Electrostatic properties of density gradient drift waves (the universal mode) in a sheared magnetic field are studied using a two‐and‐one‐half dimensional (2 1/2 ‐D) particle code. For the case of a single rational surface, the drift waves are found to be stable with an eigenmode structure that matches the linear theoretical prediction as long as the ion resonance layer is well within the system. This applies to both even and odd parity modes with respect to the rational surface. The dependence on various parameters such as the shear length is examined.