HSMP PIN diode model

hello
i want to design a multiplier with PIN diode
I read application note 1054 of Agilent technology .
now I can not find good model for HSMP PIN diode in ADS or MWoffice
and I can not understand how find input impedance of pin diode?
any one can help me?
thanks

Well, it is a voltage varying capacitance, with some conversion efficiency. So in general the shunt mounted diode is going to look like a resistor in parallel with a capacitor.

If you model the C(v) curve properly, a non linear analysis program will give you the diode impedance. The impedance is definately a "large signal" one, as it will change with input and output match at every harmonic.

A good starting point is to look at the capacitance at breakdown voltage, Cbr, for the diode and assume the capacitancive part of the impdance is 2xCbr. The resistive part is typically in the 5 to 15 ohm region, but like I said, it varies with load and bias.

Rich