In this paper, we propose a Photonic Crystal (PhC) resonator based corner reflector for sensing the Angle-of-Arrival (AoA) of the incident wave from an interrogator. The sensor is constructed of joining a flat metal plate with a one-dimensional PhC resonator at an angle of 90°. The PhC resonator is designed by inserting a defect layer between two quarter-wave Bragg mirrors in order to create a deep notch in the backscattering. While the PhC resonator provides unique spectral signatures in the ‘’specular direction” related to AoA (i.e. by shifting the notch position), the corner configuration allows the back-scattering of these signatures to the direction of the interrogator. As a proof of concept, EM simulation and measurement are performed in W-band on a 40-mm squared PhC resonator perpendicularly joined with a same size metal plate. Based on signatures, a resolution of less than 6° can be achieved in the angular range -35° to 35°. Due to the corner configuration that allows a high Radar Cross Section (RCS), the proposed sensor shows the potential of sensing the AoA at long reading ranges.