Browsing by Subject "Circuit modeling"

Now showing 1 - 4 of 4

Open Access
Electromechanical filters using micromachined coupled circular plate resonators
(2021-09) Acar, Muhammed Abdulcelil
Mechanically coupled resonators fabricated using micromachining usually require a mechanical coupling element; this introduces additional complexity to the picture. We propose a novel modeling and design approach, followed by experimental verification, for mechanically coupled clamped circular plate resonators fabricated using a commercial micromachining process in which no additional coupling element is present. In our study, the flexural mode clamped circular plate resonators overlap to an extent. Their clamps at the overlap region are removed to generate a freely moving coupling boundary between the resonators. The practical measure of the overlap is small enough to preserve the characteristics of each resonator. This result enables modeling the coupled-resonators based on the clamped circular plate resonator model. A physics-based lumped element equivalent circuit model is developed where dimensions, bias voltage, and material properties are controllable variables. Each of the model parameters is expressed as the corresponding single resonator model parameter multiplied by a function of the amount of overlap. Analytical derivations and finite element method (FEM) simulations are used to extract the dependency of the model parameters on the amount of overlap. Closed-form expressions for the coupled-resonator's center frequency, bandwidth, and termination impedance are derived using the developed model. A design procedure is introduced to determine dimensional parameters and bias voltage. The proposed coupled-resonator offers up to 5% fractional bandwidth. For a typical design using a polysilicon plate with 100 nm gap height, the ratio of the termination impedance to the center frequency is calculated to be 158 Ω/MHz. This result indicates that on-chip intermediate frequency (IF) filters can be implemented at center frequencies up to several hundred MHz using this type of coupled-resonators. A coupled-resonator is designed and realized for a proof of concept demonstration. The measurement results of the coupled-resonator show good agreement with the equivalent circuit model simulations.
Open Access
Mechanically coupled clamped circular plate resonators: modeling, design and experimental verification
(Institute of Physics Publishing Ltd., 2021-08-27) Acar, Muhammed Abdulcelil; Atalar, Abdullah; Yılmaz, Mehmet; Köymen, Hayrettin
Mechanically coupled resonators usually require a mechanical coupling element; this introduces additional complexity to the picture. We propose a novel modeling and design approach, followed by experimental verification, for mechanically coupled clamped circular plate resonators in which no additional coupling element is present. In our study, the flexural mode clamped circular plate resonators overlap to an extent, and their clamps at the overlap region are removed to generate a freely moving coupling boundary between the resonators. The practical measure of the overlapping is small enough to preserve the characteristics of each resonator. This result enables modeling the coupled resonators based on the clamped circular plate resonator model. A physics-based lumped element equivalent circuit model is developed where dimensions, bias voltage, and material properties are controllable variables. Each of the model parameters is expressed as the corresponding single resonator model parameter multiplied by a function of the amount of overlap. Analytical derivations and finite element method simulations are used to extract the dependency of the model parameters on the amount of overlap. Closed-form expressions for center frequency, bandwidth, and termination impedance of the coupled resonator are derived using the developed model. A design procedure is introduced to determine dimensional parameters and bias voltage. The proposed coupled-resonator offers up to 5% fractional bandwidth. For a typical design using a polysilicon plate with 100 nm gap height, the ratio of the termination impedance to the center frequency is calculated to be 158 Ω MHz−1. This result indicates that on-chip intermediate frequency filters can be implemented at center frequencies up to several 100 MHz using this type of coupled resonators. A coupled resonator is designed and realized for a proof of concept demonstration. The measurement results of the coupled resonator show good agreement with the equivalent circuit model simulations.
Open Access
A Miniaturized Patch Antenna by Using a CSRR Loading Plane
(Hindawi Publishing Corporation, 2015) Ramzan, M.; Topalli, K.
This paper presents a design methodology for the implementation of a miniaturized square patch antenna and its circuit model for 5.15 GHz ISM band. The miniaturization is achieved by employing concentric complementary split ring resonator (CSRR) structures in between the patch and ground plane. The results are compared with the traditional square patch antenna in terms of area, bandwidth, and efficiency. The area is reduced with a ratio of 1/4 with respect to the traditional patch. The miniaturized square patch antenna has an efficiency, bandwidth, and reflection coefficient of 78%, 0.4%, and -16 dB, respectively. The measurement and circuit modeling results show a good agreement with the full-wave electromagnetic simulations. © 2015 Mehrab Ramzan and Kagan Topalli.
Open Access
Nonlinear equivalent circuit model for circular CMUTs in uncollapsed and collapsed mode
(IEEE, 2012) Aydoğdu, Elif; Özgürlük, Alper; Oğuz, H. Kağan; Atalar, Abdullah; Kocabaş, Coşkun; Köymen, Hayrettin
An equivalent electrical circuit model valid for collapsed mode operation of CMUT is described. The across and through variables of the circuit model are chosen to be rms force and rms displacement over the surface of the CMUT membrane. The relation between rms displacement and applied voltage is obtained through analytical calculations utilizing the exact force distribution. The radiation impedance of collapsed mode CMUT is included as a load impedance in the circuit model. The resulting equivalent circuit is merged with uncollapsed mode model, to obtain a simulation tool that covers the whole operation range of CMUT. © 2012 IEEE.