Interdigital Gap Research Articles

An Improved Split-Ring Resonator-Based Sensor for Microfluidic Applications.

This study proposes an ultrahigh-sensitivity split-ring resonator-based microwave sensor for retrieving the complex permittivity of liquid samples. An interdigital capacitor structure was used to expand the sensing area and the sensitivity. A defected ground structure and A parallel dual split-ring resonator were introduced to improve the quality factor. A polydimethylsiloxane microfluidic channel substrate was placed above the interdigital capacitor structure. The channel route coincided with the interdigital gap to fully utilize the strong electric field. Ethanol-water solutions with varying ethanol fractions were injected into the channel as the testing liquid. It was demonstrated that the variation in resonant frequency can be used to retrieve the dielectric properties of liquid samples. The proposed sensor used a small liquid volume of ~0.68 μL and provided values in good agreement with the reference data.

All-solid-state planar on-chip micro-supercapacitors with excellent areal power performance at ultrahigh scan rates by photolithography

All-solid-state planar on-chip micro-supercapacitors (MSCs), as a new type of energy storage device, can be well integrated with micro-nano devices and exhibit good practical performance. Nitrogen and oxygen co-doped graphene quantum dots (GQDs), as one of the electrode materials for fabricating supercapacitors, exhibiting novel chemical/physical properties including nanometer-size, abundant edge defects, good conductivity and better surface grafting. In this article, the GQDs film was prepared by modified liquid–air interface self-assembly method and fabricated interdigital electrodes with electrode width and interdigital gap of 6 μm by simple photolithography technology. Electrochemical measurements revealed that the obtained GQDs electrodes for all-solid-state MSCs exhibited the areal power density of up to 0.107 mW cm−2 at the scan rate of 10,000 V s−1 and 95.6% capacitance after charging and discharging for 10,000 cycles. Specially, there was still the ultra-fast charging-discharging time (4.17 μs). The favorable performances make the GQDs film interdigital electrodes prepared by photolithography have good application prospects.

Purulent-necrotic lesions of finger tissues in cows and their effect on the physicochemical and biochemical properties of blood

A study was made of the prevalence, species structure and localization of purulent-necrotic ulcerative lesions of the tissues of the fingers in cows with a non-walking technology of keeping on a leash in stalls and loose in boxes, as well as an assessment of their effect on the physico-chemical and biochemical properties of blood. It was found that in conditions of loose housing, the number of cases of registration of purulent-necrotic defects in the tissues of the fingers of cows is 4.30% more than in conditions of tethered housing. The species structure of purulent-necrotic ulcers in loose keeping technology is represented by ulcerative defects in the tissues of the corolla and the arch of the interdigital fissure, the incidence of diagnosing which is higher by 7.14% and 4.76% than in the conditions of tethered keeping, and in the conditions of tethered technology, the most common are ulcerative defects in the tissues of the crumb and the base of the skin of the sole, the frequency of registration of which is higher by 7.16% and 7.24% than with loose technology. When evaluating the effect of registered forms of purulent-necrotic ulcerative lesions of the tissues of the fingers on the physical and chemical properties, it was found that the lowest concentration of hemoglobin is recorded with a purulent-necrotic ulcer of the base of the skin of the sole, which is less than with ulcerative defects of the crumb by 3.37%, with ulcerative defects in tissues of the interdigital fissure by 7.63%, with ulcerative defects of the corolla by 17.06%. In cows with ulcers of the base of the skin of the sole, crumb and tissues of the interdigital gap, hypochromic anemia was recorded, which is expressed in a decrease in the average hemoglobin content in the erythrocyte relative to the physiological norm by 20.70%, 14.42% and 3.51%, respectively. The revealed hypochromic anemia reduced the digital indicator of blood hematocrit relative to the threshold values of the physiological norm by 6.43%, 5.56%, 2.80%. When evaluating the effect of the established species structure of purulent-necrotic ulcerative defects in the tissues of the fingers on the biochemical composition of blood serum, it was determined that the highest concentration of total protein, aspartate aminotransferase and alanine aminotransferase is recorded in cows with purulent-necrotic ulcers in the tissues of the hoof corolla, total bilirubin - with purulent-necrotic ulcers of the base of the skin of the sole, alkaline phosphatase - with purulent-necrotic ulcers of the tissues of the interdigital fissure.

