نشریه صنایع الکترونیک
سال هشتم شماره 1 (پیاپی 28، بهار 1396)

In this paper, two new analog switches for very high speed applications are proposed using a body bias control circuit. In addition to using body bias technique, dummy transistor and differential structure is used so that in addition to obtaining a high speed and acceptable precision, the phase and amplitude distortion of proposed switches are quite low in track mode. The difference between the second proposed switch and the first proposed switch is using a smart body bias control circuit, which can greatly reduce non-linear effects. The first and second proposed switches acquire a bandwidth almost three times more than that of simple MOS switch. As simulations reveals these switches can accommodate up to 2.5 GHz clock and 1.25 GHz input frequency with reasonable accuracy. The SFDR at Nyquist frequency for the first and second proposed switches in comparison with the simple MOS switch are 65 dB and 69 dB and 45 dB respectively, indicating that the proposed switches are more linear than simple MOS switch.

Using metamaterials in antenna design leads to interesting features includes size reduction. Although, the antenna miniaturization is the most promising advantage especially in commercial applications, their narrow band effectiveness causes great concern for the future progress. Today, using lumped and parasitic elements for admittance compensation of electrically small antennas (ESA) is a most well-known solution to overcome this problem. In this article, a modified parasitic structure is proposed to enhance the antenna impedance matching over a wide frequency range. Moreover, a new structure based on a capacitive lumped-element has been suggested which is improved the antenna bandwidth significantly. To do this, a Z-shape shaped parasitic element incorporate with an ESA monopole antenna designed, simulated and fabricated. Simulations show great agreement with measurement results. Both simulations and measurements demonstrated that the antenna fractional bandwidth, in the first case was about 5%, which increased up to 81% in modified structure.

Stealth technology in surface vessels plays an important role in the ability to Confronting the enemy. In order to designing a stealth vessel, the vessel’s signatures that are detectable using available sensor and their resources should be known. Then, these signatures be decreased using the suitable methods and technologies for decreasing the power of vessel detection and identification by the enemy. In this paper, we study the most important detection signatures, including radar, infrared, acoustic and visual signatures and their resource. Then, using comprehensive look to efforts in the field of stealth vessels and studying the technologies that have been used in modern vessels, we present the suitable method for decreasing the vessel’s signatures and the methods that will be realized in practice in the not too distant future. Finally, the results of the simulation and measurement of a specific military vessel are investigated in the mentioned field of detection.

In the present paper the structure of a single inductor double output converter (SIDO) has been studied. One of the major challenge, to design a controller in SIDO Converters, is removing the cross-regulation among the outputs. On the other hand, the multi-stages operation of SIDO converters cause, to achieve the model which predicts their all behaviors, be more difficult than typical converters. In this paper a SIDO Boost/Boost converter is modeled by a systematic signal flow graph (SFG) modelling. Based on obtained model a multivariable control scheme has been proposed to reduce the cross regulation of the output. Finally Simulation results are included to show the validity of the obtained model and the designed Controller.

This paper presents the design and simulation of a multi-band low noise amplifier with adjustable input network suitable for multi-standard applications. This LNA is capable of single-band and concurrent dual band functioning. Three switches for restructuring and a control voltage for changing the functioning bands are used in the proposed circuit. This LNA is designed and simulated with the 0.18µm CMOS technology of TSMC. The proposed structure is suitable for use in multi-standard receivers and SDR applications. Simulation results show a noise figure lower than 2.2 dB, S11 lower than -16 dB and S21 higher than 12.3 dB for all frequency bands. The designed circuit consumes 8.55 mW power from a 1.5 V power supply. Our proposed structure supports more bands and has a better noise figure, compared to the state-of-the-art methods. Also, the gain and linearity of the proposed amplifier are acceptable, in comparison with similar structures.

In this paper, for the first time, the dynamic characteristics of optical injection locking vertical cavity surface emitting laser (OIL-QD-VCSEL) are investigated theoretically. By using the rate equations for dynamics of electrons and holes at GaAs barrier, wetting layer (WL), and three discrete QD levels and the heat equation, turn-on dynamics and also the small and large signal responses of laser without optical injection are numerically simulated. By adding the equations for the amplitude and phase of the QD-VCSEL field to the system of equations, the dynamic characteristics of optical injected laser are calculated. It is shown that due to optical injection, the electron and hole dynamics in QDs are synchronized, the modulation frequency is enhanced, the chirp is significantly reduced and QD-VCSEL manifests a high performance at the repetition frequency more than relaxation oscillation frequency (about 22 GHz).

