[17] quantum metamaterials, [18][19][20] and so on. [21][22][23][24][25][26][27] Recently, the concept of "computational metamaterials" has been proposed. [28][29][30][31][32][33] Mathematical operations, such as spatial differentiation, integration, and convolution, can be performed by using designed metamaterial blocks. The dimension at wavelength scale of such kind of computing machines offers the possibility of miniaturized fullwave computing systems that are several orders of magnitude thinner than conventional bulky lens-based optical processors.On the other hand, quantum computation has been the focus of numerous studies and is expected to play an important role in future information processing since it outperforms classical computation at many tasks. [34] The excitement over quantum computation is based on just a few algorithms, the best known being Shor's factorization algorithm [35] and Grover's search algorithm. [36] The latter is extremely important, both from a fundamental standpoint, as it is usually more efficient than the best classical algorithm, and from a practical standpoint, because fast searching is central to solving difficult problems. Up to now, Grover's search algorithm has been implemented under many standard circuit models, such as optical experiments, [37,38] NMR systems, [39,40] trapped ion, [41] and so on. The problem is whether Grover's search algorithm can be performed by using designed metamaterials. In this work, we numerically and experimentally demonstrate the implementation of Grover's search algorithm through dielectric metamaterials at microwave frequencies.The general protocol is graphically shown in Figure 1a with different colors being used to distinguish the structural regions that perform different functions. In this metamaterial-based searching protocol, the electric field amplitude of the incident microwave "E(y)" is recognized as the probability amplitude of the equivalent quantum state, spatial positions "y" are used to label the items in the database, and the maximum number of the database is fixed by the full width at half-maximum (FWHM) "D" of the incident intensity profile with near-Gaussian distribution. The designed metamaterial is comprised of four cascaded subblocks: an oracle subblock (red area, U m ), two Fourier transform subblocks (green areas, F), and a phase plate subblock (blue area, U 0 ). The role of the oracle subblock is to mark the targeted item (red arrow) |y = m〉 Metamaterials, artificially structured electromagnetic (EM) materials, have enabled the realization of many unconventional EM properties not found in nature, such as negative refractive index, magnetic response, invisibility cloaking, and so on. Based on these man-made materials with novel EM properties, various devices are designed and realized. However, quantum analog devices based on metamaterials have not been achieved so far. Here, metamaterials are designed and printed to perform quantum search algorithm. The structures, comprising of an array of 2D subwavelength air holes wit...