Photolithographic fabrication of planar on-chip micro-supercapacitors based on reduced graphene oxide films by modified liquid-air interface self-assembly

In this article, we demonstrated the fabrication of micro-supercapacitors by photolithography technology and liquid-air interface self-assembly method. A large-area uniform film with a thickness of 18 nm was fabricated by the modified liquid-air interface self-assembly, and a narrow finger gap, which was 30 μm, was manufactured by photolithography. In addition, the electrode width and the interdigital gap ratio were 3:1. The power density and energy density of the fabricated device were 1.21 W cm−3 and 2.93 mWh cm−3. There was an extremely short time constant of the fabricated device, which is 0.38 ms. All of these leaded to higher conductivity, shorter ion transmission distance and faster charge and discharge rates. In addition, 87.2% of the capacitance was retained after 10000 cycles.

Features of quantitative indicators of finger and palmar dermatoglyphics in males and females with ichthyosis

Heterogeneity by types of genodermatoses inheritance from the group of ichthyosis, which include virtually all possible variants, is the basis for the application of one of the genetic methods of human study - the method of dermatoglyphics. The purpose of the study is to determine the peculiarities of the quantitative indexes of finger and palmar dermatoglyphics in men and women with ichthyosis. Dermatological examination was performed in 49 patients with ichthyosis and 136 dermatologically healthy persons. The sample of patients was conducted randomly. All persons received informed consent for conducting observations. Fingerprint and palm prints are obtained by scanning fingerprints on paper by the Futronic's FS8 USB2.0 Fingerprint Scanner using the ftrScanApiEx.exe program, and then transferring data to a personal computer. Processing of dermatoglyphics data was carried out according to the method of Cummins H. and Midlo Ch. (1961). The quantitative indices of both finger and palmar dermatoglifics were determined. The calculation of the received results was carried out in the licensed software package “Statistica 5.5”. The average sample values (M) and dispersion (σ) were determined in the groups of the subjects surveyed. Using the Mann-Whitney U-test determined the probability of differences in the results obtained for individual groups. A certain complex of quantitative signs of palmar dermatoglyphics is revealed, which is characteristic for men suffering from ichthyosis, which includes indexes of the intensity of the comb formations, the value of the length of the segment c-t, the value of the palm corners and the Cummins index. In women suffering from ichthyosis, such a complex includes, as in men, indicators of the intensity of the combs and the length of the segment c-t, except for which - also the value of palm comb accounts. Given the specific lamellar form of ichthyosis, the dermatoglyphic picture (monomorphism of established signs on both hands: the presence of a single 4-finger flexural fold, a pattern in the III interdigital gap, low localization of the carpal angle atd, and the presence of the ulnar loop, complicated by the internal pattern on the III finger of the left and the IV the finger of the right hand brushes), the authors concluded that the study of ichthyosis should be carried out necessarily for each form of ichthyosis separately, which significantly increases the resolution of the method of dermatoglyphics.

Extended width in discontinuously connected polymer-free carbon nanotubes grown between electrodes

Polymer-free carbon nanotubes (CNTs) grown between single-gap (SG) and interdigital-gap (IG) electrodes were used to develop miniature strain gauges. The strain and stress of the gauges were approximated according to the distance lift of a screw on a cantilever silicon substrate. In our preliminary study, electrical characterization indicated the gauge factors (GFs) of SG and IG devices to be approximately 36 and 1500, respectively. This result suggests that an extended width in IG electrodes, generating a larger amount of CNTs, provides a smaller minimum tunneling distance than does the width in SG electrodes. The distance shift under a small distance is expected to generate a high ratio of tunneling resistance change. The sparser and denser distributions of CNTs in SG and IG electrodes probably caused the gauges to exhibit capacitive and inductive features, respectively. Despite having substantial GFs, the gauge may require improvement in packaging to resist environmental effects and the growth of homogeneous CNTs and, thus, be reproducible.

