CN210572106U - Flexible microwave sensor - Google Patents
Flexible microwave sensor Download PDFInfo
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- CN210572106U CN210572106U CN201921140543.8U CN201921140543U CN210572106U CN 210572106 U CN210572106 U CN 210572106U CN 201921140543 U CN201921140543 U CN 201921140543U CN 210572106 U CN210572106 U CN 210572106U
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Abstract
The utility model belongs to flexible electron device field to a flexible microwave sensor is specifically disclosed. The sensor comprises a flexible substrate, a coplanar waveguide transmission line and a complementary spiral resonator, wherein the coplanar waveguide transmission line comprises a first ground wire, a second ground wire and a coplanar waveguide signal transmission line, and the complementary spiral resonator is etched on the coplanar waveguide signal transmission line; the complementary spiral resonator comprises a conductive strip, a conductive block and a gap strip, wherein the conductive strip is in a zigzag structure, one end of the conductive strip is connected with the coplanar waveguide signal transmission line, the other end of the conductive strip is connected with the conductive block, gaps among the coplanar waveguide signal transmission line, the conductive strip and the conductive block jointly form the gap strip in the zigzag structure, the gap strip is used for forming an equivalent capacitor of the complementary spiral resonator, and the conductive strip and the conductive block jointly form an equivalent inductor of the complementary spiral resonator. The utility model discloses the detection flow of sensor is simple, and measurement accuracy is high.
Description
Technical Field
The utility model belongs to flexible electron device field, more specifically relates to a flexible microwave sensor.
Background
The microwave detection has the characteristics of simple equipment, quick real-time measurement, no limitation of severe detection environment and the like, and is widely applied to the fields of aerospace, biomedical treatment, chemical application, food industry and the like. The microwave detection technology is characterized in that interaction between microwaves and a detected material is utilized, and because electromagnetic field distribution is influenced by electromagnetic performance and geometric parameters of the detected material, whether the detected material and the inside of the detected material have defects or not or physical parameters such as dielectric/magnetic permeability can be determined by measuring changes of parameters such as reflection, scattering or transmission of microwave signals. Since microwaves cannot penetrate through metals and materials with good conductivity, microwave detection is generally used for detecting electromagnetic parameters and internal defects of non-metal (dielectric) materials, or surface crack defects and roughness of metal materials.
Common microwave sensor devices for detecting dielectric properties of non-metallic materials are generally prepared based on traditional hard substrate materials, so that the microwave sensor devices do not have the capabilities of bending, stretching and the like, are only suitable for planar detected materials, and greatly limit the practical application scenes. Moreover, most of such microwave sensing devices need to be calibrated by a known reference sample, and some of the microwave sensing devices need to process or treat a material sample to be detected, so that the detection process is complicated, and errors are easy to generate.
Therefore, what is needed in the art is a flexible microwave sensor for detecting the dielectric property of a non-metallic material, which can be well attached to the surface of the non-metallic material to be detected, and can also realize accurate detection of the dielectric property of the non-metallic material without reference to sample calibration.
SUMMERY OF THE UTILITY MODEL
Aiming at the defects or the improvement requirements in the prior art, the utility model provides a flexible microwave sensor, wherein the design is carried out through the related components of the flexible microwave sensor, the corresponding non-metallic material surface to be measured can be well jointed, the calibration of a known reference sample is not needed, and the dielectric property of the non-metallic material to be measured can be obtained without any special processing treatment on the sample to be measured; furthermore, the utility model discloses still improve through the structure and the mode that sets up of the concrete equipment and key subassembly such as ground wire, fluting, conduction band, conducting block and clearance strip to coplanar waveguide transmission line and complementary spiral resonator, corresponding can be according to flexible microwave sensor's lumped equivalent circuit model and analyze, resonance frequency point and amplitude size in combining the frequency domain transmission coefficient obtain being surveyed non-metallic material dielectric property parameter, including dielectric constant and loss tangent angle.
