This paper proposes a novel propagation based spectrum sensing method that utilizes beamforming for systems equipped with antenna arrays. Since rays are known to arrive in clusters, the arrival angles of the dominant ray clusters can be exploited to improve the spectral sensing performances. Moreover, from site-specific propagation characteristics, the dominant ray angles can be predicted without additional computational efforts in most practical environments. Numerical results based on ray-based channel models show that the proposed beamforming detection method (with or without dominant ray angle prediction) is superior to the conventional energy detection method. Numerical results also show that decreasing the angle spread, enhances the performance of the proposed method. The computational complexity and latency of the proposed method is the same as the conventional energy detection method when using dominant ray angle prediction, but increases slightly without prediction.