In this paper, a novel microstrip Quasi-Yagi antenna based on Waning Crescent elements, is presented. The proposed antenna employs a microstrip dipole as the radiating element and, optimised waning crescent shaped elements as reflector and directors. The antenna is designed and optimised to operate in the 2.4 GHz ISM band, attending the integration in a multi-sector base station antenna configuration for a Wireless Sensing Network (WSN) for environmental monitoring. In particular, specific project re quirements, such as: resonating frequency, gain, half power beam-width (HPBW) are taken into consideration when di mensioning the antenna. Simulation results ensure a realized gain of 9.4 dBi, a HPBW of 63◦ and a back-to-front ratio of 20.2 dB, at a resonating frequency of 2.45 GHz.