## Search found 20 matches

Tue 18 Dec 2018, 14:33
Forum: Usage
Topic: NF2FF Phase
Replies: 3
Views: 4481

### NF2FF Phase

Dear openEMS-users, if I do a RCS calculation in the fashion of the sphere-RCS example, how can I determine the correct complex Phase of the RCS? Is it done by specifying the radius R? If I don't specify anything the default should be R=1 m. Do I get the complex RCS at distance R from the phase-cent...
Fri 29 Jun 2018, 14:41
Forum: Usage
Topic: RCS calculation for multiple frequencies
Replies: 5
Views: 6456

### Re: RCS calculation for multiple frequencies

Hi Thorsten,
at an peak amplitude of 1 V/m for the electric field vector of my pulse, I get an amplitude
of 1e-3 outside the plane-wave-box. Is this okay, or too high?
Mon 25 Jun 2018, 09:12
Forum: Usage
Topic: RCS calculation for multiple frequencies
Replies: 5
Views: 6456

### Re: RCS calculation for multiple frequencies

Oh, I wasn't aware of this "half-cell" shift for the PMC condition, but it's of course plausible due to the shift of E/H (u/i) fields. 1. How should one deal with PMC-conditions? Say I have a PEC boundary at x = 0 and a PMC boundary at y = 0 and mesh.x = [0, 1, 2, 3, ...] mesh.y = [0, 1, 2, 3, ...] ...
Tue 19 Jun 2018, 09:00
Forum: Usage
Topic: RCS calculation for multiple frequencies
Replies: 5
Views: 6456

### RCS calculation for multiple frequencies

Hi everybody, I am trying to obtain the monostatic RCS of a perfectly conducting sphere as a function of frequency. My sphere has a radius R of 25 mm and the frequency range I am interested in leads to products of wavenumber times radius of kR > 10. Unfortunately the numerical errors at kR > 5 are a...
Sun 07 Jan 2018, 21:43
Forum: Usage
Topic: Warning: Unused primitive
Replies: 4
Views: 5502

### Re: Warning: Unused primitive

Your mesh lines should include the edges of all your box primitives - as you probably already found out.
Rounding the edge lengths of your box to a certain number of digits is certainly a good idea.
Wed 27 Sep 2017, 15:44
Forum: Development
Topic: Periodic Boundary Conditions (PBC)
Replies: 11
Views: 19031

### Re: Periodic Boundary Conditions (PBC)

Hi Thorsten, my idea is to set up the voltages and currents as usual and to "hide" the imaginary parts of "volt_im" and "curr_im" in my "engine_ext_pbc" like you suggested. The imaginary parts are initialized to 0 but once the main engine comes to the points on the grid which touch a periodic bounda...
Thu 21 Sep 2017, 15:08
Forum: Development
Topic: Periodic Boundary Conditions (PBC)
Replies: 11
Views: 19031

### Re: Periodic Boundary Conditions (PBC)

Maybe you can elaborate again why you need complex numbers in time domain?? the problem is that wheres for L-periodic structures in x-direction we would encounter a phase shift of the fields in frequency domain: u(x=0) = u(x=L) * exp(I * kx * L), for the pulses used in FDTD we would have a time shi...
Wed 20 Sep 2017, 13:02
Forum: Development
Topic: Periodic Boundary Conditions (PBC)
Replies: 11
Views: 19031

### Re: Periodic Boundary Conditions (PBC)

Do you already have an idea how to express this PBC in terms of the EC (equivalent circuit) formulation as used by openEMS? If we have periodicity in x-direction and we one have complex quantities I would just set the voltages as voltage[0/1/2][0][0][0] = voltage[0/1/2][numX][0][0] * exp(I*kx*L) an...
Tue 01 Aug 2017, 13:22
Forum: Development
Topic: Periodic Boundary Conditions (PBC)
Replies: 11
Views: 19031

### Re: Periodic Boundary Conditions (PBC)

Meanwhile I did some progress in the understanding of the CTW (constant transverse wavenumber) approach.
I think there is no way to avoid introducing complex currents and voltages. Thorsten, how nasty would you estimate the side effects of doing this?

Best regards
Tue 20 Jun 2017, 08:15
Forum: Development
Topic: Periodic Boundary Conditions (PBC)
Replies: 11
Views: 19031

### Re: Periodic Boundary Conditions (PBC)

Dear Thorsten, I have forked openEMS.git from your github repository and created 4 files in FDTD/extensions: - operator_ext_pbc.cpp - operator_ext_pbc.h - engine_ext_pbc.cpp - engine_ext_pbc.h Furthermore I added the *.cpp files to CMakeLists.txt in directory FDTD/extensions. The *.cpp source files,...