A Fully Differential Ultra-Broadband Power Divider with Integrated Resistors

A fully differential power divider with ultra-broadband performance is presented. It consists of multi-section Wilkinson power combiners vertically aligned in a multilayer circuit board, which are fed by differential via transitions. The carbon paste decoupling resistors are integrated in the stack. The measured differential-mode output isolation exceeds 10 dB above 2.9 GHz. The excess insertion loss remains below 1.0 dB up to 21 GHz and reaches 2.0 dB at 36.5 GHz. The structure, which is designed for compactness, occupies only 50 mm².