Showing 5 results for Quality Factor
Atefeh Gholipour, Khalil Mafinezhad,
Volume 14, Issue 4 (3-2018)
Abstract
In the last decade Micromechanical components for communication applications has been fabricated via IC-compatible MEMS technologies. In fact, its most important impact is not at the component level, but rather at the system level, by offering alternative transceiver architectures that reduce power consumption and enhance performance. In this paper a mixer-filter for AM frequency receiver with MEMS based on one clamped-clamped beam resonator is presented. Mixing and filtering functions are achieved by one component. By combining mixer and filter in one component, in addition to size reduction for portable communication devices, power consumption is also reduced. Mixer-filter can down-convert the RF frequency of 1.655MHz to IF frequency of 455 kHz with a bandwidth of 8 kHz by local oscillator frequency of 2.11 MHz. This technique can be used for much higher RF frequencies. The unloaded Q of this device is 7714 and it could be used as narrow band filter, this design has high linearity too with IIP3 13.6dBm. Above all, by integrating this mixer filter with the rest of the circuit it is more economical than other conventional receivers.
Phd Kiazand Fasihi, Saeide Nourouzi,
Volume 18, Issue 1 (3-2021)
Abstract
In this paper the design and three dimensions (3D) simulation of a photonic crystal (PC) pressure sensor is presented. The device is based on a 2D PC slab of PbMoO4. The simulations are based on finite element method (FEM) and finite-difference time-domain (FDTD) method and are done using CST STUDIO SUITE software. The sensitivity of the proposed sensor is calculated by considering the deformation and also refractive index variation factors. The numerical results show that when a pressure is applied, both factors cause to a reduction in the resonant wavelength of the transmission spectrum. It has been shown that the relationship between the applied pressure and the shift in the resonant wavelength of the cavity is linear. Based on the simulation results, the quality factor of the resonant peak of the transmission spectrum and the sensitivity of the proposed sensor are -2.858 nm/GPa and 1040 , respectively.
Phd Kiazand Fasihi, Razieh Yosefi Hashem Abad,
Volume 18, Issue 1 (3-2021)
Abstract
In this paper design and two dimensional (2D) simulation of a photonic crystal highly sensitive temperature sensor is presented. The 2D simulations are based on finite-difference time-domain (FDTD) method and are done using Rsoft software. The device is constructed using a cavity filled with the distilled water located in the center of the photonic crystal waveguide. The operation of the proposed sensor is investigated considering the thermal variations of the refractive index of the background material (Si) and the cavity’s filled material (the distilled water) and also the thermal expansion of the structure. It has been shown that the radii of the cavity and its surrounding holes have an important role in the performance of the device. It has been shown that the relationship between the temperature variation and the shift in the resonant wavelength of the cavity is linear. Based on the simulation results, the sensitivity, the quality factor and the transmission of the proposed sensor are 149.79 pm/c, 6105 and 0.6, respectively.
Maryam Imani, Dr. Kiazand Fasihi,
Volume 21, Issue 3 (10-2024)
Abstract
In this paper, design and simulation of an acoustic demultiplexer based on phononic crystal ring resonators is presented. The proposed structure consists of one input and three outputs. The dimensions of the structure are 180× 243 mm2 and it consists of water cylinders on a mercury bed. After applying a pulse wave in the frequency range of 74.6 to 75.4 kHz to the structure, three channels with frequencies of 74.82, 75.02 and 75.28 kHz are separated. In this study, finite element method in Comsol software is used. The proposed device with a transmittance of more in the output channels, very high quality factor and low amount of crosstalk between the output channels (which is at the worst case is -45 dB), has very suitable features for the implementation of The acoustic demultiplexer.
Dr Kiazand Fasihi, Ms Maryam Imani,
Volume 22, Issue 1 (12-2024)
Abstract
Phononic crystals consist of periodic distributions of scatterers in a host matrix. Destructive interference of several scattered waves leads to the appearance of the most prominent characteristic of phononic crystals, namely the phononic band gap. Using these crystals and creating defects in its periodicity, these crystals can be used in various applications such as filters, lenses, waveguides, demultiplexers, sensors, etc. In this study, we present two 2D phononic crystals with square and triangular lattices of water cylinders in mercury. To simulate the proposed devices, plane wave expansion method and finite element method in Comsol multiphysics software are used. The resonant frequencies of the proposed 1×4 demultiplexer with square lattice are 66.09, 68.23, 70.27 and 72.49 KHz. In this structure the mean of quality factors is 3042, the minimum crosstalk is -42 dB, and the dimensions of the structure is 218×118![]()
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