Journal of Electrical Systems and Signals
Volume:1 Issue: 2, 2013

Design of SiNx / SiOx single layer antireflection coating has been developed which tunes both the layer thickness and the deposition gas flow ratio. The method is built up for achieving maximum available carrier generation rate. The carrier generation rate estimation is based on internal and external quantum efficiency calculations. In this report the effect of optical reflection and absorption on external efficiency is widely studied. The model is based on wideband photonic parameters of silicon nitride / oxide which are deposited with PECVD machine under different deposition criteria. Effect of gas flow ratio on the dielectric refractive index and extinction factor are investigated by wideband photonic measurements. For silicon nitride anti reflection coating, the optimized coating consists of 63nm SiNx layer with Silane to Ammonia gas ratio of 4. The estimated carrier generation rate is 1.88×1017 cm-2s-1. The best possible results for silicon oxide has been derived with 88.9nm SiOx with Silane to Nitrous Oxide gas ratio of 1; In this case the carrier generation rate will be 1.83×1017 cm-2s-1. The proposed anti reflection coatings are deposited on single crystal silicon substrate, the measured optical reflection coefficients are in very good agreement with the developed theory.

This paper presents an accurate methodology for the optimum interleaved-repeater positioning in global interconnects. We have compared the analytical delay uncertainty of available repeater insertion techniques and derived analytical expressions for extracting a new optimum value for the relative position ratio of the interleaved interconnects. We have used the simple yet-realistic α-power law for MOS devices in the proposed model in order to increase the accuracy of the methodology. The new positioning method has been proven to minimize the delay uncertainty caused by the coupling capacitance of the switching adjacent lines. The measured uncertainty of the proposed methodology was less than 10% for all beyond 100-nm scaled technology nodes. It is also shown that the proposed strategy offers lower propagation delay sensitivity to variations of a segment length in comparison with commonly used repeater insertion techniques. Accordingly, using the proposed methodology, we achieve a maximum sensitivity reduction of 33% for 65-nm technology, 51% for 45-nm technology and 34% for 32-nm technology node.

Electrocardiogram (ECG) signal is widely used in the diagnosis of heart diseases. Since the amplitude of this signal is very low, a high-gain low-noise amplifier with a high common mode rejection ratio (CMRR) is needed. In portable applications a battery provides the required power for the ECG device. Hence, ECG amplifiers should have low area and power consumption. In this paper, an instrumentation amplifier for ECG application is proposed in which MOSCAPs are used to reduce the circuit area. MOSCAPs are inherently nonlinear and a technique is presented to reduce the impact of this non-linearity. In ECG systems, a driven right-leg circuit is used to increase the CMRR of the amplifier. In this paper a class AB buffer is employed to implement this circuit. The simulation results show that the gain of the proposed amplifier is 46.18 dB and its input referred noise is 7.8µVrms over the frequency range of 0.3 Hz to 150 Hz. The total power consumption of the designed amplifier is 72nW. The amplifier CMRR is 96 dB and its total harmonic distortion (THD) is 0.68% (at 60Hz).

Cognitive radio (CR) technology can effectively improve spectral efficiency by allowing secondary users (SUs) to access licensed bands without any harmful interference to primary users (PUs). Due to adverse effects of environment such as loss and fading, SUs may receive weak signals. So, in order to mitigate these effects, some SUs can act as relay nodes to improve SUs’ connectivity. Moreover, using relay nodes can increase spatial diversity and also enhance spectrum efficiency further. In this paper, a new algorithm is proposed for cooperative beamforming, power allocation and relay selection in the multiple input multiple output (MIMO) Orthogonal Frequency Division Multiple Access (OFDMA) CR systems where a pair of SU communicates with each other assisted by some single antenna relay nodes. The objective is to maximize signal to interference plus noise ratio (SINR) of SU subject to guarantee the PU's quality of service and power constraints of SU and relay nodes over all subchannels. The transmitter and receiver beamforming vectors of PU and SU are estimated by the proposed two-step iterative algorithm. The performance of the algorithm is evaluated through simulations. Simulation results show that the proposed algorithm, in addition to guarantee a required performance of the PU, increases spectrum usage efficiency by servicing the SUs. Also, by increasing the number of relay nodes, the performance of the algorithm is improved

In this paper, the power electronic interface between a spacecraft electrical power system with a photovoltaic main source and battery storage as the secondary power source is modelled based on the state space averaging method. Subsequently, a novel sliding mode controller is designed for maximum power point tracking of the PV array and load voltage regulation. Asymptotic stability is guaranteed through Lyapunov stability analysis. Afterwards, common LQR, PID and PBC controllers are provided to compare the results with those of the proposed sliding mode controller responses. Simulation of the hybrid system is accomplished using MATLAB and results are very promising.

In this paper new epsilon-zero resonance (EZR) antennas using epsilon negative (ENG) transmission line (TL) are presented. In the proposed antennas, the unit cell of the ENG TL is implemented using a modified mushroom-like structure in which the via hole is placed at the patch edge. This configuration leads to a broadside radiation pattern and also results in the unit cell size reduction. These antennas are analyzed using transmission line based metamaterials and zeroth order resonators (ZORs) theories. A one unit cell compact size antenna and a nine unit cell high gain antenna using this new configuration are designed and fabricated. The measurement results including radiation pattern, maximum gain and return loss show good agreement with simulation results.

In this paper, a new concept of serving flexible reliability (FR) is introduced in distribution network level. FR is defined as the ability of a grid to continue servicing the high priority ýcustomers in contingency states. Customers’ priority is recognized based on their required value of service reliability. Regarding this matter, the philosophy of designing a hybrid
AC-DC microgrid is introduced with the ability of offering an alternative resource for each individual customer in contingency ýstates. The analytical modeling of FR analysis besides the overall reliability analysis is proposed and the new FR index of expected energy retrieved EER is introduced. The performance of the proposed hybrid microgrid in serving FR is demonstrated through a numerical study on modified distribution network for bus four of Roy Billinton Test System (RBTS).