射频 最全的HFSS 仿例模型库60个 最全的HFSS 仿例模型60个 HFSS 计算例子模型 RCS monoRCS

Incident-wave seriesMonostatic Radar Cross SectionThe goal is to plot the monostatic radar cross section (RCS) as a function of angle for a scattering object, as shown in the figure below. The scattering object is a so-called corner reflector: three sheets of metal connected at right angles to each other. A corner reflector is often used as a calibration object in radar experiments. It has the advantage of a large RCS over a wide angular range. In the example project, symmetry has been exploited with respect to the XZ plane.Corner reflector To produce a plot of monostatic RCS through measurements, usually the incident wave is constant and the scattering object is rotated. In the numerical simulation, however, the scattering object is stationary and a collection of incident waves strikes it from many directions. In this case, we want incident waves whose directions of incidence vary from =0 to =360 degrees in the =0 plane. To visualize this, imagine the transmitting and receiving antennas going full circle in the XZ plane around the object, while always being directed towards the scattering object. The polarization is chosen to be in the direction, i.e. in the Y direction in this case. The figure above shows the k and E0 vectors for the =90 degrees case.In HFSS, the collection of incident waves is defined as shown in the figure. By requesting IwaveTheta to go from 0 deg to 360 deg in four-degree steps we obtain the collection of incident waves as described above. We will thus have a simulation with 91 excitations.Incident wave setupDuring adaptive mesh refinement, all 91 field solutions will influence the mesh refinement process.Since there are 91 excitations, the simulation will 91 field solutions to disk, which takes a lot of space. Deleting field solutions, once all far-field plots have been created and exported, can be done through HFSS Results Clean-up Solutions.In order to compute far fields you need to define a far-field setup: HFSS Radiation Insert Far-Field Setup. In most cases, you need this to define for which theta and phi values you want the software to compute far fields. In the case of monostatic radar cross section, however, theta and phi have become redundant variables. You still need a far-field setup, since it contains other necessary information, but you can fill out the panel as shown below. Defining the far-field setupTo produce the plot of monostatic RCS versus angle theta, do the following.1) Under HFSS Results Create Report, select Report Type : Far Fields.Preparing a plot of a far-field quantity2) Under the Sweeps tab, make IwaveTheta the primary sweep and make sure All Values are selected. The angles Theta and Phi are present in the panel but are redundant for monostatic RCS.Making IwaveTheta the primary sweep3) Under the Y tab, ask for Monostatic RCS and click Add Trace.Specifying the desired trace as Monostatic RCS, total, in dB.Upon pressing Done, the plot is created. This may take time, as all 91 field solutions have to be loaded and post processed. The plot is shown below. The vertical scale is in dB relative to one square meter.Monostatic RCS of the small corner reflector at 6 GHzIn this example, the edges of the triangular aperture of the corner reflector have a length of 14 cm while the wavelength is 5 cm. Hence, the corner reflector is not very large in terms of wavelength. Still, we can see that it has a large RCS when the incident wave shines into the aperture, roughly from 40 to 120 degrees. There is another peak when the wave hits perpendicularly from below, near 215 degrees.At higher frequencies, a somewhat flat maximum is expected around 90 degrees. The plot below shows part of the RCS plot at 10 GHz. At this frequency, the wavelength is 3 cm, so the corner reflector is a little larger in terms of wavelength.The high-frequency physical-optics limit of the RCS is given bywhere L is the length of an edge of the aperture, 0.12 m in this case. With this equa