Analysis of Pull-in-Voltage and Figure-of-Merit of Capacitive MEMS Switch

Santanu Maity,Rajesh Saha,Ngasepam Monica Devi,Chandan Tilak Bhunia 한국전기전자재료학회 2016 Transactions on Electrical and Electronic Material Vol.17 No.3

Theoretical and graphical analysis of pull-in-voltage and figure of merit for a fixed-fixed capacitive MicroElectromechanical Systems (MEMS) switch is presented in this paper. MEMS switch consists of a thin electrodecalled bridge suspended over a central line and both ends of the bridge are fixed at the ground planes of a coplanarwaveguide (CPW) structure. A thin layer of dielectric material is deposited between the bridge and centre conductorto avoid stiction and provide low impedance path between the electrodes. When an actuation voltage is appliedbetween the electrodes, the metal bridge acquires pull in effect as it crosses one third of distance between them. Inthis study, we describe behavior of pull-in voltage and figure of merit (or capacitance ratio) of capacitive MEMS switchfor five different dielectric materials. The effects of dielectric thicknesses are also considered to calculate the valuesof pull-in-voltage and capacitance ratio. This work shows that a reduced pull-in-voltage with increase in capacitanceratio can be achieved by using dielectric material of high dielectric constant above the central line of CPW.

Design of a Non-uniform Serpentine Asymmetric Cantilever RF-MEMS Shunt Capacitive Switch for RADAR Applications

Ch. Gopichand,Reshmi Maity,N. P. Maity,K. Srinivasa Rao,Koushik Guha,Santanu Maity,Ameen Eisnawi 한국전기전자재료학회 2020 Transactions on Electrical and Electronic Material Vol.21 No.4

This paper presents the design and simulation of Cantilever type RF-MEMS Capacitive shunt switch with meanders and perforations. The main objective of this paper is to reduce the pull-in voltage and increases isolation of the proposed switch. Electro-mechanics and Solid-mechanics are used to simulate the proposed switch by using COMSOL Multiphysics software. The capacitance, switching time, stress analysis are calculated and compare both theoretical and simulation results of the proposed switch. By varying diff erent beam thickness, materials, an air gap between the beam and signal line to calculate spring constant and pull-in voltage. The proposed switch having pull-in voltage is 1.371 V, the dielectric material Si 3 N 4 is to improve the capacitance analysis of the switch. The up and downstate capacitance is 7.073 fF, 1.259 pF. The RF performance is simulated by using Ansoft HFSS tool, the switch performs at low frequencies at 1–4 GHz range. The return (S 11 ) and insertion loss (S 12 ) of the proposed switch is − 30 dB, − 0.0516 dB and the switch having good isolation (S 21 ) is − 37.5 dB at 1.5 GHz frequency. The switch is suitable for radar and satellite communication applications.

Design of Micromachining Based Patch Antenna to Enhance Performances for RFID Tag Application

Rajesh Saha,Chandan Tilak Bhunia,Santanu Maity 보안공학연구지원센터 2015 International Journal of Future Generation Communi Vol.8 No.1

Antenna is a significant component of wireless communication system. Radio Frequency Identification (RFID) is one of the activities of Automatic Identification (AUID) system which comes under wireless system. To track any object wirelessly in RFID system, antenna acts as the primary and critical component. Radio Frequency (RF) micromachining technology provides an innovative approach in the development of effective antenna. In this paper, initially we present rectangular patch antenna resonant at 40GHz on silicon substrate. In the consecutive step, in order to improve performance of the antenna silicon micromachining has done by etching the substrate between the ground and the patch. Ansoft High Frequency Structure Simulator (HFSS) provides the simulation result and the different performance parameters like gain, return loss, bandwidths etc. are analyzed.

