You should be able to require the lib for the foundry. following is the SMIC 018 process varactor model
.subckt pvar18_ckt 1 2 lr=l wr=w nf=finger
* mos varactor scalable model parameters
Risod 3 0 1E12
Risos 4 0 1E12
MAIN 3 1 4 2 pvar18 L=lr W='wr*nf' AD=0 AS=0 PD=0 PS=0
* MOS Varactor Model
.MODEL pvar18 PMOS
+LEVEL = 49 VERSION = 3.2 TNOM = 25
+CAPMOD = 3 VOFFCV = 0.5 K1 = 0.88
+VTH0 = -1.573 ACDE = 1.596 TOX = 4.105E-9
+TOXM = 4.105E-9 NCH = 1.106E+17 ACM = 12
+CALCACM = 1 BINUNIT = 2 K2 = 0
+KT1 = 0.05
.ends pvar18_ckt