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ThesisItem Open Access Design of second order sigma delta modulator using preamplifier latch based comparator in 180 nm CMOS technology(G.B. Pant University of Agriculture and Technology, Pantnagar - 263145 (Uttarakhand), 2015-07) Farswan, Manoj Singh; Tomar, AbhishekSigma Delta Modulator (SDM) is achieving attention due to its low cost, high resolution, high signal to noise ratio etc in analog to digital converter. In SDM, the oversampling frequency is used to achieve high resolution. Also, noise shaping is inherently done to reduce noise power. The noise power in the design of SDM can be further reduced by increasing the order of the SDM. In this thesis, a second order continuous time, upto 50 kHz, SDM is designed with 1.8 V supply voltage in 180nm CMOS technology. The blocks used in SDM like integrator, subtractor and gain stages are implemented using Operational Amplifier (Op-amp) which is designed in cascade topology with miller capacitance techniques to optimize the phase margin and gain. The designed Op-amp has gain of 59.302 dB, phase margin of 59.2° and Gain Bandwidth (GBW) of 114.6 MHz. Integrator has -20 dB/decade slope for 11.12 kHz to 10.62 MHz which decides the sampling frequency of 3.2MHz. The preamplifier based latch comparator is used as a final stage of SDM. The designed preamplifier has 18.167 dB gain and 779.77 MHz 3-dB frequency which amplify low amplitude signal. The designed comparator is able to differentiate the 50uV signal and the sampling frequency is 64 MHz. The simulation is done in Cadence Virtuoso tool.With an input signal of 50 kHz and 3.2MHz clock frequency, the SNDR is 59.2 dB and power dissipation is 8.7mW of the SDM.ThesisItem Open Access Design of high frequency quadrature output ring oscillator in 0.18 µm CMOS process(G.B. Pant University of Agriculture and Technology, Pantnagar - 263145 (Uttarakhand), 2017-07) Bohra, Meenu; Tomar, AbhishekOscillation frequency, frequency tuning, phase noise and power dissipation are the important parameters in designing any ring VCO with the contemporary sub-micron technologies. The oscillation frequency, frequency tuning, phase noise and power dissipation are still not up to the mark so that ring oscillator can be used in RF application. Various designs had been developed by using effective topologies for reducing power dissipation and phase noise and improving oscillation frequency and frequency tuning. In this thesis, a novel design of ring VCO has been proposed and implemented in TSMC 0.18 µm CMOS technology. The proposed novel design is compared with the earlier proposed designs in 0.18 µm CMOS technology for oscillation frequency, frequency tuning, phase noise and power dissipation. The simulation is done using Cadence EDA tool. The simulated results shows phase noise of the proposed ring VCO equal to -102.9 dBc/Hz at a frequency offset of 1 MHz from a center frequency of 2.61 GHz. The measured power dissipation of the circuit is 25.27 mW. The tuning range of the proposed ring VCO is from 2.61 GHz to 0.2 GHz for a tuning voltage from 0 V to 1.2 V. The layout is drawn and post layout simulation is done which verifies the pre layout results.ThesisItem Open Access Design of 2-6 GHz Flat Gain CMOS LNA for WiMAX applications(G.B. Pant University of Agriculture and Technology, Pantnagar - 263145 (Uttarakhand), 2017-07) Varshney, Swati; Tomar, AbhishekRadio Frequency signal transmission via wireless technologies is becoming a major method of communication in modern age. But the signal obtained after reception is often corrupted with noise. So, to suppress noise the received signal need to be processed. LNA plays an important role in determining the receiver performance because it is used to amplify the very small signal coming from antenna while adding as little noise and distortion as possible. The main focus of this thesis is to design a Low Noise Amplifier having flat gain for the frequency range of 2-6 GHz. A novel architecture of current reuse LNA with resistive feedback and inductive source degeneration is proposed. Current reuse structure is used to reduce the power consumption and resistive feedback along with inductive source degeneration topology is used for input matching. The input and output matching is better for maximum signal transfer. 0.18 µm TSMC CMOS technology is used for designing the proposed LNA and cadence virtuoso software is used to simulate the schematic of LNA. Simulation shows that the proposed LNA has achieved flat gain, better input & output matching, good isolation and better stability. Amplifier has 15.4 dB gain with 0.3 dB variation, input return loss less than 12.4 dB, output return loss less than -17.4 dB, reverse isolation less than -48.33 dB and noise figure less than 5.2 dB. It exhibit 1-dB compression point -21.86 dBm and third order input intercept point-9.93 dBm at 4 GHz frequency respectively. The circuit draws 21.95 mW from 1.8 V supply voltage.ThesisItem Open Access A comprehensive study on MOSFET, nanowire FET and CNTFET for impact of gate dielectric on gate capacitance(G.B. Pant University of Agriculture and Technology, Pantnagar - 263145 (Uttarakhand), 2015-12) Tiwari, Manas; Sharma, K.K.ThesisItem Open Access A comprehensive study of imact of contact materials on characteristics of carbon nanotube field effect transfer(G.B. Pant University of Agriculture and Technology, Pantnagar - 263145 (Uttarakhand), 2016-01) Kohli, Vinod Chandra; Sharma, K.K.ThesisItem Open Access Reconstruction of motion blurred image using wavelet transform and neural committee machine(G.B. Pant University of Agriculture and Technology, Pantnagar - 263145 (Uttarakhand), 2016-08) Agarwal, Saitu; Mathur, SanjayImage Restoration is the process of obtaining the original image by using the knowledge of the degrading factors. Degradation comes in many forms such as blur, noise, and camera shake. One