reflection coefficient propagation
G1 = gprop(G2,bl)
reflection coefficient
phase length in radians = beta*l = 2*pi*l/lambda. For a lossy line bl can also be complex, i.e., bl-j*al
gprop(G2,bl) can be used to find reflection coeffiecients along a transmission line
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generator.....Gamma1....l....Gamma2......load
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add sample pgm