A Multiple-Feed Connected Leaky Slot Antenna for In-Antenna Power Combining in 0.13 μm SiGe BiCMOS Technology

In this paper, a differentially-driven wideband multiple-feed on-chip antenna design in $0.13\ \mu \mathrm{m}$ SiGe technology is proposed for millimeter-wave power combining applications. The in-antenna power combining concept is achieved by combining parallel amplifiers in the multi-port radiator where each port corresponds directly to a differential power amplifier (PA) stage. Specifically, the radiator is composed of a leaky slot with multiple set of differential microstrip feed lines. A wideband Marchand balun with 1.5 dB insertion loss is applied to convert the differential output to the single-ended input of microstrip feed line. In addition, the proposed differential PA has a combined output power of 10 dBm and its output is directly connected with the balun. As a result, the proposed multiple-feed antenna has four differential microstrip feed lines connected with four Marchand baluns which are driven by four parallel differential PAs respectively. Also, to compensate for the loss along the signal route such as power splitters and baluns, pre-amplification PA stage is a necessity at the input of each PA stage. In order to suppress the surface waves in the high permittivity substrate, an extended hemispherical silicon lens is integrated with the chip. Simulation results show that the antenna can cover more than 50 % fractional bandwidth at 250 GHz and calculated EIRP is 19.3 dBm.