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Showing papers by "Kamaljit Rangra published in 2019"


Journal ArticleDOI
TL;DR: In this article, a novel capacitive RF-MEMS switch is realized through two non-uniform cantilevers with dissimilar shape to achieve the different value of inductance in the downstate of the device and hence the different electrical resonant frequency.

21 citations


Journal ArticleDOI
TL;DR: In this article, a polycrystalline AlN thin film based bulk micromachned pyroelectric IR sensor is presented, which has been carried out using 3D finite element modeling (FEM) and simulations.
Abstract: Polycrystalline Aluminum Nitride (AlN) thin films are of significant interest due to their pyroelectric properties for last few years. In this paper, study on development of a polycrystalline AlN thin film based bulk micromachned pyroelectric IR sensor is presented. Structural optimization of IR sensor has been carried out using 3D finite element modeling (FEM) and simulations. A 1.0 μm thick thermally grown SiO2 layer used for thermal isolation, also serves as a diaphragm to hold the fabricated IR sensor. Rate of temperature change (dT/dt) of the sensor under dynamic heating is 0.12–0.15°K/s, and agrees well with the simulated value of 0.1°K/s. High pressure, N2 ambient sputtered Au film of thickness 160 nm has been used to enhance the IR absorptivity. IR absorptivity of sensor on medium to long wave (2.5–25 μm) radiations is nearly 67%, and creates thermal gradient of 0.23°K between sensor and substrate. Developed pyroelectric IR sensor exhibits response time 8.0 ms, pyroelectric coefficient (ρ) 0.32 × 10−4 C/m2K, ρ/e figure of merit (FOM) 3.0 μC/m2K, and pyroelectric current responsivity (Ri) of 2.5 × 10-6 A/W.

12 citations


Journal ArticleDOI
TL;DR: In this article, a hybrid technique is used for the designing of a compact, high isolation and the enhanced bandwidth SPDT RF MEMS switch for 5G applications, which offers greater than 40dB isolation over a wide frequency range (>40dB over 22.10 GHz bandwidth) with less than 0.30dB insertion loss over the entire band.
Abstract: Fifth generation (5G) communication system enables the pathway for a higher data transfer rate. The frequency bands used for 5G communication system are distributed from lower frequency range (600 MHz) to a higher frequency range (60 GHz). So it is necessary that a single switch should be able to cover the complete range of 5G frequency bands. The ohmic radio frequency-micro electromechanical system (RF-MEMS) switch has offered high isolation at lower frequencies (> 40 dB up to 2.5 GHz). However, 5G requires a higher frequency range which is covered by capacitive switch. The capacitive switch has limitations of limited bandwidth and large size. In this paper, a hybrid technique is used for the designing of a compact, high isolation and the enhanced bandwidth SPDT RF MEMS switch for 5G applications. The size of the proposed switch is half from the conventional capacitive RF MEMS switch and offer greater than 40 dB isolation over a wide frequency range (> 40 dB over 22.10 GHz bandwidth) with less than 0.30 dB insertion loss over the entire band.

5 citations


Journal ArticleDOI
TL;DR: In this article, the authors present the design, fabrication and characterization of capacitive type MEMS switch for space and terrestrial communication applications, and the deviation in measured actuation voltage and RF response of the switches are discussed in terms of the process variation which occurred unintentionally during the fabrication of devices.
Abstract: This paper presents the design, fabrication and characterization of capacitive type MEMS switch for space and terrestrial communication applications. The deviation in measured actuation voltage and RF response of the switches are discussed in terms of the process variation which occurred unintentionally during the fabrication of devices. For example the measured actuation voltage is 15 V, about 20% higher than the designed voltage of 12.25 V. The deviation corresponds to the increase in thickness of the membrane while electroplating. The impact of process parameters on mechanical resonance frequency of the switches, and on/off time is also discussed. Measured S-parameters shows isolation of > − 20 dB for 7–16 GHz and an insertion loss better than − 0.6 dB up to 20 GHz. The capacitance ratio of the fabricated switch is 77, which is 15% lower than the designed capacitance ratio. The switch has been tested for 1 million 65 thousand cycles without switching failure. The deviation of simulated and measured results is discussed in the following sections.

