Two-dimensional Kagome structure, fundamental hexagonal photonic crystal configuration

The photonic bandgap properties of the two-dimensional hexagonal Kagome str ucture have been investigated. Large TM bandgaps are found in a GaAs rod in an air configuration example.New compact and simple formulas for the desig n of digital differentiators based on the least squares method are proposed . The new expressions allow a very fast and precise computation of the filt er coefficients. Furthermore, using the proposed analytical solution, the n eed to solve the system of linear equations for the case of fullband differ entiators is avoided.