Design and Analysis of SiGe Millimeter-Wave Radio Front-End MMICs For 5G Communication

This thesis focuses on design and realization of millimeter-wave radio frontend circuits for fifth generation(5G) wireless communication in 0.13um silicongermanium(SiGe) BiCMOS process. Radio front-end includes single-pole doublethrough (SPDT) switch, low noise amplifier (LNA) and buffer amplifier(BA) as a part of radio frequency(RF) transceiver system for E-band. The SPDT switch utilizes the reveres saturated SiGe heterojunction bipolar transistor(HBT). The resulting reverse saturated switch shows an insertion loss of 1 dB , isolation of 26 dB, reflection coefficient better than 25 dB at 75 GHz and provides a bandwidth of 40 GHz. A single to differential ended low noise amplifier(LNA)is designed using transformer balun. Simultaneous noise and impedance matching is used in order to realize both low noise and low reflection at the same time. The post layout simulation of E-band low noise amplifier exhibits a gain and noise figure(NF) of 26 dB and 5.5 dB respectively with a power consumption of 33.5 mW. The buffer amplifier shows a gain of 5.5 dB at 75 GHz. Finally, the receiver achieved a gain of 19.6 dB, noise figure(NF) of 6.9 dB and impedance matching better than 13.5 dB at 75 GHz. A 3 dB bandwidth of more than 12 GHz is achieved from the receiver. Extensive simulation results showing the performance of each circuit of receiver are presented

A Two Phase Interleaved Boost Single Stage PFC Converter using Flying Capacitor

The equipment connected to an electricity distribution network customarily needs rectification. In order to decrease DC voltage ripple, a Single phase diode rectifier utilizes a large electrolytic capacitor which yields a non-sinusoidal line current. So power factor correction (PFC) techniques are required. The boost topology is utmostwidespread than others in PFC applications. Thus a two phase interleaved boost single-stage PFC converter using flying capacitor is proposed in this paper. Due to its interleaved structure, the proposed converter can operate with reduced input current ripple and peak switch currents.The proposed system is simulated in MATLAB/SIMULINK and the performance parameters such as power factor (PF) and total harmonic distortion (THD) are computed

Chronic axillary sinus in a child

Chronic discharging sinus in the axilla is of very rare occurrence in pediatric age. Such a presentation, especially with a previous history of trauma, should be viewed with caution. Various possibilities including tuberculosis are considered. Appropriate investigations and thorough wound management will help in the prevention of long-term morbidity. We report a case of the chronic discharging axillary sinus in a child and review literature

Cluster analysis studies in rice (Oryza sativa L.) using wards minimum variance method

Abstract. The nature and magnitude of genetic divergence was estimated in one hundred and fourteen F 5 families of rice obtained from six different crosses along with their seven parents using ward's minimum divergence method by considering 10 characters. Results revealed existence of considerable amount of diversity in the material. The genotypes were grouped into twelve clusters. Cluster V constituted maximum number of genotypes (27). The genotypes falling in cluster XII had the maximum divergence (123.339), which was closely followed by cluster IX (112.928). The maximum inter cluster Euclidean 2 values was observed between cluster II and XII (1882.852) followed by cluster IX and XII (1488.520) suggesting that the genotypes constituted in these clusters may be used as parents for future hybridization programme

Review of experimental methods to determine spontaneous combustion susceptibility of coal – Indian context

This paper presents a critical review of the different techniques developed to investigate the susceptibility of coal to spontaneous combustion and fire. These methods may be sub-classified into the two following areas: (1) Basic coal characterisation studies (chemical constituents) and their influence on spontaneous combustion susceptibility. (2) Test methods to assess the susceptibility of a coal sample to spontaneous combustion. This is followed by a critical literature review that summarises previous research with special emphasis given to Indian coals

Ameliorative Effects of Dimetylthiourea and N-Acetylcysteine on Nanoparticles Induced Cyto-Genotoxicity in Human Lung Cancer Cells-A549

We study the ameliorative potential of dimetylthiourea (DMTU), an OH• radical trapper and N-acetylcysteine (NAC), a glutathione precursor/H2O2 scavenger against titanium dioxide nanoparticles (TiO2-NPs) and multi-walled carbon nanotubes (MWCNTs) induced cyto-genotoxicity in cultured human lung cancer cells-A549. Cytogenotoxicity was induced by exposing the cells to selected concentrations (10 and 50 µg/ml) of either of TiO2-NPs or MWCNTs for 24 h. Anti-cytogenotoxicity effects of DMTU and NAC were studied in two groups, i.e., treatment of 30 minutes prior to toxic insult (short term exposure), while the other group received DMTU and NAC treatment during nanoparticles exposure, i.e., 24 h (long term exposure). Investigations were carried out for cell viability, generation of reactive oxygen species (ROS), micronuclei (MN), and expression of markers of oxidative stress (HSP27, CYP2E1), genotoxicity (P53) and CYP2E1 dependent n- nitrosodimethylamine-demethylase (NDMA-d) activity. In general, the treatment of both DMTU and NAC was found to be effective significantly against TiO2-NPs and MWCNTs induced cytogenotoxicity in A549 cells. Long-term treatment of DMTU and NAC during toxic insults has shown better prevention than short-term pretreatment. Although, cells responded significantly to both DMTU and NAC, but responses were chemical specific. In part, TiO2-NPs induced toxic responses were mediated through OH• radicals generation and reduction in the antioxidant defense system. While in the case of MWCNTs, adverse effects were primarily due to altering/hampering the enzymatic antioxidant system. Data indicate the applicability of human lung cancer cells-A549 as a pre-screening tool to identify the target specific prophylactic and therapeutic potential of drugs candidate molecules against nanoparticles induced cellular damages

