61 GHz millimeter wave voltage variable attenuator based on flip-chip mounted PIN-diodes

Voltage Variable Attenuators play a major role in radio frequency system design. In this paper, a voltage variable attenuator concept suitable for the 61GHz ISM band is introduced and discussed. The proposed reflection type voltage variable attenuator has a maximum attenuation of 32 dB in the 61 GHz ISM-band range, and a low phase-shift of less than 10° for low and medium attenuation values. Furthermore, a bias network is presented featuring low reflection loss, and robustness against manufacturing tolerances. For verification purposes, a voltage variable attenuator as well as a reference transmission line have been fabricated and measured.