Compact, tunable wilkinson power divider using tunable synthetic transmission line

A very compact and frequency tunable Wilkinson power divider is suggested and demonstrated for the first time. By replacing λ/4 section lines in a conventional Wilkinson power divider with varactor tunable, lumped-element synthetic transmission lines, dramatical size reduction and frequency tunability has been achieved. The prototype circuit fabricated shows excellent performance. For tunable frequencies from 0.71 to 0.99 GHz, the insertion loss is less than 3.52 dB, whereas the return loss and isolation are greater than 20 dB. Yet, the size of this voltage controllable Wilkinson power divider is only 4 mm by 8 mm, which occupies less than 3% area of original Wilkinson power divider structure.