Low Pull-in-Voltage RF-MEMS Shunt Switch for 5G Millimeter Wave Applications

P. Ashok Kumar,K. Srinivasa Rao,B. Balaji,M. Aditya,N. P. Maity,Reshmi Maity,Santanu Maity,Ameen El Sinawi,Koushik Guha,K. Girija Sravani 한국전기전자재료학회 2021 Transactions on Electrical and Electronic Material Vol.22 No.6

RF MEMS switches have been employed in many commercial and defense applications due to their high potentiality at microwave and millimeter wave frequencies. In this paper, an RF MEMS shunt switch is designed with perforations and without perforations and simulated using iterative meanders for millimeter wave 5G applications. The proposed iterative meander offers a low spring-constant of 0.68 N/m and reduces the pull-in-voltage upto 1.8 V. The proposed perforated switch design is more reliable which operates with less transition time of 11.2 μs with a quality factor of 1.69. The switch possesses high capacitance ratio of 63. During ON condition, the switch shows low insertion loss of − 0.24 dB at 41 GHz and high isolation of − 46.7 dB at 38 GHz. The performance of the switch is analyzed by simulating it using COMSOL Multiphysics 5.2v (FEM tool). The obtained simulation results shows close approximation with the theoretical results and the switch is efficiently used for 5G millimeter wave applications.

Improvement of the metabolic stability of pan-RAF/VEGFR2 dual inhibitors

Maiti Santanu,권정희,홍성표,권호석,김진호,안순길 대한화학회 2023 Bulletin of the Korean Chemical Society Vol.44 No.11

Development of dual inhibitors of pan-RAF/VEGFR2 is important for the treatment of K-Ras mutated colorectal cancer, which is one of the most common and lethal malignancies. Building upon our studies in dual inhibitors of pan-RAF/VEGFR2, we designed and synthesized new dual inhibitor candidates by installing a urea or guanidine moiety to the previously reported dual inhibitors in order to enhance both metabolic stability and solubility. Various 1-(5-((3-(9H-purin-6-yl)pyridin-2-yl)amino)-2-fluorophenyl)-3-phenylurea and 1-(5-((3-(9H-purin-6-yl)pyridin-2-yl)amino)-2-fluorophenyl)-3-phenylguanidine derivatives were synthesized, and their antiproliferative activities against LS513 cell (K-RasG12D) and VEGFR2 were evaluated. Among the tested compounds, 1-(5-((3-(9H-purin-6-yl)pyridin-2-yl)amino)-2-fluorophenyl)-3-(3-fluorophenyl)urea (7b) and 1-(5-((3-(9H-purin-6-yl)pyridin-2-yl)amino)-2-fluorophenyl)-3-(4-chloro-3-trifluoromethyl)phenyl)urea (7e) are the most potent dual inhibitors against LS513 (GI50 = 0.1 and 0.06 μM, respectively) and VEGFR2 (IC50 = 0.03 and 0.06 μM, respectively). The preclinical study with these compounds are currently underway.

ELECTRON TRANSPORT THROUGH MOLECULAR CHAINS

SANTANU K. MAITI 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2007 NANO Vol.2 No.2

We study electron transport through molecular chains attached with two nonsuperconducting electrodes by the use of Green's function technique. Here, we do parametric calculations based on the tight-binding model to characterize the electron transport through such bridge systems and see that the transport properties are significantly affected by (a) the length of the molecular chain and (b) the molecule-to-electrode coupling strength. In this context, we also discuss the steady state current fluctuations, so-called shot noise, which is a consequence of the quantization of charge and is not directly available through conductance measurements.

ELECTRON TRANSPORT THROUGH A QUANTUM INTERFEROMETER WITH SIDE-COUPLED QUANTUM DOTS: A THEORETICAL STUDY

SANTANU K. MAITI 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2010 NANO Vol.5 No.4

We study electron transport through a quantum interferometer with side-coupled quantum dots. The interferometer, threaded by a magnetic flux φ, is attached symmetrically to two semi-infinite one-dimensional metallic electrodes. The calculations are based on the tight-binding model and the Green's function method, which numerically compute the conductance–energy and current–voltage characteristics. Our results predict that under certain conditions this particular geometry exhibits anti-resonant states. These states are specific to the interferometric nature of the scattering and do not occur in conventional one-dimensional scattering problems of potential barriers. Most importantly we show that, such a simple geometric model can also be used as a classical XOR gate, where the two gate voltages, viz, Va and Vb, are applied, respectively, in the two dots those are treated as the two inputs of the XOR gate. For φ = φ0/2 (φ0 = ch/e, the elementary flux-quantum), a high output current (1) (in the logical sense) appears if one, and only one, of the inputs to the gate is high (1), while if both inputs are low (0) or both are high (1), a low output current (0) appears. It clearly demonstrates the XOR gate behavior and this aspect may be utilized in designing an electronic logic gate.

