http://210.212.227.212:8080/xmlui/handle/123456789/377 2026-05-27T20:57:50Z 2026-05-27T20:57:50Z Abhirami, S Vishnu, D http://210.212.227.212:8080/xmlui/handle/123456789/391 2023-07-05T10:03:32Z 2023-05-30T00:00:00Z

Title: OVERSAMPLED SIGMA DELTA ADC DECIMATION FILTER Authors: Abhirami, S; Vishnu, D Abstract: An analog-to-digital converter (ADC), which can be either continuous or discrete in nature, is a crucial component of a signal processing system. An oversampling ADC is currently an effective option for data converters due to its compact silicon area, low power requirement, and greater resolution as opposed to standard ones with Nyquist frequency limit. The oversampling ADCs sample analog signals at a rate that is higher than the Nyquist rate and is typically expressed as OSR. Also, they are particularly preferred for high-speed applications due to their relative simplicity and resilience to component mismatch and circuit faults. Using basic analog circuitry, the Delta Sigma ADC pushes noise to high frequency using oversampling and noise-shaping technologies. Its SNR and precision are higher than those of other conventional ADCs. To satisfy the objectives of an efficient design, the decimation filter, which is a crucial component of ADCs, needs to be improved in various areas. The first and second-order delta-sigma modulators are developed. It has been found that com pared to the 1st-order Delta-Sigma modulator, the 2nd-order Delta-Sigma modulator offers greater stability and noise immunity. This work proposes a new method for implementing a high-performing, low-power Second Order Delta-Sigma digital dec imation filter. A Cascaded Integrated Comp (CIC) filter and a Biquad filter make up the Digital Decimation filter. The Second-order Delta-Sigma Decimation Filter is designed and modeled using Simulink. The proposed ADC achieves an SNR of 73.46 dB and an ENOB of 11.91. The post-simulation demonstrates that the suggested ADC provides a Spurious Free Dynamic Range of 95.38 dB.

2023-05-30T00:00:00Z Anjaly, R Dr.Nissan, Kunju http://210.212.227.212:8080/xmlui/handle/123456789/390 2023-07-05T10:00:11Z 2023-05-30T00:00:00Z

Title: UWB ANTENNAS FOR BREAST & BRAIN TUMOR DETECTION USING MICROWAVE IMAGING Authors: Anjaly, R; Dr.Nissan, Kunju Abstract: In the last decades, microwave imaging has emerged as a new area of research due to its many advantages over current imaging systems. Microwave imaging system is used for indepth inspection of biological tissues. It aids in identification of morpho logical changes in these biological tissues, as well as their locations. The emerging Ultra Wideband (UWB) microwave imaging gives better result and has the advan tage of using non-ionizing radiation.In these systems, antennas play a very important role. Antenna design optimization has gained significance because the device is placed close to the human body.This research introduces four compact antennas for tumor detection.Two for head imaging and two for breast imaging applications.All of them is build on FR4 material.First we designed a pentagonal patch antenna for breast imaging applications,in the frequency range from 2.9 - 13 GHz with 125 % fractional bandwidth (FBW) and has maximum gain of 2.80 dBi at 8.79 GHz.The second breast imaging antenna is a blade shape patch antenna has a broad bandwidth in the fre quency range from 2.6 - 13.56 GHz with 136% FBW and has maximum gain of 6.28 dBi at 12.9 GHz.Third one is a flower shaped patch antenna for head imaging applica tion in the frequency range of 1.59 to 6 GHz with 116.20 % FBW and has maximum gain of 4 dBi at 4.62 GHz.The last antenna which we have designed for head imag ing application is a modified square patch antenna in the frequency of 1.99 to 7.45 GHz with 115.67 % FBW and has maximum gain of 3.4 dBi at 6 GHz. Here we use monostatic approach of breast and brain tumor detection. All the simulations are done using CST Microwave studio EM Solver, 2016. For detecting the presence of tumor we designed head and breast phantom model with tumor at the center of the phantom model using CST.The properties of phantom model are similar to human body.The signal that transmitted from the antenna will reach the phantom with tu mor inside, the signal will reflect from the phantom are examined to find the presence of tumor. These electromagnetic waves are capable to penetrate biological tissue in a very efficient way and maintain a reasonable attenuation.The image that received are reconstructed using image reconstruction algorithms such as DAS and DMAS al gorithm to find tumor location. And all the designed antenna are in acceptable SAR range according to FCC regulations.

