Computer Simulation Technology (CST®) 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, and will complement and extend CST’s workflows for simulating and optimizing 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 CST STUDIO SUITE® 3D EM simulation tool. 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.

“Many of InnoDev’s customers are also CST customers, and will benefit from the integration of CoupleFil into CST’s software range,” said Rony Füglistaller, co-founder of InnoDev GmbH. “We look forward to working as part of the CST team in the future development of CoupleFil, and will continue to offer customer-specific software and hardware solutions.”