نشریه صنایع الکترونیک
سال دهم شماره 2 (پیاپی 38، تابستان 1398)

Metal-semiconductor Schottky junctions as intricate part of semiconductor devices have been interested in the electronics industry. In this paper, Al/p-Si Schottky diodes which fabricated onto acceptor type silicon substrate using thermal evaporation layer deposition, were characterized in terms of thermionic emission theory. Ideality factor, reverse saturation current, Schottky barrier height, of the annealed diodes at the 150-350 °C temperature range, have been determined by measuring the current –voltage (I-V) characteristics. The effects of annealing process on the Schottky parameters have been inspected and it was found that the optimum annealing temperature was 250 °C. Then current-voltage characteristics of the processed diodes have been measured at 15 -300 °K sample temperature. Ideality factor, Schottky barrier height, and reverse saturation current and their temperature dependence have been determined. It was revealed that as the sample temperature decreases, the barrier height decreases while ideality factor increases. Finally, the Schottky barrier and Richardson coefficient have been determined taking into account the Gaussian distribution of barrier height. The unexpected high value of ideality factor can be justified in terms of ionized impurity scattering of carriers from diffused Al atoms to semiconductor near the Al/Si interface.

A broadband circularly polarized MIMO antenna array with a 2×4 feed network was proposed for C-band application. Different unique techniques were utilized in the proposed array to enhance the antenna characteristics, such as gain, 3dB Axial Ratio Bandwidth (ARBW), impedance tuning, and ruinous mutual coupling effects. For a better improvement of circular polarization features, a 2*4 MIMO Sequentially Rotated (MIMO-SR) feed network was used to achieve broader 3dB ARBW. Besides, the MIMO feature of the feed network could control the left- and right-handed CP, respectively. Moreover, electromagnetic band-gap structure was applied to enhance the overall performance of antenna array. Ultimately, specific forms of slot and slit structures were applied onto the top layer of MIMO feed network that provided a high isolation between the radiating elements and array network. The extracted measured results illustrated an impedance bandwidth of 4.6-7.3 GHz at port 1 and 4.25-7.2 GHz at port 2 for VWSR

This paper examines the role of ILS/DME ground navigation assistance devices in conducting airplanes on air routes. Due to installing limitations of these devices in various areas, it is mandatory to use GPS satellites. Since the probable transmission errors of satellite signals will reduce the accuracy of the navigation systems of the aircraft, the PBN-SBAS-GBAS-ABAS can be used to eliminate these errors and increase navigation accuracy. The aforementioned methods have many advantages in most advanced countries in the field of aviation, but due to the lack of preparation of the bases and infrastructure for the use of the above mentioned techniques in Iranian airports, DGPS method has been used to increase the accuracy of ILS/DME ground equipment. The main objective of this research is to simulate and study of the flight routes of the Mashhad international airport by using the ILS/DME navigation signals of DGPS method. The highlight of this research is plotting the curves of simulated signaling of ground-based devices such as deviation from the center line of the band, landing slope, and airplane distance to the airport by the above method and comparing it with GPS satellite signals.

Noise figure of the Low Noise Amplifier (LNA) is added directly to the system noise figure; therefore, the performance of the Low Noise Amplifiers determines the system's performance in terms of noise. In this paper, Low Noise Amplifiers have been designed in the UWB system, one of them with the ability of out of band rejection and the other with the capability of improving noise and circuit linearity by CMOS technology. In the design of LNA, subthreshold bias technique is used for low power design, chebyshev filtering for matching input impedance and cascode technique to increase inverse isolation and increase gain. In the design of the LNA, using a dual band notch filter which is implemented with low power active inductor, the out of band rejection are improved 42dB at a frequency of 2.4GHz, and 36dB at a frequency of 5.2GHz. Also by using the noise and linearity improvement techniques, 2.3dB reduction in the noise, and 9dB improvement in the circuit linearity (IIP3) is established. The designed LNA,s with a bandwidth of 3 to 5 GHz by using the 0.18 μm CMOS technology, are consumed 2.8mW and 1.9mW from a 1.8V supply voltage, respectively.

