Self-adaptive tuning radio frequency identification tag for dielectric constant measurement and use method of self-adaptive tuning radio frequency identification tag

Abstract

The invention discloses a self-adaptive tuning radio frequency identification tag for dielectric constant measurement and a use method. The self-adaptive tuning radio frequency identification tag comprises an antenna and an RFID chip. And the RFID chip has a self-adaptive tuning function. In the measuring process, the self-adaptive tuning radio frequency identification tag is attached to the surface of a measured sample, the internal capacitance of the self-adaptive tuning radio frequency identification tag is dynamically adjusted through the self-adaptive tuning function of the chip, so that the tag antenna and the chip are in impedance matching as far as possible, and a state code related to the current tuning state is returned. The dielectric constant range of the measured object can be determined according to the state code. The sensor is simple in structure, low in cost and convenient to process; the system is completely passive and long in service life; the mounting process is simple, and the device can be directly attached to the surface of a tested sample; the position of the sensor can be changed according to the actual demand of a user; the application range is wide, and dielectric constants of solid samples and liquid samples can be measured.

Description

Technical Field

[0001] The present invention belongs to the field of measurement technology and relates to dielectric constant measurement of sample materials, in particular to an adaptive tuning radio frequency identification tag for dielectric constant measurement and a use method thereof. Background Art

[0002] The dielectric constant is one of the key electrical parameters that characterizes the electrical properties of materials and is widely used in fields such as materials science, biomedicine, and environmental monitoring. Currently, there is an increasing demand for rapid dielectric constant testing in industrial manufacturing, ecological protection, and smart agriculture. This is particularly true in scenarios like recycling material sorting and initial contamination screening. Rough estimation techniques based on differences in dielectric properties can significantly shorten testing cycles and reduce analysis costs, providing an efficient screening basis for subsequent precision testing.

[0003] However, traditional dielectric constant measurement methods, such as capacitance, resonance, and transmission line methods, often require sophisticated measuring instruments, are complex to use, and have limited applicability to samples, making them difficult to implement for rapid and low-cost on-site testing. Therefore, developing an efficient and portable technique for roughly estimating the dielectric constant is crucial. Summary of the Invention

[0004] To address the shortcomings of the existing technology, the present invention proposes an adaptively tuned radio frequency identification tag and method for dielectric constant measurement. The self-tuning function of the RFID chip is utilized to adjust the frequency offset caused by the material properties of the sample being measured, and a status code related to the current tuning state is returned. From this, the range of the dielectric constant of the sample being measured can be deduced, thereby realizing rapid measurement of the sample's dielectric constant.

[0005] An adaptively tuned radio frequency identification tag for dielectric constant measurement includes an antenna and a radio frequency identification (RFID) chip, wherein the RFID chip is an Impinj Monza R6 chip.

[0006] Preferably, the antenna is a dipole antenna, a loop antenna or other structures.

[0007] Preferably, when used to measure the dielectric constant of a liquid material, the antenna is a loop antenna.

[0008] When the adaptively tuned RFID tag comes into contact with different samples, impedance mismatches occur between the antenna and the RFID chip due to differences in the sample materials being tested. The adaptive tuning feature of the Impinj Monza R6 chip adjusts its internal capacitance, changing the chip's impedance to achieve a conjugate match with the current antenna input impedance. The chip then returns a status code related to the current tuning state. By reading and analyzing this status code, the dielectric constant range of the sample being tested can be determined, enabling effective dielectric constant sensing.

[0009] The method for using an adaptively tuned radio frequency identification tag for dielectric constant measurement includes the following steps:

[0010] Step 1: attach the adaptive tuning radio frequency identification tag to the surface of a standard sample with a known dielectric constant.

[0011] Step 2: Use a reader to read the corresponding status codes of the adaptive tuning radio frequency identification tag when it is on the surface of different standard samples.

[0012] Step 3: Establish a dielectric constant-state code model based on the dielectric constant of the standard sample and the read state code.

