An x-ray phase contrast imaging apparatus for examining an object of interest, the apparatus comprising: an x-ray source for generating a beam of x-ray radiation; a detector for detecting the x-ray radiation after it has passed the object of interest; and a phase grating module (104, 105) comprising: a first phase grating positioned between an x-ray source of the imaging apparatus and a detector of the imaging apparatus, wherein the first phase grating has a first pitch (p 1); a second phase grating positioned between the x-ray source and the detector, wherein the second phase grating has a second pitch (p 2) different from the first pitch; wherein the first pitch corresponds to a first x-ray energy (E 1) of the x-ray source and the second pitch corresponds to a second x-ray energy (E 2) of the x-ray source, the first energy and the second energy being mutually different; wherein the first phase grating has a Talbot distance (d T) for the first energy (E 1) and wherein the second phase grating has the same Talbot distance (d T) for the second energy (E 2), the first and second phase gratings being arranged such that Talbot images for the first phase grating and the second phase grating are superimposed at the same location. an x-ray source for generating a beam of x-ray radiation; a detector for detecting the x-ray radiation after it has passed the object of interest; and a phase grating module (104, 105) comprising: a first phase grating positioned between an x-ray source of the imaging apparatus and a detector of the imaging apparatus, wherein the first phase grating has a first pitch (p 1); a second phase grating positioned between the x-ray source and the detector, wherein the second phase grating has a second pitch (p 2) different from the first pitch; wherein the first pitch corresponds to a first x-ray energy (E 1) of the x-ray source and the second pitch corresponds to a second x-ray energy (E 2) of the x-ray source, the first energy and the second energy being mutually different; wherein the first phase grating has a Talbot distance (d T) for the first energy (E 1) and wherein the second phase grating has the same Talbot distance (d T) for the second energy (E 2), the first and second phase gratings being arranged such that Talbot images for the first phase grating and the second phase grating are superimposed at the same location. a first phase grating positioned between an x-ray source of the imaging apparatus and a detector of the imaging apparatus, wherein the first phase grating has a first pitch (p 1); a second phase grating positioned between the x-ray source and the detector, wherein the second phase grating has a second pitch (p 2) different from the first pitch; wherein the first pitch corresponds to a first x-ray energy (E 1) of the x-ray source and the second pitch corresponds to a second x-ray energy (E 2) of the x-ray source, the first energy and the second energy being mutually different; wherein the first phase grating has a Talbot distance (d T) for the first energy (E 1) and wherein the second phase grating has the same Talbot distance (d T) for the second energy (E 2), the first and second phase gratings being arranged such that Talbot images for the first phase grating and the second phase grating are superimposed at the same location.