A new dual‐band single‐ended‐to‐balanced filtering power divider

Abstract

This article proposes a new dual-band single-ended-to-balanced (SETB) filtering power divider (FPD), which shows the excellent characteristics of wideband common-mode (CM) suppression and good selectivity. By employing the structure of double-sided parallel-strip line with a mid-inserted conductor and a T-shaped defected ground structure etched in the mid-inserted conductor, out-of-phase behavior and high CM suppression can be achieved successfully. Besides, to realize dual-wideband filtering performance and high selectivity, two pairs of step impedance stubs (SIS) loaded quarter-wavelength central line-terminal-shorted three parallel-coupled microstrip lines structure are adopted. Meanwhile, two pairs of resistors are introduced so as to realize excellent isolation. To verify effectiveness of the design method, a prototype of dual-band SETB FPD which operates at 3.2 and 4.9 GHz is designed, fabricated, and tested. Final results exhibit that the new dual-band SETB FPD possess high selective dual-band differential mode response, wideband CM suppression, and excellent isolation between the balanced output ports.