To achieve the above object, the present invention provides a flexible microwave sensor comprising a flexible substrate, and a coplanar waveguide transmission line and a complementary spiral resonator provided on an upper surface of the flexible substrate, wherein,
the coplanar waveguide transmission line comprises a first ground wire, a second ground wire and a coplanar waveguide signal transmission line, the first ground wire and the second ground wire are symmetrically arranged relative to the coplanar waveguide signal transmission line, a slot is arranged between the coplanar waveguide signal transmission line and the first ground wire and between the coplanar waveguide signal transmission line and the second ground wire, and the complementary spiral resonator is etched in the middle area of the coplanar waveguide signal transmission line;
the complementary spiral resonator comprises a conductive strip, a conductive block and a gap strip, wherein the conductive strip is of a zigzag structure, one end of the conductive strip is connected with the coplanar waveguide signal transmission line, the other end of the conductive strip is connected with the conductive block, gaps among the coplanar waveguide signal transmission line, the conductive strip and the conductive block jointly form the gap strip of the zigzag structure, the gap strip is used for forming an equivalent capacitor of the complementary spiral resonator, and meanwhile, the conductive strip and the conductive block jointly form an equivalent inductor of the complementary spiral resonator.
Further, the flexible substrate is a PET film, and the thickness of the flexible substrate is 50 um-500 um.
Furthermore, the thicknesses of the first ground wire, the second ground wire, the coplanar waveguide signal transmission line, the conductive strip and the conductive block are kept consistent and are all 1-10 um, and the first ground wire, the second ground wire, the coplanar waveguide signal transmission line, the conductive strip and the conductive block are all made of conductive materials.
Further, the conductive material is copper.
Further, the width ratio of the gap strips to the conductive strips is 1: 1-10: 1.
Further, the width ratio of the gap strips to the conductive strips is 2: 1.
Generally, through the utility model above technical scheme who thinks compares with prior art, mainly possesses following technical advantage:
1. the utility model discloses utilize flexible PET film to be flexible substrate, avoid the limitation that leads to based on traditional stereoplasm base material, can realize complementary helical resonator and the better laminating in surveyed non-metallic material surface, and simultaneously, integrate complementary helical resonator in the cavity structure of coplane waveguide transmission line, thereby found flexible microwave sensor and become rule arrangement and stable equivalent capacitance and equivalent inductance, corresponding can be according to flexible microwave sensor's lumped equivalent circuit model and carry out the analysis, resonant frequency point and range size in the combination frequency domain transmission coefficient, obtain being surveyed non-metallic material dielectric property parameter, including dielectric constant and loss tangent angle. The utility model discloses flexible microwave sensor's detection flow is simple, and measurement accuracy is high.
2. The utility model discloses the cavity structure is located coplanar waveguide signal transmission line's central zone to found flexible microwave sensor and become rule range and stable equivalent capacitance and equivalent inductance, with the calculation degree of difficulty that reduces in the testing process, improve the stability and the precision that detect.
3. The utility model discloses flexible substrate is the PET film, and its thickness is 50um ~ 500um, avoids the limitation that leads to based on traditional stereoplasm base material, can realize complementary helical resonator and the better laminating in measured non-metallic material surface.
4. The utility model discloses the width ratio of clearance strip and conductive band is 1: 1-10: 1, and further, the width ratio of the gap strips to the conductive strips is 2:1, so that the stability of the equivalent capacitance and the equivalent inductance of the sensor can be further improved, the calculation difficulty in the detection process is reduced, and the stability and the precision of detection are improved.
