A modified circular patch antenna design has been proposed in this paper, the bandwidth of this antenna is optimized using the genetic algorithm (GA) based on fuzzy decision-making. This design is simulated with HP HFSS Program that based on finite element method. This method is employed for analysis at the frequency band of 1.4 GHz- 2.6 GHz. It gives good impedance bandwidth of the order of 15.5% at the frequency band of 1.67GHz- 1.95GHz and 10.6% at 2.23GHz- 248GHz. It means that impedance bandwidth increases above 4.9% than the impedance bandwidth of ordinary circular patch antennas and band width rise from 1.78GHz- 1.98GHz (10.6%) to 1.67GHz- 1.95GHz (15.5%) and 2.23GHz- 248GHz (10.6%). The antenna fabricated with two slots on circular patch antenna. The measured results of the optimized antenna validate a high compatibility between the simulation and the measurements.      

In this paper, modelling and control of an elastic actuator for rehabilitation robots are investigated. First, the required performance of the actuator is determined, and then a model of the actuator is proposed. Further, a control algorithm is presented to meet the required performance specifications. The control algorithm consists of an external PID torque controller and an internal PI speed Controller. Experimental tests are performed on the actuator to evaluate the actuator performance. First, an accuracy evaluation test is performed on the actuator to calibrate the torque measured by the spring. The results exhibit the spring's linear characteristics and the capability of torque measurement.Second, the bandwidth of the actuator is measured through sinusoidal input. The results show that the actuator is capable of delivering the required torque in the frequency range of rehabilitation. Third, an impedance measurement test is performed on the actuator indicating that it is capable of exerting the lowest and/or highest resistance on patient movement if required. As a result, it is shown that the proposed actuator can satisfy the whole rehabilitation requirements appropriately.

Upscaling based on the bandwidth of the kernel function is a flexible approach to upscale the data because the cells will be coarse-based on variability. The intensity of the coarsening of cells in this method can be controlled with bandwidth. In a smooth variability region, a large number of cells will be merged, and vice versa, they will remain fine with severe variability. Bandwidth variation can be effective in upscaling results. Therefore, determining the optimal bandwidth in this method is essential. For each bandwidth, the upscaled model has a number of upscaled blocks and an upscaling error. Obviously, higher thresholds or bandwidths cause a lower number of upscaled blocks and a higher sum of squares error (SSE). On the other hand, using the smallest bandwidth, the upscaled model will remain in a fine scale, and there will be practically no upscaling. In this work, different approaches are used to determine the optimal bandwidth or threshold for upscaling. Investigation of SSE changes, the intersection of two charts, namely SSE and the number of upscaled block charts, and the changes of SSE values versus bandwidths, are among these approaches. In this particular case, if the goal of upscaling is to minimize the upscaling error, the intersection method will obtain a better result. Conversely, if the purpose of upscaling is computational cost reduction, the SSE variation approach will be more appropriate for the threshold setting.

This paper presents a Transimpedance Amplifier (TIA) for high sensitivity Near Infrared Spectroscopy (NIRS). The proposed TIA is based on the Regulated Cascode (RGC) structure with an extra transistor employed to implement additional feed-forward path and achieve higher gain values. The extra transistor senses a partially amplified input signal, available in the conventional circuit, and conveys an additional ac current into the load, which provides a higher gain. In addition, a bandwidth extension method is introduced using a capacitor and resistor, which can improve amplifier’s bandwidth by 40%. The proposed TIA is designed in 0.18µm CMOS technology and achieves a transimpedance gain of 101.9dB with a -3dB bandwidth of 91.2 MHz considering 2pF of photodiode capacitance at the TIA input. The input referred noise is 4.4pA/√Hz while dissipating 151µW power.