Effect of Haloperidol and Risperidone on Serum Melatonin and GAP-43 in Patients with Schizophrenia: A Prospective Cohort Study

Rituparna Maiti,Biswa Ranjan Mishra,Monalisa Jena,Archana Mishra,Santanu Nath 대한정신약물학회 2021 CLINICAL PSYCHOPHARMACOLOGY AND NEUROSCIENCE Vol.19 No.1

Objective: Serum melatonin, a biomarker of circadian rhythm, can upregulate Growth-associated protein 43 (GAP-43) which is involved in neural regeneration and plasticity. The present study was conducted to investigate the adequacy of the first-line antipsychotic drugs to improve sleep and circadian rhythm disruptions by assessing the effect of haloperidol and risperidone on serum melatonin and GAP-43 in schizophrenia. Methods: In this cohort study, 100 schizophrenic patients were recruited, and clinical evaluations were done using the Positive and Negative Syndrome Scale (PANSS) and the Pittsburgh sleep quality index (PSQI). The patients with predominantly positive symptoms taking haloperidol (Group I) and patients with predominantly negative symptoms taking risperidone (Group II) were admitted and serum melatonin, arylalkylamine N-acetyltransferase, GAP-43 and urinary melatonin were estimated. After 8 weeks, all clinical and biochemical parameters were repeated. Results: Serum melatonin (2:00 hours) was significantly decreased in both haloperidol (2.42; 95% confidence interval [95% CI]: 0.67−4.17; p = 0.008) and risperidone group (3.40; 95% CI: 0.54−6.25; p = 0.021). Urinary melatonin was significantly decreased in both haloperidol (p = 0.005) and risperidone group (p = 0.014). PSQI score was significantly increased in both haloperidol (p = 0.001) and risperidone group (p = 0.003). Serum GAP-43 was significantly decreased in both haloperidol and risperidone group (p < 0.001). PANSS decreased significantly in both the groups and there was a significant negative correlation between serum melatonin at 2:00 hours and PANSS (r = −0.5) at baseline. Conclusion: Monotherapy with haloperidol and risperidone can achieve symptomatic improvement but cannot improve sleep and circadian rhythm disturbances in schizophrenia.

Analysis of Pull-in-Voltage and Figure-of-Merit of Capacitive MEMS Switch

Saha, Rajesh,Maity, Santanu,Devi, Ngasepam Monica,Bhunia, Chandan Tilak The Korean Institute of Electrical and Electronic 2016 Transactions on Electrical and Electronic Material Vol.17 No.3

Theoretical and graphical analysis of pull-in-voltage and figure of merit for a fixed-fixed capacitive Micro Electromechanical Systems (MEMS) switch is presented in this paper. MEMS switch consists of a thin electrode called bridge suspended over a central line and both ends of the bridge are fixed at the ground planes of a coplanar waveguide (CPW) structure. A thin layer of dielectric material is deposited between the bridge and centre conductor to avoid stiction and provide low impedance path between the electrodes. When an actuation voltage is applied between the electrodes, the metal bridge acquires pull in effect as it crosses one third of distance between them. In this study, we describe behavior of pull-in voltage and figure of merit (or capacitance ratio) of capacitive MEMS switch for five different dielectric materials. The effects of dielectric thicknesses are also considered to calculate the values of pull-in-voltage and capacitance ratio. This work shows that a reduced pull-in-voltage with increase in capacitance ratio can be achieved by using dielectric material of high dielectric constant above the central line of CPW.