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

Novel Design and Implementation of MIMO Antenna for LTE Application

The quest for achieving high bandwidth connectivity that renders a complete wireless system ideal for video-intensive applications at very low power consumption using multiple inputs/multiple outputs (MIMO) dual-band combo chip with high-speed is ever-growing. A newly designed structure of the MIMO antenna four ports is implemented for efficient bandwidth broadening. The bandwidth and Sparameters of the antenna are simulated and determined. The dual-band MIMO micro-strip patch antenna comprised of four ports where the ground plane is extruded on a substrate having area 125x128 mm2 and thickness 1.6 mm. The antenna is fabricated on an inexpensive FR4 with the dielectric constant of 4.5, loss tangent ~0.019 and patch thickness of 0.035 mm. The MIMO antenna with dimension 53.5x38.25 mm2 operates at 1.8 and 2.6 GHz. The proposed antenna is found to achieve good pattern diversity, low correlation coefficient, high gain, excellent directivity, and quite reasonable bandwidth in the abovementioned range, highly suitable for LTE bands application with 10 dB return loss. The CST microwave studio program is used for the simulation, and real experimental measurements are made using Agilent Technologies E5071B VNA and the equipment inside the anechoic chamber. Measurements on the prototype antenna are carried out, and characteristic evaluations are performed for comparison. The admirable features of the results suggest that our systematic approach may constitute a basis for the design and implementation of MIMO antenna for diverse LTE applications

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