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In this paper, we have developed an in-vehicle wireless driver breath alcohol detection (IDBAD) system based on Sn-doped CuO nanostructures. When the proposed system detects the ethanol trace in the driver's exhaled breath, it can alarm and then prevents the car to be started and also sends the location of the car to the mobile phone. The sensor used in this system is a two-sided micro-heater integrated resistive ethanol gas sensor fabricated based on Sn-doped CuO nanostructures. Pristine and Sn-doped CuO nanostructures were synthesized as the sensing materials. The micro-heater is calibrated to provide the desired temperature by applying voltage. The results showed that by Sn-doping in CuO nanostructures, the sensor performance can be significantly improved. The proposed gas sensor has a fast response, good repeatability along with good selectivity that makes it suitable for being used in practical applications such as the proposed system. [ABSTRACT FROM AUTHOR]

Digital encoders are one of the key devices required in optical communication and digital signal processing systems. In this paper, a new photonic crystal structure is used to design all-optical 4 × 2 encoder constructed from GaAs rods with square lattice in the pentane background based on plasmonic effect. Gold rods have also been used at the interface of dielectric rods and lines defect, which create plasmonic properties into the photonic crystal structure. The designed optical device is composed of four input waveguides and two output waveguides with two ring resonators at the resonant wavelength of 1.14 μm with TM polarization. The presented encoder platform has the small size of 19 μm × 33 μm that makes it to integration into compact all-optical processing systems. The encoder operation is simulated and analyzed with numerical finite-difference time-domain (FDTD) method and plane wave expansion (PWE) method. In the proposed structure, we have shown that by selecting the appropriate radius size for the resonant cavities, the desirable wavelength can be obtained. The maximum values of transmission efficiency for the first and second outputs are 82% and 96%, respectively. Resonant cavities are also located in the crystal lattice in such a way that by activating third input, 50% and 48% of the input signal will be obtained in each output ports indicating (1,1) logic state. So the new plasmonic photonic crystal encoder could be future applicable in the field of optical computing. [ABSTRACT FROM AUTHOR]

In this paper, a novel RF MEMS shunt capacitive switch with application in the Ka frequency band is proposed. The spring design and the step structure added to the beam succeeded in improving the performance of the switch and reducing the stress which results in extended life-time of the switch. Also, by optimally reducing the gap between the dielectric and the beam (without problems such as self-actuation), the actuation voltage of the switch is significantly reduced. Electromechanical and scattering parameters analysis have been done by using COMSOL Multiphysics and HFSS software, respectively. The actuation voltage of the proposed device is 9.2 V. Since the aluminum has a lower mass compared to gold, an aluminum beam has been used in the switch. Desirable scattering parameters at the resonance frequency of 33.5 GHz have been obtained which include insertion loss of − 0.3 dB and return loss of − 18 dB. The high isolation of − 57 dB verifies the improved performance of the switch. Finally, as another innovation in this paper, the effect of inductor and capacitor presence in the input of transmission line is investigated. This analysis has been done by using ADS. Results of the circuit analysis presented in this paper, help the MEMS switch designers to understand the realistic switch behavior before fabrication which considerably saves cost and time. [ABSTRACT FROM AUTHOR]

In this study, a new strategy based on integrating geostatistical seismic inversion and optimized support vector regression (OSVR) will be utilized to transform multi seismic attributes to sand fraction log. In first step, owing to compatibility relation between acoustic impedance (AI) and sand fraction, a high resolution value of this important attribute was extracted through a geostatistical seismic inversion (GSI). In second step, in addition to AI, several physical attributes are obtained from seismic data and then all of extracted attributes (AI and other seismic attributes) evaluated by step-wise regression for selecting best attributes that have highest effect on predicting sand fraction. In final step, selected attributes have been fed in the bat inspired optimized support vector regression as input and the sand fraction log is estimated. For the assessment of proposed strategy, the values of predicted sand fraction are compared with their real corresponding values in a blind well. It will be evident from the results that the proposed strategy is qualified for modeling the sand fraction as a function of seismic attributes. [ABSTRACT FROM AUTHOR]

