A base station antenna , comprising: a panel that includes a ground plane ; at least a first array that includes a first plurality of linearly arranged radiating elements (122-1 to 122-11) and a second array that includes a second plurality of linearly arranged radiating elements (142-1 to 142-11) mounted on the panel , wherein the first plurality of linearly arranged radiating elements (122-1 to 122-11) of the first array are spaced apart from the second plurality of linearly arranged radiating elements (142-1 to 142-11) of the second array in a direction perpendicular to a longitudinal axis of the panel ; and a decoupling unit positioned between a first radiating element (122-4) of the first array and a first radiating element (142-4) of the second array , wherein the decoupling unit is spaced apart from the first radiating element (122-4) of the first array and from the first radiating element (142-4) of the second array , and wherein the decoupling unit is configured to reduce cross coupling between the first radiating element (122-4) of the first array and the first radiating element (142-4) of the second array , wherein the decoupling unit includes at least a first sidewall that faces the first radiating element (122-4) of the first array , a second sidewall that faces the first radiating element (142-4) of the second array , a top plate that connects an upper edge of the first sidewall to an upper edge of the second sidewall , and an internal cavity that is defined in a region between the first and second sidewalls , the top plate and the ground plane which extends between lower sides of the first sidewall and the second sidewall , and wherein the first and second sidewalls are each electrically conductive and are electrically connected to the ground plane . a panel that includes a ground plane ; at least a first array that includes a first plurality of linearly arranged radiating elements (122-1 to 122-11) and a second array that includes a second plurality of linearly arranged radiating elements (142-1 to 142-11) mounted on the panel , wherein the first plurality of linearly arranged radiating elements (122-1 to 122-11) of the first array are spaced apart from the second plurality of linearly arranged radiating elements (142-1 to 142-11) of the second array in a direction perpendicular to a longitudinal axis of the panel ; and a decoupling unit positioned between a first radiating element (122-4) of the first array and a first radiating element (142-4) of the second array , wherein the decoupling unit is spaced apart from the first radiating element (122-4) of the first array and from the first radiating element (142-4) of the second array , and wherein the decoupling unit is configured to reduce cross coupling between the first radiating element (122-4) of the first array and the first radiating element (142-4) of the second array , wherein the decoupling unit includes at least a first sidewall that faces the first radiating element (122-4) of the first array , a second sidewall that faces the first radiating element (142-4) of the second array , a top plate that connects an upper edge of the first sidewall to an upper edge of the second sidewall , and an internal cavity that is defined in a region between the first and second sidewalls , the top plate and the ground plane which extends between lower sides of the first sidewall and the second sidewall , and wherein the first and second sidewalls are each electrically conductive and are electrically connected to the ground plane . <EOS>