Circuit building blocks for efficient in-antenna power combining at 240 GHz with non-50 Ohm amplifier matching impedance

In this work active and passive circuit components suitable for efficient in-antenna power combining are investigated with focus on the matching impedance between the individual components. In the proposed concept, the input power is split by 1:4 couplers with 12.5Ω output impedance, which enables a very broadband input matching of the following single-ended amplifiers. To combine the output power of the parallelized amplifiers, an eight-feed integrated lens antenna (ILA) with 70Ω input impedance is used, which allows for compact matching to the optimum load impedance of the amplifiers. The individual circuit components are realized in IHP's SG13G2 technology and show excellent agreement with the simulation results. The four times parallelized amplifier shows a gain of roughly 5.5 dB at 240GHz excluding coupler losses.