A Fully Integrated Modular 2×4 220–260 GHz Beam-Forming Transmitter and Receiver With 50 Gbps Wireless Transmission in SiGe:C BiCMOS

This article presents a 220-260 GHz fully integrated phased-array wireless system featuring direct conversion RF beam-forming. The system is constructed using fully integrated transmitter (Tx) and receiver (Rx) chips with on-chip antenna array. A 4-channel Tx and Rx are designed and fabricated in a 130 nm SiGe BiCMOS process with <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">f</i><inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$_{\mathbf{T}}$</tex-math></inline-formula> / <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">f</i><inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$_{\mathbf{max}}$</tex-math></inline-formula> = 300 / 500 GHz. A modular design approach enables the chips as building units for 2×N phased arrays and multiple-input multiple-output (MIMO) systems. A comprehensive design approach for the Tx and Rx chips focusing on key design decisions is presented in this work. The transmitter is equipped with a local oscillator (LO) multiplication chain, IQ up <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$-$</tex-math></inline-formula> conversion mixer, active RF splitting network, vector modulator phase shifter (VMPS), temperature sensors, and high output power amplifiers (PA). The PA with power <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$-$</tex-math></inline-formula> combining boost the effective isotropic radiated power (EIRP) and reduces the need for external lenses. The receiver is equipped with an LO chain, IQ down <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$-$</tex-math></inline-formula> conversion mixer, active RF combining network, VMPS, and low noise amplifiers (LNA). In both Tx and Rx the antenna array is composed of four differential double-folded dipole antennas with local backside etching (LBE). The Tx and Rx chips consume 4.4 W and 1.84 W of power respectively from a 3.5 V supply while each occupying 25 mm <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$^\rm{2}$</tex-math></inline-formula> of silicon area. With a measured Tx array effective isotropic radiated power (EIRP) of 24 dBm, a beamforming wireless link is demonstrated supporting up to 50 Gbps of data rates across 85 cm of link distance with no need for focusing lenses and <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\pm 30^\circ$</tex-math></inline-formula> of scanning capability. With these capabilities, the presented modular chips enable future scaling for 2× N antenna arrays for sensing and communication applications.