  We investigate the electromagnetic propagation in two-dimensional photonic
crystals, formed by parallel dielectric cylinders embedded a uniform medium.
The frequency band structure is computed using the standard plane-wave
expansion method, while the propagation and scattering of the electromagnetic
waves are calculated by the multiple scattering theory. It is shown that within
partial bandgaps, the waves tend to bend away from the forbidden directions.
Such a property may render novel applications in manipulating optical flows. In
addition, the relevance with the imaging by flat photonic crystal slabs will
also be discussed.
