Photonic crystal membrane microcavities lend themselves to applications like novel highly efficient emitters of incoherent light and sensing devices, and support fundamental investigations on material properties. On the one hand these applications demand a high quality factor at a tailored resonance frequency of the cavity. On the other hand it is important to provide an efficient coupling of the emission to an optical system or waveguide. Based on these requirements photonic crystal microcavities are designed and optimized with a novel 3D Finite Element (FE) Maxwell solver which is capable of solving eigenproblems as well as source problems. The solver features the computation of the farfield to support the investigation of the spatial emission pattern and is applicable to arbitrary 3-dimensional microcavities. Different photonic crystal configurations have been investigated with respect to their coupling efficiency and optimization strategies are proposed.© (2007) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.