WAVE THEORY AND ANTENNA

Electromagnetic Waves Maxwell Equations in phasor form, Wave Equation, Uniform plane wave in homogeneous, Free space, Dielectric, Conducting medium. Polarization: Linear, Circular and elliptical polarization, Unpolarized wave. Reflection of plane waves, Normal incidence, Oblique incidence, Electromagnetic power and Poynting vector. Wave Propagation Fundamental equations for free space propagation. Ground, Sky and space wave propagations. Structure of atmosphere. Characteristics of ionized regions. Effects of earths magnetic field. Virtual height, MUF, Skip distance. Ionospheric abnormalities. Multi-hop propagation. Space link geometry. Antenna Fundamentals Types of antenna, Radiation mechanism. Antenna Terminology: Radiation pattern, Radiation power density, Radiation intensity, Directivity, Gain, Antenna efficiency, Half power beam width, Bandwidth, Antenna polarization, Input impedance, Antenna radiation efficiency, Effective length, Effective area, Reciprocity. Radiation Integrals: Vector potentials A, J, F, M, Electric and magnetic fields electric and magnetic current sources, Solution of inhomogeneous vector potential wave equation, Far field radiation. Wire Antennas and Antenna Arrays Analysis of linear and loop antennas: Infinitesimal dipole, Small dipole and finite length dipole half wave length dipole, Small circular loop antenna. Antenna Arrays: Two element array, Pattern multiplication N-element linear array, Uniform amplitude and spacing, Broad side and end-fire array, N-element array: Uniform spacing, Non uniform amplitude, Array factor, Binomial and Dolph Chebyshev array. LF to HF Antennas Structural details, Dimensions, Radiation pattern, Specifications, Features and applications of following antennas: Hertz and Marconi antennas. Effects of ground and antenna height. Electrically short antennas. Beverage antenna. Medium frequency antennas: Tower radiation, Construction, Feed, Ground system. HF antennas: Resonant and non-resonant antennas. Harmonic antenna. V-antenna. Rhombic antenna. TW antennas. Loop antenna. Ferrite rod antenna. Whip antenna. VHF to SHF Antennas Structural details, Dimensions, Radiation pattern, Specifications, Features and applications of following antennas: Folded dipole, Yagi-Uda, Biconical, Helical, Horn, Slot, Microstrip, Turnstile, Super turnstile and lens antennas. Antennas with parabolic reflectors.