A real-time imaging system for terahertz (THz) radiation is presented. The key component of the system is the focal plane array (FPA). Which is a bi-material micro-electro mechanical systems (MEMS) detector array optimized for infrared wave lengths. In order to get a better THz image, the paper presents a modified FPA for THz region. Two main methods are explored to improve the detector performance in the THz region. The first way identified is the use of novel optical readout system based on surface plasma resonator (SPR). The second detector improvement approach involving the change of the micro-cantilever structure that the cantilever of each pixel can shift in vertical direction. A model of one pixel is set up to optimize the structure. Computer simulation results show that both approaches are effective. The manufacturing of the proposed detector are also discussed. The technological investigation shows that it is feasible to employ sacrificial layer technique related to MEMS technology.