Series-cascaded absorptive notch-filters for 4G-LTE radios This paper focuses on novel filtering architectures for LTE-band transmit and receive RF-filters. For the first time, it is demonstrated that advanced filtering components with low insertion loss (2.8-4.9 dB) and large attenuation stopbands (25-50 dB) can be created by series-cascaded absorptive bandstop filters with quality factors even as low as 12-45. Transmit and receive filter modules for LTE-band 1 duplex circuits are shown. Lumped-element absorptive bandstop filters with the highest reported Q of 43 at 2 GHz are presented. Tunability of the presented filter arc hitectures is also discussed.