Deepak Bhatia

Design and optimization of high quality factor MEMS piezoelectric resonator with pseudo electrodes

The following work reports design and optimization of a MEMS resonator with some pseudo electrodes. Three, five and seven psuedo electrodes are placed and simulated. It has been observed that five psuedo electrodes structure gives very high quality factor in addition to minimum false modes interference. Simulation is done on COMSOL multiphysics. Furthermore, influence of various piezoelectric materials like AlN, PZT and ZnO were studied proving AlN as superb thin piezoelectric film or electroacoustic material, to have a very high Quality factor. Appropriate piezoelectric material is needed in addition with psuedo electrodes in order to work efficiently for filter and RF applications.

Analysis and design of compact dual-band bandstop filter using E-shaped resonators

This paper presents a compact dual-band bandstop filter (DBBSF) that features two controllable stopbands at 1.8 GHz and 5.2 GHz frequencies. A drastic reduction in size of the filter was achieved by taking advantage of a simplified architecture based on E-shaped resonator. The return losses of the simulated filter are measured to be -54.03 and -42.57 dB while the insertion losses are -0.01 and -0.10 dB at the respective stop bands. Due to its compact size and satisfactory stopband performance, the filter can be useful for modern communication technology.

Design of 2×1 circularly polarized microstrip patch antenna array for 5.8 GHz ISM band applications

This paper describes the design of a circular microstrip patch antenna for 5.8 GHz ISM band applications which is fed by a microstrip line and a two element antenna array of the same. The corporate feeding Method is used to design an array. The industrial, scientific and medical (ISM) radio bands are radio bands (portions of the radio spectrum) reserved internationally for the use of radio frequency (RF) energy for industrial, scientific and medical purposes other than communications. A suitable microstrip patch antenna (MSA) and 2×1 array should be operating in the ISM band radio frequency range and also should have satisfactory radiation property. In start, the paper presents the single element antenna structure and its simulation results and afterwards the two element array. All the simulated results obtained are presented succinctly. High frequencies structure simulation software is used to simulate and optimize the performance of the antenna array.

Analytical channel model for double layer metamaterial-improved magnetic induction communication

Magnetic Induction (MI) communication technique may provide promising solution than EM wave-based communication technique for underwater and underground applications where behavior of RF environment is complex, challenging and channel conditions are not constant. The propagation medium is other than air in such applications. MI communication technique overcomes the dynamic channel, propagation loses and antenna size issues of EM wave-based technique. In spite of these benefits, MI communication range is limited due to very fast attenuation of magnetic field with distance. Metamaterial shells are used to reduce the losses and hence improving the communication range. In M2I communication, MI coil antennas are encased by a metamaterial shells, which amplifies the magnetic field around transceivers as a result, range. In this paper, two metamaterial shells are utilized i.e. Double layer Metamaterial-Improved magnetic induction (DM2I) communication but radius of antenna with metamaterial shells is same as in M2I. Comsol Multiphysics, a Finite Element method (FEM) software is used to design and simulation of the analytical channel. The results show that the efficiency is improved in DM2I as compared with M2I.

Design and Simulation of an Electret-Based Energy Harvesting Device

This paper presents a vibration based energy harvester using stepped MEMS cantilevers. Electrets are introduced with stepped cantilever beams to store the maximum charge hence maximum voltage can be achieved at output. The enhanced value of displacement in the order of millimeters has been achieved by using the proof mass with this structure. The output voltage has been increased up to 9.18V. This energy harvester is able to overcome the battery related issues. Displacement is measured for different applied pressures and various eigen frequencies. Simulation is carried out using COMSOL multiphysics.

Stub-Based Design of Coupled Line Directional Couplers

This paper presents a new development in directional couplers to enhance their performance. The performance is enhanced by improving directivity with the help of stubs in an existing design of parallel coupled line directional coupler. In the proposed stub based microstrip design of directional couplers we were able to achieve directivity of 68dB in the proposed coupler. In the end we have compared the directivity of our proposed coupler with an earlier proposed coupler design.

Tactile Array Sensor with Piezoresistive Cantilever Embedded in Air Cavity

In this paper, we proposed array of cantilever to increase sensitivity of a Piezoresistive tactile sensor. As in conventional tactile sensor there is four cantilevers is embedded in air cavity. We formed an array of 2*2 of conventional sensing element which is embedded in air cavity. In this paper we simulate the array of cantilevers by which we confirmed that sensitivity is increased by 20 times. Tactile sensor is used in the area of robotics, manipulating objects and robot-hands is one of the main studies. To achieve exploitation with optimum pressure, as the human does, it is essential to compute as well as apply the pressure, which occurs between the target object and the robot-hands.

LH Transmission Line Based Directional Coupler Design with High Directivity and Tight Coupling

A design of directional coupler is proposed which can be applied in communication technology like personal communication services and international mobile telecommunication. In this directional coupler, we have used two coupled line sections for coupling and connected two uncoupled left handed (LH) transmission lines as delay lines. It is shown that in this design of a 3 dB directional coupler, we are able to achieve high directivity of approximately 85 dB and tight coupling within the operating frequency range. This directional coupler is behaving like an ideal coupler. When the odd and even mode velocities are made equal at a centre frequency, high directivity is obtained. Its bandwidth is between 1.65 GHz to 1.80 GHz.

A complementary multi-stepped metamaterial resonator inspired band-stop filter for wireless receiver applications

The work reports modeling of step-shaped metamaterial resonators and their application in the development of band-stop filter. The effect of discontinuities in the resonator design is studied by introducing steps in the outer and inner square ring. Two such designs have been proposed, in which outer ring and inner ring are substituted by stepped ring progressively. The structures are modeled on Roger RO4835 of relative permittivity 3.66. Design-1 and Design-2 extracted permittivity and refractive index shows a negative response at 2.8 GHz and it nearby spectrum. Bandstop filters formed by inserting the complementary configuration of Desing-1 and Design-2 into a matched transmission line, shows stop band resonance at 2.86 GHz and 2.77 GHz respectively.

A reconfigurable cascaded multi-stepped split ring resonator inspired bandpass filter for L-band applications

The paper presents a reconfigurable design of microwave bandpass filter inspired by two cascaded multi-stepped split ring resonators. The structure has an overall dimension of 32 mm × 20 mm, designed on RO4350B substrate of relative permittivity (εr = 3.6) and height 0.762 mm. A varactor diode connected between the two split ring resonators provides a change in structure electrical length required for the coarse tuning of frequency response. The designed filter offers frequency response between 2.8 GHz to 3.6 GHz depending on the reverse bias voltage of the diode.