This paper focuses on minimizing the C4D sensor for the lab-on-a-chip (LOC) and how the parameters such as the chip manufacturing materials, ion charge, frequency, and the geometry of the electrodes affect it through COMSOL software. The simulation results show if the chip is made of glass, then the current density increases to 0. 003 A/m2 at the time of ion presence. Also, the current density reaches 0.0015 A/m2 when the chip is made of poly dimethyl siloxane (PDMS). By using a combination of these two materials, in addition to achieving the benefits of PMDS, the sensitivity of the sensor also increases. Moreover, the entrance frequency enhancement prevents any sudden flow density change. By changing the ionic charge from 1 to 5, conductivity changes from 1×10-7 to 8×10-7 Siemens/m. The design of the chip with four electrodes also increases the sensitivity of the sensor due to the strong current density in the solution body. Choosing the appropriate C4D sensor on a high-sensitivity chip can in the future provide many advancements in medical and medical diagnostics.

These days, speech emotion recognition has considered in the cases where there is a relationship between man and machine. Despite many efforts in this field, there is still a great gap between the natural feelings of humans and the computer's perception of it. The main reason for this is the inability of the computer to understand the user's feelings. The purpose of this paper is to design a system to recognize Persian emotional speech database, which includes five emotions of happiness, exhausting, fear, anger and sadness. In this paper, after extraction of four-dimensional features of scale, rate (speed), time and speech frequency with the help of the human auditory model system, two-dimensional features of the scale and frequency was obtained that the maximum amount of these features was used as a feature vector. Finally, the extracted features were classified using support vector machine. The results of the experiments show that the proposed algorithm provides acceptable performance compared to automatic speech emotion recognition in Persian.

In this paper, CZTS and CZTSe thin-film solar cells with FTO / CdS / CZTS (CZTSe)/ Mo structure are simulated, considering the impact of defects and recombination. The effects of temperature, bandgap energy, thickness and doping concentration of the absorber layers, as well as the effects of the thickness and doping concentration of the buffer layer on the cells performance were investigated and compared with each other. It is shown that the CZTS solar cell has a higher open circuit voltage (Voc = 0.95 V) while the CZTSe solar cell has a higher short circuit current density (Jsc = 31 mA / cm2). At 300 k, the maximum efficiencies of 17.44% and 14.28% were obtained for the optimum CZTS and CZTSe cells, respectively. The efficiency has been improved significantly compared to the previous works. It was also shown that the efficiency of CZTS cell is less temperature dependent. All simulations were done under AM1.5 illumination.

Usually two-dimensional substitution is used for the production of integrated circuits. Due to heavy use of communications, two-dimensional substitution has high losses as well as, density of elements is low in it. To resolve this problem, three-dimensional substitution method was proposed. Rather than the two-dimensional arrangement of elements in a row, elements are layout in three dimensions in this substitution. In this paper, three-dimensional substitution algorithms using order used in two-dimensional substitution, three-dimensional substitution analysis by mPL and three-dimensional substitution simultaneous with two-dimensional substitution by mPL have been studied in terms of structure and function, and a butterfly processing element (PE) and an Advanced Encryption Standard (AES) block and a wireless MIMO decoder to assess them have been implemented with the mentioned methods. . Applying these methods shows that the use of face to face integration by microbuses in communications of substitution algorithm, on average, improves the maximum clock and block speed of AES encryption to 15.3% and the maximum clock and block speed of PE module to 22.6% as well as the maximum clock and speed of MIMO modules to 17.1%, while the use of these methods has led to the average reduction in power consumption of 2.6% for the AES module and the average reduction in power of 12.9% for the PE module and the average reduction in power consumption of 5.1% for MIMO module.