Rajveer S. Yaduvanshi

Wide Band Circularly Polarized Dielectric Resonator Antenna With Stair-Shaped Slot Excitation

A singly-fed wideband circularly polarized dielectric resonator antenna is proposed in this communication. Antenna structure contains a rectangular and two half split cylindrical dielectric resonators. Multiple orthogonal modes are excited in the antenna structure when excitation is applied through a stair-shaped slot. Measured results show that antenna provides wider 3-dB axial ratio and impedance bandwidths of 41.01% and 49.67%, respectively. Proposed antenna can be utilized in C-band applications.

Design, Development and Simulations of MHD Equations with its proto type implementations

The equations of motion of conducting fluid in a magnetic field are formulated. These consist of three sets. First is the mass conservation equation, second Navier Stokes equation which is Newton’s second law taking into account the force of magnetic field on moving charges. The electrical field effects are neglected as is usually done in MHD. The third set is Maxwell’s equation especially to monopole condition along with Ampere’s law with the current given by ohm’s law in a moving frame (the frame in which the moving particles of fluid is at rest).The mass conservation equation assuming the fluid to be incompressible leads us to express the velocity field as the curl of a velocity vector potential. The curl of the Navier Stokes equation leads to the elimination of pressure, there by leaving with an equation involving only magnetic field and the fluid velocity field. The curl of the Ampere law equation leads us to another equation relating to the magnetic field to the velocity field. A special case is considered in which the only non vanishing components of the fluid are the x and y components and the only non vanishing component of the magnetic field is z component. In this special case the velocity vector potential only has one non zero component and this is known as stream function. The MHD equation in this reduces to three partial differential equations for the three functions in 2D model. ? stream function embeds and components. Application of MHD system prototype has been worked and presented.

EM Wave Transport 2D and 3D Investigations

Boltzmann Transport Equation [1-2] has been modelled in close conjunction with Maxwell’s equation, investigations for 2D and 3D transport carriers have been proposed. Exact solution of Boltzmann Equation still remains the core field of research. We have worked towards evaluation of 2D and 3D solutions of BTE. Application of our work can be extended to study the electromagnetic wave transport in upper atmosphere i.e. ionosphere. We have given theoretical and numerical analysis of probability density function, collision integral under various initial and final conditions. Modelling of coupled Boltzmann Maxwell’s equation taking binary collision and multi species collision terms has been evaluated. Solutions of Electric Field (E) and Magnetic Field (B) under coupled conditions have been obtained. PDF convergences under the absence of electric field have been sketched, with an iterative approach and are shown in figure 1. Also 3D general algorithm for solution of BTE has been suggested.

Conical shape dielectric resonator antenna for ultra wide band applications

This paper represents the antenna with a Dielectric Resonator of conical shape fed by micro-strip line providing the results for Ultra Wide Band region satisfying the limits set by FCC for UWB region i.e. 3.1-10.6 GHz. Theoretical results are achieved for the design with range of frequencies 2.72-11.36 GHz and covering the further region of frequency band from 20 GHz to onward. Detailed study of the effect of various parameters variation of the conical DR along with the circular slot provided for aperture coupling in ground plane is notified and simulated.

Design for enhancing gain in multimodal cylindrical dielectric resonator antenna

Communication of present era involves Wi-Fi, Wimax and WLAN. Proposed antenna is designed keeping in mind for these particular requirements. Narrow beam may impart large amount of gain for one particular communication requirements. This paper investigates cylindrical dielectric resonator antenna with introducing band gap structure on the circular patch of DRA for imparting high gain. The application of this antenna can had in the field of WLAN. In this paper characteristics of cylindrical Dielectric Resonator Antenna (DRA) using BaZrO3 (εr=27) material, are studied. The DRA antenna is designed by using HFSS software which employs the FDTD method for solution. The characteristics of these antennas are investigated with both co-axial feeding and used for exciting the DRA. The experiment is performed on cylindrical DRA shape fed by coaxial and BaZrO3 material of dielectric constant 27.

