We propose a photonic beamforming network scheme based on a broadband optical source and chirped fiber grating. The principle and feasibility are proved by both theoretical analysis and experiments. In 1- to 18-GHz microwave band, experimental results show a good delay time consistency and the ratio of signal-to-noise met the practical application demands. The time consistency errors are smaller than 1 ps in 9.25- to 10.25-GHz band. Especially, the effects of group delay ripple are effectively mitigated compared with the tunable laser source scheme, which agree well with the theoretical results.