A modified RF nMOS model is presented for high-frequency circuit design. The high-frequency nMOS model is based on a SPICE level 3 model, by adding parasitic passive components to describe the microwave behavior. This hybrid RF model can well predict the MOSFET behavior up to 10 GHz under various biasing conditions. A spiral inductor model is also presented. The inductance at 2.4 GHz is 2.4 nH, with a quality factor of 4. Based on these models, we designed a 180/spl deg/ active-balanced circuit. The 180/spl deg/ balanced circuits consist of a MOSFET (0.6 /spl mu/m gate length and 200 /spl mu/m gate width), and input/output matching networks. The unbalanced phase was about 180/spl deg/ in the 1-2.5 GHz frequency band, and the insertion loss was about 6 dB. The magnitude difference between two output ports is less than 0.7 dB.
[1]
N. Camilleri,et al.
Extracting small-signal model parameters of silicon MOSFET transistors
,
1994,
1994 IEEE MTT-S International Microwave Symposium Digest (Cat. No.94CH3389-4).
[2]
R. Anholt,et al.
Equivalent-circuit parameter extraction for cold GaAs MESFET's
,
1991
.
[3]
G. Dambrine,et al.
A new method for determining the FET small-signal equivalent circuit
,
1988
.
[4]
R. Groves,et al.
Temperature dependence of Q in spiral inductors fabricated in a silicon-germanium/BiCMOS technology
,
1996,
Proceedings of the 1996 BIPOLAR/BiCMOS Circuits and Technology Meeting.