negative resistance circuit design help

[ash1024200]

does anyone know where to find information on the design of active capacitance circuits? it should emulate a capacitor in parallel with a negative resistance, e.g. by using a transistor with feedback.

 

[kspalla]

you may check the link below

 

[LvW]

I am afraid, the above link will not help too much.

Hi ash1024200,

why not using an opamp in NIC (negative impedance converter) configuration?
With this circuitry you can convert each load impedance into its negative equivalent.
It's a basic circuit which can be found in nearly all electronic books and introductory articles.

 

[ash1024200]

thanks, LvW
i forgot to mention that the circuit is meant to operate at a frequency of 1.9GHz. an op amp will not function at this frequency, right?
i have found a circuit that uses a FET, the diagram is attached(the software is awr microwave office).
the relevant intrinsic parameters are: Cgs=1pf, Cgd=0.2pf. i am supposed to bias this circuit at Ids=15ma and Vds=2V. but i don't know how to do that without interfering with the input impedance. do you have any suggestions?