Abstract : We have investigated biological inspired RF direction finding techniques with the goal to learn and utilize the amazing acoustic direction finding capabilities of human and achieve compact, high performance and low-cost RF direction finding devices. Our initial simulation and experimental results are very encouraging. Through the 9-month STIR program "Human Ears Inspired Microwave Passive Direction Finding", prototype direction finding systems including antennas, human head like low-pass scatter and digital receiver have been successfully designed and built. Several biological inspired hardware configurations (i.e., head-like scatters of various properties, omni-directional antennas) and preliminary algorithms have been theoretically and experimentally tested. The effectiveness of the novel human head-like scatter has been clearly demonstrated. In addition, we have performed initial investigation of single antenna direction finding for broadband RF signals. The most important goal of the STIR program, which is to develop an experimental test bed so that it can be used in the near future to study and develop novel RF direction finding techniques inspired by the amazing human auditory system, has been achieved.