Sensors having gap-based sensing devices and methods of making and using the same

Abstract

The invention of the present disclosure is entitled "Sensor with gap-based sensing device and method of making and using the same", and provides a sensor. The sensor includes at least one sensing device and an antenna in operative association with the sensing device, the sensing device including a first electrode and a second electrode and a gap defined as a distance between one or more facing inner surfaces of the first and second electrodes, wherein the gap distance at least partially determines a threshold value of one or more sensing parameters.

Description

Background Art

[0001] The present invention relates to sensors, and more particularly to chemical, physical or biological sensors.

[0002] Typically, radio frequency identification (RFID) tags are used for asset tracking. For example, RFID tags can be used to track the removal of objects from a location and the replacement of objects at that location. RFID tags have been combined with biometric readers. Such RFID circuits use certain functional blocks to process biometric signals and RFID signals. RFID tags can have unique numbers and can be used to read these identification numbers with information related to the items to which the tags are attached. RFID tags are also used to detect unauthorized opening of containers and luggage bags. RFID tags can be included in a variety of items, such as stamps and other mailing labels, clothing, and many other items. RFID systems have recently been applied to wireless sensing applications, such as RFID-based temperature sensors.

[0003] These and other properties of RFID tags can be used to form sensors capable of detecting chemical, biological, and physical properties. Summary of the invention

[0004] In one embodiment, a sensor is provided. The sensor includes at least one sensing device and an antenna in operative association with the sensing device, the sensing device including a first electrode and a second electrode and a gap defined as a distance between one or more facing inner surfaces of the first and second electrodes, wherein the gap distance at least partially determines a threshold value of one or more sensing parameters.

[0005] In another embodiment, a radio frequency based sensor is provided. The sensor includes a sensing gap defined by two or more electrodes and an antenna in operative association with the sensing gap and the electrodes.

[0006] In yet another embodiment, a method of making a sensor is provided. The method includes providing an antenna having one or more turns, and forming a sensing gap including first and second electrodes and defined by a distance between one or more facing inner surfaces of the first and second electrodes, wherein the gap distance at least partially determines a threshold of one or more sensing parameters, and wherein the sensing gap is in operative association with the antenna. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] These and other features, aspects and advantages of the present invention will be better understood when the following detailed description is read with reference to the accompanying drawings, in which like characters represent like parts throughout the drawings, and in which:

[0008] Figure 1-3is an illustration of a sensor having a separate sensing device in electrical communication with an antenna;

[0009] Figure 4-6 is an illustration of a sensor in which a portion of an antenna is configured to function as a sensing device;

[0010] Figure 7 is a top view of a sensing device having an electrode with a plurality of holes;

[0011] Figure 8 yes Figure 7 A side view of a sensing device;

[0012] Fig. 9 It is a graphical representation of the signal changes of a sensing device when detecting a physical, chemical or biological parameter of interest;

[0013] Figure 10-12 is a graphical representation of the sensor's detection principle; and

[0014] Fig.13 Is a graphical representation of the sensing events detected and recorded by the sensor when the sensor is physically located in the measurement environment.

[0015] These and other features, aspects and advantages of the present invention will become better understood when the following detailed description is read with reference to the accompanying drawings, in which like characters represent like parts throughout the several views. DETAILED DESCRIPTION

[0016] Embodiments of the technology are directed to a sensor having at least one sensing device. The sensing device has a first electrode and a second electrode. The sensing device also includes a gap defined as a distance between one or more facing inner surfaces of the first and second electrodes. The gap distance at least partially determines a threshold of one or more sensed parameters. The sensed parameters may include physical parameters (e.g., pressure), chemical parameters (e.g., pH, glucose levels, gases), and biological parameters (e.g., viruses, proteins, DNA).

[0017] The sensing device with the gap can be in electrical communication with the antenna. The sensing device can be electrically connected to the antenna in series or in parallel. In some embodiments, the sensor can be wireless or wired or electronic, based on (radio frequency identification) RFID, based on non-RFID, or a combination of two or more items. In an embodiment where the sensor is an RFID-based sensor, the sensor can be a wireless sensor. In addition, the RFID-based sensor can include a passive RFID tag or a semi-passive RFID tag or an active RFID tag. In addition, the RFID tag can be configured to operate in a frequency range such as, but not limited to, a low frequency range from about 125 KHz to about 135 KHz, a high frequency range of about 13.56 MHz, an ultra-high frequency (UHF) range from about 850 MHz to about 960 MHz, and a microwave frequency range of about 2.45 GHz - 5.8 GHz.

