A wide bandwidth circuit board arrangement includes two coplanar substrates separated by a predetermined gap, and at least one bond wire arranged across the gap and interconnecting a respective conducting microstrip line on a first side of each respective substrate. Further, the arrangement includes at least one open stub arrangement configured on the first side of each respective substrate, each open stub arrangement comprising a microstrip extending at an angle from an end of each conducting strip on each respective substrate. Finally, the arrangement includes a ground layer on a second side of each respective substrate, and a defected ground structure arranged on the second side of each respective substrate and laterally overlapping each respective open stub arrangement arranged on the first side.