Design of an asymmetrical dual-band WLAN filter in liquid crystal polymer (LCP) system-on-package technology

A single-input-single-output (SISO) dual-band filter operating at ISM 2.4-2.5GHz and UNII 5.15-5.85GHz frequency bands, using the novel "dual behavior resonators" technique has been developed. Exploiting the strong second resonant frequency of resonators to realize the filtering response, allows for achieving the asymmetric shape and the good rejection between the two bands. The insertion loss and return loss at the central frequency are -2.4 dB and -15 dB for the 2.4-GHz band, respectively, and -1.8 dB and -10 dB for the 5-GHz band, respectively. The filter has been fabricated using the novel liquid crystal polymer (LCP) based multilayer packaging technology, enabling a low cost SOP implementation.