The MESFET model level 1 is derived from the GaAs FET model of Statz et al. as described in [11]. The dc characteristics are defined by the parameters VTO, B, and BETA, which determine the variation of drain current with gate voltage, ALPHA, which determines saturation voltage, and LAMBDA, which determines the output conductance. The formula are given by:

[\begin{array}{ll} {I_{d} = \begin{cases} {\frac{B\left( V_{gs} - V_{T})^{2} \right.}{1 + b\left( {V_{gs} - V_{T}} \right)}\left| {1 - \left| {1 - A\frac{V_{ds}}{3}} \right|^{3}} \right|\left( {1 + LV_{ds}} \right)} & {{for}0 < V_{ds} < \frac{3}{A}} \ {\frac{B\left( V_{gs} - V_{T})^{2} \right.}{1 + b\left( {V_{gs} - V_{T}} \right)}\left( {1 + LV_{ds}} \right)} & {{for}V > \frac{3}{A}} \ \end{cases}} & \ \end{array}]

Two ohmic resistances, rd and rs, are included. Charge storage is modeled by total gate charge as a function of gate-drain and gate-source voltages and is defined by the parameters cgs, cgd, and pb.

Device instance:

z1 2 3 0 mesmod area=1.4

Model:

.model mesmod nmf level=1 rd=46 rs=46 vt0=-1.3 
+ lambda=0.03 alpha=3 beta=1.4e-3