Active Multiple Feed On-Chip Antennas With Efficient In-Antenna Power Combining Operating at 200–320 GHz

The design and measurement of active multiple-feed on-chip antennas realized in a SiGe seven metal layer backend process are presented for millimeter-wave applications. To prevent the excitation of surface waves, the principle of an integrated lens antenna (ILA) is used. In-antenna power-combining is realized by using a novel concept in which the outputs of two or more parallel differential amplifiers are directly combined in the radiating element itself. The proof-of-concept is shown by characterizing the antennas directly without the amplifiers being connected and by using adequate feeding networks capable of demonstrating high ILA bandwidths. Further, the power-splitting is realized through distributed transformer circuits, which offer high bandwidths at low losses. Different antennas are evaluated in order to attain reflection coefficients better than -10 dB over the entire frequency band of 200-320 GHz. Finally, the power-combining capabilities of such antennas are demonstrated by connecting a four-feed differential antenna to four single stage cascode amplifiers in parallel.