# Design of Ultra Wide Band MMIC Digital Attenuator using Switched-T Attenuator

• 주인권 (한국전자통신연구원 광역무선기술연구그룹) ;
• 염인복 (한국전자통신연구원 광역무선기술연구그룹)
• Ju, In-Kwon (Global Area Wireless Technology Research Group, ETRI) ;
• Yom, In-Bok (Global Area Wireless Technology Research Group, ETRI)
• 발행 : 2005.11.05
• 97 8

#### 초록

A broadband DC to 40 GHz 5-bit MMIC digital attenuator has been developed. The ultra broadband attenuator has been achieved by newly inserted the transmission lines in conventional Switched-T attenuator and the optimization of the transmission line parameters. Momentum was employed in design for an accurate performance prediction at high frequencies and Monte Carlo analysis was applied to verify performance stability against the MMIC process variation. The attenuator has been fabricated with 0.15 $\mu$m GaAs pHEMT process. This attenuator has 1 dB resolution and 23 dB dynamic range. High attenuation accuracy has been achieved over all attenuation range and full 40 GHz bandwidth with the reference state insertion loss of less than 6 dB at 20 GHz. The input and output return losses of the attenuator are better than 14 dB over all attenuation states and frequencies.