BITS Faculty Publications
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Item Cost-Effective Approach for the Determination of Specific Absorption Rate of Liquid Phantom(IEEE, 2021) Rano, DineshIn this paper, point thermal specific absorption rate (SAR) of the liquid phantoms are determined by simulation and measurement on an elliptical cylinder for a microstrip patch antenna (MPA) operating in the medical body area network (MBAN) band. For this, we measured the temperature rise of the liquids exposed to EM wave (MPA) for a given time. The liquid phantom (homogeneous) is developed by varying the percentage of salt and sugar in 250g of water, whereas, skin phantom is developed by varying the weight of water in 200g of glycerin. The reported technique to measure SAR can provide measurements without the need for an expensive arrangement of dielectric probe kit and this demonstrates the cost-effectiveness of the proposed technique. Finally, we validated our proposed theory with simulation by keeping the conditions identical to measurement which demonstrates excellent resemblance.Item Comparative analysis of performance improvement of MPA by using EBG and DGS structures(IEEE, 2016) Rano, DineshThis paper present different design methods to improve the performance of MPA. A comparative analysis of EBG and DGS structures in terms of performance has been given. The proposed DGS structure improves gain, efficiency and the return loss of the antenna. The antenna w/o EBG and DGS resonates at 2.4 GHz offering bandwidth of 67.8 MHz. Three different types of DGS structure have been designed and their effects on the antenna performance have been tabulated. The DGS structure provides good matching with reduction in size more than 4%Item Determination of Effective Dielectric Constant and Resonant Frequency of Microstrip Patch Antenna with Multilayered Superstrate Structures(IEEE, 2019) Rano, DineshA generic iterative empirical model to compute the effective permittivity (ε eff ) and resonant frequency (f r ) of microstrip patch antenna (MPA) covered with multi-layered superstrates is reported. For an MPA covered with multi-layers of superstrate the presented technique makes use of conformal mapping (CM) of dielectric boundaries and series-parallel combination of capacitances between the metallic patch and ground plane to determine ε eff . The developed model can accurately predict ε eff and f r of multi-layered superstrate structure with permittivity greater than 4.5 which is higher than the previous state-of-the-art (i.e. ε r >2.32). It can predict f r of an MPA with relative %error of 1.6% and 0.1% for superstrate having permitivities of 3.66 and 4.7 respectively for considerably thicker superstrates. The presented theory is validated by developing prototypes and a good agreement between the measured and the simulated results confirm this premise. In essence, the technique presented is first of its type to anticipate f r of an MPA covered with superstrate layers of relatively higher permitivities with very small relative %error than the previous works. An algorithm to integrate the developed model with any standard microwave simulator is also proposed. Finally, the proposed theory is applicable for wearable sensors with antenna in it and covered with dielectric superstrate for protection from the environment.Item A New Model to Determine Effective Permittivity and Resonant Frequency of Patch Antenna Covered With Multiple Dielectric Layers(IEEE, 2020-02) Rano, DineshThis paper reports a model to determine effective permittivity (ε eff ) and resonant frequency (f r ) of microstrip patch antenna (MPA) covered with multiple dielectric layers. This model is augmented with a newly developed empirical expression to determine the ε eff of multi-layered superstrates over a substrate. The development of empirical formulation makes use of conformal mapping approach (CMA) and series-parallel combination of dielectric boundaries between the ground plane and patch of the MPA. In this work, the MPA is designed on substrate having dielectric constant of ε 1 whereas the superstrate layers have dielectric constants of ε 2 , ε 3 ...ε n . It is shown that the proposed technique is able to predict the f r of MPA with error of 1.8%, 3.5%, and 1.4% when it is covered with a single dielectric layer with superstrate height of 4.5mm for respective conditions of ε 1 = ε 2 , ε 1 > ε 2 and ε 1 <; ε 2 (ε 1 = 3.66, ε 2 = 2.2/4.7). Furthermore, the developed technique is analyzed for distinct combination of substrate and two superstrate layers for the cases ε 1 = ε 2 > ε 3 , ε 1 = ε 2 <; ε 3 , ε 1 <; ε 2 > ε 3 , ε 1 > ε 2 <; ε 3 , and ε 1 > ε 2 > ε 3 . Subsequently, the viability of the proposed technique is demonstrated in practical scenarios for body centric communications by considering single (e.g., jeans cotton, pure cotton, rayon, polyester, felt fabric, terry wool, and leather) and multiple (e.g., wool over jeans cotton and polyester, felt fabric over pure cotton and rayon) layers of textiles over MPA. The measurement results on various dielectric superstrates and textiles show excellent agreement with the corresponding theoretical results and thereby validate the reported theory. Finally, a comparison with the seminal works clearly shows the promise of the reported technique in this paper.