Amit Kumar

Bio: Amit Kumar is an academic researcher from Central Electronics Engineering Research Institute. The author has contributed to research in topics: Surface micromachining & Microelectromechanical systems. The author has an hindex of 4, co-authored 21 publications receiving 68 citations. Previous affiliations of Amit Kumar include Academy of Scientific and Innovative Research & The National Academy of Sciences, India.

Low voltage driven RF MEMS capacitive switch using reinforcement for reduced buckling

Abstract: Variation in actuation voltage for RF MEMS switches is observed as a result of stress-generated buckling of MEMS structures. Large voltage driven RF-MEMS switches are a major concern in space bound communication applications. In this paper, we propose a low voltage driven RF MEMS capacitive switch with the introduction of perforations and reinforcement. The performance of the fabricated switch is compared with conventional capacitive RF MEMS switches. The pull-in voltage of the switch is reduced from 70 V to 16.2 V and the magnitude of deformation is reduced from 8 µm to 1 µm. The design of the reinforcement frame enhances the structural stiffness by 46 % without affecting the high frequency response of the switch. The measured isolation and insertion loss of the reinforced switch is more than 20 dB and 0.4 dB over the X band range.

Improved Design of Ohmic RF MEMS Switch for Reduced Fabrication Steps

Abstract: RF MEMS ohmic switches are prone to stiction and contact degradation. In literature, bumps are made at the contact area to reduce stiction with additional fabrication steps. In this article, ohmic switch based on cantilever configuration is developed without using any additional step. The switch structure is modified to improve its mechanical parameters, such as pull-in voltage and switching speed. The measured switching time of the switch is $1.8~\mu \text{s}$ . A footprint of the developed single pole single throw (SPST) switch is 0.9 mm2. The insertion loss and isolation of the SPST switch are better than 0.8 and 20 dB, respectively. The switch has a wide bandwidth of 10 GHz (dc to 10 GHz). The switch has completed 725 million hot cycles at 1-dBm power.

Design and fabrication of a reduced stiction radio frequency MEMS switch

Abstract: The design, fabrication, and mechanical characterization of a compact-reduced stiction see-saw radio frequency MEMS switch are presented. The switch has a resonance frequency of 9.8 kHz with a corresponding switching speed of 46 μs. Use of a floating metal layer and optimal contact area ensures reduced stiction and smaller capacitive leakage. Overall size of the switch is 0.535 (0.50×1.070) mm2. Reduction in up-state capacitance also results in improvement in self-actuation voltage, insertion, and return loss. The optimized topology has improved the stiction and power handling of the switch.

Synthesis and characterization of magnesium doped cerium oxide for the fuel cell application

Abstract: Cerium oxide has attained much attentions in global nanotechnology market due to valuable application for catalytic, fuel additive, and widely as electrolyte in solid oxide fuel cell. Doped cerium oxide has large oxygen vacancies that allow for greater reactivity and faster ion transport. These properties make cerium oxide suitable material for SOFCs application. Cerium oxide electrolyte requires lower operation temperature which shows improvement in processing and the fabrication technique. In our work, we synthesized magnesium doped cerium oxide by the co-precipitation method. With the magnesium doping catalytic reactivity of CeO2 was increased. Synthesized nanoparticle were characterized by the XRD and UV absorption techniques.

Comprehensive Study on RF-MEMS Switches Used for 5G Scenario

Abstract: This paper presents a comprehensive study on radio frequency-microelectromechanical systems (RF-MEMS) switches, which are expected to be extensively integrated into 5G infrastructures. The specifications of the RF-MEMS switch in use case and scenario for 5G have been summarized in part 2 and followed by the study of the state-of-the-art RF-MEMS switches in part 3. Both metal-contact and capacitive RF-MEMS switches, which have been developed and fabricated within the last two decades, are studied and tabled. In order to meet with the specification requirements of 5G scenario, the performance and characteristics of the RF-MEMS switches should be enhanced, such as acceptable RF performance, low actuation voltage, good reliability, short switching time, multiband topology, and on-chip integration and packaging. Different techniques for the improvement of the RF-MEMS switches' properties, for instance low spring constant, large actuation area, diverse actuation methods, push-pull mechanism, modified driving voltage waveform, inductive compensation, and so on, have been thoroughly investigated, classified, and summarized in part 4, which serves as the main contribution of the review. The findings from this review can be beneficial for further RF-MEMS switches' design and improvement. The upgraded RF-MEMS switches are capable of satisfying the growing need of cutting edge performance for 5G or high-performance applications.

Research Status and Development Trend of MEMS Switches: A Review.

Abstract: MEMS switch is a movable device manufactured by means of semiconductor technology, possessing many incomparable advantages such as a small volume, low power consumption, high integration, etc. This paper reviews recent research of MEMS switches, pointing out the important performance indexes and systematically summarizing the classification according to driving principles. Then, a comparative study of current MEMS switches stressing their strengths and drawbacks is presented, based on performance requirements such as driven voltage, power consumption, and reliability. The efforts of teams to optimize MEMS switches are introduced and the applications of switches with different driving principles are also briefly reviewed. Furthermore, the development trend of MEMS switch and the research gaps are discussed. Finally, a summary and forecast about MEMS switches is given with the aim of providing a reference for future research in this domain.

A review on the statics and dynamics of electrically actuated nano and micro structures

Abstract: Nano and micro electro-mechanical systems (NEMS and MEMS) have been attracting a large amount of attention recently as they have extensive current/potential applications. However, due to their scale, molecular interaction and size effects are considerably high which needs to be considered in the theoretical modelling of their electro-mechanical behaviour. Both nano- and micro-scale electrically actuated structures are discussed when subjected to constant and time-varying voltages, and different theories and models, introduced in the past few years for modelling such small structures, are discussed. It is highlighted that considering the intermolecular forces and size-dependence effects can change both the static and dynamic behaviours of such systems significantly. This review presents the current stage of the research on electrically actuated NEMS/MEMS by analysing the latest models and studies in this field in the framework of electro-mechanical coupling and small-size effects.

Low voltage driven RF MEMS capacitive switch using reinforcement for reduced buckling

Abstract: Variation in actuation voltage for RF MEMS switches is observed as a result of stress-generated buckling of MEMS structures. Large voltage driven RF-MEMS switches are a major concern in space bound communication applications. In this paper, we propose a low voltage driven RF MEMS capacitive switch with the introduction of perforations and reinforcement. The performance of the fabricated switch is compared with conventional capacitive RF MEMS switches. The pull-in voltage of the switch is reduced from 70 V to 16.2 V and the magnitude of deformation is reduced from 8 µm to 1 µm. The design of the reinforcement frame enhances the structural stiffness by 46 % without affecting the high frequency response of the switch. The measured isolation and insertion loss of the reinforced switch is more than 20 dB and 0.4 dB over the X band range.