117-11HMWRK4 - th edition. 3. Do problem 9.2 in Ulaby 6 th...

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Prof. E. Yablonovitch ELECTROMAGNETIC FIELDS AND WAVES EE117 Homework #4; assigned: Feb. 28, 2011 Due 5PM, Monday, Mar. 7, 2011 Please put the completed homework in the plastic tray on my door, 267M Cory 1. You have an infinitely long bar magnet, in the form of an iron cylinder 1cm in diameter, centered at the origin, and pointing in the z-direction. The permanent magnetic field inside the iron cylinder is B=1Tesla. (a) Using the definition of Vector Potential B ≡∇× A, please give a numerical formula for A(x,y,0) outside the magnetic cylinder. (b) Please give a numerical formula for A(x,y,0) inside the magnetic cylinder. (Note 1: Since the bar magnet is infinitely long, the field is concentrated inside the magnet, and the B-field outside the magnet, in the z=0 plane is negligible. Note 2: Please note, surprisingly, that A 0 even in regions of space where B=0.) 2. Do problem 7.6 on page 346 in Ulaby 6
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Unformatted text preview: th edition. 3. Do problem 9.2 in Ulaby 6 th edition on page 450. 4. Do problem 7.32 on page 348 in Ulaby 6 th edition. 5. Actually the official government specifications for safe exposure to microwaves is expressed per unit volume, cm 3 , and not per unit area, cm 2 . For example, in some jurisdictions the requirement is that human tissue should absorb <10mWatt/cm 3 of radio energy. Repeat problem 4 with this new understanding, on a flat surface of the torso, at ~900MHz, which is the lower cellphone band. You will need the dielectric properties of human tissue. Assume that human tissue has the same dielectric properties as sea water, which is given in Appendix B on page 477 of the book. (The actual specific absorption rate {SAR} limit in the USA is set by the FCC: <1.6Watt/kilogram~1.6mWatt/cm 3 . The European standard is <2Watt/kilogram)...
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This document was uploaded on 03/01/2011.

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