Ansys has recently added the Nuhertz FilterSolutions product to its portfolio, enabling the customer to design RF/Microwave filters very quickly and accurately. The new product assists engineers in the design, synthesis and optimization of RF, microwave, and digital filters, lowering the development cost, reducing the time to market, and optimizing the product performance. “Today, it is difficult to find RF designers who are acquainted with and have the expertise for filter design”, said Shawn Carpenter, Product Manager for the Nuhertz FilterSolutions product at Ansys.
Starting with AEDT 2022R2, FilterSolutions has been Integrated with HFSS, the gold-standard for accuracy, for 3D EM analysis and optimization. The software is launched from Tools, as shown in Figure1.
Figure 1. Filter Solution launching within AEDT
Starting FilterSolutions launches the GUI user interface Menu as shown in Figure 2. The software has two design options. Particularly useful for new users is the FilterQuick interface (Figure 2) which allows users to synthesize and design a filter quickly and accurately. The advanced option (shown in Figure 3) is the preferred option by seasoned filter guru to use all the tweaks of synthesis to achieve optimal results.
Figure 2. Filter Quick Option
Figure 3. Advanced Option
Filtersolutions dramatically speeds up the design of lumped element (surface mount) and planar filters. It can evaluate the widest range of filter topologies (Bessel, Butterworth, Chebyshev I and II, Elliptic, Gaussian, Delay, Hourglass, Legendre, Matched, Raised Cosine, Tubular, Zigzag, Coupled-Resonator and Cross-Coupled Folded Resonator). A library of vendor components is available for lumped element designs for instant prediction of circuit performance.
Filter design is often complex, especially for high-performance microwave and millimeter-wave designs. RF and microwave filters are prone to EM cross-coupling, which is often a source of inaccuracies in the circuit modeling approaches. A filter design which lacks accuracy will require an expensive bench tuning phase during production. This situation is usually aggravated if the tolerances of the components are not given proper consideration. For example, if a distributed filter design is considered, the analysis in FilterSolutions may not be sufficient to take 3-D elements discontinuities and arbitrary coupling effects into account. The employment of a 3D electromagnetic field simulator is often required. A fully parametrized design using FilterSolutions can be exported to Ansys 3D EM simulation tools (HFSS and HFSS 3D) for accurate Full 3D simulation and optimization as shown in Figure 4.
Figure 4. Option to export designed filter to Circuit/HFSS and HFSS 3D for full EM simulation
Once, the parametrized geometry is exported to HFSS full wave simulation is carried out and the design can be optimized to meet requirement.