International Journal of Engineering, Science and Mathematics Vol. 6 Issue 3, July 2017, ISSN: 2320-0294 Impact Factor: 6.765 Journal Homepage: http://www.ijesm.co.in , Email: ijesmj@gmail.com 89 International Journal of Engineering, Science and Mathematics http://www.ijesm.co.in , Email: ijesmj@gmail.com ANALYSIS OF MAGNETICALLY BIASED MICROSTRIP EQUILATERAL TRIANGULAR PATCH ANTENNA ON FERRITE SUBSTRATE USING GA * Naveen Kumar Saxena * R.K. Verma * P.K.S. Pourush * N. Kumar ** Abstract A Theoretical analysis by Genetic Algorithm for optimization of important parameters (Directivity, Radiation Power, Impedance etc.) of magnetically biased microstrip antenna fabricated on ferrite substrate is reported. The effect of magnetic field (H o ) on ferrite antenna during electromagnetic propagation is incorporated in function analysis with the help of extraordinary propagation constant (k), which is new one in this type of optimizing analysis. Functions for the fitness of the GA program is developed using cavity model of the analysis of microstrip antenna. The genetic algorithm was run for 500 generations. The probability of crossover was varied from 0.7 to 0.85 and the probability of mutation was varied from 0.001 to 0.002. The computed results are in good agreement with the results obtained experimentally. Keywords: Genetic algorithm; Magnetically biased; Cavity model; Equilateral triangular ferrite microstrip antenna; Copyright © 2017 International Journals of Multidisciplinary Research Academy. All rights reserved. Author correspondence: Naveen Kumar Saxena 1 Microwave Lab, Department of Physics, Agra College Agra, PIN 282002 (U.P) India. I. INTRODUCTION Microstrip patch antennas of all shapes are widely used in communication systems where their small size, conformal geometry and low cost can be used to advantage. Due to the recent availability of low loss commercial microwave ferrites, there is an increasing interest in the performance of the patch antennas printed on ferrite substrates in the effect of external dc-magnetic field. External magnetic field makes the patch antennas very versatile in the sense of scanning without mechanical movement, low RCS and also bandwidth enhancement [12-17]. Although some work [1-6] have been performed for microstrip antenna with GA approach for the patch antennas without magnetic biasing but analysis of almost all important parameters for ferrite substrate under magnetic biasing for circular patch antenna is new one. Present analysis also incorporate the dispersion effects due to magnetic field biasing in the form of effective propagation constant (k) which is not discussed in the referenced articles. Some similar referenced works [7-11] also have done mathematically or by conventional methods for optimization but this technique is rather precise, accurate and sensitive to optimize parameters of patch antenna as well as other type of antenna also. There are many optimization techniques frequently using for the same work for example Broyden– Fletcher–Goldfarb–Shanno (BFGS), Davidon–Fletcher–Powell (DFP), Nelder–Mead downhill simplex (NMDS), Steepest descent, etc. GA was introduced by Holland [24] and was applied to many practical problems by Goldberg [25, 26]. It is well known that search technique, the genetic algorithm is a parallel, robust and probabilistic search technique that is simply and easily implemented without gradient calculation, compare with the conventional gradient base search procedure. Most important of all, the GA proposed also provides a mechanism for global search that is not easily trapped in local optima. The GA proposed here an adaptive mutation rate strategy [28-29].