Evaluation of magnetic properties of thin magneto-dielectric films deposited from beam plasma in medium vacuum

By electron-beam evaporation of a solid state dielectrics (alumina ceramics) and a magnetic material (steel-3) in fore-vacuum, thin films of several μm, possessing both dielectric and magnetic properties, were deposited on a substrate. The work shows that the microstrip resonator method can be used to assess the presence of magnetic properties in films.

A New ANFIS-based Hybrid Method in the Design and Fabrication of a High-performance Novel Microstrip Diplexer for Wireless Applications

In this work, we have used a novel adaptive neuro-fuzzy inference system (ANFIS) method to design and fabricate a high-performance microstrip diplexer. For developing the proposed ANFIS model, the hybrid learning method consisting of least square estimation and back-propagation (BP) techniques is utilized. To achieve a compact diplexer, a designing process written in MATLAB 7.4 software is introduced based on the proposed ANFIS model. The basic microstrip resonator used in this study is mathematically analyzed. The designed microstrip diplexer operates at 2.2[Formula: see text]GHz and 5.1[Formula: see text]GHz for wideband wireless applications. Compared to the previous works, it has the minimum insertion losses and the smallest area of 0.007 [Formula: see text] (72.2[Formula: see text]mm2). It has flat channels with very low group delays (GDs) and wide fractional bandwidths (FBWs). The GDs at its lower and upper channels are only 0.48[Formula: see text]ns and 0.76[Formula: see text]ns, respectively. Another advantage of this work is its suppressed harmonics up to 12.9[Formula: see text]GHz (5th harmonic). To design the proposed diplexer, an LC model of the presented resonator is introduced and analyzed. To verify the simulation results and the presented ANFIS method, we fabricated and measured the proposed diplexer. The results show that both simulations and measurements data are in good agreement, which give reliability to the proposed ANFIS method.

On the design and characterisation of a microwave microstrip resonator for gas sensing applications

This study focuses on the microwave characterisation of a microstrip resonator aimed for gas sensing applications. The developed one-port microstrip resonator, consisting of three concentric rings with a central disk, is coupled to a 50-Ohm microstrip feedline through a small gap. A humidity sensing layer is deposited on this gap by drop-coating an aqueous solution of Ag@alpha-Fe₂O₃ nanocomposite. The operation principle of the developed humidity sensor is based on the change of the dielectric properties of the Ag@alpha-Fe₂O₃ nanocomposite when the relative humidity is varied. However, it should be underlined that, depending on the choice of the sensing material, different target gases of interest can be detected with the proposed structure. The frequency-dependent response of the sensor is obtained using the reflection coefficient measured from 3.5 GHz to 5.6 GHz with relative humidity ranging from 0 %rh to 83 %rh. The variation of the humidity concentration strongly impacts on the two resonances detected in the measured reflection coefficient. In particular, an increase of the humidity level leads to lowering both resonant frequencies, which can be used as sensing parameters for humidity monitoring purpose. An exponential function has been used to accurately model the two resonant frequencies as a function of the humidity.

Mutual Coupling Reduction In Microstrip Patch Antenna Arrays Using Simple Microstrip Resonator

In this paper a novel ladder resonator is introduced to decrease mutual coupling effect between two microstrip patch antennas. Applied patch antennas are operating at 2.45 GHz frequency (ISM band), which specially used for multiple-input–multiple-output (MIMO) systems. The edge-to-edge distance between two microstrip patch antennas is 0.05 λ. The proposed ladder resonator impressively blocks the surface current between two patch antennas at the operating frequency, which results in mutual effect reduction. The proposed configuration has been fabricated and tested. Scattering parameters with and without of proposed resonator has been investigated. The results show that, the proposed configuration increases isolation between two microstrip patch antennas about 42dB.

Study of Decoupling between Closely Spaced Microstrip MIMO antennas using Microstrip Resonator

This paper presents a novel decoupling technique between two closely spaced MIMO antennas whose edge to edge spacing is0.03λ (1.975mm).A microstrip resonator is used in between the antennas that act as a decoupled device. The MIMO plays an important role in the current communication system due to its enhanced data transferring rate. However, the closely spaced MIMO antennas have a major disadvantage of high mutual coupling (MC). MC affects the entire characteristics of MIMO antennas and as a result, the performance of the antenna degrades. To overcome this problem, we have introduced a microstrip resonator that acts as an electrical wall between the MIMO antennas. The antenna has been simulated by using an IE3D EM simulator and a suppression of 48dB MC is achieved at a resonant frequency of 4.85 GHz. The MIMO antennas have been fabricated and the results are compared with the simulated ones. This antenna can be used in wireless communication, WLAN and satellite communication.