Ali Ahmadikia - Department of Electrical Engineering Sharif University of Technology Tehran, Iran
Poorya Karami - Department of Electrical Engineering Sharif University of Technology Tehran, Iran
Seyed Mojtaba Atarodi - Department of Electrical Engineering Sharif University of Technology Tehran, Iran

This paper presents an analytical evaluation of theloading effect between the stages in a digital step attenuator withswitched π/T/bridge-T structure. Based on the results of theanalysis, an X-band 6-bit attenuator is designed in 0.18 μmCMOS technology with attenuation coverage and LSB of 31.5 dBand 0.5 dB, respectively. The RMS gain error and the RMS phaseerror are less than 0.29 dB and 1.7 degree at 8-12 GHz,respectively.

Attenuator, CMOS switch, loading effect, digital step attenuator, rms gain error, rms phase error