Microwave Tunable Notch Filter Based on Liquid Crystal Using Spiral Spurline Technology Articles uri icon

publication date

  • October 2013

start page

  • 2420

end page

  • 2423


  • 10


  • 55

international standard serial number (ISSN)

  • 0895-2477

electronic international standard serial number (EISSN)

  • 1098-2760


  • In 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.


  • lcs; notch filter; spiral spurline structure; tunable devices