Back amorphous‐crystalline silicon heterojunction (BACH) photovoltaic device with facile‐grown oxide ‐ PECVD SiNx passivation

AbstractThis article reports on the integration of facile native oxide‐based passivation of crystalline silicon surfaces within the back amorphous‐crystalline silicon heterojunction solar cell concept. The new passivation scheme consists of 1‐nm thick native oxide and nominally 70‐nm thick PECVD silicon nitride. The low temperature passivation scheme provides uniform high quality surface passivation and low parasitic optical absorption. The interdigitated doped hydrogenated amorphous silicon layers were deposited on the rear side of the silicon wafer using the direct current saddle field PECVD technique. A systematic analysis of a series of back amorphous‐crystalline silicon heterojunction cells is carried out in order to examine the influence of the various cell parameters (interdigital gap, n‐doped region width, ratio of widths of p, and n‐doped regions) on cell performance. A photovoltaic conversion efficiency of 16.7 % is obtained for an untextured cell illuminated under AM 1.5 global spectrum (cell parameters: VOC of 641 mV, JSC of 33.7 mA‐cm − 2 and fill factor of 77.3 %). Copyright © 2014 John Wiley & Sons, Ltd.

Reflectarray element using interdigital gap loading structure

A novel reflectarray element using an interdigital gap loading structure is proposed. A wide reflection phase range of more than 1000° is obtained, which can support a sufficient phase range for a large scattering angle (up to 60°) reflectarray. Furthermore, this element has a feature of equal element size because the reflection phase is adjusted by controlling the finger length of the interdigital gap. Thus, abrupt geometry variations for consecutive cells in the traditional reflectarray can be avoided. A Ku-band reflectarray has been fabricated and measured results show good agreement with simulation.

Development of electrically small planar antennas with transmission line based impedance matching circuit for a 2.4 GHz band

We designed an electrically small antenna (ESA) with the impedance matching circuit on the thin patterned circuit board. Matching circuit is realized by using interdigital gap and transmission line which is composed of coplanar waveguide (CPW). By using our new impedance matching circuit, we can reduce the total antenna size much smaller than one-wavelength. Moreover, we design some ESAs with impedance matching circuit, which have various gains, and discuss about the relations between peak realized gains and S-parameters. Also, we fabricated and measured the ESAs, and compared experimental results of S-parameters and simulated gains.

Observation of Metallic Resistance Down to 56 K in Langmuir–Blodgett Films Based on Ditetradecyldimethylammonium–Au(dmit)2 Salt

A metallic temperature dependence of the resistance of ditetradecyldimethylammonium–Au(dmit)2 [2C14–Au(dmit)2] Langmuir–Blodgett (LB) film is observed in a wide temperature range of 56–293 K. While a weak metallic temperature dependence of resistance has been observed down to 216 K in a case where the electrode gap for the measurement is 0.5 mm (500 µm), an unambiguous metallic behavior is observed down to 56 K when utilizing a narrower interdigitated gap of 5 µm for the measurement.

Design of a Miniaturized Superconducting Bandpass Filter by Evaluating the Kinetic Inductance in the K-Inverter

SUMMARY We propose a design theory of the miniaturized high temperature superconducting (HTS) coplanar waveguide (CPW) bandpass filter (BPF), which is composed of meanderline quarter-wavelength resonator, J -a ndK-inverters. The J -a ndK-inverters are realized by using interdigital gap and meander-shape inductor. To evaluate the kinetic inductance of the K-inverter, we fabricate the YBCO resonator connected with K-inverters and redesigned the YBCO filter parameters. Finally, we designed and fabricated the YBCO CPW quarter-wavelength resonator BPF by taking account of the kinetic inductance of the K-inverter. The experi

