In RFIC device such as PA and Mixer, combiner/divider is required for its operation. Wilkinson power divider is one of the passive components widely used for power splitting/combining. However, conventional Wilkinson power divider employs quarter-wavelength line, which highly increases the circuit size and manufacturing cost.
In this work, in order to realize miniaturized Wilkinson power divider, we propose π-type multiple coupled microstrip line structure (MCMLS), and present the method to reduce the length of quarter-wavelength line. Concretely, Wilkinson power divider was highly miniaturized by substituting quarter-wavelength line for π-type MCMLS. In the π-type MCMLS, the characteristic impedance of the line doesn't increase rapidly, though the line is shortened by shunt capacitors, which facilitated the fabrication of the miniaturized RF passive component. Concretely, using π-type multiple coupled microstrip line structure (MCMLS), we fabricated highly miniaturized Wilkinson power divider on Teflon. The line length of the power divider was reduced to about 1/11, and its size was 37% of conventional Wilkinson power divider. The novel power divider showed good RF performances in S/C band. Using π-type multiple coupled microstrip line structure, we also fabricated highly miniaturized Wilkinson power divider on GaAs MMIC. The line length of the power divider was reduced to about 1/20, and its size was 15% of Wilkinson power divider fabricated by conventional microstrip kines on MMIC. The novel power divider showed good RF performances in C/X band.