diff --git a/FDTD/operator.cpp b/FDTD/operator.cpp
index e917c22..c506d3b 100644
--- a/FDTD/operator.cpp
+++ b/FDTD/operator.cpp
@@ -84,6 +84,7 @@ void Operator::Init()
 	}
 
 	m_Exc = 0;
+	m_TimeStepFactor = 1;
 }
 
 void Operator::Delete()
@@ -891,6 +892,8 @@ int Operator::CalcECOperator( DebugFlags debugFlags )
 	else
 		CalcTimestep();
 
+	dT*=m_TimeStepFactor;
+
 	m_Exc->Reset(dT);
 
 	InitOperator();
@@ -1484,6 +1487,18 @@ bool Operator::Calc_EC()
 	return true;
 }
 
+void Operator::SetTimestepFactor(double factor)
+{
+	if ((factor<=0) || (factor>1))
+	{
+		cerr << "Operator::SetTimestepFactor: Warning, invalid timestep factor, skipping!" << endl;
+		return;
+	}
+
+	cout << "Operator::SetTimestepFactor: Setting timestep factor to " << factor << endl;
+	m_TimeStepFactor=factor;
+}
+
 double Operator::CalcTimestep()
 {
 	if (m_TimeStepVar==3)
diff --git a/FDTD/operator.h b/FDTD/operator.h
index 30b4ad9..b164027 100644
--- a/FDTD/operator.h
+++ b/FDTD/operator.h
@@ -78,7 +78,9 @@ public:
 
 	//! Set a forced timestep to use by the operator
 	virtual void SetTimestep(double ts) {dT = ts;}
+	virtual void SetTimestepFactor(double factor);
 	bool GetTimestepValid() const {return !m_InvaildTimestep;}
+
 	virtual double GetNumberCells() const;
 
 	virtual unsigned int GetNumberOfNyquistTimesteps() const {return m_Exc->GetNyquistNum();}
@@ -180,6 +182,7 @@ protected:
 
 	//Calc timestep only internal use
 	int m_TimeStepVar;
+	double m_TimeStepFactor;
 	virtual double CalcTimestep();
 	double opt_dT;
 	bool m_InvaildTimestep;
diff --git a/matlab/InitFDTD.m b/matlab/InitFDTD.m
index fd28b3a..a775d31 100644
--- a/matlab/InitFDTD.m
+++ b/matlab/InitFDTD.m
@@ -12,6 +12,8 @@ function FDTD = InitFDTD(NrTS, endCrit, varargin)
 % optional field arguments for usage with openEMS:
 %   OverSampling:   nyquist oversampling of time domain dumps
 %   CoordSystem:    choose coordinate system (0 Cartesian, 1 Cylindrical)
+%   TimeStep:       force to use a given timestep (dangerous!)
+%   TimeStepFactor: reduce the timestep by a given factor (>0 to <=1)
 %
 % examples:
 %   %default init with 1e9 max. timesteps and -50dB end-criteria
diff --git a/openems.cpp b/openems.cpp
index aebb7bc..4112c30 100644
--- a/openems.cpp
+++ b/openems.cpp
@@ -652,6 +652,9 @@ int openEMS::SetupFDTD(const char* file)
 	FDTD_Opts->QueryDoubleAttribute("TimeStep",&timestep);
 	if (timestep)
 		FDTD_Op->SetTimestep(timestep);
+	double timestepfactor=0;
+	if (FDTD_Opts->QueryDoubleAttribute("TimeStepFactor",&timestepfactor)==TIXML_SUCCESS)
+		FDTD_Op->SetTimestepFactor(timestepfactor);
 
 	if (m_CSX->GetQtyPropertyType(CSProperties::LORENTZMATERIAL)>0)
 		FDTD_Op->AddExtension(new Operator_Ext_LorentzMaterial(FDTD_Op));