[0013] Step 4: attach the adaptive tuning RFID tag to the surface of the sample to be tested, use a reader to read the status code returned by the adaptive tuning RFID tag, and determine the dielectric constant of the sample to be tested based on the dielectric constant-status code model.

[0014] Preferably, the structure of the antenna in the adaptive tunable RFID tag is adjusted to prepare different adaptive tunable RFID tags. The state codes corresponding to the different adaptive tunable RFID tags on the surface of different standard samples are read to establish a dielectric constant-antenna structure-state code model.

[0015] Preferably, a loop antenna is used as the antenna of the adaptively tuned radio frequency identification tag, and a solid sample is placed on the inter-finger capacitor surface of the feeding loop to measure the dielectric constant.

[0016] Preferably, a fluid channel is formed in the inter-finger capacitance gap of the feeding loop of the loop antenna, and a liquid sample is injected into the fluid channel to measure the dielectric constant.

[0017] The present invention has the following beneficial effects:

[0018] The adaptive tuning RFID tag has a simple structure, requires no additional electronic components or equipment, is easy to use, has a simple installation and testing process, can be accessed at any time, and is flexible to various application scenarios. Its passive design does not require battery power, has a long service life, and is environmentally friendly. Compared with traditional dielectric constant measurement equipment, it is low-cost and has a simple testing process. It can meet the dielectric constant measurement needs of a variety of sample materials, including solids and liquids, and has a wide range of applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is the basic model of the adaptive tuning radio frequency identification tag used for dielectric constant measurement in Example 1.

[0020] Figure 2The dielectric constant range of the testable sample of the adaptively tuned RFID tag in Example 1 is shown in FIG.

[0021] Figure 3 This is the basic model of the adaptive tuning radio frequency identification tag used for dielectric constant measurement in Example 2.

[0022] Figure 4 It is the power transmission coefficient of the adaptively tuned RFID tag when the dielectric constant of the sample in Example 2 is 1.5.

[0023] Figure 5 It is the power transmission coefficient of the adaptive tuning RFID tag when the dielectric constant of the sample in Example 2 is 2.5.

[0024] Figure 6 The dielectric constant range of the testable sample of the adaptively tuned RFID tag in Example 2 is shown in FIG. DETAILED DESCRIPTION

[0025] The present invention will be further explained below with reference to the accompanying drawings;

[0026] Example 1

[0027] The present embodiment provides an adaptive tuning radio frequency identification tag for dielectric constant measurement, including a dipole antenna and an RFID chip. The RFID chip is an Impinj Monza R6 chip, and its adaptive adjustment function means that the chip adaptively adjusts the internal capacitance each time it is activated, thereby maximizing the tag sensitivity and power transmission efficiency in the current environment. Therefore, when the adaptive tuning function of the Impinj Monza R6 chip is turned on, the chip will adjust the internal capacitance based on the environment in which it is located. The adjustable range of its input capacitance is -100fF, -60fF, 0fF, +60fF, +100fF, and the corresponding status codes are 0, 1, 2, 3, and 4, respectively. The operating frequency of the tag is set to 915MHz, and the adaptive tuning radio frequency identification tag is as follows: Figure 1 shown.

[0028] The adaptive tuning radio frequency identification tag is attached to the surface of the sample to be tested. The RFID chip is activated by receiving the electromagnetic signal emitted by the reader through the antenna. It then automatically fine-tunes its internal impedance based on the environment to ensure impedance matching between the antenna and the RFID chip. At the same time, it returns an adaptive tuning status code reflecting the current tuning status, which is read by the reader.

[0029] Figure 2 This embodiment provides a state code read by a reader when an adaptively tuned radio frequency identification tag for dielectric constant measurement is attached to the surface of samples with different dielectric constants. Figure 2 The dielectric constant-state code model shown in Table 1 can be established:

[0030] Table 1

[0031] Dielectric constant range Status Code 9～12 4H 12～14 3H 14～16 2H 16～19 1H 19～20 0H

[0032] The self-adaptive tuning radio frequency identification tag is attached to the surface of the sample to be tested, and the status code is read by a reader to obtain the dielectric constant range of the sample to be tested according to Table 1.

