Dual-band and Tri-band Balanced-to-Single-Ended Power Dividers with Wideband Common-mode Suppression

A new design approach of developing multi-band balanced-to-single-ended (BTSE) power dividers is presented in this brief. The design is based on flexible coupling schemes which can guide designing multi-band balanced-to-single-ended power dividers with arbitrary number of bands and controllable bandwidth. Microstrip-to-slotline transitions are used to suppress the transmission of common-mode signals at all frequencies, which lead to an ultra-wide bandwidth of common-mode suppression. Slotlines play a critical role for they have two functions, one is to control the external coupling between ports and resonators, and the other one is to prohibit the propagation of common-mode signals. Based on the design approach, a dual-band and a tri-band balanced-to-single-ended power divider are modeled and simulated in the full-wave simulation environment. Prototypes are fabricated and tested, and the experimental results demonstrate that dual-band and tri-band filtering responses are realized in BTSE power dividers successfully. Moreover, the common-mode suppression and mode conversion levels of both designs are less than −29.5 dB at all frequencies (common-mode suppression fractional bandwidth is 200%), which is extremely desired in balanced circuits and systems.