Radio frequency pressure sensor
By designing an RF capacitor array and a PDMS flexible pressure cell layer, the sensitivity and resolution of the pressure sensor are improved, solving the problem of low sensitivity when sensing pressure changes, and achieving high-precision pressure, liquid concentration, and liquid level detection.
Patent Information
- Application Number
- CN202423301516.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-31
- Publication Date
- 2025-12-19
- Estimated Expiration
- 2034-12-31
AI Technical Summary
Existing pressure sensors are not sensitive enough to detect pressure changes, making it difficult to accurately capture subtle pressure fluctuations. Furthermore, the sensing module design is simple and lacks resolution, failing to provide fine and accurate measurement data in complex and variable pressure environments.
The system employs an RF capacitor array containing several cascaded planar capacitor units. The plates are arranged in a comb-like structure to form an interdigitated structure. Combined with the protruding modules of the PDMS flexible pressure unit layer, pressure measurement is achieved through changes in capacitance value, and the capacitance effect is enhanced by RF electromagnetic flux radiation.
It significantly improves the sensor's sensitivity and resolution, enabling it to accurately capture minute pressure changes and ensure the accuracy of measurement results, while also expanding its application range to liquid concentration and level detection.
Smart Images
Figure CN223691891U_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The utility model relates to a radio frequency pressure sensor belongs to the field of sensor. BACKGROUND
[0002] Pressure sensor is a kind of device for measuring gas or liquid pressure, is widely used in industry, medical treatment, aerospace etc. The basic principle of pressure sensor is to convert pressure signal into electric signal.
[0003] With the progress of science and technology, the development trend of pressure sensor includes: high precision and high sensitivity: the application of new materials and new technologies makes the measurement accuracy and sensitivity of sensor continuously improve. Miniaturization and integration: with the development of integrated circuit technology, the volume of pressure sensor is continuously reduced, and the integration degree is improved. Intelligentization: combined with Internet of Things (IoT) technology, realize remote monitoring and data analysis. Flexibility and wearable: the use of flexible materials makes pressure sensor can be applied to wearable devices and biomedical field.
[0004] In the existing pressure sensor, the relative area between the two polar plates is greatly compressed in limited space, so it is relatively small, which directly leads to the insufficient sensitivity of the sensor when sensing pressure change, and it is difficult to accurately capture subtle pressure fluctuations. At the same time, the design of pressure sensing module is relatively single, lacks diversified sensing mechanism, and the space contact mode of capacitor is limited by physical structure, which further limits the resolution of sensor, so that it is difficult to provide enough fine and accurate measurement data when facing complex and changeable pressure environment. UTILITY MODEL CONTENTS
[0005] In order to improve sensitivity and resolution, the utility model provides a radio frequency pressure sensor, the specific scheme is as follows:
[0006] The radio frequency capacitor array of the utility model comprises a plurality of cascaded planar structure capacitor units, the polar plate of the planar structure capacitor unit comprises a plurality of comb-shaped structures, and the comb-shaped structures of the two polar plates jointly form a plurality of interdigital structures.
[0007] The radio frequency pressure sensor of the utility model comprises a PDMS flexible pressure unit layer and a radio frequency capacitor array layer.
[0008] The radio frequency capacitor array layer comprises a plurality of cascaded planar structure capacitor units, the polar plate of the planar structure capacitor unit comprises a plurality of comb-shaped structures, and the comb-shaped structures of the two polar plates jointly form a plurality of interdigital structures.
[0009] The PDMS flexible pressure unit layer comprises a substrate and a protruding module on the substrate, and the shape and position of the protruding module are complementary to the space between the capacitor array.
[0010] In one embodiment, the protrusion module contacts the capacitor array when pressed, causing a change in the capacitance value, and the change in the capacitance value is used to measure the pressure.
[0011] In one embodiment, the change in the capacitance is directly proportional to the number of protrusion modules contacting the capacitor array.
[0012] In one embodiment, the sensor further comprises a capacitance detection circuit, including any one of a frequency modulation circuit, an amplitude modulation circuit, and a bridge circuit.
[0013] In one embodiment, the capacitor array includes 200 cascaded capacitor units.
