Let K = 10^(A_dB / 20) (Voltage ratio) or K_p = 10^(A_dB / 10) (Power ratio)

Pi Network (Zin = Zout = Z0):

R_shunt = Z0 * (K+1)/(K-1) ; R_series = Z0 * (K^2-1)/(2K)

Tee Network (Zin = Zout = Z0):

R_series = Z0 * (K-1)/(K+1) ; R_shunt = Z0 * (2K)/(K^2-1)

Bridged-T (Zin = Zout = Z0):

R1 = R2 = Z0 (series) ; R_bridge = Z0*(K-1) ; R_shunt = Z0/(K-1)

L-Pad (Minimum Loss Match):

If Z1 > Z2: R_series = sqrt(Z1*(Z1-Z2)), R_shunt = sqrt((Z1*Z2^2)/(Z1-Z2))