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Kamaljit Rangra

Bio: Kamaljit Rangra is an academic researcher from Indian Institute of Technology, Jodhpur. The author has contributed to research in topics: Insertion loss & Capacitive sensing. The author has an hindex of 11, co-authored 80 publications receiving 511 citations. Previous affiliations of Kamaljit Rangra include University of Trento & The National Academy of Sciences, India.


Papers
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Journal ArticleDOI
TL;DR: In this paper, a symmetric toggle switch (STS) is proposed for 8-14 GHz applications with low actuation voltage and high isolation, for high power and reliability applications in telecommunication.
Abstract: In this paper, we present a new type of rf MEMS switch with low actuation voltage and high isolation, for high rf power and reliability applications in telecommunication. ‘Symmetric toggle switch’ (STS) is based on push–pull mechanism and utilizes torsion springs and levers, placed symmetrically and transverse to CPW line. The switches designed for 8–14 GHz applications have analytically calculated and FEM simulated actuation voltages in the range of 8–10 V. The simulated insertion loss and isolation for the devices are 0.25 and 35 dB, respectively, at 10 GHz. The fabrication process and preliminary experimental results are also presented.

66 citations

Journal ArticleDOI
TL;DR: In this article, a novel torsional RF MEMS capacitive switch design on silicon substrate is presented, which optimized switch topology such as reduction in up-state capacitance results in insertion loss better than 0.1 dB till 20 GHz.
Abstract: A novel torsional RF MEMS capacitive switch design on silicon substrate is presented. The optimized switch topology such as reduction in up-state capacitance results in insertion loss better than ź0.1 dB till 20 GHz. Off to on state capacitance ratio is also improved by 18 fold and isolation is better than ź43 dB at 9.5 GHz. The achieved on state return loss is ź38 dB as compared to ź21 dB at 9.5 GHz. An optimized reduction in contact area and use of floating metal layer increases the switching speed from 56 to 46 μsec. It also increases the switch reliability by alleviating the stiction.

56 citations

Journal ArticleDOI
TL;DR: In this article, a low insertion loss capacitive shunt RF-MEMS switch with float metal concept is proposed to reduce the capacitance in up-state of the device.
Abstract: This paper presents a low insertion loss capacitive shunt RF-MEMS switch. In the presented design, float metal concept is utilized to reduce the capacitance in up-state of the device. Float metal switch shows an insertion loss <0.11 dB, a return loss below 26.27 dB up to 25 GHz as compared to 0.81 dB insertion, 8.67 dB return loss for the conventional switch without float metal. OFF state response is same for the both devices. Further pull-in voltage of 12.75 V and switching time of 69.62 µs have been observed in case of the conventional switch whereas device with float metal have 11.75 V and 56.41 µs. Improvement of around 2.5 times in bandwidth and 4 times in input power has been observed without self actuation, hold down problem. The designed switch can be useful at device and sub-system level for multi-band applications.

48 citations

Journal ArticleDOI
TL;DR: In this paper, CdO thin films were grown by e-beam evaporation technique on glass, indium tin oxide (ITO), fluorine-doped tin dioxide (FTO), and silicon (Si) wafer.

34 citations

Journal ArticleDOI
TL;DR: In this paper, a low voltage driven RF MEMS capacitive switch with the introduction of perforations and reinforcement is proposed, which reduces the pull-in voltage from 70 V to 16.2 V and the magnitude of deformation from 8 µm to 1 µm.
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.

25 citations


Cited by
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Journal ArticleDOI

[...]

08 Dec 2001-BMJ
TL;DR: There is, I think, something ethereal about i —the square root of minus one, which seems an odd beast at that time—an intruder hovering on the edge of reality.
Abstract: There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality. Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

33,785 citations

Journal ArticleDOI
TL;DR: In this article, the authors investigate poly(methylmethacrylate) (PMMA) development process with cold developers for its effect on resolution, resist residue, and pattern quality of sub-10 nm electron beam lithography (EBL).
Abstract: We investigate poly(methylmethacrylate) (PMMA) development processing with cold developers (4–10 °C) for its effect on resolution, resist residue, and pattern quality of sub-10 nm electron beam lithography (EBL). We find that low-temperature development results in higher EBL resolution and improved feature quality. PMMA trenches of 4–8 nm are obtained reproducibly at 30 kV using cold development. Fabrication of single-particle-width Au nanoparticle lines was performed by lift-off. We discuss key factors for formation of PMMA trenches at the sub-10 nm scale.

232 citations

Book ChapterDOI
01 Jan 2005
Abstract: Design and technology is an inspiring, rigorous and practical subject. Using creativity and imagination, pupils design and make products that solve real and relevant problems within a variety of contexts, considering their own and others’ needs, wants and values. They acquire a broad range of subject knowledge and draw on disciplines such as mathematics, science, engineering, computing and art. Pupils learn how to take risks, becoming resourceful, innovative, enterprising and capable citizens. Through the evaluation of past and present design and technology, they develop a critical understanding of its impact on daily life and the wider world. High-quality design and technology education makes an essential contribution to the creativity, culture, wealth and well-being of the nation.

95 citations

Book ChapterDOI
28 Apr 2017

68 citations