Drawings
Fig. 1 is a schematic structural diagram of a flexible microwave sensor according to an embodiment of the present invention;
FIG. 2 is a top view of the flexible microwave sensor referred to in FIG. 1;
3 fig. 33 3 is 3 a 3 schematic 3 sectional 3 view 3 taken 3 along 3 line 3 a 3- 3 a 3 in 3 fig. 32 3. 3
The same reference numbers will be used throughout the drawings to refer to the same or like elements or structures, wherein: 1-flexible substrate, 2-coplanar waveguide transmission line, 3-complementary spiral resonator, 21-first coplanar waveguide signal transmission line, 22-first ground line, 23-second ground line, 24-slot, 25-second coplanar waveguide signal transmission line, 31-gap strip, 32-conductive strip, 33-conductive block.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention. Furthermore, the technical features mentioned in the embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.
As shown in fig. 1, fig. 2 and fig. 3, the present invention relates to a flexible microwave sensor, which includes a flexible substrate 1, a coplanar waveguide transmission line 2 and a complementary spiral resonator 3, wherein the coplanar waveguide transmission line 2 and the complementary spiral resonator 3 are both disposed on the upper surface of the flexible substrate 1. The coplanar waveguide transmission line 2 includes a ground line module including a first ground line 22 and a second ground line 23 symmetrically disposed at both left and right ends of the upper surface of the flexible substrate 1. The first ground wire 22 and the second ground wire 23 are identical in size. The coplanar waveguide transmission line 2 further includes a coplanar waveguide signal transmission line 21, the coplanar waveguide signal transmission line 21 being disposed between the first ground 22 and the second ground 23, and having left and right ends spaced apart from the first ground 22 and the second ground 23 by the slots 24. The central region of the coplanar waveguide signal transmission line 21 is also etched with a complementary spiral resonator 3. The complementary spiral resonator 3 includes a conductive strip 32 and a conductive block 33, wherein the conductive strip 32 is a zigzag structure, one end of which is connected to the coplanar waveguide signal transmission line 21, the other end of which is connected to the conductive block 33, and the conductive block 33 is a square structure coaxial with the coplanar waveguide signal transmission line 21. The gaps between the coplanar waveguide signal transmission line 21, the conductive strip 32 and the conductive block 33 together constitute a gap stripe 31 of the zigzag structure, the gap stripe 31 constitutes an equivalent capacitance of the complementary spiral resonator 3, and at the same time, the conductive strip 32 and the conductive block 33 constitute an equivalent inductance of the complementary spiral resonator 3.
As shown in fig. 3, the flexible substrate 1 is a PET film with a thickness of 50um to 500um, and when the microwave frequency sweeping signal is 1GHz to 3GHz, the dielectric constant is 3.22 and the loss tangent angle is 0.01. The first ground wire 22, the second ground wire 23 and the coplanar waveguide signal transmission line 21 are all made of conductive material, in the preferred embodiment of the present invention, the conductive material is copper. The thicknesses of the first ground wire 22, the second ground wire 23 and the coplanar waveguide signal transmission line 21 are kept consistent and are all 1 um-10 um. The width ratio of the gap strips 31 to the conductive strips 32 is 1: 1-10: 1. In a preferred embodiment of the present invention, the width ratio of the gap strips 31 to the conductive strips 32 is 2: 1.
The preparation method of the flexible microwave sensor comprises the following steps:
step 1: attaching a PET film on a clean silicon wafer, performing carving treatment on the PET film to obtain a flexible substrate 1, spin-coating a forward photoresist on the upper surface of the flexible substrate 1, and heating to cure the forward photoresist.
Step 2: exposing and developing the flexible substrate 1 with the forward photoresist spirally coated on the upper surface by using a mask to obtain the patterns of the coplanar waveguide transmission line 2 and the complementary spiral resonator 3;
and step 3: and sputtering a layer of adhesive material and conductive material on the patterns of the coplanar waveguide transmission line 2 and the complementary spiral resonator 3 in sequence to obtain the coplanar waveguide transmission line 2 and the complementary spiral resonator 3 which are adhered on the flexible substrate 1. Wherein the adhesion material is chromium, and the conductive material is copper.
And 4, step 4: and cleaning the prepared flexible substrate 1 adhered with the coplanar waveguide transmission line 2 and the complementary spiral resonator 3 and peeling the substrate from the silicon wafer to prepare the flexible microwave sensor.
