An Eight-Element 370–410-GHz Phased-Array Transmitter in 45-nm CMOS SOI With Peak EIRP of 8–8.5 dBm

This paper presents a 370-410-GHz phased-array transmitter, which is based on a W-band distribution network, amplifiers, and vector modulators, feeding a linear eight-element quadrupler array. The quadrupler outputs are connected to high-efficiency microstrip antennas. The design is scalable to a large number of elements, since most of the chip operates at W-band frequencies. The chip is built using 45-nm CMOS silicon on insulator technology, which offers transistors with ft and fmax of 250-260 GHz referenced to the top metal. The phased array results an equivalent isotropic radiated power (EIRP) of 5 dBm at 375-405 dBm with a peak EIRP of 7-8.5 dBm at 380-400 GHz and with a pattern scan of +/-35° in one plane. To the best of our knowledge, this is one of the first demonstrations of a phased array operating at 400 GHz using CMOS technology and with wide operating bandwidth.

I. Introduction

The use of silicon SiGe and CMOS technologies in millimeter-wave (mm-wave) and terahertz (THz) transmitters and receivers has been an active area of research due to the potential of building large-scale imaging arrays and high data-rate communication links at relatively low cost [1]–[18]. For imaging systems, silicon allows the construction of single-chip focal-plane arrays with integrated antennas and detectors, together with all the multiplexing and readout electronics, thus reducing the system cost. Silicon also results in high yield and in uniformity from pixel-to-pixel, which is a prerequisite for fully integrated systems. For communication systems, silicon offers acceptable performance for mixers and modulators up to 150–300 GHz [19]–[21], and while these are not as competitive as their GaAs counterparts, they are good enough for short distance communication systems.