance and outputting sound intensity. Therefore, the receiving device not only receives microwave energy but also achieves directional sound field formation without a mechanical diaphragm, local power supply, or active audio power amplifier circuit, improving near-field output efficiency and privacy.

[0052] The passive audio receiving method based on the above system includes the following steps:

[0053] S1. The transmitting end loads the audio signal to be transmitted onto a high-frequency carrier wave to obtain a high-frequency audio signal;

[0054] S2. The transmitting end amplifies and radiates the high-frequency audio signal into space.

[0055] S3. The pixelated microwave thermoacoustic receiving array built into the passive audio receiving device receives the high-frequency sound carrier signal, causing each pixel unit to generate transient thermal changes synchronized with the audio envelope under the excitation of the high-frequency sound carrier signal, and converting the high-frequency sound carrier signal into a thermoacoustic pressure wave through the microwave thermoacoustic effect.

[0056] S4. The thermo-induced acoustic pressure wave is guided to the user's ear through an acoustic coupling cavity, a sound guiding channel, or a sound outlet, and the generated sound intensity is restored as an audio signal for playback.

[0057] In this invention, the microwave thermoacoustic (TA) downlink calculation is as follows:

[0058] Treating the radiation at the effective aperture of the transmitter as spherical diffusion, the power density obtained after introducing antenna gain, atmospheric attenuation, and illumination on the surface of the passive audio receiver is:

[0059]

[0060] in, The power density absorbed by the water surface. For transmission power, For the phased array antenna gain, (Dimensionless) represents the water surface reflectance coefficient. This is the atmospheric attenuation coefficient.

[0061] The microwave thermoacoustic wave equation is known to be:

[0062] in, For sound pressure, At the speed of light, For time, () is the coefficient of thermal expansion. For specific heat capacity, Heat density per unit volume

[0063] The relationship between the generated sound intensity and the power density received on the surface of the passive audio receiver, obtained after solving, is as follows:

[0064]

[0065] in The speed of sound in the medium. The heat density absorbed per unit time. For electrical conductivity, This represents the real part of the intrinsic impedance of the dielectric. This represents the pulse width.

[0066] This yields the complete downlink calculation formula, which provides the calibration relationship between the high-frequency carrier signal transmission power and the required sound intensity.

[0067] The following calculations are performed based on the above formula:

[0068] Let the frequency of the high-frequency carrier be... Transmit antenna gain The distance from the transmitter to the surface of the receiver Atmospheric decay Pulse width The equivalent dielectric parameters of the receiving medium are taken as follows: Equivalent receiving unit area Sound propagation distance is taken The sound frequency is taken .

[0069] When the transmission power At that time, by:

[0070]

[0071] The incident power density above the surface of the receiving device is approximately The power transmission coefficient is calculated based on the interface reflection coefficient. Therefore, the effective power density entering the thermoacoustic receiving structure is approximately If according to The converted microwave power obtained by a single equivalent receiving unit is approximately .

[0072] Under these incident conditions, the equivalent conductivity was calculated. The electric field strength inside the receiving structure is approximately Heat power density per unit volume Single-pulse energy deposition density Then, based on the Grünesen parameters... Obtain the initial sound pressure level of thermoacoustics ;through Dissemination and Agreement After total propagation loss, the sound pressure level at the receiver is approximately Converted to The received sound power on is approximately .

[0073] If the output is located near the user's ear... For the target, i.e., the target sound pressure Since the thermoacoustic pressure in this link is approximately proportional to the received power density and the transmitted power in the small signal range, the required transmitted power can be calculated proportionally to be approximately... At this time, the incident power density on the surface of the receiving device is approximately The effective power density transmitted into the thermoacoustic receiving structure is approximately ;according to The equivalent microwave receiving power is approximately The initial sound pressure level of the thermoacoustic wave is approximately After being transmitted, it is received at the receiving end. Sound pressure, equivalent to received sound power of approximately .

Claims

1. A passive audio receiving method based on a pixelated microwave thermoacoustic phased array, characterized in that, Includes the following steps: S1. The transmitting end loads the audio signal to be transmitted onto a high-frequency carrier wave to obtain a high-frequency audio signal; S2. The transmitter amplifies the power of the high-frequency audio signal and wirelessly transmits it to the passive audio receiver. S3. The pixelated microwave thermoacoustic receiving array built into the passive audio receiving device receives the high-frequency sound carrier signal, causing each pixel unit to generate transient thermal changes synchronized with the audio envelope under the excitation of the high-frequency sound carrier signal, and converting the high-frequency sound carrier signal into a thermoacoustic pressure wave through the microwave thermoacoustic effect. S4. The thermo-induced acoustic pressure wave is guided to the user's ear through an acoustic coupling cavity, a sound guiding channel, or a sound outlet, and the generated sound intensity is restored as an audio signal for playback.

