M Tech Dissertations
Permanent URI for this collectionhttp://ir.daiict.ac.in/handle/123456789/3
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Item Open Access Computational investigation of patch antennas in plasma environment(Dhirubhai Ambani Institute of Information and Communication Technology, 2016) Vyas, Hardik; Chaudhury, Bhaskar; Gupta, SanjeevMicrostrip antennas are extensively used in spacecraft systems and other applicationswhere they encounter a plasma environment. A detailed computationalinvestigation of change in antenna radiation properties in the presence of plasma has been done. The study shows antenna properties such as the resonant frequency,return loss, radiation properties and the different characteristics of the antenna changes when it is surrounded by plasma. Particular focus of the work is to understand the causes behind these changes by correlating the complex propagation constant in the plasma medium, field distribution on the patch and effective dielectric of the antenna substrate with antenna parameter variations. Besides this, the study also provides important insights to explore the possibilities of designing frequency reconfigurable microstrip antenna where the substrate can be replaced with plasma and important antenna characteristics can be controlled by varying the plasma density. Plasma can be the potential frequency reconfigurable element since its dielectric properties can be varied by varying plasma density. It has high microwave power handling capability which makes it preferrable over current semiconductor technologies in situations such as electromagnetic attacks.Followed by this, minimization of power required to sustain plasma in a reconfigurable antenna has been done by using microplasma technology.Item Open Access Dual-band and shorted microstrip patch antenna design for communication system applications(Dhirubhai Ambani Institute of Information and Communication Technology, 2011) Rai, Karishma K.; Gupta, SanjeevDual-band and miniaturized microstrip patch antennas are in much demand due to their small size, light weight and planar configuration. In this thesis, an attempt is made to design and analyze miniaturized microstrip patch antennas, patch arrays and dual-band microstrip patch antennas. These antennas can be used in any application, over a wide frequency range of 1 GHz to 10 GHz. An array of shorted microstrip patches has been designed to operate at the desired frequency. The dual-band operation is obtained by either creating a notch on one of the radiating patch of the microstrip patch antenna or loading the radiating patch by a slot. The patch used for this dual-band operation is shorted using a shorting wall. The results of both the designs are analyzed. The study carried on, helps to find the various antenna parameters and the optimized design of an antenna array and dual-band antenna.Item Open Access Multi band fractal antenna for satellite application(Dhirubhai Ambani Institute of Information and Communication Technology, 2008) Kalariya, Vishalkumar Rameshbhai; Gupta, SanjeevFractal Antenna is the current topic for the research engineering because Fractal Technology allow us to design miniature antennas and integrate multiple band in single device. This antenna is a type of Micro strip antenna so it can be mount on the same PCB on which other RF components are mounted. There is not exact method to predict the resonance frequency of the Fractal antenna. Current research work tell that the prediction of resonance frequency of the Antenna is made from the simulation result. But in this work we try to predict the resonance frequency by mean of Network connection method. In this method each small segment of fractal shape antenna is treated as the single square patch and by analysis the separate patch and combing the total impedance by mean of Network connection method and the prediction of the resonant frequency is done by this thesis work. By using the Cavity model approach we find the impedance of the separate patch and by the Network connection model approach we can combine the total resistance and find the input impedance of the fractal antenna and we are trying to design the Multi band Fractal antenna for the L band(1.4GHz), C band(5.35GHz) and last is X band(9.65GHz) which is resonating at three band of frequency by this method.Item Open Access Dual-band microstrip antenna design(Dhirubhai Ambani Institute of Information and Communication Technology, 2005) Desai, Bhumi; Gupta, SanjeevMulti-frequency microstrip antennas are very much in demand due to their physical and mechanical properties like small size, lightweight, thin profile, low power consumption, and ease of implementation in the domestic applications. Some designs of dual-band microstrip patch suitable for GSM 900/1800 base station operation are already a research topic. Dual frequency microstrip antennas are also used in GPS and SAR. Commercially, these are deployed in RFID tags. But for the antenna to be useful in all these applications, its behavior like return loss, bandwidth, beam width, radiated power, gain, and directivity, at both the frequencies, should be nearly identical. The purpose of this work is to design the microstrip patch for dual frequencies of 945 MHz and 1960 MHz. Two new approaches called Coplanar patches and Overlapped patches are proposed. Then some of the existing techniques like Stacked patches, Dual slot loaded patches and Dual frequency PIFA are explored for our design specifications. Finally, the comparison of all the design aspects including the proposed ones is carried out in this work.Item Open Access Shorted microstrip patch antenna(Dhirubhai Ambani Institute of Information and Communication Technology, 2005) Bala, Shashi; Gupta, SanjeevIn this thesis, electrically small microstrip patches incorporating shorting posts are thoroughly investigated. These antennas are suitable for mobile communications handsets where limited antenna size is a premium. In particular, it is shown that the zero mode of the unloaded MSA (Microstrip Antenna) plays a central role for reducing the lowest operation frequency of the loaded MSA. The studies carried out allow the determination of all relevant antenna parameters for different post specifications and can easily be extended for different patch architectures.