Novel dual mode microstrip bandpass-filter [Technical Committee]

A novel four-pole, dual-mode bandpass filter is presented. It is based on microstrip meandered ring resonators, where dual-mode resonances are utilized through well-placed discontinuities in the symmetry plane of the ring structure. These filter types show very compact size, low insertion loss, and high stopband attenuation as well as steep filter slopes. The investigation was carried out within the student paper contest "Packaged X-Band Filter" at IMS 2008. Therefore, the passband is defined between 7.145--7.235 GHz, while the insertion loss is less than 5 dB and the return loss exceeds 15 dB. Between 8.4--8.5 GHz, the stopband attenuation should exceed 45 dB. This article presents the filter construction and simulation results. The integration into the given package as well as measurement results are presented.