Can photonic bandgap completely shift to higher wavelength

I have two questions. Number one is i am performing experiment with hexagonal lattice and when i produce defect by removing the central hexagon in structure bandgap shifts completely to higher wavelengths.*I could not find the theoretical explanation.*I am looking for some paper reference or if you can explain theory behind this.

Secondly my structure has complex permittivity and i am using mpb to find photonic band structures. Can i relate the simulations with real permittivity to the one with complex permittivity. How much is the change with complex permittivity. Will the mid band gap frequency also shift or just the band gap will be squeezed. Thanks

Can photonic bandgap completely shift to higher wavelength by producing big defect in PC structure? -

You're right, that shouldn't happen. How large is your lattice?