An antenna unit for receiving and/or emitting electromagnetic waves having a certain wavelength is described. Said antenna unit is a slotline antenna unit having a slot region. Said antenna unit comprises at least one antenna element and a carrier. Said carrier is made by a dielectric material wherein said carrier has at least one cutout in said slot region. Said antenna element is made by a printed circuit board. Said antenna element and said carrier are attached to each other wherein said carrier has a thickness being less than one fifth of said wavelength. Further, a radio frequency circuit and a method for manufacturing an antenna unit are described.