Impedance , of the coupling capacitance, Xc is simply Xc=1/(2πfC) and the voltage loss approaches the load impedance , Zo with the ratio Zo/(Zc+Zo)
Since power is V²/Zo, It is easy to derive the Isolation and insertion loss in dB
With Zo terminated at both ends (2Z0), Insertion loss, IL of the series diode, Rs.... becomes
Insertion =20 log [1+ (Rs/2Zo)] ( Pin bias ON controls Rs )
Isolation = 10 log [ 1+ Xc/(2Zo) ]² ( C controls isolation )
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