The Concerto FDTD analysis module uses the Finite Difference Time Domain method to quickly and accurately model microwave devices. The FDTD method is known for its accuracy and reliability, and can model very large models with ease.

The unique Conforming Mesh technology allows Concerto FDTD to include curved and inclined surfaces without having to create small "staircase" meshing. The surface is modeled with precision, without any reduction in time step.

Applications of Concerto FDTD include:

• Antennas: A range of antennas can be modeled using the special techniques available. With near-to-far field transformation, both 2D and 3D radiation plots can be produced. For complex structures the conforming mesh is essential. Patch antennas can be modeled by using infinitely thin metal layers. Special techniques take into account the field singularities near metal corners, improving the accuracy for these applications.
• Waveguides: Concerto FDTD is well suited to this class of model and can be relied on to give accurate results. Waveguides can be part of larger systems.
• Cavities and Resonators: Concerto FDTD can be used to quickly obtain the resonant frequencies of cavity structures (such as RF cavities and microwave ovens) including lossy walls and lossy loads. For each resonant mode, the Q-factors can be computed and the model shape interrogated.
• Filters: For this demanding application the techniques within Concerto FDTD give accurate solutions. The fields near corners are modeled accurately (including the field singularity), thin sheet models can be utilized for planar filters and local grid refinement can be used where extra precision is required. With the unique Prony module, the analysis time is reduced significantly without loss of accuracy.
• Microwave Heating: A specialized module to model temperature rise in materials is included. Material properties are defined as functions of temperature, giving accurate predictions of temperature rise as a result of microwave heating.

Key Features of Concerto FDTD include:

• Large, complex models can be run with ease as it is not necessary to store large matrices
• Wideband analysis can be performed in a single run.
• The Geometric Modeler is used to import CAD files and to add or modify them as required.
• The Modeler is run independently of the analysis modules (the Modeler can be used to prepare the next model ready for analysis whilst the first analysis is still running).
• The Simulator is launched directly from the Modeler, and has its own Dynamic Multi-Window Visualization tool, allowing the user to interact with the Simulator as the analysis progresses, changing what is displayed and where.
• For larger analyses, the solution can be "frozen", freeing up the computer for other work, and then returning to the simulation and restarting from where it was "frozen".
  Command Files can be created for use in running both the Modeler and the Simulator.

Additional Features available for Concerto FDTD

For high Q devices, the energy can remain within the device for some time, slowing the overall calculation time. This can be overcome by switching on the Prony algorithm, which applies signal processing to the computed results to isolate the true solution.

The Prony solution is an excellent approximation to the true solution, and is available without having to wait for the complete solution to converge. This can give a saving of a factor of 10 in the overall solution time of a model.

For hardware that has multi-cores or multi-processors, the multi-thread options can give extra savings in computation time. The options available split the simulation process into 1, 2 or 4 threads, so are ideally suited for 1, 2 and 4 core/processor hardware respectively.

• 1 Thread: all the computational effort is carried out on a single thread.
• 2 Thread: the computation is performed on one thread, and the dynamic visualization in the second (such as S-parameter calculations, contour plot graphics).
• 4 Thread: the 3 components of the FDTD calculation are separated, so that the x, y and z components are computed as separate threads. The dynamic visualization is then a separate thread.

The Thermal module can be used to include effects such as microwave heating. The electromagnetic solution is used to compute the heat generated in lossy loads, which are then passed to the Thermal module to compute temperature rise.

Material properties can be tabulated to include non-linear properties (as a function of temperate), including phase changes. As the temperature rises, and material properties change, so the electromagnetic solver is re-run to re-compute the field distributions and the new heat distributions.

Both adiabatic heating and diffusion models can be used in the Thermal module, depending on the nature of the system being analyzed.