Microwave Filter & Components applications

Communication networks, in both terrestrial and space applications, are becoming more demanding on the use of the frequency spectrum. In order to deal with stringent spectrum needs, filters are used. The design and analysis of such devices can be challenging and simulation can play a vital part in the development process. CST Studio Suite offers a range of solutions for different implementations.

Filter Designer 3D is a general purpose bandpass filter and diplexer synthesis tool. It uses the well-established coupling matrix synthesis and offers tuning assistance with a robust filter parameter extraction from S-parameters. This technique is also built into a dedicated optimizer for filter models that achieves fast convergence without having to do tedious space-mapping or port-tuning routines. This can even be used on the workbench where hardware can be tuned with the assistance of real-time coupling matrix extraction performed on the measurements.

To go from the filter specifications and synthesis to a fully parameterized 3D model, a range of options is available. With Filter Designer 3D a general approach is provided that makes use of the component library. The user can either select from the different available building blocks or customize it entirely according to their technology requirements. The blocks are automatically assembled according to the synthesized topology to produce a fully parameterized model that includes the optimization setup. For specific waveguide-based lowpass, wideband or dual-mode filters, the wizards in Fest3D can also be used.

Filter Designer 2D is used for generating filters in planar technologies such as microstrip, stripline, suspended stripline, etc. This includes a range of direct synthesis techniques for low-, high- and band-pass filters. It also features lumped component filters where SMDs can be selected and interconnections are automatically generated. With the push of a button all the building blocks are placed on the schematic, a full-wave 3D model is built and an optimizer task is automatically set up.

Fest3D provides fast analysis of different components in waveguide technology, which is essential when it comes to optimization routines or complex divide-and-conquer workflows. It also provides model synthesis of dual-mode circular cavities through to corrugated waveguide filters. These projects can also be connected in the schematic environment of CST Studio Suite in order to establish co-simulations with other solver technologies – e.g. a waveguide feeding network cascaded with a horn antenna.

Circulator components typically also require coupled simulations where ferrite materials are involved. A static field is required to bias the ferrite that would establish the non-reciprocity, which again is required for the high frequency operation of the circulator. This can be seamlessly achieved in the same environment using a single model in a coupled workflow.

High power microwave components typically require the analysis of multi-physical phenomena to understand their power handling abilities. There are always some conducting losses in the device which leads to thermal heating. This can cause the structure to deform and finally it may compromise the electromagnetic performance. To analyze these three different physical domains, a coupled workflow can be conducted using only a single model for the device.

RF breakdown is another phenomenon that has the potential to destroy a device. High intensity oscillating fields have the potential to ionize the gas inside a device which can then lead to a corona discharge; or in the absence of gas and with the presence of free electrons, multipaction can occur. Spark3D provides advanced technologies to calculate these physical domains and has been proven to be highly accurate when compared to well-controlled measurement data.

It is important to take all this into account early in the development process in order to avoid unforeseen failure of sophisticated or critical components.