An Ising Machine Based on Millimeter-Wave Coupled LC Oscillators

An Ising machine is presented in this paper using millimeter-wave (mm-wave) coupled LC oscillators showing an increased speed and a significant reduction in the time needed to find a solution. The Ising machine is designed in a 45nm CMOS technology and the oscillators operate at 32.2 GHz. The Ising machine uses second harmonic injection at the gates of the tail transistors of the oscillators. The coupling mechanism is implemented using injection at the tank, which can be activated or deactivated by controlling the bias of the coupling circuitry. A max-cut problem is solved using an undirected graph in simulation utilizing the proposed Ising machine and the solution is obtained within 0.5ns.