how attain slant polarization 45 in monopole ?

I assume you mean 45 degrees ?

angle the radiator at 45 deg to the vertical

Dave

yeah, what he said.

Was this supposed to be a trick question?

It will work better with a dipole than a monopole, by the way. a ground plane can get in the way

dear biff44
our concern is while tilting the ground plane to 45 degree any distortion will happen to the radiation pattern(azimuth & elevation)