Design of dual-mode dual-band bandpass filters with controllable frequencies for multimode wireless communication applications

Abstract

A flexible approach for designing dual-mode dual-band bandpass filters with controllable passband frequencies is presented. Two dual-mode dual-band bandpass filters are proposed for experimental verification. The first filter, whose two passbands are centered at 3.4 and 5.5 GHz with the corresponding fractional bandwidth of 19 and 13%, respectively, is suitable for the applications of worldwide interoperability for microwave access (WiMAX) and wireless local area network. The second filter, whose two passbands are centered at 4 and 7.4 GHz with the corresponding fractional bandwidth of 25 and 13%, respectively, is suitable for the downlink of C-band and X-band satellite communication systems. Both filters have been designed, fabricated, and measured. The measured results show good agreements with those of the simulation.

Keywords:

• dual-mode
• dual-band
• bandpass filter
• stub-loaded open-ended resonator

Acknowledgments

This work was supported by the National Basic Research Program of China (973 Program, Grant No. 2013CB328904), the Open Research Fund of Key Laboratory of Cognitive Radio and Information Processing of Ministry of Education of China (Grant No. 2011KF05), and the Fundamental Funds of the Central Universities (SWJTU12ZT08).