Shape memory polymers (SMPs) are smart materials with shape memory effect that can be used in various industries. Recently, deployable structures are widely used for space structures. Using SMP as a material for deployable structures can have the benefit of high reliability, low weight, and cost-effective compared to usual deployable structures. In this study, a self-thickness-growing sandwich panel with multiple wavy core strips crisscrossing each other in orthogonal directions is proposed to have isotropic bending stiffness in orthogonal directions. SMP is used as the upper and lower layers of the structure. The core is made of a polyethylene naphthalate (PEN) sheet and is attached to the SMP sheet with double-sided tapes. The panel can be compressed to a thin layer at high temperature and can keep the shape after cooling down. After being heat up again, the structure can return to its original thickness with high bending stiffness. Through multiple times of deployment experiments, it is shown that the structure is functional and is possible to be used for application after further development for specific purposes. Bending test shows that the panel has reasonable bending stiffness while they have an individual difference in the bending stiffness because all of them are handmade.