Passive radio frequency identification (RFID) is an emerging technology allowing the automatic identification of passive devices, called tags, when interrogated by RFID readers. Because of its reasonable cost and its ease of use, RFID is being adopted more and more in many contexts, including robotics, where it is used as supplementary support for the navigation and localization of robots. Indeed, when an RFID reader placed on the robot reads a tag marking a certain map point, specific algorithms can be used to estimate tag and/or robot position. Nevertheless, in most literature, commercial RFID devices, not specifically thought of for robotic applications, are adopted, with consequent strong impact on overall system performance and robustness. In this paper, customized RFID reader antennas and platform-robust tags are designed and realized according to several requirements specifically individuated for the addressed application. Moreover, the new hardware is tested in two practical cases related to tag and robot indoor localization, respectively. In spite of the use of rough-and-ready algorithms, the obtained results are impressive and demonstrate the goodness of the proposed solution.