Phase retrieval technique using the directly measured intensity distribution to recover phase information and reconstruct the wave function is an important research area of optics and image processing. A new setup for structured illuminations in diffraction imaging is proposed. In the new setup, the object is placed against the mask, and mutual position can be interchanged. Multiple structured illuminations are used to collect several diffraction patterns. In the absence of extra information of the signal, the phase information is obtained. Simulation results show that the new setup is simple, and can achieve the success of phase retrieval. In addition, the Toeplitz mask and circulant mask are used to collect diffraction patterns for phase retrieval. The two masks need to collect fewer diffraction patterns than binary mask does and need to collect diffraction patterns as many as Gaussian mask does. Compared with Gaussian mask, the two masks are easy to realize in physics.