One last hint for test pillboxes: Although it mostly does, sometimes a very small extension, like 1 or 2 mm is needed to make sure the solver converges. Measurements), also there the value at FWHM can be used. In order to compare the results with bench top measurement (bead pull The value at the FWHM of this curve can be used as a starting pointįor the calculation of the impedance integrals. The field extension can be plotted in the post processor 2D and 3D fields results → Evaluate field in arbitraryĬoordinates. If calculated over the whole longitudinal extension of the design. So the value of Rs/Q or shunt impedance will not be accurate Geometry in a way, that fields extend into the pipe region.
While this is true for beam pipes with small radii, larger beam pipes affect the whole cavity The beam pipes should in principle not contribute to the overall impedance of the cavity, so beam pipes can be omitted Relationship of Q value the power loss is scaled accordingly. The values of power loss and total stored energy are scaled such that the total energy is 1 Joule. Then you add a second task which is a sweep task for the variable, and inside the sweep task, put the template based post processing inside of the sweep loop.
Inside “Block” you choose project type “High Frequency” and Solver type “Eigenmode”. In the schematics create a new variable, then add a new task “Block”. First create the cavity in the 3D model, then click on the schematics. The newest version of CST allows parameter sweeping in the schematic section. To achieve this, a post processing rule must be added manually for each This option is called “consider particle velocity”īy fixing the direction of integration path, but changing the transversal offset, one can calculate the longitudinal More suitable for comparison with bench-top measurements. The effect of the transit time factor TTF can be turned off resulting in the so called frozen shunt impedance, which is Like in Superfish, CST uses the following definition for theĬalculation of the shunt impedance and Rs/Q Longitudinal extension or a section can be specified. In the menu the direction and length of integration can be entered, whereas either maximum The characteristic impedance (sometimes called the geometric factor) Rs/Q can be calculated in the post processor form 2D and 3D fields results → 3D Eigenmode Result. One can choose how many modes the solver should calculate, using the meshing scheme. In the post processing step, the PEC is considered as copper for loss calculations. Perfectly electrical conductor PEC, instead of creating a positvie geometry. In the eignemode solver, it is convenient to carve away the geometry from within the background which is made of It should be noted that depending on the symmetry plane, some modes are not possible, so these But in order to use the symmetry axes, one must enter theįull geometry first. In CSR, each symmetry axis reduces the calculation domain in half. First, the following points might be interesting: Use of symmetry axes We have performed simulations on a simple pillbox to verify the simulation results and compare them with analytical and those of Superfish simulation code. CST Studio Suite ® can provide accurate simulations of cavity parameters.