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![]() The a, b are the propagation constants and of course, 'to' is not the 'angle' of the Reflection Coefficient rho but that of Z0 = Ro +j Xo. It has rather to do with the emotional charge of the moments... Sincerely, pez SV7BAX |
#2
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In articles and ,
"pez" wrote: 1. The well known relation |rho| = 1 + Sqrt[2] has been sharpened to be exactly |rho| = Sqrt[(1+Sin|to|)/(1-Sin|to|)] where 'to' is the 'angle' of rho. 'to' is not the 'angle' of the Reflection Coefficient rho but that of Z0 = Ro +j Xo. It has rather to do with the emotional charge of the moments... Sincerely, pez SV7BAX In article the argument I gave showed that if you look at an ellipse with foci at Z_0 and at - Z_0 then among the points Z_L on any such ellipse that are in the fourth and first quadrants, the one for which the magnitude of the reflection coefficient (non-conjugate definition, of course) is maximized is the one on the imaginary axis near - Z_0 and far from Z_0, i.e. having opposite reactance to that of Z_0. If you then use geometry, or algebra, or even calculus if you feel compelled to use it, to see which such point on the imaginary axis is best (i.e., which of the ellipses of various eccentricities has the best "best" point) you will find that the maximum occurs when the magnitude of Z_L is the same as that of Z_0. In symbols, you will want to have Z_L = +/- j sqrt ((R_0)^2 + (X_0)^2), where Z_0 = R_0 + j X_0 and the sign to be chosen (+/-) is the opposite to that of X_0. When you use this value of Z_L you will indeed get a reflection coefficient magnitude of sqrt [(1 + sin |t_0|)/(1 - sin |t_o|)], thereby confirming your formula |rho| = sqrt [(1 + sin |t_o|)/(1 - sin |t_o|)]. This is a _claim_ that no one else has verified it. Now some one has. Details left for the reader -- you can think of what I wrote above as a "Heathkit proof" ;-)! I used to enjoy giving "Heathkit proofs" for my students to build; as they became more proficient, the construction manuals offered became sketchier and sketchier. Eventually the students got to the point where they could design and build their own rigs (er, proofs) and the days of "Heathkit proofs" were over for them. 2. Also, the well known relation |Xo|/Ro = 1 is sharpened too, to be exactly |Xo|/Ro = min{ a/b, b/a }. This is as well a _claim_ no one else has verified it yet. I'll see if I can sketch a nice demonstration of this second result, preferably one that does *not* involve calculus ;-)! David, ex-W8EZE, retired math professor, and not quite finished with either of these things -- David or Jo Anne Ryeburn To send e-mail, remove the letter "z" from this address. |
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