M Tech Dissertations

Permanent URI for this collectionhttp://ir.daiict.ac.in/handle/123456789/3

Browse

Filters

2005 - 200912010 - 20181

Settings

Has files: YesSubject: search.filters.subject.Antenna

Search Results

Now showing 1 - 2 of 2
  • Thumbnail Image
    ItemOpen Access
    Novel circular fractal antenna array
    (Dhirubhai Ambani Institute of Information and Communication Technology, 2018) Chauhan, Rahul; Gupta, Sanjeev
    Traditional antennas work well only for one resonant frequency and using multiple antennas for different frequencies is a complex task, therefore multiband circular fractal antenna was designed which have a small size and multiple resonating frequencies for UltraWideband Applications (UWB). For designing and fabrication of the antenna the substrate used is FR4 which have dielectric constant 4.4 and whose dimensions are 48 96mm2. For the excitation of the antenna microstrip feed line of 50W is fed to the circular fractal patch for impedance matching. The UWB characteristics can be achieved using fractal concept. Also to increase the bandwidth, slots of different dimensions are etched out from the ground plane from the basic fractal configuration. Slots dimensions are adjusted in each iteration to achieve the desired results. In the later part of the work, different array configurations of the circular fractal antenna are analyzed. The various arrays design configurations are 1 2, 1 4, 2 2 and 2 4. The substrate used is FR4 whose dimension is varied according to the array configurations. Similar to basic antenna design a 50W microstrip feedline is used to excite the antenna for all the configurations. The antenna shows stable radiation patterns and good return loss values i.e better than 10dB at multiple frequencies. All the analysis is done in HFSS 2014.
  • Thumbnail Image
    ItemOpen Access
    Performance of MIMO in correlated rayleigh flat fading channels
    (Dhirubhai Ambani Institute of Information and Communication Technology, 2005) Jain, Alok; Jadhav, Ashish
    The recent interest in Multiple Input Multiple Output (MIMO) communication systems was initiated by the theoretical work of Telatar. The development in the field of random matrix theory is the basis of these studies. The assumption in the mathematical model for studying MIMO turned out to be too idealistic for realistic (correlated) channel condition. This lead to an exaggeration of performance of MIMO. This thesis deals with quantification of performance of MIMO in realistic channel conditions with the emphasis on study of working of MIMO receivers. Our definition of MIMO contains both diversity systems and spatial multiplexing systems. For the simulation of realistic channel conditions a correlated fading channel model with lack of rich scattering is used. To perform simulations for N transmit and M receive MIMO systems there is a need for having N x M correlated fading envelops. We propose a novel and simplified technique to extend the algorithm for two correlated fading envelops given by Richard and Jeffery. Various analytical studies on the effect of correlated multi-path channel on performance of spatial multiplexing have been done. These studies focus on capacity cumulative distribution function. Effect of various degree of correlation on other performance measures like diversity gain and error probability have been not done. This is due to lack of simple method of generation of correlated Rayleigh fading envelops. By making use of the extended algorithm we have been successful in carrying out simulation to observe the effects on the performance. Recently there is interest in extending the concept of MIMO in wireless communication for sensor networks. The motivation behind it is energy efficiency of sensor nodes. Our results have implications on this venture.