What are Sonnet's Capabilities?

The analysis engine of the Sonnet Suite, em, performs electromagnetic analysis for arbitrary 3-D planar (e.g., microstrip, coplanar, stripline, etc.) geometries, maintaining full accuracy at all frequencies. Em is a "full-wave" analysis in that it takes into account all possible coupling mechanisms. The analysis inherently includes dispersion, stray coupling, discontinuities, surface waves, moding, metalization loss, dielectric loss and radiation loss. In short, it is a complete electromagnetic analysis. Since em uses a surface meshing technique, i.e. it meshes only the surface of the circuit metalization, em can analyze predominately planar circuits much faster than volume meshing techniques.

Em does a full three dimensional analysis that includes both 3-D fields and 3-D currents. This is in contrast to 2.5-D analyses which, while including full 3-D fields, allow only 2-D currents. Thus, a 2.5-D analysis does not allow vias or any other vertical current.

Em analyzes 3-D structures embedded in planar multilayered dielectric on an underlying fixed grid. For this class of circuits, em can use the FFT (Fast Fourier Transform) analysis technique to efficiently calculate the electromagnetic coupling on and between each dielectric surface. This provides em with its several orders of magnitude of speed increase over volume meshing and other non-FFT based surface meshing techniques.

Applications

Em is appropriate for a wide range of 3-D planar structures. The via capability allows analysis of airbridges, wire bonds, spiral inductors, wafer probes and internal ports as well as for simple grounding.

It is appropriate to use em for:

• Evaluation of specific discontinuities or groups of interacting discontinuities to assist in the design of a 3-D planar circuit
• Em provides ultra-precise S-parameters for discontinuities allowing designers to work with confidence. Em can also quickly synthesize an equivalent lumped model for discontinuities. The lumped model can be used directly in circuit theory programs.
• Design validation
• Using em for design validation effectively eliminates expensive design iterations (i.e., "tweak", refabricate, etc.) of the passive, planar portion of a circuit

If a circuit is designed from the start with electromagnetic analysis in mind, larger circuits can be done. For example, the analysis works best with tightly packed, rectangular circuits, designed on a common dimension grid.

• Microwave package evaluation
• It is important to assess how a circuit will operate in the package environment. Em analyzes a circuit inside a conducting box. If the box (acting as a dielectric loaded resonator) is resonant at a frequency where the circuits still have gain, poor performance results. Em provides an analysis of a package prior to fabrication. Resonances can then be dealt with on the computer rather than on the test bench.
• Microstrip antennas
• The "top" of em’s box can be effectively removed. While radiation is outside of em’s primary thrust, a wide variety of microstrip antennas and radiating discontinuities can be evaluated.
• High speed digital interconnect
• When an approximate model is not good enough, em can synthesize a SPICE lumped model including all delays and couplings. The lumped model is synthesized directly from electromagnetic data.

Em is not appropriate for doing an initial design. Rather, the faster circuit theory simulators (which do not typically include stray coupling) should be used for the first cut. Em can then enhance the simulator performance by providing custom, ultra-precise discontinuity data and by validating large portions of the final circuit, including all stray interactions.

Em is designed to work with your existing CAE software. Since em allows the user to choose from a wide range of standard output formats, em provides a seamless interface to your CAE tool.