A special finite-difference time-domain (FD-TD) formulation which allows electromagnetic (EM) wave wideband simulations of oblique incidence for periodic media is used for the design and analysis of an infrared photonic crystal filter with dual stopbands at 3-5 pm and 8-12 pm. The transmission coefficient in the main stopband (8-12 [tim) is below-10 dB. Scattering coefficients are calculated for different inci-First of all, I would like to thank Professor Kong for his teaching and kindness, and Dr. Eric Yang for guiding me through this research. They have given me valuable insights. I would also like to thank Simon, Alex and Bob Atkins from Lincoln Laboratory for their valuable help and discussions and introducing me to this project. I would like to acknowledge the help Andrew Kao gave me to understand his code. Without him, this project would have been very hard. Yan, Henning and Joe helped me so much throughout the project in many aspects, thank you very much. I also want to thank Dr. Ding, Dr. Jerry Akerson, Dr. Sean Shih, Chi, Chris and Peter, for their friendship. Last but not least, I want to thank my parents, my brother and Mimi for their love, patience and support. To my parents, my brother and Mimi