Microstrip Bandpass Filter with Reconfigurable Notch Response at 5.2 GHz using Defected Microstrip Structure

An investigation of a new design of short circuit stub wideband bandpass filter integrated with reconfigurable notch characteristic is presented. The wideband bandpass filter was designed from a quarter-wavelength short circuit stub with folded topology in order to reduce overall physical dimension. The U-shaped DMS was designed on a microstrip line by defecting the bandpass filter. The reconfigurable characteristic was then realized by introducing PIN diode (BAP 64-02) as a switching element that is placed on top of the U-shaped DMS. When the diode was OFF, it produced a wideband bandpass response from 3.0 GHz to 6.0 GHz. On the other hand, when the PIN diode was ON, a sharp rejection of notch response at 5.2 GHz with a very low passband transmission coefficient was finally demonstrated. This type of filter is very useful in radar and wireless communication systems

Control Radiation Pattern for Half Width Microstrip Leaky Wave Antenna by Using PIN Diodes

In this paper, a novel design for single-layer half width microstrip leakywave antenna (HW-MLWA) is demonstrated. This model can be digitally control its radiation pattern at operation frequency and uses only two values of the bias voltage, with better impedance matching and insignificant gain variation. The scanning and controlling the radiation pattern of leaky-wave antennas (LWA) in steps at an operation frequency, by using switches PIN diodes, is investigated and a novel HW-MLWA is introduced. A control cell reconfigurable, that can be switched between two states, is the basic element of the antenna. The periodic LWA is molded by identical control cells where as a control radiation pattern is developed by combining numerous reconfigurable control cells. A gap capacitor is independently connected or disconnected in every unit cell by using a PIN diode switch to achieve fixedfrequency control radiation pattern scanning. The profile reactance at the free edge of (HW-MLWA) and thus the main lobe direction is altered by changing the states of the control cell. The antenna presented in this paper, can scan main beam between 18o to 44o at fixed frequency of 4.2 GHz with measured peak gain of 12.29 dBi

A Study of Different Substrate Material on Air Gap Radial Line Slot Array (RLSA) Antenna at 28 GHz

This paper compared the performance of the conventional Radial line slot array (RLSA) antenna structure. Two different substrates of RLSA antennas were used: The FR4 with the relative permittivity (εr) value of 4.5 and the Duroid/RT5880 with the relative permittivity (εr) value of 2.2. Both substrates had their own thickness, where the Rogers RT Duroid 5880 was thinner with the value of 0.254 mm compared to FR4 which was 1.600 mm. There were two antenna cavities, which were the FR4 hybrid with air gap and the Duroid/RT5880 hybrid with air gap. Based on different substrate, this RLSA antenna was simulated using the CST Microwave Studio simulation software and measured using the Vector Network Analyzer (VNA) equipment that can measure the frequency range (10.0 MHz to 50.0 GHz). Moreover, this RLSA antenna was presented, experimented and measured for millimeter wave frequency, which is within the frequency range (24.0 GHz to 32.0 GHz). In the middle of the rectangular, slots on radiating plate, located with fed coated of 50 Ω SSMA connector as a coaxial to waveguide transition frequency reconfigurable millimeter-wave antenna for 5G networks is presented. The results of the simulation and measurement of this RLSA antenna with different substrates show the S11 and wider value of impedance bandwidth performance in millimeter wave frequency

Analysis on Energy and Coverage Issues in Wireless Sensor Network

Two major fundamental issues in Wireless Sensor Network (WSN) are energy efficiency and coverage. Energy efficiency is the result of controlling and maintaining the energy usage. A method is considered as energy efficient if it can provide more services with the same amount of energy input, while coverage efficiency is measured by how long and how well a sensor monitors the subjected area. Hence, to obtain an energy and coverage efficiency, maximizing the coverage by reducing the energy consumption needs to be achieved. Our paper presents the potential of Derivative Harmon Search Algorithm (DHSA) in a connected WSN to achieve deployment of node that can cover optimal area and at the same time give low energy consumption

