diff --git a/src/antenna/model/uniform-planar-array.cc b/src/antenna/model/uniform-planar-array.cc
index eec7b33c8..5debed34a 100644
--- a/src/antenna/model/uniform-planar-array.cc
+++ b/src/antenna/model/uniform-planar-array.cc
@@ -359,7 +359,7 @@ UniformPlanarArray::ArrayIndexFromPortIndex(uint16_t portIndex, uint16_t subElem
     auto firstPolPortIdx = portIndex;
     auto polarizationOffset = 0;
     auto arraySize = GetNumHorizontalPorts() * GetNumVerticalPorts();
-    if (firstPolPortIdx > arraySize)
+    if (firstPolPortIdx >= arraySize)
     {
         firstPolPortIdx = portIndex - arraySize;
         polarizationOffset = GetNumColumns() * GetNumRows();