Design of the quarter-mode substrate integrated waveguide in-phase and out-of-phase filtering power divider

In this paper, a series of the quarter-mode substrate integrated waveguide (QMSIW) Altering power dividers (FPD)s with compact size are proposed. The FPDs are designed in two forms which are in-phase and out-of-phase topologies, respectively. As for the in-phase FPD, two QMSIW cavities are coupled by the inductive windows in the single-layered substrate to obtain a two-pole filtering response. As for the out-of-phase FPD, the multilayer substrate integrated waveguide structure is utilized to achieve a 180° reverse phase characteristic between two outputs. Measured results show that, the proposed in-phase QMSIW FPD has a 3-dB fractional bandwidth of 41.4% (4.6-7 GHz). Moreover, the amplitude and phase imbalances are measured less than 0.3 dB and 2.4°, respectively. The out-of-phase QMSIW FPD is measured at 5.8 GHz. In addition, the amplitude and phase imbalances are measured less than 1 dB and 2.6°, individually.