[0033] Example 2

[0034] This embodiment is based on the embodiment 1, and the antenna of the adaptive tuning RFID tag is replaced by Figure 3 Solid samples with dielectric constants of 1.5 and 2.5 were placed on the inter-finger capacitor surface of the feeding ring, and the power transmission coefficient of the adaptive tuning RFID tag under different samples was measured at 900MHz. The results are shown in Figure 4 、 5 As shown, it can be seen that the status codes returned by the tag are different for different samples, indicating that the adaptive tuning RFID tag can return different status codes according to samples with different dielectric constants. Therefore, the adaptive tuning RFID tag can be used to measure the dielectric constant of samples.

[0035] In addition, the tag described in this embodiment can measure liquid samples. Specifically, a fluid channel needs to be made in the inter-finger capacitance gap of the loop antenna feeding ring, and then the liquid sample is injected into the fluid channel.

[0036] Figure 6 This embodiment provides an adaptive tuning radio frequency identification tag for dielectric constant measurement. When testing samples with different dielectric constants, the status code read by the reader is Figure 6 The dielectric constant-state code model shown in Table 2 can be established:

[0037] Table 2

[0038] Dielectric constant range Status Code 1～1.5 4H 1.5～2 3H 2～2.5 2H 2.5～3 1H 3～4 0H

[0039] By combining Table 1 and Table 2, a dielectric constant-antenna structure-state code model can be established, thereby expanding the measurement range of the dielectric constant of the adaptive tuning radio frequency identification tag.

Claims

1. Adaptively tuned radio frequency identification tag for dielectric constant measurement, characterized by: It includes an antenna and an RFID chip; the RFID chip has an adaptive tuning function. When the adaptive tuning radio frequency identification tag contacts the sample to be tested, an impedance mismatch occurs between the antenna and the RFID chip. The RFID chip changes the impedance by adjusting the internal capacitance and returns a status code related to the current tuning state.

2. The adaptively tuned radio frequency identification tag for dielectric constant measurement according to claim 1, wherein: The RFID chip is an Impinj Monza R6 chip.

3. The adaptively tuned radio frequency identification tag for dielectric constant measurement according to claim 1, wherein: The antenna is a dipole antenna, a loop antenna or other structures.

4. The adaptively tuned radio frequency identification tag for dielectric constant measurement according to claim 1, wherein: When used to measure the dielectric constant of a liquid material, the antenna is a loop antenna.

5. The method for using the adaptively tuned radio frequency identification tag for dielectric constant measurement according to any one of claims 1 to 4, characterized in that: The specific steps are as follows: Step 1: attaching the adaptive tuning radio frequency identification tag to the surface of a standard sample with a known dielectric constant; Step 2: Using a reader to read the state code corresponding to the adaptive tuning radio frequency identification tag when it is on the surface of different standard samples; Step 3: Establish a dielectric constant-state code model based on the dielectric constant of the standard sample and the read state code; Step 4: attach the adaptive tuning RFID tag to the surface of the sample to be tested, use a reader to read the status code returned by the adaptive tuning RFID tag, and determine the dielectric constant of the sample to be tested based on the dielectric constant-status code model.

6. The method for using the adaptively tuned radio frequency identification tag for dielectric constant measurement according to claim 5, wherein: A loop antenna is used as the antenna of an adaptively tuned RFID tag, and a solid sample is placed on the inter-finger capacitor surface of the feeding loop to measure the dielectric constant.

7. The method for using the adaptively tuned radio frequency identification tag for dielectric constant measurement according to claim 5, wherein: A fluid channel is made in the inter-finger capacitance gap of the feeding ring of the loop antenna, and a liquid sample is injected into the fluid channel to measure the dielectric constant.

8. The method for using the adaptively tuned radio frequency identification tag for dielectric constant measurement according to claim 5, wherein: The structure of the antenna in the adaptive tuning RFID tag is adjusted to prepare different adaptive tuning RFID tags; the state codes corresponding to the different adaptive tuning RFID tags on the surface of different standard samples are read to establish a dielectric constant-antenna structure-state code model.

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