GALGOTIAS COLLEGEGALGOTIAS COLLEGE OF ENGINEERING ANDOF ENGINEERING AND

TECHNOLOGYTECHNOLOGY

MINOR PROJECT MINOR PROJECT SYNOPSISSYNOPSIS

SUBMITTED SUBMITTED BYBY

ABHISHEK ABHISHEK SINGH (0709731006)SINGH (0709731006)

VIVEK SINGH VIVEK SINGH (0609731097)(0609731097)

SUMIT SUMIT YADAV (1609731022)YADAV (1609731022)

NARENDRA NARENDRA YADAV (0709731065)YADAV (0709731065)

ACKNOWLEDGEMENT

We would like to express a profound sense of gratitude to our PROJECT COORDINATOR PROFESSOR, Mr. R.L. YADAV for his valuable guidance and support for carrying the work on such an innovative idea of designing a project on ‘MICROSTRIP ANTENNA ON FERRITE SUBSTRATES’. We are thankful to him for his gentle encouragement and pains; he took in while guiding us through the completion of the Minor Project.

We are also thankful to the entire staff of Electronics & Communication Department who classified our doubts & confusion even

during their busy hours in the college. It was a great satisfying experience in carrying out our bachelor degree in such a professional organization where the process of learning is never ending.

MICROSTRIP ANTENNA ON FERRITE SUBSTRATES

INTRODUCTION

Ferrite material is attractive for application in microwave and millimetre wave integrated circuit technologies due to its nonreciprocal material properties. In addition, the applied dc magnetic field changes the permeability tensor and thus the electrical properties of the material. For microstrip antenna elements on a ferrite substrate, it is possible to change the antenna characteristics dynamically without changing the operating frequency or the hardware configuration. In this work, the method of moments is employed to study the physical phenomena of a printed dipole on a ferrite substrate.

ABSTRACT

A rigorous moment method is used to find the radiation properties of a centre-fed microstrip dipole on a ferrite substrate. The radiation characteristics of a microstrip dipole, including input impedance, antenna gain radiation efficiency, as a function of dipole size, frequency and ferrite material characteristics are studied parametrically using a moment method solution. It is demonstrated that the bias magnetic field that the bias magnetic field may dynamically change the antenna characteristics

FORMULATION

The geometry of a microstrip on a ferrite substrate is shown in the figure 1. The integral equation of the pertinent problem is

On the strip dipole

(1)

where the dipole is oriented in the x direction. The integral in the Eq. 1 is a surface integral over the strip dipole. Gzz is the Green’s function corresponding to the Ez component due to the µ current source in the x direction. The spectral component of this Greens function can be found in (1).

I n the moment method procedure, the current on the strip dipole is expanded in the piecewise modes with a Maxwellian function as the transverse dependence. Using a standard moment method followed by a Galerkin’s procedure, where the expansion and testing function are used, the integral equation is converted into a matrix equation. The impedance elements are in the form of

The numerical algorithm can be used to compute Zmn

RESULT

Antenna characteristics of a printed dipole on a ferrite substrate are studied through the example of a ferrite substrate of a 0.8 mm in thickness, saturation magnetization µo Ms= 0.25 T, dielectric constant 12.6 and dipole width 0.4 mm. The dipole resonant length versus

frequency is shown in fig. 2. The condition of resonance is when the input is reactance is zero (0). The star dotted line is for the isotropic case and the solid line is for the case and the solid line is for the case of a bias H field 0.225 T in the direction of the strip dipole current. It is also observed that with the applied bias, the resonant length increases. This implies that the bias H field tends to increase the effective wavelength of the structure. Radiation efficiency as a function of a bias H field for a dipole of 5 mm long is shown. Radiation efficiency is defined as the ratio of total power fed into the dipole. For a lossless material, this lossless material, this loss is due to surface waves. It is seen that the increase of the bias H field increases radiation efficiency monotonically.In other words, the applied bias is capable of reducing the surface waves.

BIBLIOGRAPHY

1. J.L. TSALAMENGAS AND N.K. UZUNOGLU,---- “RADIATION FROM A DIPOLE IN THE PROXIMITY OF A GENERAL ANISOTROPIC GROUND LAYER”

2. H.Y. YANG,A.NAKATANI, & J.A. CASTANDA,--- -“EFFICIENT EVALUATION OF SPECTRAL INTEGRAL IN THE MOMENT METHOD SOLUTION OF MICROSTRIP ANTENNAS AND CIRCUIT”

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