diff --git a/tidy3d/components/simulation.py b/tidy3d/components/simulation.py
index 4b3b1e82f0..4d668735aa 100644
--- a/tidy3d/components/simulation.py
+++ b/tidy3d/components/simulation.py
@@ -2692,6 +2692,15 @@ def _projection_monitors_homogeneous(cls, val, values):
         if val is None:
             return val
 
+        sim_size = values.get("size")
+
+        # Validation if is 2D simulation and find the index of 0
+        is_2d = False
+        zero_dim_index = None
+        if sim_size.count(0.0) == 1:
+            is_2d = True
+            zero_dim_index = sim_size.index(0.0)
+
         # list of structures including background as a Box()
         structure_bg = Structure(
             geometry=Box(
@@ -2707,7 +2716,13 @@ def _projection_monitors_homogeneous(cls, val, values):
         with log as consolidated_logger:
             for monitor_ind, monitor in enumerate(val):
                 if isinstance(monitor, (AbstractFieldProjectionMonitor, DiffractionMonitor)):
-                    mediums = Scene.intersecting_media(monitor, total_structures)
+                    if is_2d and zero_dim_index is not None:
+                        modified_size = list(monitor.size)
+                        modified_size[zero_dim_index] = inf
+                        modified_monitor = monitor.updated_copy(size=modified_size)
+                        mediums = Scene.intersecting_media(modified_monitor, total_structures)
+                    else:
+                        mediums = Scene.intersecting_media(monitor, total_structures)
                     # make sure there is no more than one medium in the returned list
                     if len(mediums) > 1:
                         raise SetupError(