Lumped-element quadrature power splitters using mixed right/left-handed transmission lines

This paper presents the design of lumped quadrature power splitters (LQPSs) based on unit cells of right-handed (RH) and left-handed (LH) synthetic transmission lines (TLs). The LQPSs include a lumped Wilkinson splitter, with phase-adjusting RH/LH TLs at the outputs. Two topologies, considered to be advantageous with regards to size and electric characteristics, are studied in detail. For these two, closed-form design equations are derived and the performances are analyzed by circuit simulations. The theory and simulation results are experimentally validated by monolithic-microwave integrated-circuit prototypes designed for a center frequency of 2.5 GHz. Both prototypes have performance that agree well with theory and design simulations. Within the frequency range of 2-3 GHz, the maximum amplitude and phase errors are less than 0.3 dB and 3/spl deg/, respectively. All reflections and the isolation are better than -10 dB. The effective areas of the two prototypes are 900/spl times/700 /spl mu/m/sup 2/ and 720/spl times/520 /spl mu/m/sup 2/, respectively.