Basu, NilabhNilabhBasuChen, Ting-YiTing-YiChenChien, Jun-ChauJun-ChauChienWEI-CHANG LI2026-03-162026-03-16202607413106https://www.scopus.com/record/display.uri?eid=2-s2.0-105029318284&origin=resultslisthttps://scholars.lib.ntu.edu.tw/handle/123456789/736340This letter demonstrates local-oscillator-(LO)-free frequency down-conversion using combination resonance (CR) in a CMOS-MEMS resonator. A single RF tone injected into an engineered three-mode cluster triggers CR and produces low-frequency components—including an IF tone selectable by a baseband filter—without any locally generated reference. The modal triplet is deterministically placed by optimizing VIA locations using a particle swarm optimization (PSO) algorithm to satisfy the CR condition in a 0.35-μm CMOS-MEMS process. Measurements confirm LO-free translation and the emergence of a distinct IF component under single-tone excitation; representative spectra below and above the onset are presented. This work establishes the feasibility of LO-free down-conversion in standard CMOS-MEMS, offering a monolithic solution for secure wake-up receivers with intrinsic hardware-level interference rejection.falseCMOS-MEMS resonatorcombination resonanceLO-free down-conversionlocal oscillatorsmonolithic integrationparticle swarm optimizationjournal article10.1109/LED.2026.36590892-s2.0-105029318284