[0018] In certain embodiments, an RFID tag may be converted into an RFID sensor. In these embodiments where an RFID tag is converted into an RFID sensor, a sensing device having a gap is incorporated into the RFID tag. In these embodiments, a gap configured to act as a sensing area may be provided on the RFID tag such that the gap is operatively associated with the antenna of the RFID tag. Figure 1-3 As shown, the gap can be a separate entity from the antenna of the RFID tag. Figure 4-6 As shown, the gap can be part of the antenna. Although not shown, Figure 1-6 The illustrated embodiment may include two or more sensing devices. In some embodiments, the size of the antenna may be in the range of from about 0.5 mm x 0.5 mm to about 100 x 100 mm. In one embodiment, the size of the antenna may be about 10 mm x 10 mm.

[0019] In general, when a portion of an antenna is configured to act as a sensing device, the spacing between antenna loops or windings in these portions can be in the range of about 0.005 microns to about 500 microns. In one embodiment, the spacing between the windings of the antenna in the portion configured to act as a sensing device is about 25 microns.

[0020] When a sensing device is combined in an RFID tag, the electrical response of the sensor can be one or more of a resistance change, a capacitance change, or a combination of resistance and capacitance changes. In one embodiment, by combining a sensing device in an RFID tag, the electrical response of the RFID sensor is converted into a resonant change in the complex impedance response of the antenna. The signal from the RFID tag is reflected as one or more of the appearance or disappearance of the digital ID read by the RFID tag of the digital reader / writer or the change in the resonant property of the complex impedance of the antenna. When used in this article, the term "digital reader / writer" is a device that reads digital information from the memory chip of the RFID tag and writes user-defined digital information to the memory chip. The digital reader / writer may also be referred to as a "reader" or "interrogator" or "writer" in this application. In some embodiments, adding a sensing device to an RFID tag may result in the formation of a resonant sensing structure. In these embodiments, environmental changes affect the resonance of the sensor. The digital writer writes the time series of data into the memory chip. If the resonance of the sensor changes due to the sensing device, so that the resonant frequency position is outside the frequency range of the written digital data, and / or the resonant amplitude is outside the amplitude range (smaller or larger) of the written digital data, then some values ​​are not written to the chip, thereby permanently storing the time series data. For time-critical applications that need to track the time the sensor is exposed to the environment, digital data is recorded to the chip only when the parameter of interest exceeds the threshold.

[0021] In one embodiment, the digital reader / writer can be combined with a scanner of the impedance of the resonant sensor to determine the properties of the sensor resonance. As used herein, the term "scanner of the impedance of the resonant sensor" is a device that scans the frequency across the resonance of the sensor and determines the properties of the sensor resonance. Non-limiting examples of properties of the sensor resonance may include the width, shape, symmetry of the shape, peak height, and peak position of the complex impedance signal.

[0022] When a digital reader / writer device is combined with a scanner of the impedance of a resonant sensor, the data stored in the memory of the memory chip of the RFID sensor can contain at least one attribute of the sensor resonance (e.g., the width, shape, symmetry of the shape, peak height, and peak position of the complex impedance signal). This sensing information is stored in the memory chip together with the time series of data. The sensing information is not one-bit information (on-off response), but quantitative information with an information resolution that is not limited by the sensor, but by the scanner of the impedance of the resonant sensor.

[0023] The shape of the sensing gap may include a time gap, an array of time gaps, a morphologically induced shape, a serpentine, a coil, a fragmented shape, or a combination thereof. In some embodiments, the gap may be in the form of a channel, an interdigitated electrode structure, a three-dimensional (3-D) electrode structure, or a combination thereof. In some embodiments, the gap may include a zero-dimensional gap structure, a one-dimensional gap structure, a two-dimensional gap structure, and a three-dimensional gap structure. A zero-dimensional gap structure is a gap structure formed by electrodes with a smaller cross-section, so that the gap between the electrodes is small enough to accommodate only one target species (e.g., only one spore, only one bacterium, etc.). A one-dimensional gap structure is a gap structure formed by electrodes with a smaller cross-section in one direction, so that the gap is small enough to accommodate only a one-dimensional array of target species (e.g., spores or bacteria in a row). A two-dimensional gap structure is a gap structure formed by electrodes with a small cross-section in two directions. A three-dimensional gap structure is a gap structure formed by electrodes with a small cross-section in three directions. The structure of the gap may also be changed according to the ease of manufacture, and also based on the physical properties and / or chemical and / or biological species to be detected.