[0014] The liquid concentration detection sensor of the utility model, including substrate layer and the radio frequency capacitor array on substrate layer, the radio frequency capacitor array contains several cascaded plane structure capacitor units, the polar plate of plane structure capacitor unit includes several comb tooth shape structure, the comb tooth shape structure of two polar plates forms several interdigital structures in common.
[0015] The liquid level detection sensor of the utility model, including substrate layer and the radio frequency capacitor array on substrate layer, the radio frequency capacitor array contains several cascaded plane structure capacitor units, the polar plate of plane structure capacitor unit includes several comb tooth shape structure, the comb tooth shape structure of two polar plates forms several interdigital structures in common.
[0016] The utility model discloses a liquid level detection sensor, including substrate layer and the radio frequency capacitor array on substrate layer, the radio frequency capacitor array contains several cascaded plane structure capacitor units, the polar plate of plane structure capacitor unit includes several comb tooth shape structure, the comb tooth shape structure of two polar plates forms several interdigital structures in common.
[0017] The radio frequency capacitor array of the utility model greatly increases the number of cascaded capacitor arrays and the protrusion module of PDMS flexible pressure unit, so that a certain number of protrusion modules can contact the capacitor array under the condition of small pressure change, and the resolution ability of the capacitor to the pressure is improved significantly.
[0018] The radio frequency capacitor array provided by the utility model can also be used for liquid concentration detection and liquid level detection, and the accurate detection of liquid concentration and liquid level can be realized through the change of the liquid sample medium coefficient between the capacitance value and the metal of the capacitor unit, and the radio frequency capacitor array can be widely applied to the fields of non-contact liquid contraband rapid detection, industrial liquid level monitoring, environmental monitoring, flood warning and water resource management. BRIEF DESCRIPTION OF DRAWINGS
[0019] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings needed in the embodiment description. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without any creative effort on the basis of these drawings.
[0020] Figure 1 is a structural diagram of one of the PDMS flexible pressure unit layer and the radio frequency capacitor array layer of the present application from a perspective.
[0021] Figure 2 is a structural diagram of the other perspective of the PDMS flexible pressure unit layer and the radio frequency capacitor array layer of the present application.
[0022] Figure 3 is a structural diagram of the PDMS flexible pressure unit layer of the present application.
[0023] Figure 4 is a plan view of the PDMS protrusion module of the present application.
[0024] Figure 5 is a capacitor array sensing chip of the present application.
[0025] Figure 6 is a capacitor unit diagram of the present application.
[0026] Figure 7 is a capacitance value change diagram obtained by simulation when the protrusion module contacts the capacitor array in different numbers. DETAILED DESCRIPTION
[0027] In order to make the purpose, technical solutions and advantages of the present application more clear, the following will further describe the embodiments of the present application in combination with the drawings.
[0028] Embodiment one:
[0029] The present embodiment provides a radio frequency pressure sensor, as shown in Figures 1 to 6 The sensor includes a PDMS flexible pressure unit layer and a radio frequency capacitor array layer.
[0030] The structure of the radio frequency capacitor array is as shown in Figure 5 It includes a plurality of parallel capacitor units, and one capacitor array in the present embodiment is composed of 10 capacitor units, Figure 6 is a local enlarged view of each capacitor unit, which is composed of a series of planar structure interdigital capacitors, the medium in the middle is air, and the corresponding capacitance in the process required in the modern integrated circuit design is satisfied, reaching the order of pF. Figure 7The results of the simulation of the capacitor are shown in the figure, and the experimental data are shown in the figure. With the increase of the number of capacitive units, the simulation curve is obtained, and with the increase of the frequency, the trend of the simulation curve is first increased and then decreased. At the same frequency, the larger the capacitive unit, the larger the capacitance.
[0031] The structure of the PDMS flexible pressure unit is shown in Figure 3 The PDMS (polydimethylsiloxane) material is used to prepare the substrate and the protruding module on the substrate. The shape and position of the protruding module are complementary to the space between the capacitive plates, forming a "sawtooth structure". When the protruding module is pressed to produce displacement, the number of contacts with the capacitive array under different pressures is different. The greater the pressure, the more the number of contacts, and the greater the change of the capacitance value.