Textile Dual Band Circular Ring Patch Antenna under Bending Condition

Textile flexible wearable antenna is becoming a popular study in antenna technology. In this paper, the dual band textile circular patch antenna under bending condition has been designed and analysed. The antenna characteristics such as scattered parameters and radiation pattern has been analysed and compared for normal and bended conditions. Main desired application for the antenna might be on body network which required the wearable condition which incorporated on human torso. The reflection coefficient of the antenna has been determined at 2.4GHz and 5.2GHz which make the antenna to be suitable for WLAN application. To make the antenna suitable to attach on human torso sizes, three bending radii has been chosen, which are 33.5 mm, 47.5 mm and 58.5 mm. The simulated and measured results have been presented and analysed. The antenna with smaller bending radius has shown severe effect on the antenna resonant frequency. However, only slight effect on radiation pattern with compared to the flat antenna. Hence, from the result and analysis, the developed textile antenna is seen to be immune towards the effect of bending and suitable for wearable especial for WLAN application

Wearable Textile Antenna on Electromagnetic Band Gap (EBG) for WLAN Applications

This paper presents a new dual band wearable textile antenna for on body application, at 2.4 GHz and 5.2 GHz. The performance of the antenna is described with the integration of an electromagnetic band gap (EBG) structure. The antenna and EBG structure aremade of jeans material which has a dielectric constant of 1.7, with the thickness of 1.2 mm and 0.025 loss tangent. The conductive component used in this paper is copper tape with thickness of 0.02 mm. The EBG array consists of 6 elements which are arranged in circular pattern surrounding the antenna patch. The effect of placing the EBG below the conventional antenna is studied and compared with the performance of the antenna alone. The gains of the antenna are improved by 63.7% and 121.4% at 2.4 GHz and 5.2 GHz respectivelyafter integrating the EBG structure. At least 10 dB of backward radiation is reduced with the presence of the EBG structure. The integration of EBG with the conventional antenna has improved the antenna performance. The simulated and measured return loss, together with E-plane and H-plane polar pattern are presented in this paper for both condition

Improved Location and Positioning Utilizing Single MIMO Base Station in IMT-Advanced System

This paper discusses an improvement of location and positioning estimation using one of the IMT-Advanced systems known as the mobile WiMAX. The Single MIMO Base Station (SMBS) in mobile WiMAX is combined with a virtual technique, known as the Virtual Base Stations, created a novel algorithm for location and positioning (L&P) purposes. This algorithm based on the angle of arrival (AOA) and angle of departure (AOD) measurement parameter completed the new SMBS algorithm with virtual base station (SMVirBS). The developed algorithm includes the effect of the geometric dilution of precision (GDOP) to assist with the location estimation accuracy. The simulation results showed that the proposed SMVirBS technique always outperforms the linear least square (LLS) algorithm in terms of estimated location accuracy. The technique also has the capability to work well in non-line of sight errors (NLOS)

Observation of competing, correlated ground states in the flat band of rhombohedral graphite

In crystalline solids, the interactions of charge and spin can result in a variety of emergent quantum ground states, especially in partially filled, topological flat bands such as Landau levels or in magic angle graphene layers. Much less explored is rhombohedral graphite RG , perhaps the simplest and structurally most perfect condensed matter system to host a flat band protected by symmetry. By scanning tunneling microscopy, we map the flat band charge density of 8, 10, 14, and 17 layers and identify a domain structure emerging from a competition between a sublattice antiferromagnetic insulator and a gapless correlated paramagnet. Our density matrix renormalization group calculations explain the observed features and demonstrate that the correlations are fundamentally different from graphene based magnetism identified until now, forming the ground state of a quantum magnet. Our work establishes RG as a platform to study many body interactions beyond the mean field approach, where quantum fluctuations and entanglement dominat

Optimization of Location Estimation Utilizing GDOP Technique with Cooperation of Relay Station

Geometric Dilution of Precision (GDOP) has always played an important role in satellite navigation system. This paper presents the extension of GDOP as a location estimation technique to determine the location of a Relay Station (RS). The proposed RS scheme and architecture showed a promising potential in increasing the network coverage and extending the range of a base station. The simulation results indicate that the application of GDOP to optimize RS position has improved the Mobile station (MS) estimation accuracy