Fluid Frame Magneto-hydrodynamic Antenna

A rotating fluid frame Antenna consisting of conducting fluid (saline water) is radiating under controlled electric field and magnetic field conditions. Water molecules oscillate due to impact ionization inside the fluid and contribute to radiate energy. Resonant frequency depends on volume, type of fluid, shape of tube, chemical properties of fluid used, DC magnetic bias and electric bias conditions. The prototype model is presented with analytical and experimental solutions. Mathematical formulations have been set up in support of detailed study of MHD antenna. The radiation patterns and impedance in this class of antenna become function of conducting fluid velocity v, magnetic field intensity H and electric fields intensity E due to Centrifugal and Coriolis forces in MHD phenomenon. Here Poynting vector of the antenna is different from the conventional type because of additional velocity field is involved.

Gain and bandwidth controlling of dielectric slab rectangular dielectric resonator antenna

Reconfigurability in an antenna is basic requirement in Military communication. If control on resonant modes can be developed, the antenna will have reconfigurability. This paper presents a control mechanism for Gain and bandwidth using resonant modes in stacked rectangular dielectric resonator antenna. Simply the bands of multiband dielectric resonator antenna are forced to shift their position and consequently the bandwidth of antenna has been improved significantly by merging neighboring bands. Change in the field confinement due to perturbations introduced inside the Dielectric Resonator causes the variation in the gain of antenna.

Analytical Computation of Resonant Frequency of Rectangular Dielectric Resonator Antenna By Including Effective Dimensions of DRA

In this paper, a new concept of effective dimensions of rectangular dielectric resonator antenna (DRA) is introduced to calculate the resonant frequency of rectangular DRA accurately. Mathematical modeling for computation of resonant frequency is developed using transcendental equation and appropriate boundary conditions of rectangular dielectric resonator antenna. Difference between effective and actual physical dimensions are analysed for different modes in details. Important parameters that control the effective dimensions, that is, physical dimensions, orientation, and dielectric constant of DRA, have been studied. E-fields inside the rectangular DRA have also been studied for different frequencies. Simulations and experimental measurements were carried out to verify the proposed concept. Theoretical, simulated, and experimental results of resonant frequency of the dielectric resonant antenna have been compared and are found to be in agreement with each other.

An Investigation of Massive Gain in Hybrid Configurable Cylindrical Dielectric Resonator Antenna

In this article a high gain of two layer cylindrical dielectric resonator antenna fed through coaxial probe is projected and developed and conjointly offer complete implementation of superstrate dielectric resonator antenna on patch. The hybrid structure is operated under controlled electric field and magnetic field. The design is loaded with superstrate. The results on reflection coefficient S11, Gain of assorted stages of antenna design are simulated victimisation high frequency structured simulator and conferred. High permittivity material is used as a fluid inside the cylindrical resonator. The resonant frequency of the antenna can be modified by ever-changing the dielectric constant of fluid. It has been investigated that use of superstrate increases antenna gain from by varied biasing voltage reconfigurability are often obtained. The measured gain found to be 11dBi. Reconfigurability is the key parameter during this work a completely unique cylindrical stacked dielectric resonator antenna of high gain with band is presented for Wi-Fi, Wi-max and WLAN communications. The concept becomes compatible with patch antennas for high Gain applications.

Investigations into Polarisations in Dielectric Resonator Antenna

This paper presented investigations into polarization for designing antennas. The left-hand and right-hand polarization switchable cylindrical DRA has been investigated using two crossed slots of unequal lengths. They couple energy through an aperture-coupled microstrip feed line. Circular polarization with left-hand and right-hand circular polarizations can be achieved with the proposed antenna. Operating frequency of the antenna is 5.8 GHz. The antenna is designed to introduce polarization diversity, i.e., the signal can be transmitted at the same frequency while switching from LHCP to RHCP and vice versa. Hence, the designed antenna has frequency reuse features embedded in it. Measured and simulated results of VSWR are below 2, and axial ratio is below 3 dB. The polarization diversity of this designed antenna plays a vital role in wireless networks to minimize fading and multipath. The simulated and measured results of cylindrical DRA using TMM-13 substrate have been found to be in close proximity. This antenna can be used for WLAN, WiMAX, and Wi-Fi applications.