The Localization based on particle filter is one of the important methods. However, this approach has high computational cost, inconsistency and degeneracy problem. In this paper, to solve these problems, the localization problem is converted to an optimization problem. Then the differential evolution algorithm is used to solve this problem. The proposed algorithm searches stochastically along the state space of robot and obtain the best estimate position based of odometery, laser range finder and map of environment. One advantage of the proposed method is that it requires no proposal distribution and resampling step like localization based EKF and PF. Therefore, the risk of degeneracy decreases. The performance of localization on differential evolution (DE) is compared with localization based on extended Kalman filter (EKF) and particle filter. Simulation result shows that performance of localization based on differential evolution filters is better than others algorithms of localization.

In Air conditioning systems (HVAC), including heating, cooling and ventilation systems use much of the total energy consumed in commercial buildings. Air Handling Unit (AHU) is one of the most important parts in air conditioning systems. In a survey of the UK buildings, data has shown that 25-50% of energy is wasted due to errors in air-conditioned buildings. If these errors are identified in the early stages before unacceptable damage occur and recognized, this range can be reduced to below 15%.
Along with the evolution of energy-efficient air conditioning in commercial buildings, a wide range of diagnostics and fault detection methods continuously increased in the fields of air conditioning. Different techniques are developed using computer with the low installation cost for years to increase real-time detection of errors.
In this study, a method of fault recovery in temperature sensor of air handling unit has been proposed using simulation of field programing analog array (FPAA) and genetic algorithms as evolutionary algorithms. It is assumed that multiple sensors are working and the output is the average temperature sensors. In faulty situation, using the fault recovery method, the system is able to work properly with one of the sensors. The study consists of two parts, which is a part related to bias, scale and drift fault detection using time series method, noise fault detection using the sample standard deviation, constant fault detection using a voter and the another part is fault recovery using FPAA.

Power consumption is one of the most challenging issues in design of electronic circuits. Reversible logic is a solution for power optimization. In this paper, we propose three fault-tolerant serial multiplier designs based on the reversible logic with error detection capability. The first proposed serial multiplier which is based on the Booth's algorithm utilizes a new arrangement of reversible gates. The second proposed serial multiplier for signed numbers is based on a newer algorithm called the K algorithm. This algorithm requires less cost compared to the Booth's algorithm. The third proposed fault-tolerant serial multiplier which is optimized for unsigned number multiplication is based on the conventional Add & Shift method. The comparative results show that the proposed multipliers are much better than the existing designs considering the main criterions used in reversible logic circuits which include quantum cost, number of gates, number of garbage outputs, delay, and computational complexity.

For acoustic imaging of underwater moving target, multi-static inverse synthetic aperture sonar idea can be used. Although, proper imaging algorithm has been derived but related parameters have not been discussed. In this paper, after reviewing multi-static inverse synthetic aperture sonar idea and relevant imaging algorithm, effective factors on underwater imaging of moving target such as target dimensions, range, depth and movement, sonar depth and specifications and underwater acoustic channel characteristics are analyzed and practical imaging limitations are derived for the first time. Effects of mentioned factors on target image are simulated and accuracy of analysis is validated.

Application of SRAM-based FPGAs in harsh environments like industrial, military and space locations has attracted many engineers due to their reconfiguribility. However, they are vulnerable to SEU (Single Effect Upset) effects in the mentioned conditions. Hamming code is used in the switch modules of SRAM-based FPGAs for SEU mitigation. The method is capable of correcting single bit errors, however; in recent high density SRAMs, a high energy particle can affect multi-bits that are usually adjacent cells. In this paper two new selective bit placements are proposed for switch level that has led to improved adjacent error detection from 11.11% to 66.66% in the switch box and an increase of detection rate from 3.75% to 75% in switch modules. In addition, another optimized utilization of shortened Hamming code is proposed based on Genetic Algorithm that results in 88.88% detection rate of adjacent bit error in switch box level. The proposed methods do not burden any extra redundancy.

In image processing, a natural and normal action is to capture an image. In capturing an image, interfering noise from certain sources contaminates the image and degrades its quality. This noise may not be erased easily. Non linear filters can achieve noiseless pictures better than linear ones. In this article, an effective and robust method against interfering noise in restoration of infrared images is proposed. An improved hybrid median filter is initially introduced in this proposal, and in conjunction with a Wiener filter the noise is removed using a method based on wavelet transform. Combination of spatial and wavelet transform domain filters is the idea proposed in this paper to cover the shortcomings of both domains. The results of simulations show that the proposed methods are better than other popular noise rejection methods in terms of image quality and PSNR.