Torrecilla Rosell, JavierAvila Navarro, EUrruchi del Pozo, VirginiaSánchez-Pena, José ManuelArias, JuliaSánchez López, María M.Marcos Lucas, Carlos2014-10-102014-10-102013-10Microwave and Optical Technology Letters (2013), 55 (10), 2420-2423.0895-2477https://hdl.handle.net/10016/19465In this article, the design, fabrication, and characterization of a tunable microwave notch filter based on liquid crystal (LC) using inverted-microstrip technology is presented. A spiral spurline structure is used because of its good performance as a single-resonator notch filter. Based on the LC dielectric anisotropy, a voltage-controlled rejection frequency of the filter is achieved, ranging from 3.40 to 3.75 GHz, which means that the tuning range relative to the central rejection frequency is about 10%. At the same time, this device exhibits negative group delay around the rejection frequency and the measured values throughout the tuning frequency range are presented.4application/pdfeng© 2013 Wiley Periodicals, Inc.LCsNotch filterSpiral spurline structureTunable devicesresearch articleElectrónicaÓptica10.1002/mop.27812open access2420102423Microwave and Optical Technology Letters55AR/0000013791