Computer Simulation Technology (CST) has announced that it has acquired all intellectual property of the CoupleFil software developed by InnoDev GmbH. CoupleFil is a synthesis tool for designing cross-coupled bandpass filters. Cross-coupled filters are commonly used for high-frequency, high-performance applications where narrow passbands and steep roll-off are required, for example in telecom base stations and satellites. Cross-couplings (couplings between non-adjacent resonators) can be used to modify the filter transfer function. They are mostly employed for improving the filter selectivity by producing transmission zeroes. Depending on their sign, they can also be employed for improving filter phase linearity.
In traditional filter design, the tuning of the filter and placement of the transmission zeroes required both considerable analytic work to calculate filter coefficients and manual fine-tuning. CoupleFil simplifies the process substantially by automatically calculating the necessary coupling matrix and suggesting filter topologies that match the user’s requirements. These requirements can include multiple pass-bands and arbitrary transmission and reflection zeroes.
Once CoupleFil has synthesized a filter, it can generate a 3D model of the design which can be exported directly into the 3D EM simulation tool CST STUDIO SUITE®. A full 3D simulation can then be carried out to optimize the filter and to allow its performance to be calculated as constructed using a virtual prototype. By combining synthesis and simulations, users can get from specifications to tuned design more quickly, saving both time and money.
CST has traditionally been strong in the microwave and RF market, and CST STUDIO SUITE is used by engineers to design and analyze a very wide range of high-frequency components and systems. In recent years, CST has focused on strengthening its offering for filters in particular, with the introduction of optimization techniques especially well-suited to filter tuning and the integration of FilterDesigner 2D into CST STUDIO SUITE. The addition will complement and extend CST’s workflows for simulating and optimizing filters.