5 citations


Journal ArticleDOI
TL;DR: In this paper, the effect of various N2 pressure on resistivity and hardness of TiN thin film was investigated in a DC magnetron reactive sputtering using a four inch high purity titanium target in a nitrogen (N2) environment.
Abstract: In this paper, TiN film has been deposited and optimized at room temperature for high power radio-frequency microelectromechanical system (RF-MEMS) applications. Being hard, titanium nitride is used in the contact area. The contact material should have low resistance and high hardness. TiN thin films were deposited by DC magnetron reactive sputtering using a four inch high purity titanium target in a nitrogen (N2) environment. X-ray diffraction (XRD) analysis is used to confirm crystal structure and purity of TiN film. The effect of various N2 pressure on resistivity and hardness of TiN thin film is investigated. The resistivity of the film decreases and hardness increases with N2 pressure.

4 citations


Journal ArticleDOI
TL;DR: In this article, the authors extracted the RF MEMS capacitive switch LCR parameters considering parasitic capacitance to explain the mismatch of measured results, which is a function of switch geometry and directly proportional to dielectric constant of the substrate material.
Abstract: Radio frequency micro-electro-mechanical system (RF MEMS) switch is basic component for transponders used in communication system. Switch “OFF/ON” capacitance ratio plays major role in controlling signal to noise ratio. Theoretically, with high dielectric constant material or floating metal concept, capacitance ratio can be improved up to 2000 or even more. Whereas, in most of the practical cases, measured ratio is less than 200. In present paper, RF MEMS capacitive switch LCR parameters are extracted considering parasitic capacitance to explain the mismatch of measured results. Parasitic capacitance is independent from device overlap area. Parasitic capacitance is function of switch geometry and directly proportional to dielectric constant of the substrate material.

4 citations


Journal ArticleDOI
TL;DR: In this paper, inverted silicon cavity is used for capping the MEMS devices and the electrical and mechanical characteristics of the RF MEMS switch are analyzed using finite element method simulations.
Abstract: Packaging is one of the most critical tasks for MEMS devices. Unlike solid state devices, MEMS structures involves moving structures which needs to be protected from outer environment ensuring free movement of the structure. In the present paper, inverted silicon cavity is used for capping the MEMS devices. However, in case of RF MEMS, silicon cavity would add parasitics and affects its electrical performance. Enclosing the MEMS structure, its mechanical response will also alter. The electrical as well as mechanical characteristics of the RF MEMS switch are analyzed using finite element method simulations. The electrical response of the fabricated switch after packaging is compared with unpackaged device.

2 citations


Journal ArticleDOI
TL;DR: In this paper, the authors presented the design and fabrication of MEMS based electro-thermally actuated square membrane/plate with gold and silicon dioxide bimorph beams.
Abstract: This paper presents the design and fabrication of MEMS based electro-thermally actuated square membrane/plate with gold and silicon dioxide bimorph beams. The main objective of this work is to generate a suspended bimorph structure for tunable cavity filters and resonators. A surface micromachining process has been employed in which bimorph structure is suspended by removing underneath sacrificial layer of photoresist through dry and wet etching. A major fabrication challenge is the release of square plate bimorph structure. Increase in temperature during subsequent processing steps cause excessive baking of photoresist. The possible reason of the hard sacrificial resist is baking beyond its thermal budget. Active layer of silicon dioxide utilized as a reinforcing layer during release. In the proposed process, over etched silicon dioxide and presence of sacrificial resist leads to process failure. Controlled thermal budget of sacrificial resist is essential for fully suspended structure.

2 citations