What kind of itterations was done here

[dan_smith]

Hello , in the attached photo there is a an examle in which we want a 20dB coupling with 1dB ripple, so Cmax is -19 and Cmin is -21.
in the marked table in red they do a "trial and error"' itterations

what kind of itterations?, why they pick each time a different C_max?
C max is -19 dB which is 0.112202
C max and Cmin are given to us from the question

Thanks

 

[dan_smith]

ok they pick combinations of C1 and C2 , for what purpose?

in the solution they say
that at minimum point:

theta=pi/2
C_min=-21dB=0.089125
C=C_1*sin(3/2*pi)+(C_2-C_1)sin(pi/2)=-C_1+C_2-C_1=C_2-2*C_1

eq1.
0.089125=C_2-2*C_1

C_max=-19dB=0.1122there are lots of combinations for C_1 and C_2 to match eq1. how do i test a combination to see that it fits?
what is the addional criteria for C1 and C2 to fit?
Thanks