We present a linear theory to explain the experimentally observed emission angle scanning of an injection‐locked diode laser array when the frequency of the injected light is changed. This theory is based on eigenmode analysis of the coupled waveguides and on the use of the antenna array theory for the far‐field pattern. The experimental results are explained in terms of the resonant excitation of eigenmodes, which selects the far‐field pattern associated with the resonant mode. The agreement with published results is good.