HFSS Tip 1

Tip 1: Which Sweep to Use?

So you drew the structure that you want to simulate, but which sweep should you use? As seen in Fig. 1, HFSS has three types of sweeps; discrete, fast, and interpolating. Depending on your frequency bandwidth and processing power (i.e. how long you are willing to wait for simulation completion), the most appropriate sweep can be chosen.

Discrete Sweep

The discrete sweep is the most accurate since it resolves the problem at each frequency point in your frequency bandwidth. However, it is the slowest and the adaptive frequency should be set at the higher limit of your bandwidth or at the frequency where the wavelength is smallest.

Fast Sweep

The fast sweep requires less simulation time than the discrete sweep but at the expense of a limited frequency bandwidth range and reduced accuracy. The adaptive frequency should be set within the center of your frequency bandwidth and should coincide within the pass-band of your structure. Typically, the bandwidth is should be 6~8 GHz; if your adaptive frequency is 5 GHz, your frequency sweep can go from 1 GHz to 9 GHz.

Interpolating Sweep

The interpolating sweep is the fastest, but the least accurate sweep. In addition, the field data cannot be saved for the frequency range and therefore has limited post processing attributes. The frequency bandwidth can be wideband, but the adaptive frequency has to be set high. The interpolating sweep basically does a curve fit and should be used for non-resonant structures.