Compact differential power divider with enhanced bandwidth and in-phase or out-of-phase output ports

A differential power divider using coupled microstrip line is proposed. The differential-mode response can be controlled by the odd-mode of the coupled microstrip line and resistors. Compared with the reported differential power dividers, the proposed one shows the advantages of compact size, wide bandwidth and easy connection with radio frequency (RF) chips. Furthermore, both in-phase and out-of-phase output ports can be realised using different connection ways. Two prototypes have been fabricated with the same size of 0.185λ_g × 0.245λ_g, one with in-phase output ports and the other with out-of-phase output ports, showing the same minimum insertion loss of 0.2 dB and relative frequency bandwidths for |S_dd11| <;-15 dB of 75 and 78%, respectively.