An antenna device comprising: a substrate including a conductive groundplane, the conductive groundplane having an edge; at least first and second antennas (4,5) formed on a groundplane-free end area of the substrate and connected to the edge of the conductive groundplane; at least one notch formed as a cut-out in the edge of the conductive ground plane between the first and second antennas (4,5), the notch extending by a predetermined width (w) along the ground plane edge and a predetermined depth (d) into the groundplane and having a mouth portion at the edge of the conductive groundplane; a first electrical pathway (11, 13) connecting opposite side edges of the notch across the mouth of the notch, the first electrical pathway (11, 13) being formed by a conductive track having an inductance and at least one capacitor, wherein the conductive track and the at least one capacitor are connected in series across the mouth of the notch forming a parallel circuit configuration with an inductive path defined along the edge of the notch, and the first electrical pathway (11, 13) being configured to tune the notch to improve isolation between the first and second antenna (4,5) at a first frequency of operation; and a second electrical pathway disposed across the notch at a predetermined distance from the first electrical pathway (11, 13) and connecting the opposite side edges of the notch, the second pathway comprising a resonant series circuit (21, 22) resonant at a second frequency of operation higher than the first frequency and is configured to improve isolation between the first and second antennas (4,5) at said second frequency. a substrate including a conductive groundplane, the conductive groundplane having an edge; at least first and second antennas (4,5) formed on a groundplane-free end area of the substrate and connected to the edge of the conductive groundplane; at least one notch formed as a cut-out in the edge of the conductive ground plane between the first and second antennas (4,5), the notch extending by a predetermined width (w) along the ground plane edge and a predetermined depth (d) into the groundplane and having a mouth portion at the edge of the conductive groundplane; a first electrical pathway (11, 13) connecting opposite side edges of the notch across the mouth of the notch, the first electrical pathway (11, 13) being formed by a conductive track having an inductance and at least one capacitor, wherein the conductive track and the at least one capacitor are connected in series across the mouth of the notch forming a parallel circuit configuration with an inductive path defined along the edge of the notch, and the first electrical pathway (11, 13) being configured to tune the notch to improve isolation between the first and second antenna (4,5) at a first frequency of operation; and a second electrical pathway disposed across the notch at a predetermined distance from the first electrical pathway (11, 13) and connecting the opposite side edges of the notch, the second pathway comprising a resonant series circuit (21, 22) resonant at a second frequency of operation higher than the first frequency and is configured to improve isolation between the first and second antennas (4,5) at said second frequency.