of the disadvantages of existing method is that some methods make restrictive assumptions on the Point Spread Function or the true image that limits the algorithm's portability to different applications in conventional approach; deblurring filters are applied on the degraded images without the knowledge of blur and its effectiveness. The proposed algorithm is used for the reconstruction of motion blurred images. Two factors which mainly affect an image are length of blur and angle of blur. In this thesis, concept of Wavelet decomposition and neural committee machines are applied for restoring problems in which images are degraded by blur function and corrupted by noise. In the first step of reconstruction, blurred image is decomposed using wavelet transform based on multi resolution analysis and then correlation analysis is performed to reduce the dimensionality of image pattern space and in the next step a multi layer feed forward neural network based on ensemble averaging technique is used to estimate the parameter which causes blurring. The proposed methodology uses highly non linear back propagation neuron for image restoration to get a high quality of restored image. The estimated parameters are used to calculate the value of degradation factor corresponding to blurred image and then deconvolution is performed to get the original image. Results show that the images restored using the proposed method have mean square error in the range of 0.001-.005 and peak signal to noise ratio in the range of 69dB-75dB.ThesisItem Open Access Multiband metamaterial antenna with omega shaped SRR structure for wireless communication(G.B. Pant University of Agriculture and Technology, Pantnagar - 263145 (Uttarakhand), 2016-07) Santosh Kumar; ParasMetamaterial as a special type of structure using natural electromagnetic material having EM properties can be very useful in different fields. It can play crucial role in communication field and can provide multiband characteristics with wider bandwidth and high gain as required in all field of RF communication on very small sized structures. The proposed antenna has been designed by using TLM equations that calculate the rectangular patch of size 40x40 mm2 having resonant frequency of 5 GHz and on the 1.58 mm height of substrate. The substrate material used is FR4 which is having a permittivity of 4.4 and loss tangent of 0.02. To enhance the performance, the rectangular patch has been changed to the circular patch that has radius of 7 mm at a substrate height of 1.58 mm and also size of the proposed antenna is reduced to 24.5x30mm2. The proposed antenna has a combination of conducting wire and omega shaped SRR structure to obtain metamaterial characteristics. The inter-digital structure of hexagon SRR has been used to achieve the negative permittivity and closed ring resonator to achieve the negative permeability and hence the combined structure can achieve the resonance in desired frequency band. The proposed antenna is simulated on HFSS software. Simulation results show that there are wide ranges of multi-bands from 1.4-7.6GHz, 9-11.4GHz, 11.6-15.25GHz and 15.5-17.6GHz and corresponding bandwidths are 6.2GHz, 2.4GHz, 3.65GHz and 2.1GHz respectively. The average gain of near 7.0 dB has been achieved. Proposed antenna is fabricated using lithography process. Its parameters have been tested on PNA. Radiation pattern is measured in an anechoic chamber. There is a good agreement between the simulated and fabricated results. The proposed antenna is reduced in size, having multiple bands with higher bandwidth as compare to previously fabricated antenna. The proposed antenna has application in Wi-MAX, WLAN, satellite communication, radar communication, space vehicles etc.ThesisItem Open Access Hexagonal-patch slotted partial-ground ultra wideband metamaterial antenna for wireless applications(G.B. Pant University of Agriculture and Technology, Pantnagar - 263145 (Uttarakhand), 2016-07) Mittal, Paridhi; ParasThesisItem Open Access Hexagonal-patch slotted partial-ground ultra wideband metamaterial antenna for wireless applications(G.B. Pant University of Agriculture and Technology, Pantnagar - 263145 (Uttarakhand), 2016-07) Mittal, Paridhi; ParasMetamaterial, due to their non conventional EM properties improves the performance of antenna in terms of gain, bandwidth and is useful in the field of wireless communication. Ultra Wide Band (UWB) communication system has become an attractive topic in wireless communication since the Federal Communication Commission (FCC) has allocated utilization of the 3.1–10.6 GHz unlicensed band for commercial UWB application. The main objective of this thesis is to develop a multiband antenna in UWB frequency range using metamaterial for wireless application. The proposed antenna has been designed using Transmission Line Model at setup frequency of 4.6 GHz. The simulation of the antenna is done using HFSS 15.0 to calculate the different parameters. The simulated S11 is below -10 dB in the frequency range from 2.8 to 4.8 GHz, 7.2 to 7.7 GHz, 9.1 to 9.9 GHz, 13.3 to 13.9 GHz, and 15.2 to 17.6 GHz. The bandwidth obtained is 2 GHz, 0.5 GHz, 0.8 GHz, 0.6 GHz, and 2.4 GHz, respectively with VSWR in accordance with the S11. Two metamaterial SRR has been used to increase the gain of the antenna. The slots in the patch and ground are made to increase the resonating bands. The proposed antenna is fabricated on FR4substrate and SMA connector is soldered to fabricated antenna and connected to PNA for the measurement of S11 and VSWR. The measured S11 shows that there are dips at 2.6 GHz, 4.7 GHz, 7.4 GHz, 9.5 GHz, 13.6 GHz, 15.7 GHz and 17.34 GHz measuring -17.37dB, -21.05 dB, -26.21 dB, 51.81 dB, -19.41 dB, -19.21dB and -11.77 dB. Radiation pattern is measured in an anechoic chamber. The proposed antenna has been fabricated and the measured results are found to be close with the simulated results.