And 5: two miniature SMA joints are adhered to a flexible substrate 1 which is adhered with a coplanar waveguide transmission line 2 and a complementary spiral resonator 3 by adopting silver conductive adhesive so as to input and output microwave frequency sweeping signals, and the connected miniature SMA joints are packaged by utilizing ultraviolet light curing adhesive so as to ensure good conductivity and stability in the test process.
In the utility model, L and C are respectively the equivalent inductance and the equivalent capacitance of the coplanar waveguide transmission line 2; l iscAnd CcRespectively, the equivalent inductance and the equivalent capacitance of the complementary spiral resonator 3; rcDielectric losses from the flexible substrate 1 and conductor losses from the conductive material.
When the flexible microwave sensor is used for detecting the dielectric property of a detected non-metallic material, the detected non-metallic material is placed on the complementary spiral resonator 3, and different detected non-metallic materials have different dielectric properties (specifically, dielectric constant and loss tangent angle), so that the electromagnetic field distribution in the gap strip 31 area of the complementary spiral resonator 3 is changed, further, the electromagnetic field distribution is changed into the changes of equivalent capacitance and equivalent inductance, and the changes of a resonant frequency point and signal amplitude on a frequency domain transmission coefficient are caused. Through theoretical analysis and calculation of the lumped equivalent circuit model, a dielectric constant and loss tangent angle calculation model of the measured non-metallic material can be obtained.
The utility model discloses flexible microwave sensor's detection method specifically includes following step:
step 1: establishing a lumped equivalent circuit model of the flexible microwave sensor to obtain the equivalent inductance L of the complementary spiral resonator 3 under the no-load conditionCAnd an equivalent capacitance CCAnd measuring to obtain resonance frequency point and signal amplitude S on frequency domain transmission coefficient under no-load condition of the flexible microwave sensor21；
Step 2: according to the equivalent inductance L of the complementary spiral resonator 3 under no-load conditionCAnd an equivalent capacitance CCEstablishing a frequency domain resonance frequency point model under the no-load condition of the flexible microwave sensor:
and step 3: according to the signal amplitude S of the resonance frequency point21Establishing a dielectric loss model of the flexible substrate 1 and conductor loss models of the coplanar waveguide transmission line 2 and the complementary spiral resonator 3 under no load condition:
wherein Z isOThe characteristic impedance of the coplanar waveguide transmission line 2.
And 4, step 4: the measured non-metallic material is placed on the complementary spiral resonator 3, and because different measured non-metallic materials have different dielectric properties (specifically, dielectric constant and loss tangent angle), the electromagnetic field distribution of the gap strip 31 area of the complementary spiral resonator 3 is changed, and at the moment, the equivalent capacitance C of the complementary spiral resonator 3 under the condition of loading the measured non-metallic material is measured and obtainedc' and measuring to obtain the resonance frequency point and the signal amplitude S ' after deflection on the frequency domain transmission coefficient under the condition that the flexible microwave sensor loads the measured non-metallic material '21。
And 5: according to the equivalent capacitance C of the complementary spiral resonator 3 under loadingcEstablishing a frequency domain resonance frequency point offset model under the loading condition of the flexible microwave sensor:
step 6: amplitude S 'after signal deflection according to resonance frequency point'21The dielectric loss of the flexible substrate 1 under loading and the conductor loss of the coplanar waveguide transmission line 2 and the complementary spiral resonator 3 are modeled:
and 7: and constructing a dielectric constant model of the measured non-metallic material according to the frequency domain resonance frequency point model and the frequency domain resonance frequency point offset model:
wherein epsilonrIs the dielectric constant, epsilon, of the flexible substrate 1MUTIs the dielectric constant of the non-metallic material to be measured.
