All-Frequency-Three-Port-Reflectionless Wideband Filtering Power Divider Using Self-Packaged SCPW-MS With Broadside-Coupled Technique

In this article, an all-port and all-frequency reflectionless filtering power divider (FPD) with a flat-in-band group delay is presented based on asymmetric stepped impedance resonators (SIRs). It is mainly composed of asymmetric SIRs, isolation resistors, absorption resistors, absorption stubs, and resistively terminated bandstop-filter branches. The wideband FPD is realized by the broadside coupling between asymmetric SIRs. Appropriate absorption circuits, including quarter-wavelength short-circuit stubs series with the resistors, the stepped three-line coupling resonator series with resistor, and resistively terminated bandstop-filter branches, are connected at the three ports of the FPD to realize the absorption of the out-of-band reflected signals. For demonstration, a wideband reflectionless wideband FPD centering at 4.9 GHz is designed, fabricated, and tested. The measured result shows that the 3-dB fractional bandwidth (FBW) is 55%, and the insertion loss is 0.5 dB. Moreover, the FBW of 10-dB return loss for all three ports is 200%.