[0024] In some embodiments, the material present in the gap may include metal, organic material, semiconductor material, organic electronic material, dielectric material or a combination thereof. In some embodiments, the gap may include a sensing material for detecting chemical, biological and / or physical changes around the gap sensor. Non-limiting examples of sensing materials in the gap region include nanowires, nanofibers, nanoparticles, configured materials with functional additives, doped conjugated polymers, inorganic materials, organic materials, polymeric materials, biomaterials, living cells, biomolecule receptors, antibodies, aptamers, nucleic acids, biomolecules functionalized by metal particles, biomolecules functionalized by polymer particles, biomolecules functionalized by silicon particles, and any other known sensing materials and combinations thereof that produce detectable changes in resistance and / or capacitance when the chemical, biological and / or physical changes around the sensing device occur.

[0025] In other embodiments, the gap may be substantially free of electrode material. In embodiments where the gap does not contain any sensing material, the signal change may result from a change in the composition of the sample in the gap. Non-limiting examples of changes in the composition of the sample include water vapor concentration (relative humidity) in air or any other gas in water, ion concentration (e.g., deionized water vs. drinking water vs. seawater), organic matter concentration in wastewater, biological matter (e.g., bacteria, cells, viruses) concentration in water.

[0026] In some embodiments, the distance between the facing inner surfaces of the first and second electrodes can be in the range of about a few nanometers to about several thousand nanometers. In one embodiment, the gap distance is in the range of about 2 nanometers to about 10,000 nanometers. The gap distance can be determined based on the parameters to be detected. For example, the gap distance can be determined based on the size of the biological attribute to be detected. In another example, for detecting bacteria that are generally tens of microns in size, the gap distance can be larger, while for detecting viruses that are tens of nanometers, the gap distance can be smaller.

[0027] In one embodiment, the first electrode or the second electrode or both have a continuous surface. For example, the first or second electrode can be a continuous rectangle, square, circle, or any other geometric shape. In another embodiment, the first or second electrode can have a discontinuous surface. For example, the first or second electrode can have a patterned surface such as a grid, a surface with holes (wherein the holes can be or are not through holes), a surface with protruding structures, or a combination thereof. In addition, the first and second electrodes can have the same or different types of surfaces. In one embodiment, a dielectric material can be applied to one or more exposed surfaces of the first electrode or the second electrode or both to prevent the electrodes from shorting when the sensor is exposed to a conductive fluid.

[0028] In certain embodiments, the electrode material may be capable of transmitting an electrical current with certain electrical properties. Non-limiting examples of electrode materials include copper, aluminum, gold, silver, copper alloys (e.g., brass, bronze), aluminum alloys (e.g., Nambe TM 、Silumin TM ), gold alloys (e.g., Electrum TM ), conductive polymers, doped conductive polymers (such as doped polyacetylene, doped polyaniline, doped polythiophene), carbon nanotubes, carbon fibers, carbon particles, carbon paste, conductive ink or a combination thereof.

[0029] In one embodiment, the electrical impedance of the electrode material is less than about 100 ohms. In another embodiment, the electrical impedance of the electrode material is less than about 50 ohms or less than about 0.5 ohms. The electrical impedance of the antenna structure may be in the range of about 0.5 ohms to less than 100 ohms.

[0030] In some embodiments, a method of making a sensor may include providing an antenna having one or more turns. In addition, a sensing gap including first and second electrodes is made. In some embodiments, the antenna may be made by using techniques such as microlithography and / or nanolithography. The sensing gap or sensing device may be made by using techniques such as, but not limited to, self-assembly, roll-to-roll processing, photolithography, liquid deposition, milling, focused ion beam milling, or microlithography. In one embodiment, the first and second electrodes may be formed by a batch manufacturing process. In embodiments where a portion of the antenna is configured to act as a sensing device, the gap may be made separately by using the techniques listed above. In embodiments where the sensing device is a separate entity from the antenna, the sensing device may be made separately and subsequently coupled to the antenna. In addition, the sensing device may be coupled to the antenna in a parallel or series electrical connection by using the manufacturing techniques listed above. In one embodiment, the sensor may be arranged on a silicon surface such that the silicon surface within the gap does not contain any surface modification for non-specific binding of molecules and molecular assemblies.

