Programmable Active Mirror: A Scalable Decentralized Router

A. Fikes, P.P. Khial, S. Nooshabadi, A. Hajimiri

Click Here for Open Access Full Paper pdf from IEEE

This work proposes and demonstrates the scal- able router array that eliminates the internal centralization of conventional arrays, unlocking scalability, and the potential for a system composed of spatially separated elements that do not share a common timing reference. Architectural variations are presented, and their specific tradeoffs are discussed. The general operation, steering capabilities, signal and noise considerations, and timing control advantages are evaluated through analysis, simulation, and measurements. An element-level CMOS radio frequency integrated circuit (RFIC) is developed and used to demonstrate a four-element 25 GHz prototype router. The RFIC’s programmable true time delay (TTD) control is used to correct path-length-difference-induced intersymbol interference (ISI) and improve a rerouted 270-Mb/s 64-QAM constellation from a completely scrambled state to an EVM of 4% rms (−28 dB). The prototype scalable router’s concurrent dual-beam capabilities are demonstrated by simultaneously steering two full power beams at 24.9 and 25 GHz in two different directions in a free-space electromagnetic setup.