Nonlinear distortion in a 8-pole quasi-elliptic bandpass HTS filter for CDMA system

• Published in: IEEE transactions on applied superconductivity 2005-06, Vol.15 (2), p.992-995
• Main Authors: Collado, C., Mateu, J., Menendez, O., O'Callaghan, J.M.
• Format: Article
• Language: English
• Subjects: Applied sciences; Band pass filters; Broadband; Capacitors. Resistors. Filters; Circuit properties; Circuit simulation; Degradation; Distortion; Electric, optical and optoelectronic circuits; Electrical engineering. Electrical power engineering; Electronic circuits; Electronics; Equivalent circuit; Equivalent circuits; Exact sciences and technology; Frequency filters; High temperature superconductors; HTS filters; Intermodulation; Multiaccess communication; Nonlinear distortion; nonlinearities; Nonlinearity; Simulation; Superconducting filters; Superconducting materials; Superconductivity; superconductor; Various equipment and components; Wireless communication; Wireless communication systems
• ISSN: 1051-8223; 1558-2515
• DOI: 10.1109/TASC.2005.850165

High Temperature Superconductor materials are known to produce intermodulation and other nonlinear effects which may restrict their use in wireless communication systems. Quantifying this degradation is crucial in determining if the use of HTS filters in the receiver is beneficial. In this work we use an approach for representing the HTS filter nonlinear equivalent circuit and simulating its performance. We have tested the approach on a planar, 8-pole quasielliptic (QE) filter, showing agreement between simulations and measurements of intermodulation products (IMD). The nonlinear equivalent circuit is then used to predict the nonlinear behavior of the filter and its effects on system parameters when it is subject to broadband signals like those used in wireless communication systems.