An improved optically controlled phase shifter on Si wafer

AbstractThe transmission characteristics of an improved optically controlled microstrip interdigital gap structure on a high‐resistivity silicon substrate are reported. When irradiated with an optically controlled power as low as 8 mw, a maximum signal‐phase change of 37° is obtained while the signal amplitude remains nearly constant. The proposed device can potentially be used as an optically controlled phase shifter. © 2005 Wiley Periodicals, Inc. Microwave Opt Technol Lett 44: 540–541, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20690

Design and performance of miniaturized superconducting coplanar waveguide filters

Design and performance of coplanar waveguide (CPW) microwave filters using high Tc superconducting films have been studied. The bandpass filter made of CPW requires the coating of only one side of the substrate with a superconductor, and the width of the CPW filter can be uniformly reduced in scale without changing its characteristic impedance, leading to a miniaturized filter by adopting the meanderline geometry. In order to realize the miniaturized filter we investigate the interdigital gap with strong coupling and the modeling of the corner bend. It is shown that the size of the filter can be greatly reduced by introducing CPW with a meanderline geometry. Experiments of a prototype miniaturized CPW filter with its computer-simulated performance have been presented.

New electrode separation technology using anodic oxidation and application to SAW interdigital transducers

By anodic oxidation of the edges of the portions of the Al film under photoresist, controllable gaps between electrodes with good insulation can be obtained. These techniques are applied to realize a surface-acoustic-wave (SAW) narrow gap interdigital transducer (NG-IDT) and narrow gap unidirectional transducer (NG-UDT). The experimental result shows 7.2 dB insertion loss with amplitude ripples of +/-1.2 dB for a conventional NG-IDT. Directives of 3-dB/transducer at 440 MHz (fundamental) and 13-dB transducer at 870 MHz (second-harmonic operation) for a new floating electrode type unidirectional transducer (NG-FEUDT) are demonstrated. Also a three transducer low loss filter using a combination of NG-IDT and NG-FEUDT exhibits 3.46 dB insertion loss at 894 MHz (second-harmonic operation, electrode width of 1.7 mum) with sidelobe suppression greater than 35 dB.

Phase and amplitude characteristics of InP:Fe modified interdigitated gap photoconductive microwave switches

The transmission amplitude and phase characteristics of InP:Fe modified interdigitated gap photoconductive microwave switches are reported. Measurements in the 0.1-1 GHz frequency range show that the phase is shifted approximately 90 degrees and that the corresponding change in amplitude ranges from 43 dB at 0.1 GHz to 23 dB at 1 GHz when the illumination-induced conductance is switched from a low OFF-state value ( approximately 4*10/sup -8/ S) to a high ON-state value (5 mS). The observed characteristics can be described by a phase-shifting region and an amplitude modulation region. In the phase-shifting region the phase strongly depends on the conductance, and the amplitude is almost constant. In the amplitude modulation region both the amplitude and the phase depend on the conductance but the effect on the amplitude is much more pronounced. A lumped-element model describing the device performance is presented. It is concluded that these optoelectronic microwave switching devices are suitable for high-speed amplitude modulation but are not promising as high-speed phase shifter.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Integrated Monolithic Crystal Filter for Citizen Band Transceivers

This paper will describe a SSB 10.7 MHz IF filter for CB band transceivers employing an integrated capacitor circuit and four dual mode Monolithic Crystal Filters (MCFs) of AT cut Quartz. With a narrow bandwidth of 2 × 10−4, an insertion loss of less than 5 dB, and a low temperature coefficient of the center frequency of within ± 20 ppm over the range of − 35 to + 65℃, this filter also meets mechanical shock‐resistance requirements. The integrated capacitor circuit consists of thin film Ta2O5 capacitors and interdigital gap capacitors formed on both sides of a Fine Grain Alumina (FGA) substrate. Four MCFs are directly soldered to the substrate of the integrated capacitor circuit, allowing this filter to be made smaller and lighter and have better resistance to mechanical shock. Also important, the manufacturing process is suitable for mass production.