4-Way 0.031-mm2 Switchable Bidirectional Power Divider for 5G mm-Wave Beamformers

This paper presents a miniaturized bidirectional power divider (PD) which incorporates the function of a single-pole-double-throw (SPDT) switch in addition to its regular operation. Therefore, the new component can be used as a transmitting/receiving (TRx) switch. With the proposed solution, several PDs are removed, and the SPDT is integrated, thereby saving area and reducing the overall insertion loss (IL) in phased antenna arrays. Moreover, due to its compact size and simplified routing strategy, the design is also suitable whenever many TRx elements are required, i.e., especially for 5G mm-wave beamformers. A 4-way prototype has been fabricated in a 130-nm SiGe BiCMOS technology to validate the concept and occupies an effective area of 180x170 µm2. Measurements results show an IL of 3.1 dB at 28 GHz and isolation higher than 19 dB. In addition, phase and amplitude errors are lower than 3° and 0.2 dB, respectively. In conclusion, a device that integrates the functionalities of SPDTs and PDs is reported without increasing area occupation compared to state-of-the-art PDs and, therefore, paving the way for compact, cost-effective beamformer chips.