Constructing a loss tangent model of the measured non-metallic material according to the dielectric loss of the flexible substrate 1 under the no-load condition and the loading condition, the coplanar waveguide transmission line 2 and the conductor loss model of the complementary spiral resonator 3:
wherein, tan deltaMUTThe loss tangent angle of the measured non-metallic material is shown.
Thereby completing the detection of the dielectric property of the non-metallic material to be detected.
The utility model discloses electric capacity C is introduced owing to pass surveyed non-metallic material to part electromagnetic field under the fluting regionc_MUTAnd a resistance Rc_MUTAnd the relationship between the equivalent capacitance and the inductance of the complementary spiral resonator loaded with the measured non-metallic material is as follows:
wherein epsilonrIs the dielectric constant, epsilon, of the flexible substrate 1MUTIs the dielectric constant, C, of the non-metallic material to be measuredcAnd RcRespectively, the equivalent capacitance and the equivalent inductance, R, of the complementary spiral resonator shown in no-loadc' is the equivalent resistance of the complementary spiral resonator shown after loading the measured non-metallic material.
It will be understood by those skilled in the art that the foregoing is merely a preferred embodiment of the present invention, and is not intended to limit the invention to the particular forms disclosed, but on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention as defined by the appended claims.
Claims (7)
1. A flexible microwave sensor comprising a flexible substrate (1), and a coplanar waveguide transmission line (2) and a complementary helical resonator (3) provided on an upper surface of the flexible substrate (1), wherein,
the coplanar waveguide transmission line (2) comprises a first ground wire (22), a second ground wire (23) and a coplanar waveguide signal transmission line (21), the first ground wire (22) and the second ground wire (23) are symmetrically arranged relative to the coplanar waveguide signal transmission line (21), a slot (24) is arranged between the coplanar waveguide signal transmission line (21) and the first ground wire (22) and the second ground wire (23), and the complementary spiral resonator (3) is etched in the middle area of the coplanar waveguide signal transmission line (21);
complementary spiral resonator (3) include conductive strip (32), conducting block (33) and clearance strip (31), conductive strip (32) are the structure of returning the words line, and its one end is connected with coplanar waveguide signal transmission line (21), the other end with conducting block (33) are connected, the clearance between coplanar waveguide signal transmission line (21), conductive strip (32) and conducting block (33) constitutes clearance strip (31) of returning the words line structure jointly, and this clearance strip (31) are used for constituting complementary spiral resonator (3)'s equivalent capacitance, simultaneously, conductive strip (32) and conducting block (33) constitute complementary spiral resonator (3)'s equivalent inductance jointly.
2. The flexible microwave sensor according to claim 1, characterized in that the flexible substrate (1) is a PET film, and the thickness of the flexible substrate (1) is 50-500 um.
3. The flexible microwave sensor according to claim 1, wherein the first ground line (22), the second ground line (23), the coplanar waveguide signal transmission line (21), the conductive strip (32) and the conductive block (33) have the same thickness, which is 1um to 10 um.
4. The flexible microwave sensor according to claim 1, wherein the first ground line (22), the second ground line (23), the coplanar waveguide signal transmission line (21), the conductive strip (32) and the conductive block (33) are made of conductive materials.
5. The flexible microwave sensor of claim 4 wherein the conductive material is copper.
6. The flexible microwave sensor according to claim 1, characterized in that the width ratio of the gap strips (31) to the conductive strips (32) is 1: 1-10: 1.
7. The flexible microwave sensor according to claim 1, characterized in that the width ratio of the gap strips (31) to the conductive strips (32) is 2: 1.
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN110320266A (en) * | 2019-07-19 | 2019-10-11 | 华中科技大学 | A kind of flexible microwave sensor and preparation method thereof and detection method |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN110320266A (en) * | 2019-07-19 | 2019-10-11 | 华中科技大学 | A kind of flexible microwave sensor and preparation method thereof and detection method |
| CN110320266B (en) * | 2019-07-19 | 2023-12-05 | 华中科技大学 | Flexible microwave sensor and preparation method and detection method thereof |
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