[0031] Now refer to Figure 1 , the sensor 10 comprises a sensing device 12 having a gap 14 between facing inner surfaces of two electrodes 16, and a gap length 13 is defined as the distance along the two electrodes 16. The sensing device 12 is electrically coupled to an antenna 18 by using a connector 17. Figure 1 In the illustrated embodiment of the sensor 10, the sensing device 12 and the antenna 18 are connected in series. In one example, the connector 17 can be a conductive cable, wire, strip or the like. The sensor 10 also includes an antenna 18 having two ends 20 and 22. The ends 20 and 22 of the antenna are electrically connected using a conductor medium 24 (such as a conductor wire, a conductor strip or a conductor cable) in a manner that the conductor medium 24 does not electrically short-circuit other areas of the antenna 18 across which the conductor medium crosses. A memory chip 26 is used to store information. The chip 26 can be activated by a radio frequency signal transmitted from a read / write unit. The antenna 18 of the sensor 10 receives and transmits signals. The signal transmitted by the antenna 18 is picked up by a reader or a pickup coil (not shown) arranged in the operational proximity of the sensor 10. The pickup coil can be part of the reader. In one example, the sensor 10 and the pickup coil can be coupled via inductive coupling. Alternatively, in another embodiment, the sensor 10 and the pickup coil do not have to be coupled via electrical contact. In such an embodiment, the sensor 10 and the pickup coil can be adapted to communicate wirelessly.

[0032] like Figure 2As shown, the sensor 30 includes a sensing device 32 having a gap 34 defined by an electrode 36. The sensing device 32 is electrically coupled to an antenna 38 by using an electrical conductor 40. The electrical conductor 40 is in turn coupled to a sub-connector 42, which is directly coupled to the sensing device 32. In one embodiment, the electrical conductor 40 and the sub-connector 42 may be identical, that is, the electrical conductor 40 and the connector 42 may form a continuum of a connecting medium. In another embodiment, the electrical conductor 40 and the connector 42 may be different physical entities. The sensor 30 also includes a memory chip 44. In addition, the two ends 46 and 48 of the antenna 38 are electrically connected using a conductor medium 50 (such as a conductor wire, a conductor strip, or a conductor cable), and the electrical connection is made in such a way that the conductor medium does not electrically short-circuit other areas of the antenna 38 that are crossed by the conductor medium.

[0033] Now go to Figure 3 , the sensor 52 includes a sensing device 54 having a gap 56 defined by electrodes 58. The sensing device 54 is electrically coupled to a memory chip 62 by using an electrical conductor 60. The electrical connection between the sensing device 54 and the memory chip 62 is performed via an analog input in the memory chip. The memory chip 62 is in turn coupled to an antenna 64. The two ends 66 and 68 of the antenna 64 are electrically connected using a conductor medium 70 (such as a conductor wire, a conductor strip or a conductor cable), and the electrical connection is made in such a way that the conductor medium 70 does not electrically short-circuit other areas of the antenna 64 across which the conductor medium crosses.

[0034] Figure 4-6 An embodiment is shown in which a portion of the antenna is configured to act as a sensing device. Figure 4 In the illustrated embodiment of FIG. 8 , sensor 72 includes antenna 74. A portion 78 of antenna 74 is configured to function as sensing device 80. The portion 78 of antenna 74 includes a discontinuity in the antenna that functions as a gap 76 for sensing device 80. Although not shown, there may be two or more such gaps in antenna 74. Antenna 74 also includes two ends 82 and 84 electrically connected using a conductor medium 86. Sensor 72 also includes a memory chip 87.

[0035] Figure 5A sensor 88 is shown with an antenna 90. The antenna 90 includes two sensing devices, namely a first sensing device 92 and a second sensing device 94. The first sensing device 92 includes a first gap 96 formed between portions of windings 98 and 100 and having a gap length 95. Similarly, the second sensing device 94 includes a second gap 102 formed between portions of windings 104 and 106 and having a gap length 93. As shown, the distances between windings 98 and 100 and 104 and 106 are smaller than the distances between the remaining windings of the antenna 90. These smaller distances enable the formation of the sensing devices 92 and 94. The antenna 90 also includes two ends 108 and 110 electrically connected using a conductor medium 112. The sensor 88 also includes a memory chip 114.

[0036] Figure 6 A sensor 120 is shown that employs an antenna 122. Projections 124 and 126 are configured to function as a single sensing device 128. Sensing device 128 includes a gap 130 having a gap length represented by dashed line 131 and defined between winding portions 132 and 134. Gap 130 continues from one projection 124 to the other projection 126. Antenna 122 also includes two ends 136 and 138 that are electrically connected using a conductor medium 140. Sensor 120 also includes a memory chip 142. Individual gap lengths 95 and 93 (see FIG. 1 ) of sensing devices 92 and 94 are provided. Figure 5 ) respectively, the gap length 131 of the sensing device 128 is longer, thereby providing an increased sensing area. In biological detection of bacteria, spores or viruses, a longer gap provides a higher probability of capturing the target species within the gap. In chemical detection of gases and liquids, a longer gap provides a greater signal response due to the increased sensing area.

