fix bug in TerminalComponentModeler.get_antenna_metrics_data

Author: dmarek-flex

CHANGELOG.md

@@ -29,6 +29,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Removed sources from `sim_inf_structure` simulation object in `postprocess_adj` to avoid source and background medium validation errors.
 - Revert overly restrictive validation of `freqs` in the `ComponentModeler` and `TerminalComponentModeler`.
 - Fixed `ElectromagneticFieldData.to_zbf()` to support single frequency monitors and apply the correct flattening order.
+- Bug in `TerminalComponentModeler.get_antenna_metrics_data` when port amplitudes are set to zero.
 
 ## [2.9.0] - 2025-08-04
 

tests/test_plugins/smatrix/test_terminal_component_modeler.py

@@ -1141,6 +1141,15 @@ def test_get_combined_antenna_parameters_data(monkeypatch, tmp_path):
         antenna_params.radiation_efficiency, single_port_params.radiation_efficiency
     )
 
+    # Define port amplitudes
+    port_amplitudes = {modeler.ports[0].name: 1.0, modeler.ports[1].name: 0.0}
+    port2_zero_params = modeler.get_antenna_metrics_data(port_amplitudes)
+    # Should give idential results to only exciting one port
+    assert np.allclose(port2_zero_params.gain, single_port_params.gain)
+    assert np.allclose(
+        port2_zero_params.radiation_efficiency, single_port_params.radiation_efficiency
+    )
+
 
 def test_run_only_and_element_mappings(monkeypatch, tmp_path):
     """Checks the terminal component modeler works when running with a subset of excitations."""

tidy3d/plugins/smatrix/component_modelers/terminal.py

@@ -808,9 +808,10 @@ def get_antenna_metrics_data(
         Parameters
         ----------
         port_amplitudes : dict[str, complex] = None
-            Dictionary mapping port names to their desired excitation amplitudes. For each port,
+            Dictionary mapping port names to their desired excitation amplitudes, ``a``. For each port,
             :math:`\\frac{1}{2}|a|^2` represents the incident power from that port into the system.
-            If None, uses only the first port without any scaling of the raw simulation data.
+            If ``None``, uses only the first port without any scaling of the raw simulation data.
+            When ``None`` is passed as a port amplitude, the raw simulation data is used for that port.
             Note that in this method ``a`` represents the incident wave amplitude
             using the power wave definition in [2].
         monitor_name : str = None
@@ -849,6 +850,8 @@ def get_antenna_metrics_data(
         # Retrieve associated simulation data
         combined_directivity_data = None
         for port, amplitude in port_dict.items():
+            if amplitude == 0.0:
+                continue
             sim_data_port = self.batch_data[self._task_name(port=port)]
             radiation_data = sim_data_port[rad_mon.name]