Active multiple-feed on-chip radiator with in-antenna power-combining approach

This paper shows an active multiple-feed on-chip antenna for an efficient power-combining of 8 amplifiers at millimeter-wave (mmW) frequencies. The feed network consists of a delay line with eight outputs and a matching resistor at it's end to prevent standing waves. The center frequency of the antenna is 78GHz. With connected amplifiers, the 3 dB bandwidth is 35GHz. The primary antenna is implemented in the backend process of a 250 nm SiGe process and radiates on the basis of an integrated lens antenna (ILA). The antenna input impedance is matched to the amplifiers output impedance of 85Ω and the subsequent phase-shifted feed elements act as a power-combiner due to their mutual coupling.