[0037] Figure 7 A top view of an embodiment of a sensing device 146 that can be employed in the technology is shown. The sensing device 146 includes a plurality of holes 148 on a top electrode 150 supported between support structures 152. In one embodiment, the diameter of the holes can be in a range from about 5 nanometers to about 20,000 nanometers. The top electrode 150 can have a geometric shape such as a square, rectangle, circle, hexagon, triangle, or any other polygon. Figure 8A cross-sectional side view of a sensing device 146 is shown. As shown, the device also includes a bottom electrode 154. As with the top electrode 150, the bottom electrode may have different geometric shapes such as square, rectangular, circular, hexagonal, triangular or any other polygon. Although not shown, the top and bottom electrodes 150 and 154 may or may not have flat surfaces. For example, there may be depressions or protrusions on one or both electrodes to customize the gap of the sensing device. In one embodiment, the bottom electrode 154 may have a protrusion in the direction of the top electrode 150 so that the distance between the top electrode 150 and the bottom electrode 154 is smaller in the area with the protrusion.

[0038] Fig. 9 The changes in the signal of the sensing device when detecting the physical, chemical or biological parameter of interest are shown. In the embodiment currently considered, the changes in the resonant properties of the complex impedance of the antenna are measured. In the illustrated embodiment, the complex impedance response of the antenna is shown on the ordinate 160, and the abscissa 162 represents the scanning frequency of the resonance of the RFID sensor. Curves 164, 166, 168 and 170 represent the changes in the complex impedance of the sensor as a function of frequency when the sensor is exposed to different samples or the samples around the sensor change their physical, chemical or biological properties. As shown in the figure, the response changes of the sensor are reflected as changes in the width, shape, symmetry of the shape, peak height and peak position of the complex impedance signal, that is, curves 164, 166, 168 and 170.

[0039] In some embodiments, when the antenna does not detect any species or parameters that reach a certain threshold, the circuit of the antenna is incomplete in the initial stage. In these embodiments, the circuit of the antenna is physically incomplete due to the discontinuity of the gap formation. In these embodiments, in the initial state, the impedance of the incomplete circuit of the antenna may be greater than or equal to about 1000 ohms. When the physical property changes of the species or samples to be detected affect the resistance and capacitance of the gap so that the amplitude of the resonance is higher than the determined threshold in the operating frequency range of the digital reader / writer, the circuit of the antenna is complete. At this stage, the reader / writer is able to read or identify the memory chip. The digital writer writes the time series of data into the memory chip. Non-limiting examples of physical properties that affect the response of the sensor are ionizing radiation (e.g., gamma radiation, beta radiation, X-ray) dose, liquid conductivity, temperature, pressure, acceleration, or a combination thereof.

[0040] In one embodiment, the addition of the sensing device results in the formation of a resonant structure, and the sensing device affects the resonance of the structure as a function of environmental changes. If the resonance is altered due to the sensing device attached to the RFID so that the resonance falls outside the frequency range for writing digital data for the sensor, certain values ​​of the sensor response are not written to the memory chip, thus permanently storing the time series data.

[0041] Figure 10-12 The concept of appearance or disappearance of a digital ID read by a digital reader / writer is shown. The midpoint represents the operating frequency range of the digital writer / reader. The operating frequency range of the digital writer / reader can be from about 120 KHz to about 5.8 GHz. In one example, the midpoint can be at about 13.56 MHz frequency. Fig.10 As shown, the complex impedance response of the antenna at frequency F 176 plotted on ordinate 172 and abscissa 174 is represented by curve 178. Fig.10 In the embodiment shown in FIG. 1 , the resonance amplitude of the antenna is too weak due to the response of the sensing device (curve 180). In this case, the writer cannot detect the RFID sensor and therefore does not write part of the time series into the memory chip. Fig.11 As shown, the impedance / resonance response of the sensor (curve 182) has shifted due to the sensor response, and because the response of the sensing device is too far from the midpoint (as shown by arrow 184), the reader / writer cannot find the RFID sensor and does not write part of the time series to the memory chip. Now referring to Fig.12 , the resonance moves away from the midpoint 176 as shown by arrow 188 before the sensor responds, and overlaps with the midpoint when the sensor responds (186), the reader / writer finds the RFID sensor and writes part of the time series into the memory chip. Accordingly, the reader / writer cannot detect the RFID sensor and therefore does not write part of the time series into the memory chip.