Isolation and actuation voltages are important parameters in micro-electro-mechanical switches. These parameters can be destroyed by the effect of creating bulge and erosion in the surface of the beam. In this paper, a fabrication method is proposed to create a smooth and flat beam. Additionally, using two short high impedance transmission lines, the destructive effects on the input/output matching have been reduced. S-parameters and mechanical parameters of the proposed switch are calculated by the network analyzer and laser Doppler vibrometer. According to the results obtained from the proposed switch in the C–K band, the return loss, which is less than − 20 dB, and the highest isolation value, which is equal to − 20 dB, occur at the frequency of 21 GHz. Furthermore, the insertion loss is better than − 1 dB in the full frequency band, which is very desirable. The actuation voltage and resonance frequency were obtained at 18 V and 164 kHz, respectively. Finally, four steps are proposed to optimize the actuation voltage, isolation, stress and switching time, which results in reducing the actuation voltage by 37% and the isolation will increase by 46%. Maximum stress in the initial state is 25 MPa, and decreases to 10 MPa after optimization, which increases the lifetime of the switch. [ABSTRACT FROM AUTHOR]

MEMS capacitive switches have longer lifetimes compared to other types of metal-to-metal switches, and when placed on the membrane on the transmission line, they can easily return to the up-state due to a dielectric layer. They also transmit the input signal with more power and frequency and therefore, they are better than metal-to-metal switches. In this paper, first three switches were considered as the basic structures. Then, in order to demonstrate the credibility and high quality of the simulations, the same switches were simulated. The obtained results are very close to the results of fabrication of these switches. In the next step, with the presentation of three new structures, stimulation voltage, stress, switching time and isolation were improved in four steps. The mechanical simulation of the switch was performed to determine the amount of displacement, the amount of stress and the resonant frequency using the COMSOL software. In addition, electrical simulation of the switch was performed to obtain the S-parameter using the HFSS software. The simulation results demonstrate that the isolation is 57–66 dB and the insertion loss is 0.3–2 dB in the desired frequency band (1–50 GHz). Using new spring structures, the actuation voltage was reduced from 4.8 V in basic structures (the smallest in three structures) to 2.4 V in new structures, which is considered excellent. In order to increase the lifetime of the switch, the stress in the new switches is reduced from 12 to 4.5 MPa compared to the basic switches. [ABSTRACT FROM AUTHOR]

RF-MEMS switches may be divided into capacitive and metal-to-metal types in terms of type of connection. In capacitive switches in the OFF-state the beam does not attach to the transmission line due to the presence of a thin dielectric layer and it gets released easily. Capacitive switches are better compared with the metal-to-metal types due to their ability to transmit signals of higher frequency and power. In this paper, a novel RF MEMS shunt capacitive switch with a unique spring design is proposed. The proposed design benefits from high isolation, low loss, low actuation voltage, small size and weight compared to similar switches and is designed for application in the Ka-band. Step structure is used in the mechanical design of the switch to reduce the air gap between the bridge and the transmission line that has resulted in reduction of actuation voltage to 2.2 V. The proposed switch has been placed upon a coplanar waveguide (CPW) line with an impedance of 50 Ohms. SiO2 with a thickness of 1000 Å has been used as dielectric to increase isolation and down-state capacitance. The unique design of the spring results in the reduction of stress to a minimum at all points of the switch especially the springs at the time of applying the actuation voltage. This advantage would reduce switch failures as time passes and results in increased life of the switch. Up-state capacitance is 93.3 fF and down-state capacitance is 2.64 pF. Therefore, a capacitive ratio of 28 is obtained. The dynamic behavior of the switch is studied by using the COMSOL Multiphysics software package and the RF characteristics have been obtained by using the HFSS software and show good RF performance. The results show that in the up-state, the designed switch including S11 is less than − 11.5 dB and S21 is more than − 0.85 dB at 1-40 GHz. In the down-state, the switch has excellent isolation in the Ka-band. Maximum isolation is − 71 dB that occurs at the resonance frequency of 30.5 GHz. [ABSTRACT FROM AUTHOR]