Tunable millimeter-wave power divider for future 5G cellular networks

A modified Wilkinson power divider operating at the millimeter wave band (28 GHz) for future 5G mobile systems is presented. This power divider has the ability to change continuously the output power division ratio by using two varactors. Instead of connecting the two branch lines of the conventional Wilkinson power divider directly to the isolation resistor and the output ports, two varactors are inserted in the output terminals of the input T-junction to tune the equivalent impedance of these two branch lines. Quarter-wavelength transformers are deployed at the input and output ports to enhance the matching in all ports across the tuning range. The simulation results indicate that the ratio of output power can be adjusted from 1: 1 to 1: 2.4 across the band from 27 to 29 GHz. The return loss is more than 11 dB, while the isolation is more than 13 dB. In addition, the phase and amplitude imbalances are less than 6 degrees and 0.8 dB, respectively.