[0042] Fig.13 A digital data stream 192 is shown, which has sequences 194, 196 and 198 that are not written to the memory chip by the writer, while sequences 200 and 202 are written to the memory chip by the writer. The digital data stream is generated by a reader / writer. The sensor is physically located in the measurement environment. For time-critical applications that require tracking the time of exposure exceeding a predetermined limit, digital data is recorded on the chip only when the parameter of interest exceeds a threshold. The horizontal axis 204 represents time. For time intervals 206 and 208 where the values ​​210 and 212 of the parameter of interest are respectively higher than the threshold 214, the data stream is recorded. For time intervals 216, 218 and 220 where the values ​​222, 224 and 226 of the parameter are respectively lower than the threshold 214, the data stream is not recorded.

[0043] The values ​​recorded in the memory chip contain a digital data stream related to the time of the recorded event and the sensed value of the response of the gap-based device. The sensed value of the response of the gap-based device is related to the concentration or level or amplitude of the physical, chemical or biological parameter of interest in the measurement sample surrounding the sensor.

[0044] While only certain features of the invention have been shown and described herein, many modifications and changes will become apparent to those skilled in the art. It is, therefore, to be understood that the appended claims are intended to cover all such modifications and changes as fall within the scope of the invention.

Claims

1. A sensor, comprising: at least one sensing device comprising a first electrode and a second electrode and a gap defining a distance between one or more facing inner surfaces of the first electrode and the second electrode, wherein a change in a physical property of a sample to be detected provides a change in capacitance and / or resistance of the gap; an antenna having ends spaced apart from one another and connected to one another via a conductive medium, the antenna comprising a plurality of windings; as well as an RFID tag incorporating a memory chip, wherein the RFID tag is coupled to the at least one sensing device to form a resonant sensing structure, wherein the change in capacitance and / or resistance is converted into a change in the resonant frequency of the resonant sensing structure, so that the RFID tag enables the memory chip to be accessed only when the resonant frequency is within an operable frequency range of the RFID tag, The first electrode and the second electrode are respectively formed by a first winding and a second winding of the plurality of windings, wherein one or more of the first and second windings have at least one protrusion, and the gap has a length extending along the at least one protrusion. 2 . The sensor of claim 1 , wherein the gap between the inner surfaces of the first and second electrodes is in the range of 5 nm to 10,000 nm.

3. The sensor of claim 1, wherein a portion of the antenna is configured to function as the sensing device.

4. The sensor of claim 1, wherein the sensor is configured to detect chemical species or biological species or physical properties or a combination thereof.

5. The sensor of claim 1, wherein the gap is free of electrode material or sensing material or both.

6. The sensor of claim 1, wherein the gap comprises air, dielectric material, metal, semiconductor material, organic electronic material, biosensing material, organic sensing material, inorganic sensing material.

7. The sensor of claim 1, wherein the sensor is disposed on a silicon surface without any surface modification to enable non-specific binding of molecules, molecular assemblies, or both.

8. The sensor of claim 1, wherein the electrode material comprises metal, conductive polymer, doped polyacetylene, doped polyaniline, doped polythiophene, carbon nanotubes, carbon fibers, carbon particles, carbon paste, conductive ink, or a combination thereof.

9. The sensor of claim 8, wherein the metal comprises copper, aluminum, gold, silver, an alloy of copper, an alloy of aluminum, an alloy of gold, or a combination thereof.

10. A radio frequency based sensor comprising: a sensing gap defining the distance between one or more facing inner surfaces of two or more electrodes, wherein a change in a physical property of a sample to be detected provides a change in capacitance and / or resistance of said sensing gap; an antenna operatively associated with the sensing gap and the electrode, wherein the antenna has ends spaced apart from one another and connected to one another via a conductive medium, the antenna comprising a plurality of windings; as well as An RFID tag incorporating a memory chip, wherein the RFID tag is configured to form a resonant sensing structure, wherein the change in capacitance and / or resistance is converted into a change in the resonant frequency of the resonant sensing structure, so that the RFID tag enables the memory chip to be accessed only when the resonant frequency is within an operable frequency range of the RFID tag, The two or more electrodes are respectively formed by two or more windings of the plurality of windings, wherein one or more of the two or more windings have at least one protrusion, and the sensing gap has a length extending along the at least one protrusion.

