Paper Describes Claude Opus Agent Designing Sub-THz Transmitter

A paper posted to arXiv on October 22, 2026 describes an experiment in handing a large language model agent control of the software engineers already use to design radio chips, rather than building a new tool around the model. The authors, Tristan Liang and Aravind Nagulu, call the framework TACS-RF, for Tool-driven Agentic Circuit Synthesis of RF and mmWave modules. The agent in the loop is Claude Opus 4.8, run as a coding agent that issues commands to Cadence Virtuoso and Spectre for schematic capture and simulation, Calibre for physical verification, Cadence EMX for electromagnetic extraction of passives, and Ansys HFSS for full-wave electromagnetic analysis. These are the standard, expensive, license-gated tools that analog and RF chip designers already use, which is the detail that separates this from a demo built around a toy simulator.

To test the framework the authors had the agent design a sub-THz transmitter intended to operate between 240 and 251 GHz, built in a 90 nanometer silicon-germanium BiCMOS process. The agent worked semi-autonomously through the sub-blocks: a 60 GHz push-push Colpitts voltage-controlled oscillator with second-harmonic extraction, multistage differential cascode power drivers, a push-push frequency doubler, a differential bowtie antenna, and the interstage matching networks that connect them. The finished chain, with devices extracted for parasitics and passives verified against electromagnetic simulation, delivered output power from +5.1 to +6.3 dBm across an 11 GHz varactor-only tuning range, with phase noise of -80 to -88 dBc/Hz at a 1 MHz offset, while drawing 361 mW of DC power.

The paper frames this as a step toward what the authors call a “text-to-ASIC” future, and spends part of its discussion on the division of labor that emerged between the human designers and the agent rather than claiming the agent worked unsupervised. The work has been accepted for presentation at the 2027 IEEE Radio and Wireless Week, in its Silicon Monolithic Integrated Circuits in RF Systems track, which puts it in front of the specific community of RF chip designers who would judge whether the output is genuinely usable silicon or a carefully chosen demonstration case.

The numbers

Figures above are drawn directly from the abstract: the transmitter’s operating band, its output power range, its tuning range and its DC power draw, each one a property of the finished chip rather than a claim about the agent’s process.