A microstrip antenna includes at least one dielectric material forming a dielectric layer structure having a first main side, at least one antenna structure formed on the first main side; and a ground plane. The dielectric layer structure is positioned between said antenna structure and the ground plane (19, 43). Each of said at least one antenna structure comprises a microstrip conductor that in turn comprises a slot structure. For each of said at least one antenna structure, the microstrip conductor and the slot structure mainly extend in the direction of a longitudinal extension.