Abdullah Eroglu

RF/Microwave Engineering and Applications in Energy Systems


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it can be seen that the time derivative of a harmonic function means multiplying the same function by jω in the frequency domain. This can be shown as

      (1.121a)StartFraction partial-differential upper F left-parenthesis r overbar comma t right-parenthesis Over partial-differential t EndFraction left-right-arrow normal j omega upper F left-parenthesis r overbar right-parenthesis for scalars

      (1.121b)StartFraction partial-differential ModifyingAbove upper F With bar left-parenthesis r overbar comma t right-parenthesis Over partial-differential t EndFraction left-right-arrow normal j omega ModifyingAbove upper F With bar left-parenthesis r overbar right-parenthesis for vectors

      Example 1.6 Maxwell's Equations

      Derive the phasor representation of Maxwell's equations in free space with no source.

      Solution

      We begin with the equation given in (1.88) as

nabla times Re left-brace ModifyingAbove upper E With bar left-parenthesis r overbar right-parenthesis e Superscript italic j omega t Baseline right-brace equals minus Re left-brace normal j omega ModifyingAbove upper B With bar left-parenthesis r overbar right-parenthesis e Superscript italic j omega t Baseline right-brace

      or

nabla times upper E overbar plus normal j omega upper B overbar equals 0

      or

      (1.124)nabla times upper E overbar equals minus normal j omega upper B overbar

      (1.125)StartLayout 1st Row nabla times upper E overbar equals minus normal j omega upper B overbar 2nd Row nabla times upper H overbar equals upper J overbar plus normal j omega upper D overbar 3rd Row nabla dot upper D overbar equals rho Subscript v Baseline 4th Row nabla dot upper B overbar equals 0 EndLayout

      1 Zahn, M. (1987). Electromagnetic Field Theory: A Problem Solving Approach. Krieger Pub Co.

      2 Eroglu, A. (2010). Wave Propagation and Radiation in Gyrotropic and Anisotropic Media. Springer.

      Problem 1.1

      If K(1,2,0), L(2,5,0), and M(0,4,7) are given, calculate

      1 KL × KM

      2 the angle between KL and KM

      Problem 1.2

      Find vector AB in the Cartesian coordinate system if points A(2m,π,0) and B(2m,3π/2,0) are given in a cylindrical coordinate system.

      Problem 1.3

      If bold upper A bold equals minus 2 ModifyingAbove a With ampersand c period circ semicolon Subscript x Baseline plus 2 ModifyingAbove a With ampersand c period circ semicolon Subscript y Baseline plus 2 ModifyingAbove a With ampersand c period circ semicolon Subscript z and bold upper B bold equals minus ModifyingAbove a With ampersand c period circ semicolon Subscript x Baseline plus ModifyingAbove a With ampersand c period circ semicolon Subscript y, then find unit vector nor mal to these two vectors.

      Problem 1.4

      If a plane is defined by 3x + 4y + 5z = 10, find the unit vector normal to this plane.

      Problem 1.5

      If two arbitrary vectors are given as bold upper K bold equals ModifyingAbove a With ampersand c period circ semicolon Subscript x Baseline plus 4 ModifyingAbove a With ampersand c period circ semicolon Subscript y Baseline plus 3 ModifyingAbove a With ampersand c period circ semicolon Subscript z and bold upper L equals 4 ModifyingAbove a With ampersand c period circ semicolon Subscript x Baseline plus 2 ModifyingAbove a With ampersand c period circ semicolon Subscript y Baseline minus 4 ModifyingAbove a With ampersand c period circ semicolon Subscript z, how can you prove they are perpendicular?

      Problem 1.6

      Calculate the gradients of the following functions.

      1 f = x3y2z

      2  (cylindrical coordinate)

      3 

      Problem 1.7

      Calculate the divergence of the following vectors

      1 

      2 Figure 1.20 Geometry for Problem 1.9.Figure 1.21 Geometry for Problem 1.10.

      3 

      Problem 1.8

      Find the curl of the following vectors (a) K = 3xy2z−1 ModifyingAbove a With ampersand c period circ semicolon Subscript x (b) L