11. A method for making a sensor, comprising: providing an antenna having a plurality of windings, wherein the antenna has ends that are spaced apart from one another and connected to one another via a conductive medium; as well as forming a sensing gap comprising first and second electrodes and defining a distance between one or more facing inner surfaces of the first and second electrodes, wherein a change in a physical property of a sample to be detected provides a change in capacitance and / or resistance of the sensing gap, providing an RFID tag incorporating a memory chip, wherein the RFID tag is configured to form a resonant sensing structure, wherein changes in the capacitance and / or resistance are converted into changes in a resonant frequency of the resonant sensing structure, such that the RFID tag enables the memory chip to be accessed only when the resonant frequency is within an operable frequency range of the RFID tag, wherein the sensing gap is associated with the antenna operation, The first electrode and the second electrode are respectively formed by a first winding and a second winding of the plurality of windings, wherein one or more of the first and second windings have at least one protrusion, and the sensing gap has a length extending along the at least one protrusion.

12. A sensor comprising: at least one sensing device comprising a first electrode and a second electrode and a gap defining a distance between one or more facing inner surfaces of the first electrode and the second electrode, wherein a change in a physical property of a sample to be detected provides a change in capacitance and / or resistance of the gap; an antenna having ends spaced apart from one another and connected to one another via a conductive medium, the antenna comprising a plurality of windings; as well as an RFID tag incorporating a memory chip, wherein the RFID tag is coupled to the at least one sensing device to form a resonant sensing structure, wherein the change in capacitance and / or resistance is converted into a change in the resonant frequency of the resonant sensing structure, so that the RFID tag enables the memory chip to be accessed only when the resonant frequency is within an operable frequency range of the RFID tag, The first electrode and the second electrode are formed by a first winding and a second winding of the plurality of windings, respectively, and the distance of the gap between the first and second windings is smaller than the corresponding distance between the remaining windings of the plurality of windings.

13. The sensor of claim 12, wherein the gap between the inner surfaces of the first and second electrodes is in the range of 5 nm to 10000 nm.

14. The sensor of claim 12, wherein the sensor is configured to detect a chemical species or a biological species or a physical property or a combination thereof.

15. The sensor of claim 12, wherein the gap is free of electrode material or sensing material or both.

16. The sensor of claim 12, wherein the gap comprises air, dielectric material, metal, semiconductor material, organic electronic material, biosensing material, organic sensing material, inorganic sensing material.

17. The sensor of claim 12, wherein the sensor is disposed on a silicon surface without any surface modification to enable non-specific binding of molecules, molecular assemblies, or both.

18. The sensor of claim 12, wherein the electrode material comprises metal, conductive polymer, doped polyacetylene, doped polyaniline, doped polythiophene, carbon nanotubes, carbon fibers, carbon particles, carbon paste, conductive ink, or a combination thereof.

19. The sensor of claim 18, wherein the metal comprises copper, aluminum, gold, silver, an alloy of copper, an alloy of aluminum, an alloy of gold, or a combination thereof.

20. A radio frequency based sensor comprising: a sensing gap defining the distance between one or more facing inner surfaces of two or more electrodes, wherein a change in a physical property of a sample to be detected provides a change in capacitance and / or resistance of said sensing gap; an antenna operatively associated with the sensing gap and the electrode, wherein the antenna includes at least a portion of the two or more electrodes, and wherein the antenna has ends spaced apart from one another and connected to one another via a conductive medium, the antenna including a plurality of windings; and An RFID tag incorporating a memory chip, wherein the RFID tag is configured to form a resonant sensing structure, wherein the change in capacitance and / or resistance is converted into a change in the resonant frequency of the resonant sensing structure, so that the RFID tag enables the memory chip to be accessed only when the resonant frequency is within an operable frequency range of the RFID tag, The two or more electrodes are respectively formed by two or more windings of the plurality of windings, and the distance of the sensing gap between the two or more windings is smaller than the corresponding distance between the remaining windings of the plurality of windings.

21. A method for making a sensor, comprising: providing an antenna having a plurality of windings, wherein the antenna has ends that are spaced apart from one another and connected to one another via a conductive medium; as well as forming a sensing gap comprising first and second electrodes and defining a distance between one or more facing inner surfaces of the first and second electrodes, wherein a change in a physical property of a sample to be detected provides a change in capacitance and / or resistance of the sensing gap, providing an RFID tag incorporating a memory chip, wherein the RFID tag is configured to form a resonant sensing structure, wherein changes in the capacitance and / or resistance are converted into changes in a resonant frequency of the resonant sensing structure, such that the RFID tag enables the memory chip to be accessed only when the resonant frequency is within an operable frequency range of the RFID tag, wherein the sensing gap is operatively associated with the antenna, and wherein the antenna comprises at least a portion of the first and second electrodes, The first electrode and the second electrode are formed by a first winding and a second winding of the plurality of windings, respectively, and the distance of the gap between the first and second windings is smaller than the corresponding distance between the remaining windings of the plurality of windings.

