Compact EBG in-phase hybrid-ring equal power divider

A novel electromagnetic-bandgap (EBG) in-phase hybrid-ring equal power divider is described. Coupled with the closed-form analytical expressions for the EBG structure, a systematic technique of design is presented for the first time. Compared to the conventional hybrid-ring equal power divider, based on the 15-dB return-loss criteria, an increase in both the input and output impedance bandwidth of approximately 10% from a starting frequency of 2.5 GHz, and a phase error of 0.006° within the passband have been achieved for the proposed structure. The proposed in-phase hybrid-ring equal power divider, besides providing a much broader bandwidth and occupying a smaller estate area, also possesses good harmonic suppression characteristic.