Millimeter-Wave Front-End Circuits for Wireless Communications

This thesis focuses on the design and characterization of millimeter-wave monolithic active and passive circuits for 5G-and-beyond 5G communication systems. Specifically, this thesis focuses on different active and passive components, the transmit-receive (T/R) switch, the low-noise amplifier (LNA), the power amplifier (PA), the bidirectional PALNA, the power detector, the phase shifter, and the receiver chain for mm-wave applications. This dissertation presents an overview of the research topic and summarizes the major outcomes of this thesis presented in six publications. Various issues and challenges associated with the design of mm-wave passive and active components in nanoscale BiCMOS technologies are described. Brief design details of different passive and active components have been presented. Among mm-wave passive components, different transmission lines including the microstrip line and coplanar waveguide are studied and modeled. The on-chip transformer and Marchand baluns are designed and utilized in different circuits. A wideband, low-loss and compact 3-dB differential quadrature generator is designed. The RF pads with the GSG configuration are designed with a compensation structure beneath the signal pad. The modeling techniques of the transistor operating in the high mm-wave region are presented. An E-band semi-switchless PALNA with a single-ended LNA and high-power differential PA is designed. The LNA and the PA are isolated from each other by the impedance matching networks and a differential switch. The semi-switchless PALNA achieves the lowest NF of 5.8 dB and the highest FOM in receive mode compared to the literature while it delivers a maximum power of +9.2 dBm at 76 GHz in the transmit mode. A compact and high-performance RF power detector is designed. It is demonstrated that the Meyer topology can be used to detect power at mm-wave frequencies with a suitable impedance matching network. The design of an E-band receiver front-end containing an LNA, a phase shifter, a buffer amplifier, and a switch at the input and the output for a phased array application is presented. The measured peak gain is 18.5 dB with a 3-dB bandwidth of 23 GHz from 56 to 79 GHz and the minimum noise figure is 9 dB at 75 GHz. A compact vector modulator phase shifter operating from 200 GHz to 250 GHz is designed utilizing a compact and differential I/Q generator. The achieved gain is -10.3 dB at 230 GHz with the maximum gain setting and the maximum rms gain and phase errors of 1.25 dB and10o  from 200 GHz to 250 GHz, respectively. A high-gain phase shifter chain is designed by adding an LNA to the input of the phase shifter and an additional gain amplifier at the output of the phase shifter. The measured peak gain from the phase shifter chain is 20 dB at 230 GHz and the minimum noise figure of 11.5 dB at 230 GHz. The high-gain phase shifter is capable of 360◦ phase tuning and 10 dB of gain tuning.

A Novel Direct Drive Linear Ocean Energy Converter Based on Nonlinear Oscillator System

This PhD research presents novel analytical, numerical and experimental modelling of single-degree-of-freedom, two-degree-of-freedom and three-degree-of-freedom magnetic spring-based non-linear oscillator systems to harness energy from ocean waves. The proposed energy harvesters overcome the bandwidth problem in the previous linear generator studies which cannot work satisfactorily in the low-frequency range. The outcomes of this research work provide the mathematical foundation for the modelling and upcoming advancement of multi-degree-of-freedom magnetic spring (nonlinear oscillator) based energy generators

Instrumentation in Underwater Environment

Abstract For underwater observation and exploration, the accurate measurement of few basic parameters is very important. During measurement process underwater noise plays an adverse effect, so noise measurement is essential to refine the result of other parameters. Sound, distance, and fish population measurements are common activities in oceanography. Finding proper instrumentation in this field is quite challenging due to the uncertain environment. This chapter describes the construction, operation, and performance of the different measurement system with different techniques for specific underwater applications. In addition, advances in sensors and processors with proper design ensure accurate measurement

A Review of the Linear Generator Type of Wave Energy Converters’ Power Take-Off Systems

The traditional wave energy converters (WECs) use hydraulic or turbine-type power take-off (PTO) mechanisms which consist of many moving parts, creating mechanical complexity and increasing the installation and maintenance costs. Linear generator-based direct-drive WECs could be a solution to overcome this problem, but the efficiency of the single conventional linear generator is not high enough, and it cannot work satisfactorily in the low-frequency range. This article reviews the recent research developments of the linear permanent magnet (PM) generator-based WEC to harness maximum energy from ocean waves. It starts with a brief introduction and background of wave energy converters using linear generators. Following this, the working principle of the WECs with linear PM generators is briefly outlined. Subsequently, the analytical model of the linear PM generator-based WEC is studied. After that, the up-to-date developments of the linear PM generator-based PTO systems are studied. Despite some modifications resulting in complexity in the linear PM generator’s structure and a rise in manufacturing costs, the study shows the systems’ efficiencies increased by increasing magnetic flux and reducing cogging force. The key parameters and improvement issues that can increase the performances and efficiencies of the PTO systems are identified to help future researchers for further development. Moreover, the review discusses the numerical and experimental analysis tools, the typical control systems used by the researchers and the challenges of the linear generator-based wave energy conversion system. Finally, conclusions about the significant beneficial characteristics and design choice of the WEC linear generator structure are provided and related to the application conditions