[0032] The change of the capacitance is proportional to the number of contacts of the protruding module with the capacitive array. The deformation of the protruding module of the PDMS flexible unit will cause the change of the capacitance value of the expected contact capacitive unit in the capacitive array. In this way, the PDMS flexible unit can realize the precise deformation of the pressure, and then realize the precise change of the capacitance value.
[0033] The process of making the protruding module structure on the PDMS can be realized by various methods, which usually involves the preparation of the mold and the pouring of the PDMS. The following is a basic step:
[0034] Step 1: Design the sawtooth structure. Use computer-aided design (CAD) software to design the model of the sawtooth structure.
[0035] Step 2: Make the mold. Choose a suitable material for the mold, such as silicone, resin or metal. 3D printing: import the design file into the 3D printer and print the mold. Milling or carving: use metal or other hard materials to make the mold by milling or carving.
[0036] Step 3: PDMS preparation
[0037] Step 31: Material selection: choose suitable PDMS material, usually Sylgard 184 or similar products.
[0038] Step 32: Mix: mix the base and curing agent of the PDMS in proportion (10:1).
[0039] Step 33: Deaeration: put the mixed PDMS into a vacuum box to remove bubbles to ensure the integrity of the final structure.
[0040] Step 4. Pouring PDMS
[0041] Step 41: Pour the mold: pour the deaerated PDMS into the prepared mold to ensure that the mold is completely filled.
[0042] Step 42: Curing: Place the PDMS-filled mold into an oven and follow the manufacturer's guidelines for temperature and time (60-80°C for 1-2 hours).
[0043] Step 5: Demolding: After curing, gently remove the PDMS sawtooth structure from the mold.
[0044] Step 6: Post-processing
[0045] Step 61: Surface Treatment: Treat the PDMS surface, such as coating or modification, to enhance its performance or change surface properties.
[0046] Step 62: Assembly: Assemble the sawtooth structure with other components.
[0047] Through the above steps, a sawtooth structure is successfully made on the PDMS.
[0048] In addition, in order to convert the capacitance change into a useful output signal, additional circuitry is usually required to detect the change in capacitance. Common methods include: Frequency Modulation (FM) circuit: uses the frequency change of an LC oscillator to reflect the change in capacitance. Amplitude Modulation (AM) circuit: reflects the change in capacitance by changing the amplitude of the oscillator. Bridge circuit (such as Wheatstone bridge): indirectly measures the change in capacitance by measuring the change in resistance in the bridge.
[0049] The radio frequency pressure sensor of the present embodiment can significantly increase the number of cascaded capacitance arrays and the protruding modules of the PDMS flexible pressure unit, so that a certain number of protruding modules can still contact the capacitance array under the condition of small pressure change, significantly improving the resolution of capacitance to pressure. At the same time, through the electromagnetic flux radiation scheme of radio frequency, the overall capacitance effect is further enhanced, and the sensitivity is qualitatively improved. In addition, by using the strict proportional relationship between the change amount of capacitance and the number of protruding modules contacting the capacitance array, the small pressure change is accurately captured, and the problem of low precision is successfully solved, achieving the remarkable effect of both high sensitivity and high resolution.
[0050] Embodiment Two:
[0051] The present embodiment provides a liquid concentration detection sensor, comprising a substrate layer and a radio frequency capacitance array located on the substrate layer.
[0052] The structure of the radio frequency capacitance array is the same as in Embodiment One, and it includes several cascaded planar structure capacitance units, each planar structure capacitance unit includes several comb-shaped structures, and the comb-shaped structures of the two polar plates form several interdigital structures together.
[0053] The liquid concentration detection sensor of the embodiment realizes the detection of liquid concentration through the change of the dielectric constant of the liquid sample medium filled between the capacitance value and the metal of the capacitance unit. Different concentrations of liquid often exhibit different dielectric constants. When the liquid to be measured contacts the capacitance array, the capacitance also changes accordingly. Through the measurement circuit, the change of the capacitance is converted into an electrical signal output, thereby realizing the measurement of the concentration, which can be used for non-contact liquid contraband rapid detection, such as alcohol with a concentration of 50% or more.
