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Paper presentation – Ultra-Portable Devices Paper: Jaechun Lee and Sangwook Nam, Effective Area of a Receiving Antenna in a Lossy Medium. IEEE Transactions on Antennas and Propagation,Vol. 57, No.6, June 2009 Presented by: Rohit Chandra 2010-05-09 Paper Presentation - Ultra Portable Devices 1

Outline • Introduction • Radiation Property of Hertzian dipole in Lossy medium • Effective Area • Simulation • Results • Summary 2010-05-09 Paper Presentation - Ultra Portable Devices 2

Introduction • Antennas in Lossy Medium:    z 1   t 0   2 t 1 o Geophysical Survey e ˆ   ( ) H z dt  1 j t   o Submarine Communication o Implants in human body Hankel Function of 2nd kind 2010-05-09 Paper Presentation - Ultra Portable Devices 3

Introduction • A derived using gain and e 2    P impedance of small dipoles in    RX G G free space in Friis Formula  TX RX   4 P R TX • In lossy medium gain and impedance cannot be obtained simply as in free space Friis Formula in free space • Small dipole  Hertzian dipole, infinite power is consumed in vicinity in lossy medium    2    • Insulated Hertzian Dipole A G    e RX  4  2010-05-09 Paper Presentation - Ultra Portable Devices 4

Radiation Property of an Insulated Hertzian Dipole in a lossy medium    4 ˆ ˆ   ' * 2 Re ( ) ( ) | | P j H ka H ka TX in 1 1 3 Input Power derived by integration of complex Poynting Vector over the surface at r = a T is derived by continuity of Electric and Lossless Sphere Magnetic field at r = a Lossy Medium     2 2 r r 1 e e     ' 2 2 sin Re[ ] | | P TX G P  r in 2 2 2 4 r r    3 Re       2 sin G D ˆ ˆ  eff ' * 2 Re ( ) ( ) j H ka H ka Radiated Power density in far field 1 1 r  ∞ and α is attenuation constant 2010-05-09 Paper Presentation - Ultra Portable Devices 5

Radiation Property[contd..] Two factors of loss in lossy medium 1. Attenuation loss in propagation   2 r e   ' P D P 4  r eff in 2 r 2. Disspiation Loss in the reactive energy stored in the near field 2010-05-09 Paper Presentation - Ultra Portable Devices 6

Effective Area 2 E l  in P RX 8 R in 2 2     3 1   E     2 0 sin Re       i eff 2 2   2 2 Re k      2 2 2 Re P k l 2   0 in R T      in 2 2 3 4 ' I    P eff eff A G    e plane 4   k  2      0 sin   E TE 0 in i eff   * k Re 2010-05-09 Paper Presentation - Ultra Portable Devices 7

Friis Formula for Lossy Medium 2    P    R   eff RX G G e    TX RX  4  P R TX 2010-05-09 Paper Presentation - Ultra Portable Devices 8

Simulation 2010-05-09 Paper Presentation - Ultra Portable Devices 9

Summary • Effective area has been derived for estimation of power transmission in Lossy medium • When medium is both electric as well as magnetic lossy the extended Friis formula for the lossy medium can be used. 2010-05-09 Paper Presentation - Ultra Portable Devices 10