2. The passive audio receiving method based on a pixelated microwave thermoacoustic phased array as described in claim 1, characterized in that, In step S2, the transmission power of the high-frequency carrier signal... Calibration is performed based on the target output sound intensity matching the following thermoacoustic conversion sound intensity formula: ； in, Indicates the target output sound intensity. For the speed of sound in air, () represents the thermal expansion coefficient of the thermoacoustic conversion layer. The specific heat capacity at constant pressure of the thermoacoustic conversion layer, The equivalent conductivity of the microwave absorption structure of the pixel unit. This represents the real part of the intrinsic impedance of the microwave absorbing medium. This represents the pulse width.

3. The passive audio receiving method based on a pixelated microwave thermoacoustic phased array as described in claim 2, characterized in that, In step S2, the pixelated microwave thermoacoustic receiving array is composed of multiple pixel units arranged together, so that the thermoacoustic pressure waves generated by each pixel unit are coherently superimposed in the direction of the ear canal to form sound intensity, and partially canceled out in the non-target direction.

4. The passive audio receiving method based on a pixelated microwave thermoacoustic phased array as described in claim 3, characterized in that, The pixelated microwave thermoacoustic receiver array is arranged as follows: 1) Multiple pixel units are arranged in an M×N matrix, where M and N are both integers greater than or equal to 2; the center distance between adjacent pixel units is determined according to the target audio wavelength, the position of the ear canal entrance and the shape of the receiving device, so that the heat-induced acoustic pressure waves generated by each pixel unit have a predetermined phase relationship at the ear canal entrance. 2) Multiple pixel units are arranged along the extension direction of the auricle, ear hook or temple of glasses, and preset phase compensation is achieved through the geometric distance difference between each pixel unit and the ear canal entrance, so that the sound pressure waves are superimposed in the direction of the user's ear; 3) The pixel unit is set on a curved base that conforms to the ear contour to improve the receiving area and wearing fit, while reducing sound leakage in non-target directions. 4) Divide the pixelated microwave thermoacoustic receiver array into multiple subarrays, each subarray corresponding to a different matching branch, absorption region or acoustic coupling cavity; each subarray forms different equivalent phase and amplitude weights through the feed path length, impedance matching parameters, absorption layer size or thermoacoustic conversion layer thickness, so as to achieve near-ear sound field focusing.

5. The passive audio receiving method based on a pixelated microwave thermoacoustic phased array as described in claim 3, characterized in that, The pixel unit includes at least one microwave thermoacoustic receiving unit, which is a passive microstructure device capable of converting incident high-frequency acoustic signals into thermo-induced acoustic pressure waves. The microwave thermoacoustic receiving unit includes a microwave absorbing structure, a thermoacoustic conversion layer, and an acoustic coupling cavity. When a high-frequency audio signal is incident on a microwave absorption structure, the microwave loss generated by the microwave absorption structure causes the thermoacoustic conversion layer to generate transient thermal deposition that changes synchronously with the audio envelope. Transient thermal deposition drives the acoustic coupling cavity to undergo thermal expansion and contraction, thereby generating pressure disturbances and outputting thermoacoustic pressure waves.

6. The passive audio receiving method based on a pixelated microwave thermoacoustic phased array as described in claim 5, characterized in that, The pixelated microwave thermoacoustic receiving array is externally provided with a heat-insulating support structure, a temperature-limiting gap, or a thermally conductive isolation layer to reduce the transfer of heat to the user's ear side, so that the heat is confined between the thermoacoustic conversion layer and the acoustic coupling cavity to participate in sound pressure conversion.

7. The passive audio receiving method based on a pixelated microwave thermoacoustic phased array as described in claim 6, characterized in that, In step S1, the high-frequency carrier signal is a microwave signal; the audio signal to be transmitted is loaded onto the microwave signal through one or more of the following methods: amplitude modulation, pulse modulation, envelope modulation, double-sideband modulation, or single-sideband modulation.

8. The passive audio receiving method based on a pixelated microwave thermoacoustic phased array as described in claim 7, characterized in that, The passive audio receiving device is a wearable near-ear device, including in-ear receiving devices, ear-hook receiving devices, ear clip receiving devices, adhesive receiving devices, or near-ear receiving devices integrated with the temples of glasses.

9. The passive audio receiving method based on a pixelated microwave thermoacoustic phased array as described in claim 8, characterized in that, The original audio signal includes at least one of voice, music, and device notification sounds.

10. A passive audio receiving system based on a pixelated microwave thermoacoustic phased array, used to implement the passive audio receiving method according to any one of claims 1-9, characterized in that, The system includes an active audio transmitting module and a passive audio receiving module; The active audio transmission module includes an audio input unit, a mixer, a high-frequency signal generation unit, and a radio frequency (RF) transmission unit. The audio input unit transmits the audio signal to be transmitted to the mixer. The high-frequency signal generation unit generates a high-frequency carrier wave and transmits it to the mixer. The mixer loads the input audio signal onto the high-frequency carrier wave to generate a high-frequency carrier signal and transmits it to the RF transmission unit. The RF transmission unit amplifies the high-frequency carrier signal and radiates it outwards. A passive audio receiving module includes a housing and a pixelated microwave thermoacoustic receiving array built into the housing; the housing is a wearable near-ear device; the pixelated microwave thermoacoustic receiving array is used to receive the high-frequency audio signal and convert it into sound intensity output.

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