[0054] Embodiment three:
[0055] The embodiment provides a liquid level detection sensor, which comprises a substrate layer and a radio frequency capacitance array located on the substrate layer.
[0056] The structure of the radio frequency capacitance array is the same as that in Embodiment One, and both comprise a plurality of cascaded planar structure capacitance units. The pole plate of each planar structure capacitance unit comprises a plurality of comb-shaped structures, and the comb-shaped structures of the two pole plates together form a plurality of interdigital structures.
[0057] The liquid level detection sensor of the embodiment realizes the detection of the liquid level through the change of the dielectric constant caused by the change of the amount of liquid filled between the capacitance value and the metal of the capacitance unit. The amount of liquid between the pole plates often exhibits different dielectric constants, and the capacitance also changes accordingly. Through the measurement circuit, the change of the capacitance is converted into an electrical signal output, thereby realizing the measurement of the liquid level.
[0058] The liquid level detection sensor of the embodiment can be applied to the liquid level monitoring of liquid storage tanks, containers and pipeline systems in the field of industrial liquid level monitoring, and can be used for monitoring the liquid level changes of various liquids such as chemicals, fuels and liquid gases. In environmental monitoring, it can be used for monitoring the liquid level changes of natural water bodies such as water sources, rivers and lakes, and for environmental monitoring, flood warning and water resource management.
[0059] Radio frequency capacitors with high design flexibility and accurate capacitance values have a wide range of applications. In wireless communication systems, radio frequency capacitors are used for tuning and matching circuits to ensure effective transmission and reception of signals. In RFID tags, capacitors are used to adjust frequency and signal strength to improve tag reading performance. In wireless charging systems, capacitors are used for energy transmission and power management to improve charging efficiency. In radio frequency amplifiers, capacitors are used for coupling and decoupling to maintain signal purity and stability. In various signal processing circuits, radio frequency capacitors are used for filtering and signal shaping to optimize system performance. In radar systems, high-precision radio frequency capacitors are used for signal generation and tuning to ensure the accuracy of target detection. In some biomedical instruments, radio frequency capacitors are used for signal transmission and processing to achieve efficient medical monitoring and diagnosis.
[0060] The radio frequency capacitor array provided by the utility model can realize various capacitance values under different requirements through different capacitor unit quantities; secondly, various capacitor units are realized through a cascade structure, and each capacitor unit structure can be finely tuned through a laser trimming mode; that is, within the processing error range allowed by the integrated circuit technology, the measured capacitance value can have a certain deviation from the expected required capacitance value, and the great laser trimming allowance given by the array structure can accurately realize the required capacitance value.
[0061] The above merely describes the preferred embodiments of the utility model, and is not intended to limit the utility model, and any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the utility model shall be included in the protection scope of the utility model.
Claims
1. A radio frequency pressure sensor, characterized by, The sensor comprises: a PDMS flexible pressure unit layer and a radio frequency capacitor array layer; the radio frequency capacitor array layer comprises a plurality of cascaded planar structure capacitor units, the pole plate of the planar structure capacitor unit comprises a plurality of comb-shaped structures, and the comb-shaped structures of the two pole plates jointly form a plurality of interdigital structures; the PDMS flexible pressure unit layer comprises a substrate and a protruding module on the substrate, the shape and position of the protruding module are complementary to the space between the capacitor arrays.
2. The radio frequency pressure sensor of claim 1, wherein, When pressed, the protruding module contacts the capacitor array, causing the capacitance value to change, and the pressure is measured through the capacitance value change.
3. The radio frequency pressure sensor of claim 2, wherein, The change of the capacitance is proportional to the number of the capacitor arrays contacted by the protruding module.
4. The radio frequency pressure sensor of claim 1, wherein, The sensor further comprises a capacitance detection circuit, which comprises any one of a frequency modulation circuit, an amplitude modulation circuit and a bridge circuit.
5. The radio frequency pressure sensor of claim 1, wherein, The capacitor array comprises 200 cascaded capacitor units.