Accurate Design Method for Millimeter Wave Distributed Amplifier Based on Four-Port Chain (ABCD) Matrix Model

This article presents a matrix-based model suitable for millimeter-wave (mm-wave) distributed amplifier (DA) design, based on four-port chain (ABCD) formalism. Using this model, an algorithmic design methodology for DA, built upon a loss-compensation technique, is also provided that maximizes its bandwidth (BW) for a given flatness goal. The design approach provides fast and accurate design space exploration (DSE) plots that enable one to examine the tradeoffs between gain, BW, power consumption ( \mathrm {P}_{\mathrm {DC}} ), and the size and number of Gm-cells, and arrive at the optimum desired design. Its benefit is demonstrated by means of a computer-automated design (CAutoD) example where 55-nm CMOS STMicroelectronics (ST) process is used and DAs with BWs \ge80 GHz were desired to be sized; reporting 216 feasible DA options to explore from. The global optimum DA amplifying frequencies up to 100 GHz was then implemented as a circuit prototype. The measured DA provided 6.7-dB power gain while requiring a power consumption ( \mathrm {P}_{\mathrm {DC}} ) of 30 mW from a 1.2-V supply. The chip occupied a total area of 0.83 mm2. Compared to state-of-the-art FET-based small-signal DAs, the fabricated circuit reports the highest gain-bandwidth product (GBP) per \mathrm {P}_{\mathrm {DC}} ( {\mathrm {GBP}} \mathord {\left /{ {\vphantom {{\mathrm {GBP}} \mathrm {P}_{\mathrm {DC}}} }\right. } \mathrm {P}_{\mathrm {DC}} ) of 6.01 GHz/mW while being power-efficient.