A 20-W wideband voltage controlled attenuator for millimeter-wave applications

In this paper, we present a distributed voltage controlled attenuator (VCA) featuring an extremely high power handling capability of 20 W. Theoretical analyses have been performed to simultaneously achieve a wideband, low insertion loss, and high attenuation dynamic range performance. Implemented in a commercial 0.25-μm GaN-on-SiC high electron mobility transistor (HEMT) technology, a 1- to 25-GHz VCA was measured to perform a dynamic range of 24 dB, an average insertion loss of 3.4 dB, and an average input 1-dB compressed power (P_1dB) of 43 dBm across the frequencies of interest. To the best of the authors' knowledge, this paper presents the monolithic microwave integrated circuit (MMIC) VCA with the reported highest power handling capability in such compact chip area, while maintaining a nice operating bandwidth and dynamic range.