A High-gain, fully balanced preamplifier is presented. The proposed structure advantages flipped voltage follower scheme to achieve a compact current conveyor with very low input impedance. The presented current conveyor then is used as a core element to realize a high-gain, gm-enhanced trans-conductance amplifier. The presented amplifier is suitable for application as a preamplifier. The high gain of amplifier makes it very suitable to be configured in a feedback form to deliver a high-precision predefined or programmable amplification gain. The proposed structure draws a very low power of 150nW from a 0.6V supply voltage. The Spectre Post-layout simulations with TSMC 180nm CMOS technology have been performed. The proposed amplifier exhibits an open-loop DC gain of 141.5dB and 3-dB frequency bandwidth of 2.4kHz at 60dB closed-loop configuration. The load capacitance is set to be 5pF. The proposed structure also delivers high CMRR and PSRR values of 148.3dB and 153.7dB, respectively.

The purpose of the present study was to examine the effects of Bandwidth Modeling on learning a simple timing task. Twenty eight right handed subjects (14 males, 14 females, aged 19-20) voluntarily participated in the study and were assigned randomly to two groups of bandwidth and yoked. The task was pressing the keys number 2, 6, 8 and 4 on a sequential timing apparatus while keeping certain absolute timing. People in the bandwidth group received the model whenever their performance went out from predetermined bandwidth around the goal movement time (a 10 percent bandwidth), while subjects in the other group were yoked with bandwidth group. The experiment consisted of acquisition, retention and transfer phases and absolute timing error was used as dependent variable. The results of retention and transfer tests showed that bandwidth group had less errors than yoked group. The findings of present experiment were in accordance with anticipations of Challenge Point Theory, and showed that bandwidth modeling is an appropriate technique for adjusting learning condition with learner’s needs. Also advantages of bandwidth method that in past just had been confirmed in KR presentation scheduling domain, nicely generalized to observational learning domain.

In this paper two recently developed meta-heuristic optimization methods, known as Colliding Bodies Optimization (CBO) and Enhanced Colliding Bodies Optimization (ECBO), are used for optimum nodal ordering to minimize bandwidth of sparse matrices. The CBO is a simple optimization algorithm which is inspired by a collision between two objects in one-dimension. Each agent is modeled as a body with a specified velocity and mass. A collision happens between pairs of bodies and the new positions of the colliding bodies are updated based on the collision laws. The enhanced colliding bodies optimization (ECBO) utilizes memory to save some best so-far-solution to improve the performance of the CBO without increasing the computational cost. This algorithm utilizes a mechanism to escape from local optima. The bandwidth of some graph matrices, which have equivalent pattern to structural matrices, is minimized using these approaches. Comparison of the obtained results with those of some existing methods shows the robustness of these two new meta-heuristic algorithms for bandwidth optimization.

A compact, wideband, low cost, high radiation efficiency and planar half mode substrate integrated waveguide (HMSIW) horn antenna is proposed in this work. For the first time, HMSIW is used to design a horn antenna. By using HMSIW waveguide structure instead of Substrate Integrated Waveguide (SIW), the impedance bandwidth of antenna is increased significantly. The use of this waveguide structure in the design of the horn and its feeding system has increased the impedance bandwidth of the antenna. In fact, leaking the electromagnetic waves gradually along the horn increases the bandwidth of antenna. By applying the design equations of the H-plane horn antenna and half mode substrate integrated waveguide, the initial dimensions of the antenna have been obtained, then the best possible solution has been extracted by parametric study and optimization. Simulation results exhibit an impedance bandwidth of 50% from 24GHz to 40GHz. Also, the proposed design shows a gain between 7dB and 10 dB together with radiation efficiency higher than 95% over the frequency band of 25 to 35GHz. The innovation of this work is in providing a new horn structure based on HMSIW with wide impedance bandwidth. In the previously presented works, which are mainly based on SIW, the antenna suffers from a narrow impedance bandwidth.

In this paper a new topology based on “Z source inverters” is introduced. In the proposed structure, two inductors of the impedance network in conventional Z Source Inverter are replaced by two transformers with three windings. Voltage gain of the new inverter is higher than other Z Source networks with any duty cycle. In order to access high output power quality, the proposed inverter operates at a higher modulation index (near 1). Thereby, stress of switching devices is reduced. The performance of the proposed inverter is verified using the MATLAB/SIMULlNK software.