This work presents the concept and development of the tridimensional Yagi antenna, which is a novel type of Yagi antenna operating in P band. It is idealised from two other types of Yagi antennas: Quasi-Yagi and Yagi-Uda. The resultant antenna is based on a microstrip balun, as in the first, and its driver and directors are made from metal tubes, as in the second, both integrated to a reflecting plane. The key point of this new antenna model is its asymmetric and reconfigurable radiation pattern and therefore the possibility of a high rejection between sectors in a plane. This feature was accomplished with the new concept of progressive rotation of directors around the driver. The authors present a design methodology to adjust return loss and radiation pattern characteristics. The final prototype presents 9.4 14 dB gain at 450 14 MHz and 47% bandwidth centred at 425 14 MHz. © 2010 © The Institution of Engineering and Technology.