Comparative analysis of RC- and RLC-complex filters for microwave microelectronic phaseshifters

In this paper two main approaches to the realization of vector-modulation phase shifters quadrature formers based on RC and RLC structures are considered for the case of microwave 180 nm CMOS technology. The choice of unbalanced input structure is explained due to CMOS balun characteristics. Phase and amplitude errors are compared, as well as input matching. In conclusion, main advantages and disadvantages of the considered Alter structures are summarized, with RC structure being proven as a better choice for minimum phase error phaseshifters.