Interest in simultaneously operating MR-PET systems as a means of accessing multiple biological parameters with high spatial and temporal resolution is increasing. In a hybrid acquisition, the RF antenna is used inside the PET FOV generating potential photon loss and artefacts. A multi-channel J-pole antenna array, which does not include any high-density parts in the imaging FOV, has been recently introduced, and its outstanding performance has been demonstrated. To prevent interference between MR and PET, including an RF shield is necessary. Here, we conducted a simulation to compare the characteristics of the J-shape antenna array with and without the shield.