  We present theory to describe an engineering dispersion technique to obtain a
broadband effective index near zero with an asymmetric planar photonic crystal.
The theory provides the manipulating surface plasmon polariton (SPP) to provide
alternating symmetric stacks of negative and positive effective indices. The
odd alternating effective indices, including positive and negative refraction,
arise from transverse resonance that depends on the geometry of the planar
photonic crystal. The purposed technique remains wavepacket in zero phase
dispersion since the created parity-time symmetries keep the phase constant in
propagation direction. We use the plane wave expansion method to calculate band
structure and transmission spectrum then validate with FDTD simulation. The
results are compared to the recent experimental reports and they will be of
significant interest to emerging applications in designing and fabricating
metamaterials, optical filters, photonic sensors, photonic integrated circuits,
near-field optics, and optofluidic biosensing applications.
