Planar 10:1 unequal three-port power dividers using general design equations

A microstrip three-port power divider with a power division ratio of 10 is suggested and fabricated. To reduce the size and difference between four transmission-line sections, a modified T-equivalent circuit is employed. The total transmission-line length required for the fabrication is only 44.4% of the conventional design and the measured results are in good agreement with predicted ones, showing that with the power division ratio of 10, return losses at all ports are better than 19.7%dB and isolation is better than 35%dB at a design centre frequency of 1%GHz.