2023-05-30T00:00:00Z Divya, S Nishanth, N http://210.212.227.212:8080/xmlui/handle/123456789/389 2023-08-19T08:40:18Z 2023-05-30T00:00:00Z

Title: DESIGN AND SIMULATION OF OPTIMUM ANTENNA FOR IOT BASED GEOSATELLITE SYSTEM Authors: Divya, S; Nishanth, N Abstract: Small-sized antennas are preferred for geostationary satellites for a number of reasons. The cost of manufacturing and launching smaller antennas is generally lower than that of larger ones. It is particularly important for commercial satellite operators who wish to minimize costs and maximize profits. It is more difficult and more expensive to launch large antennas into space due to their weight. It is easier to launch small antennas into orbit because they are lighter. The GEO satellites are located at an altitude of approximately 36,000 kilometers and have a limited amount of space. With smaller antennas on a satellite, more equipment can be installed. Beam coverage: Small antennas provide a narrow beam coverage with a high gain. In order to operate in a fixed position relative to the Earth and to cover a large area on the ground, geostationary satellites require highly directional antennas. In general, small sized antennas are preferred for geostationary satellites due to their cost-effectiveness, lightweight, ability to take up less space, and narrow beam coverage with high gain. In view of the fact that antennas designed for Geo-satellites were large and bulky, we are currently developing antennas that are smaller in order to be used in agri cultural fields and other remote locations. In this case, the antenna will have direct access to the Geo-satellite without using the terrestrial network, since the use of the terrestrial network would cause a bottleneck in the communication between the an tenna and the satellite. For the purpose of avoiding the bottleneck connection, a direct connection will be estimated based on a link budget. Based on the link budget, the antenna was designed and simulated. In this work, we are aiming to simulate a small size, base heavy antenna for Geo satellite which can work in the power range from 20-35dB. And has a gain more than 2 dB. So, that the antenna can communicate without the use of terrestrial networks.

2023-05-30T00:00:00Z Elsa, Cleetus Saniya, Azeem http://210.212.227.212:8080/xmlui/handle/123456789/388 2023-07-05T09:51:54Z 2023-05-30T00:00:00Z

Title: SIMULATION AND EXPERIMENTAL INVESTIGATION OF MITIGATION OF FWM EFFECTS IN FRONTHAUL TRANSMISSION SYSTEM Authors: Elsa, Cleetus; Saniya, Azeem Abstract: Over the recent years, the need for high capacity and high broadband wireless access were in demand and in order to satisfy it various technologies were intro duced among which RoF came into existence which has low attenuation, immunity to electromagnetic interference and superior signal integrity. Therefore, it enables the transmission of signal over long distance and thus improves the capacity and mobility of the optical transmission system. In this review, we would concentrate on analyz ing the effect of fiber nonlinearity such as Four wave mixing (FWM) effect in long haul transmission system. Basically, FWM is an impairment due to the interaction of field intensity with the fiber refractive index which results in signal broadening, undesirable signal modulation and attenuation and thereby limiting the transmission capability of long-haul system. A parametric analysis for reducing the power level of crosstalk generated by FWM by incorporating various optical components in the communication link is done and optimization based on channel spacing, input power, fiber length, bitrate, is performed. This article discusses the nonlinear effect, four-wave mixing (FWM), which lowers the performance of optical communication systems. The concept of Linear polariza tion was introduced to reduce the effects of FWM. Here, orthogonal polarization is used with the modulation technique NRZ. Linear polarization was found to reduce the effect of FWM more than round polarization. Weaknesses of the four wavelength mixes were analyzed for various levels of input power. The capacity of a four-wave mixing product (FWM) is assessed by an optical spectrum analyzer. System perfor mance is analyzed in terms of quality factors and BER.

2023-05-30T00:00:00Z