As electronic circuits get progressingly smaller to the nanometre scale, th
e quantum wave nature of the electrons starts to play a dominant role. It i
s thus possible for the devices to operate by controlling the phase of the
quantum electron waves rather than the electron density as in present-day d
evices. This paper presents a highly accurate numerical method to treat qua
ntum waveguides with arbitrarily complex geometry. Based on this model, a v
ariety of quantum erects can be studied and quantified.