A Novel 180^° Phase Difference Wideband UFPD Without Extra Phase Delay Structure

In this paper, a 180° phase difference wideband bandpass unequal filtering power divider (UFPD) without an extra phase delay structure is presented. It consists of a three-order Chebyshev impedance transformer (IT), a quarter wavelength impedance transformer, an isolation structure and a short-stub. The proposed UFPD has a flat phase difference response between two output ports without the need for an extra phase delay structure. For verification, a 2:1 bandpass UFPD with a 180° phase difference has been designed, fabricated and measured. The UFPD could achieve a 39 % fractional bandwidth (FBW) and a $182^{\circ} \pm 1^{\circ}$ phase difference in passband. The return loss (RL) is below -12.3 dB, and the isolation level is below -17.5 dB in passband. Measured and simulated results are matched well.