A 6-way ring combiner/divider

Abstract

A 6-way planar ring for combining/dividing signals is presented in this paper. Conventional planar power combining/dividing structures use derivatives of the Wilkinson combiner in a ladder like structure, or radial combiners. The ring combiner can be made smaller, provide higher port isolation, improved harmonic suppression and a single isolation port (e.g., delta output port), allowing energy harvesting in outphasing applications. The presented ring combiner achieves a measured insertion loss of < 1dB from 5.5–5.8 GHz, while achieving > 25 dB isolation. The isolation notch is tunable by adjusting a static phase offset between the inputs. When linearly combining six, 26 dBm amplifiers, measurement results show 31dBm output. A 5-MHz, 64QAM LTE up-link signal is amplified without DPD and achieves an average out-put power of 24.1 dBm with an ACLR of >35 dBc. The power handling capability of the ring is only limited by the trace width and dielectric material, hence higher powers are achieveable.