A portable heater that includes a ceramic substrate with a heating element configured to define a field of direct radiation, a heat reflector with a concave reflective surface configured to define a field of reflective radiation, a grill cover mounted on the heat reflector, where the ceramic substrate is mounted on an interior side of the grill cover with the heating element facing the concave reflective surface such that the field of direct radiation onto the concave reflective surface is unobstructed.