Nuhertz Software provides automatic filter design for:
- Lumped filters, presenting synthesized filter schematics that fulfill the filter performance specification. Also provides values for filters realized on PCBs with surface mount or thru-hole discrete components.
- Distributed (transmission line filters) – High-performance distributed filters manufactured on microwave or mmWave substrates.
These filters are usually realized with transmission lines, open or shorted stubs, vias, coupled lines and cross-coupled transmission
line systems. A broad class of microwave and mmWave filters can be realized through precision patterning of conductors on one to three planar substrates. - Digital filters realized in software for digital signal processing (DSP) systems or on microcontrollers. These are software programs, applied to digital signal processing operating on data from digital sampling systems.
- Zero-inductor analog filters – Popular at lower frequencies (audio and mid-frequency analog systems), these filters can be realized on PCB process technology with OpAmps in an analog filter format.
- IC-based filters in the form of non-programmable digital filters can also be implemented in IC processes utilizing MOSFETS and capacitors to occupy minimum real estate and utilize a switched-capacitor approach.

What differentiates Nuhertz FilterSolutions?
- Performance specification for Layout-to-EM-Optimization in a single smooth workflow
- Highly accurate distributed filter layout synthesis based on EM-derived model discontinuities and couplings
- Ability to evaluate the widest range of filter topologies (Bessel, Butterworth, Chebyshev I and II, Elliptic, Gaussian, Delay, Hourglass
- Integrates with HFSS for gold-standard EM analysis accuracy and for EM-based optimization
- Ability to synthesize filter topologies for analog and digital filter topologies; a single tool for creating accurate filters for both
analog and digital signal processing (DSP) applications - Planar filter realizations in the widest available media classes (microstrip, stripline, asymmetric stripline, suspended substrate)
Ansys Nuhertz FilterSolutions Key Features

- The Distributed Filter module synthesizes filter layouts on physics accurate materials, incorporating transmission lines and hybrid lumped elements.
- Filter layouts can be realized in a variety of substrate formats, including microstrip, suspended substrate and stripline.
- Physical layouts (including metallization and substrate material properties) can be realized quickly and accurately. Filter layouts are fully parameterized and may be opened in HFSS.
- For immediate EM analysis; all geometries, materials, ports and analysis setups are automatically created.
- HFSS designs are fully parameterized and optimization setups are provided, so the designer can proceed directly to design optimization to desired response goals.
- Synthesizes a lumped component filter (single or double-termination) of a selected filter topology to realize user-specified performance characteristics.
- Standard value components may be applied, with standard (or non-standard) tolerance values for Monte-Carlo analysis.
- Components have ideal or finite Q or may be based upon vendor component library models.
- Another zero-inductor realization: Switched capacitor filters are generally realized in semiconductor processes where capacitors and switching transistors occupy comparatively small spaces.
- Switched-capacitor filters may be used to realize digital filters and involve sampling circuit topologies.
- The Switched-Capacitor Filter module synthesizes designs in IIR and FIR realizations, as well as Bilinear, Matched-Z, Step Invariant, Modified Impulse Invariant and custom Z-transform designs.
- For DSP and sampled systems, FilterSolutions takes user-specified performance specifications and a desired topology and synthesizes filter coefficients to realize the digital filter.
- Digital transformations are provided to Bilinear, Impulse Invariant, Step Invariant, Matched-Z and Finite Impulse Response (FIR) approximation.
- Filter realizations are provided in the form of the discrete transfer function, filter tap/block coefficients or as C-code ready for incorporation into a DSP code block.
- Some filter designs call for elimination of inductors and active filter designs with OpAmps can sometimes provide an attractive alternative.
- The FilterSolutions Active Filter module synthesizes filters to meet user-specified performance requirements in a wide range of filter topologies, such as Thomas, Akerberg-Mossberg, Sallen-Key, Multiple Feedback, Leapfrog, GICs and more.
- Incorporate OpAmp models from your favorite vendor and include finite Q and gain effects in your active filter designs.
- Zmatch starts with complex load definitions and synthesizes a matching network for maximum power transfer.
- Includes both Discrete Frequency and Broadband Match modes.
- Optimal matching networks are provided in lumped, distributed and hybrid realizations
Gaussian, Bessel, Butterworth, Legendre, Chebyshev (I and II), Hourglass, Elliptic, Raised Cosine, Matched, Delay. Check Ansys for additional updates.
Lumped Translation, Inductor Translation, Stepped Impedance, Shunt Stub Resonators, Open Stub Resonators, Spaced Stubs, Dual Resonators, Spaced Dual Resonators, Parallel Edge Coupled, Hairpin, Miniature Hairpin, Ring Resonator, Interdigital, Combline. Check Ansys for additional updates.
- Thomas 1 and 2
- Sallen & Key
- Parallel
- Akerberg
- Multiple Feedback (MFB)
- GIC Biquad
- GIC Ladder
- Leap Frog
Lumped Translation, Inductor Translation, Stepped Impedance, Shunt Stub Resonators, Open Stub Resonators, Spaced Stubs, Dual Resonators, Spaced Dual Resonators, Parallel Edge Coupled, Hairpin, Miniature Hairpin, Ring Resonator, Interdigital, Combline
- Bilinear
- Impulse Invariant (IIR)
- Matched Z
- Step Invariant
- FIR Approximation.
FIR Filter Types:
- Rectangular
- Bartlett
- Hanning
- Hamming
- Blackman
- Blackman-Harris
- Kaiser
- Dolph-Cheby
Remez - Raised Cosine
- Root Raised Cosine
- Cosine Filter
- Sine Filter
- Matched Filter
- Delay Filter