22. A sensor comprising: at least one sensing device comprising a first electrode and a second electrode and a gap defining a distance between one or more facing inner surfaces of the first electrode and the second electrode, wherein a change in a physical property of a sample to be detected provides a change in capacitance and / or resistance of the gap, and wherein one of the first and second electrodes has at least one aperture; an antenna operatively associated with the sensing device, wherein the antenna has ends spaced apart from one another and connected to one another via a conductive medium, the antenna comprising a plurality of windings; as well as an RFID tag incorporating a memory chip, wherein the RFID tag is coupled to the at least one sensing device to form a resonant sensing structure, wherein the change in capacitance and / or resistance is converted into a change in the resonant frequency of the resonant sensing structure, so that the RFID tag enables the memory chip to be accessed only when the resonant frequency is within an operable frequency range of the RFID tag, The first electrode and the second electrode are respectively formed by a first winding and a second winding of the plurality of windings, wherein one or more of the first and second windings have at least one protrusion, and the gap has a length extending along the at least one protrusion.

23. The sensor of claim 22, wherein the gap between the inner surfaces of the first and second electrodes is in the range of 5 nm to 10000 nm.

24. The sensor of claim 22, wherein a portion of the antenna is configured to function as the sensing device.

25. The sensor of claim 22, wherein the sensor is configured to detect a chemical species or a biological species or a physical property or a combination thereof.

26. The sensor of claim 22, wherein the gap is free of electrode material or sensing material or both.

27. The sensor of claim 22, wherein the gap comprises air, dielectric material, metal, semiconductor material, organic electronic material, biosensing material, organic sensing material, inorganic sensing material.

28. The sensor of claim 22, wherein the sensor is disposed on a silicon surface without any surface modification to enable non-specific binding of molecules, molecular assemblies, or both.

29. The sensor of claim 22, wherein the electrode material comprises metal, conductive polymer, doped polyacetylene, doped polyaniline, doped polythiophene, carbon nanotubes, carbon fibers, carbon particles, carbon paste, conductive ink, or a combination thereof.

30. The sensor of claim 29, wherein the metal comprises copper, aluminum, gold, silver, an alloy of copper, an alloy of aluminum, an alloy of gold, or a combination thereof.

31. A radio frequency based sensor comprising: a sensing gap defining a distance between one or more facing inner surfaces of two or more electrodes, wherein a change in a physical property of a sample to be detected provides a change in capacitance and / or resistance of said sensing gap, wherein one of said two or more electrodes has at least one aperture; an antenna operatively associated with the sensing gap and the electrode, wherein the antenna has ends spaced apart from one another and connected to one another via a conductive medium, the antenna comprising a plurality of windings; as well as An RFID tag incorporating a memory chip, wherein the RFID tag is configured to form a resonant sensing structure, wherein the change in capacitance and / or resistance is converted into a change in the resonant frequency of the resonant sensing structure, so that the RFID tag enables the memory chip to be accessed only when the resonant frequency is within an operable frequency range of the RFID tag, The two or more electrodes are respectively formed by two or more windings of the plurality of windings, wherein one or more of the two or more windings have at least one protrusion, and the sensing gap has a length extending along the at least one protrusion.

32. A method for making a sensor, comprising: providing an antenna having a plurality of windings, wherein the antenna has ends that are spaced apart from one another and connected to one another via a conductive medium; as well as forming a sensing gap comprising first and second electrodes and defining a distance between one or more facing inner surfaces of the first and second electrodes, wherein a change in a physical property of a sample to be detected provides a change in capacitance and / or resistance of the sensing gap, providing an RFID tag incorporating a memory chip, wherein the RFID tag is configured to form a resonant sensing structure, wherein changes in the capacitance and / or resistance are converted into changes in a resonant frequency of the resonant sensing structure, such that the RFID tag enables the memory chip to be accessed only when the resonant frequency is within an operable frequency range of the RFID tag, wherein the sensing gap is operatively associated with the antenna, and wherein one of the first and second electrodes has at least one aperture, The first electrode and the second electrode are respectively formed by a first winding and a second winding of the plurality of windings, wherein one or more of the first and second windings have at least one protrusion, and the gap has a length extending along the at least one protrusion.

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