Showing papers by "Kamaljit Rangra published in 2016"
TL;DR: In this paper, float metal concept is utilized to reduce the RF overlap area between the movable structure and central conductor of CPW for improving the insertion loss of the device, which has been achieved without affecting the downstate response.
22 citations
TL;DR: In this paper, a single-pole double-throw (SPDT) switch based on series capacitive configuration is proposed, and the critical process parameters are analyzed to improve the fabrication process.
Abstract: A compact radiofrequency (RF) MEMS single-pole double-throw (SPDT) switch based on series capacitive configuration is proposed. The critical process parameters are analyzed to improve the fabrication process. A technique of cold–hot thermal shock for lift-off method is explored. The residual stress in the structure is quantified by lancet test structures that come out to be 51 MPa. Effect of residual stress on actuation voltage is explored, which changes its value from 24 to 22 V. Resonance frequency and switching speed of the switch are 11 kHz and 44 μs, respectively, measured using laser Doppler vibrometer. Measured bandwidth of the SPDT switch is 20 GHz (5 to 25 GHz), which is verified with finite element method simulations in high frequency structure simulator© and an equivalent LCR circuit in advanced design system©. Insertion loss of the switch lies in −0.1 to −0.5 dB with isolation better than −20 dB for the above-mentioned bandwidth.
14 citations
TL;DR: In this article, HfO2 thin film (100nm) has been deposited by sputtering technique and annealed at various temperatures ranging from 400 to 1000°C (in step of 200°C) in O2 ambient for 10min.
Abstract: In the present work, HfO2 thin film (100 nm) has been deposited by sputtering technique and annealed at various temperatures ranging from 400 to 1000 °C (in step of 200 °C) in O2 ambient for 10 min. The samples have been characterized using XRD, FTIR, EDAX, AFM and Laser Ellipsometer. The impact of annealing temperatures in O2 ambient on structural properties such as crystallite size, phase, orientation, stress have been studied using XRD. The Hf–O phonon peaks in the infrared absorption spectrum are detected at 512, 412 cm−1. The stretching vibration modes at 720 and 748 cm−1 correspond to HfO2. AFM data show mean grain size in the range of 38–67 nm. The film reveals variation in structural properties, which appears to be responsible for variation in oxygen percentage, refractive index (1.96–2.01) at 632 nm wavelength and roughness (6.13–16.40 nm). Annealing temperature as well as ambient condition has significant effects on stress, crystal size and thus the arrangement of atoms. For good quality film, annealing temperature larger than 600 °C is desired.
12 citations
13 Apr 2016
TL;DR: In this paper, the effect of sputtering power on the electrical and structural properties of Ru films was investigated experimentally using high-resolution X-ray diffraction and atomic force microscopy (AFM).
Abstract: Ruthenium is deposited by DC magnetron sputtering at different powers and is characterized. The effect of sputtering power on the electrical and structural properties of the film is investigated experimentally. High resolution X-ray diffraction is used to characterize the microstructure of Ru films deposited on SiO2 surface. The peak (002) is more sharp and intense with full width at half maximum (FWHM) of 0.37° at 250W. The grain size increases with increase in sputtering power improving the crystallinity of the film. The film deposited at high sputtering power also showed lower resistivity (12.40 µΩ-cm) and higher mobility (4.82 cm2/V.s) as compared to the film deposited at low power. The surface morphology of the film is studied by atomic force microscopy (AFM).
4 citations
TL;DR: In this paper, a compact DMTL based phase shifter for Ku band applications is presented, where a novel approach is adapted to reduce the size as well as the number of switches by optimizing different unit cells for each section rather than fixed MIM capacitor.
Abstract: This paper presents a compact design of DMTL based phase shifter for Ku band applications. Conventional approach for DMTL based phase shifters is to load CPW transmission line periodically with similar type of MEMS capacitors at particular spacing. In this paper, a novel approach is adapted to reduce the size as well as the number of switches by optimizing different unit cells for each section rather than fixed MIM capacitor. A4-bit phase shifter demonstrates an average insertion loss of 2.98 dB at 17GHz and has size of 4.5 mm with 7 MEMS bridges compared to 15 or 30 MEMS bridges using conventional approach. The pull-in voltage is simulated to 16 V and switching time is calculated to H ≍ 56μs at 20V.
2 citations
13 Apr 2016
TL;DR: In this paper, the authors present design, simulation results and envisaged fabrication process for a versatile MEMS bimorph actuator with large out-of-plane displacement and high resolution.
