A Reconfigurable Filter Using Defected Ground Structure for Wideband Common-Mode Suppression

• Published in: IEEE access Vol. 7; pp. 36980 - 36990
• Main Authors: Zeng, Zhibin, Chen, Shengjian Jammy, Fumeaux, Christophe
• Format: Journal Article
• Language: English
• Published: Piscataway IEEE 2019; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Broadband; Capacitance; common-mode suppression; defected ground structures; Equivalent circuits; Integrated circuit modeling; Miniaturization; Reconfigurable filter; Reconfiguration; Resonant frequency; varactor diode; Varactor diodes; Varactors; Wideband
• ISSN: 2169-3536; 2169-3536
• DOI: 10.1109/ACCESS.2019.2906340

A wideband common-mode (CM) suppression reconfigurable filter is proposed for high-speed all-pass differential circuits. The filter adopts three varactor-loaded compact defected ground structures (DGSs) to achieve continuous reconfigurability in its operation frequency with a large CM suppression dynamic range in the bandwidth. The varactors play an important role in widening the accessible instantaneous bandwidth and miniaturizing the structure. The three DGS cells with a total area of 15 mm × 10 mm are implemented symmetrically under the differential lines, to obtain reconfigurable CM bandstop characteristics which can be continuously adjusted from 1.8 to 8.1 GHz. A coupled LC resonator equivalent model is developed to represent and analyze the proposed filter, which explains its operation principle and assists in accelerating the reconfiguration design method. A good agreement between full-wave simulations and measured results is demonstrated, which validates the proposed design.