Microstrip Patch Antenna for GPS Application

The study and the design of rectangular microstrip patch antenna for multiband applications are presented in this paper. They can be simulated on antenna design software’s such as High Frequency Simulation Software (HFSS), Advanced Design System Momentum (ADS) and Agilent Vector Network Analyzer (E8361A) where different feeding techniques have been deployed to get the desired results. Two rectangular microstrip patch antennas of frequencies 1.5 GHz and 2.4 GHz are designed and simulated on HFSS

Microstrip Patch Antenna for GPS Application

The study and the design of rectangular microstrip patch antenna for multiband applications are presented in this paper. They can be simulated on antenna design software’s such as High Frequency Simulation Software (HFSS), Advanced Design System Momentum (ADS) and Agilent Vector Network Analyzer (E8361A) where different feeding techniques have been deployed to get the desired results. Two rectangular microstrip patch antennas of frequencies 1.5 GHz and 2.4 GHz are designed and simulated on HFSS

Issues Pertaining to Dielectric Assessment of Soil Moisture in a Coaxial Cell

The study considered a pre-existing coaxial cell design and attempted to improve upon the accuracy of the coaxial cell as a measurement device. The cell was modeled with a revised transmission line model. Simulations were conducted using MatLab and were compared to data taken from an Agilent Vector Network Analyzer using Root Mean Square Error (RMSE) analysis to estimate the relative permittivity of samples contained in the coaxial cell's sample chamber. It was found that while the new transmission line model was more rigorous in its representation of the coaxial cell, accuracy was still very limited. As a result, the coaxial cell should be redesigned to eliminate possible complications resulting from its current structure. A transmission line model may not be complex enough to properly represent the cell.School of Electrical & Computer Engineerin

Impedance and Instability Studies in LEIR with Xenon

In 2017, the LEIR accelerator has been operated with Xe39+ beam for fixed target experiments in the SPS North Area. The different ion species, with respect to the standard Pb54+, allowed for additional comparative measurements of tune shift versus intensity at injection energy both in coasting and bunched beams. The fast transverse instability observed for high accumulated intensities has been as well characterized and additional observations relevant to impedance have been collected from longitudinal Schottky signal and BTF measurements. The results of these measurements are summarised and compared to the currently developed machine impedance model

Temperature dependent dynamic and static magnetic response in magnetic tunnel junctions with Permalloy layers

Ferromagnetic resonance and static magnetic properties of CoFe/Al2O3/CoFe/Py and CoFe/Al2O3/CoFeB/Py magnetic tunnel junctions and of 25nm thick single-layer Permalloy(Py) films have been studied as a function of temperature down to 2K. The temperature dependence of the ferromagnetic resonance excited in the Py layers in magnetic tunnel junctions shows knee-like enhancement of the resonance frequency accompanied by an anomaly in the magnetization near 60K. We attribute the anomalous static and dynamic magnetic response at low temperatures to interface stress induced magnetic reorientation transition at the Py interface which could be influenced by dipolar soft-hard layer coupling through the Al2O3 barrier

RF MEMS Based Tunable Bowtie Shaped Substrate Integrated Waveguide Filter

A tunable bandpass filter based on a technique that utilizes substrate integrated waveguide (SIW) and double coupling is presented. The SIW based bandpass filter is implemented using a bowtie shaped resonator structure. The bowtie shaped filter exhibits similar performance as found in rectangular and circular shaped SIW based bandpass filters. This concept reduces the circuit foot print of SIW; along with miniaturization high quality factor is maintained by the structure. The design methodology for single-pole triangular resonator structure is presented. Two different inter-resonator couplings of the resonators are incorporated in the design of the two-pole bowtie shaped SIW bandpass filter, and switching between the two couplings using a packaged RF MEMS switch delivers the tunable filter. A tunning of 1 GHz is achieved for two frequency states of 6.3 and 7.3 GHz. The total size of the circuit is 70mm x 36mm x 0.787 mm (LxWxH)

A Wide-angle Multi-Octave Broadband Waveplate Based on Field Transformation Approach

J.Z. acknowledge the support from the National Nature Science Foundation of China (61571218, 61571216, 61301017, 61371034, 61101011), and the Ph.D. Programs Foundation of Ministry of Education of China (20120091110032, 20110091120052). Y. H. acknowledge the support from the UK EPSRC under the QUEST Programme Grant (EP/I034548/1)