A microstrip trapezoidal patch antenna structure has been proposed to serve different space applications including the fixed satellite applications, mobile and radiolocation services. This structure utilizes a 0.787 mm thick RT Duroid (5880) substrate of relative permittivity 2.2 and a dielectric loss tangent of 0.0009. A trapezium shaped patch has been formed on it. The patch is compact and has a novel geometry. The feeding technique employed is coaxial/probe feed. The parametric analysis done over HFSS-15 software to study the effects of the structural design over the behavior of antenna reveals the potentiality of the designed antenna to maintain a nearly constant gain upon the variation of several parameters individually. The use of parallel slots in the design offer a reduction in the size of the patch [5]. The performance of the antenna has been analyzed in terms of reflection coefficient, bandwidth and radiation pattern. The antenna yielded a simulated single band reflection coefficient of -22.5 dB and a peak gain of 4.7 dBi at 3.64 GHz and an impedance bandwidth of 10 MHz at -10 dB reflection coefficient. The fabricated design was tested over VNA for its reflection coefficient. The measured results have been included.

This paper presents a method of designing microstrip dual-band bandpass filter fed with lumped capacitors. Unlike the tapping or coupling feeding structures, the lumped capacitors could make the external quality factors have suitable values in two different pass bands. Thus no impedance transformers are needed when designing dual-band bandpass filter fed with lumped capacitors. An example of this kind of filter is designed, fabricated and measured. The measured results accord well with the simulated results, showing validity of the proposed method.

This article demonstrates for the proposed all optical binary subtractor network. Performance explored by exploiting nonlinear attribute the cross gain modulation with semiconductor optical amplifier which otherwise considered as cons if used as an amplifying tool. Numerical simulations have been executed, accordingly accustomed data inputs at 100Gbps data rate employed, generated aspired difference and the borrow outputs concurrently. The design’s performance for the non return to zero, return to zero and Manchester modulation formats have been analyzed, according to it is key performance parameter the extinction ratio. Investigations inferred optimum performance for the non return to zero modulation format outcome extinction ratio of 13.5dB,together with difference and borrow output have been successfully confirmed. Further designs execution with non return to zero modulation format for the key parameters range of data rates, laser peak power, the normalizer power, pump current, the current injection efficiency and the modulator bias voltage have been evaluated. Evaluation inferred that optimum performance is subject to the pertinent election of the vital design parameters. The proposed design is simpler by virtue of key attributes low power consumption and stability altogether with higher integration capability as well provides output generation simultaneously at higher data rate. It was lacking with preceding elucidations. Accordingly, this illustration could be an assistance towards novel contemporary complex digital optical computing combinational networks.

Cyber security is of topical concern in the computing industry and in organizations that require ICT infrastructure for business-related activities. Theft or disrupting the flow of data and information can cause devastating damage to an institution’s reputation and this may lead to huge financial losses. More mayhem can be perpetrated by malicious codes such as worms to organizations that use wireless sensor networks for collecting and transmitting data and information. To tackle this issue of cyber security, researchers have used epidemiological models (such as SEIR and SEIR-V) to gain insight into malicious code propagation. However, topological concerns and its impact in worm propagation haven’t been thoroughly studied. Here, we modify older models by applying a different expression for sensor deployment area; we intend to highlight the spatial parameters that may allow for the extinction of worms in wireless sensor networks amidst countermeasures deployed by network managers.

A simple compact H shaped MIMO antenna for WLAN application at resonating frequency 5.8 GHz is propose in this paper. The center to center spacing between closely placed H shaped MIMO antenna is 0.311λo. The mutual coupling between the proposed antenna is reduced by using dumbbell shaped DGS at the center of the groundplane. These dumbbell shape defect act as bandstop filter because of its inductance and capacitance effect, helps to suppress the surface wave propagation of waves. The filter characteristic of the dumbbell shaped DGS is studied to achieve isolation over the 5.725-5.875 GHz frequency band. Further the parametric study such as length, width and the spacing of dumbbell shaped DGS is optimized and studied in order to achieve good isolation among the MIMO antenna elements. The proposed MIMO structure is fabricated on low cost FR4 substrate having thickness of 1.6mm and the overall dimension of MIMO antenna is 40mm x 24 mm leading to compact size of antenna. The mutual coupling reduces from 24 dB to 34 dB by placing dumbbell shaped DGS. The envelope correlation coefficient for the proposed antenna is below less than 0.04 dB for the operating frequency band. The proposed H shaped MIMO antenna is tested and the measured result follows the simulation results. Therefore the proposed antenna is a good candidate for WLAN application.

In recent decades Significant expansion and popularity of wireless sensor networks in various applications have attracted the attention of many researchers. The main challenges of WSN for the researchers are Energy and security restrictions. Recently trust as a new, efficient and soft method has been able to provide satisfactory security in WSN. In this study by using a simple method, first each node calculates the trust values of neighbors and according to these values exchanges data with neighbor nodes, then from each cluster, a node whose trust is greater than a threshold value can be candidate for being cluster head. Finally by using fuzzy logic a node with the most trusted neighbors and desirable energy level among the candidate nodes is selected as a cluster head. Simulation results show that proposed system has been able to greatly improve security and prevent untrusted and malicious nodes from becoming the cluster head.