Abstract: This paper presents design, simulation results and envisaged fabrication process for a versatile MEMS bimorph actuator with large out of plane displacement and high resolution. A comparative study of mechanical, thermal and electrical response of the micro-actuator is presented by using two well-known MEMS simulation tools. The bimorph structure measuring 700 × 1280 mm2 is fully integrable with CMOS fabrication process. It is indented for tunable filter applications where the precise vertical motion of the payload, the top metallic electrode anchored rigidly to bimorph ‘springs’ spans the vertical range of 250-300 microns with submicron resolution. Each bimorph spring resembles a hair pin structure and is composed of materials with large difference in thermal expansion coefficients e.g. electroplated gold and polysilicon for optimal out-of-the plane deflection. The novel structure can also be configured for analog micro-mirror based optical and IR spectroscopy applications by controlling the actuation bias and top electrode surface parameters.
1 citations
13 Apr 2016
TL;DR: In this article, the authors derived the effective characteristic length with reference to the packaging height of an open MEMS device and modified it with the packaging cavity height to obtain the gap between the MEMS bridge and underneath actuation electrodes.
Abstract: Fluid continuity theory is used to describe the dynamic response of open Micro-Electro-Mechanical-System (MEMS) devices. For a packaged device, at low pressure, the fluid continuity theory is no longer valid and a rarefication theory based on a Knudsen number is used. In an open MEMS device, the characteristic length which determines the Knudsen number is represented by the gap between the MEMS bridge and underneath actuation electrodes. On the other hand, for a packaged device, effective characteristic length is modified with the packaging cavity height. In this paper, for a packaged MEMS device, effective characteristic length with reference to the packaging height is derived.
Central Electronics Engineering Research Institute1, Post Graduate Institute of Medical Education and Research2, Guru Gobind Singh Indraprastha University3, Council of Scientific and Industrial Research4, International Rice Research Institute5, Banasthali Vidyapith6, Indian Institute of Technology, Jodhpur7
TL;DR: In this article, double layer of photoresist is optimized for lift-off process, which offers process simplicity, low cost, over conventional single layer lift off or bilayer lift off with LOR.
Abstract: The patterning of thin films play major role in the performance of MEMS devices. The wet etching gives an isotropic profile and etch rate depends on the temperature, size of the microstructures and repetitive use of the solution. Even with the use of selective etchants, it significantly attacks the underlying layer. On the other side, dry etching is expensive process. In this paper, double layer of photoresist is optimized for lift-off process. Double layer lift-off technique offers process simplicity, low cost, over conventional single layer lift-off or bilayer lift-off with LOR. The problem of retention and flagging is resolved. The thickness of double coat photoresist is increased by 2.3 times to single coat photo resist.
13 Apr 2016
TL;DR: In this paper, a coupled beam bandpass disk filter is designed for 1.5 MHz bandwidth and the simulation results show that the insertion loss minimum is 151.49 dB, insertion loss maximum is 213.94 dB, and 40 dB shape factor is 4.17.
Abstract: In this paper, coupled beam bandpass Disk filter is designed for 1 MHz bandwidth. Filter electrical equivalent circuit simulation is performed using circuit simulators. Important filter parameters such as insertion loss, shape factor and Q factor aresetimated using coventorware simulation. Disk resonator based radial contour mode filter provides 1.5 MHz bandwidth and unloaded quality factor of resonator and filter as 233480, 21797 respectively. From the simulation result it’s found that insertion loss minimum is 151.49 dB, insertion loss maximum is 213.94 dB, and 40 dB shape factor is 4.17.
13 Apr 2016
TL;DR: In this paper, a dual-type switch is proposed for T-type RF MEMS switch cross-over junction, implemented using symmetric toggle switch (STS) as a basic building block.
Abstract: This paper presents a novel design approach of T-type RF MEMS switch cross over junction, implemented using symmetric toggle switch (STS) as a basic building block. T-type switches are key elements for designing redundancy switch matrices. Proposed design is a dual type switch, i.e. under operation same bridge is used as an ohmic series switch as well as a capacitive shunt switch. This reconfigurable switch constitutes the cross over junction part for the T-type switch. Simulated results show an insertion loss of < 0.2 dB upto 10 Ghz and isolation is better than −20 dB over a band of 5 Ghz through capacitive path and is better than −80 dB up-to 10 Ghz through ohmic contact path. STS as a building block is used for designing cross over junction and is a technologically mature device. The designed actuation voltage of this cross over switch is 4.75 Volts and simulated resonant frequency is 3.253 KHz.