is this Nonlinear device model is spice model?
then you can in AWR MWO as netlist Project->Add netlist->Import netlist->Import file as PSPICE or HSPICE...
If not upload ur file here so that we can help you...
If so, First save this as D2294UK.spu as *. cir note not as *.txt extension
Then to import to Microwave Office go Project->Add netlist->Import netlist->Import file as PSPICE netlist files as (*.CIR))
If no error/warnings then create new circuit schematic & select Add Subcircuit to call the model...