Question

A wave is normally incident from air into a good conductor having mu = mu_0, epsilon = epsilon _0, and conductivity sigma, where sigma is unknown. The following facts are provided: (1) The standing wave ratio in Region 1 is SWR = 13.4, with minima located 7.14 and 22.14 cm from the interface. (2) The attenuation experienced in Region 2 is 12.2 dB/cm Provide numerical values for the following: a) The frequency f in Hz b) The reflection coefficient magnitude c) the phase constant beta_2. d) the value of sigma in Region 2 e) the complex-valued intrinsic impedance in Region 2 f) the percentage of incident power reflected by the interface, P_ref/P _inc Warning: Since region 2 is a good conductor, the parameters in region 1 are very insensitive to the permittivity of region 2. Therefore, you may get very Strange answers for epsilon_r if you try to determine it as well as sigma (you probably will not get 1.0). You should be able to get the correct sigma.

Answer 1

Explanation: A continuous traveling wave with amplitude A is incident on a boundary. The continuous reflection, with a smaller amplitude B, travels back through the incoming wave. The resulting interference pattern is displayed in Fig. 16-51. The standing wave ratio is defined to be

The reflection coefficient R is the ratio of the power of the reflected wave to the power of the incoming wave and is thus proportional to the ratio . What is the SWR for (a) total reflection and (b) no reflection? (c) For SWR = 1.50, what is expressed as a percentage?

Standing Wave Ratio for total reflection is

Standing Wave Ratio for no reflection is 1

R (reflection coefficient) for Standing Wave Ratio = 1.50 is 4.0%.