APPLICATION OF 1-D FDTD

ASHISH S. PATILME MICROWAVE ROLL NO.14MV009

APPLICATION OF FDTD

Reflection at an Interface

Determination of Propagation Constant

Design of Material Absorber

Exponential Time-Stepping Algorithm in the Lossy Region

Extraction of Frequency Domain Information from the Time Domain Data

Simulation of Lossy , Dispersive Materials

Reflection at an Interface

Electromagnetic device is the reflections suffered by the incident wave.

Important locate these reflections to improve the device design.

Determine the reflection coefficient at the interface of two media ?

STEP 1: Consider the discretized medium :- first few layers in the free space (εr = 1) and the rest in a medium characterized by ε0 , εr and μ0 STEP 2: Let TEM wave incident on interface with electric field tangential to it

STEP 3: Reflection coefficient due to impedance mismatch

STEP 4 :The transmission coefficient is given as

1 D FDTD equation modified to include the effect of dielectric loading

simulation results for n = 400

centered at about 160∆x

Simulation results for n = 700

Reflected pulse centered 190 ∆ x

Transmitted pulse peaking near 275 ∆ x.

Determination of Propagation Constant

1 D FDTD equation modified to include the effect of conductor loss to calculate attenuation constant along with phase constant

The amplitude of the standing wave depends on the phase relationship between the two waves and therefore on n.

To calculate attenuation constant

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