A Novel Differential Filtering SIW Power Divider with High Selectivity

A novel differential power divider with bandpass filtering response using the substrate integrated waveguide (SIW) technology is presented. An SIW resonant cavity operated in a balanced resonant mode with odd symmetric electric field distribution is utilized to provide both balanced inputs/outputs and expected common-mode (CM) suppression in a certain band. Meanwhile, by properly constructing the cross-coupled topology of SIW resonant cavities, the proposed differential power divider achieves a high-selectivity bandpass filtering response with two transmission zeros on both sides of the passband. The differential power divider is designed and prototyped on a single-layer printed circuit board (PCB). The measured center frequency is at 10.6 GHz with 490 MHz 3-dB bandwidth. A good CM suppression can also be achieved within the operating band. The measured in-band differential-mode imbalance for magnitude is +/- 0.3 dB, while for phase is 0 degrees-4 degrees. (C) 2015 Wiley Periodicals, Inc.