A systematic design approach of 5-bit digitally controlled attenuator using 130nm SiGe based BiCMOS technology for Ka –band applications

Abstract

This paper present Ka-band 5-bit digital controlled attenuator with maximum attenuation   of 31.0 dB (32 states). The proposed attenuator has design using 130nm SiGe based BiCMOS technology. The proposed 5-bit digital controlled attenuator has design using simple approach. All the bits of attenuator have design using switch pi network topology to achieve the desired attenuation range, with low insertion loss and good input and output return loss. Traditionally pi attenuator design using two shunt arms with two individual grounds, but proposed attenuator used only one shunt arm grounding for reduce the size of layout. This is the novelty of design. This circuit achieved better than -10.0dB of input return loss over 32 states and -10.0dB of output return loss over 28 states and better than-9.5dB of output return loss in remaining 4 states at ka-band (35.5GHz-36.5GHz). This circuit achieved -7.678±0.2dB of insertion loss in reference state with less than +0.345dB of r.m.s. attenuation error at ka-band (35.5GHz-36.5GHz). With all including pad, the layout dimension of circuit is 1.289x0.404mm².