About

Luca Colombo is an Assistant Research Professor in the Department of Electrical and Computer Engineering at Northeastern University. His research focuses on wireless sensing technology, including the development of reprogrammable on-chip antennas and embedded intelligence capabilities in wireless sensor tags. Colombo has contributed to advancements in the Internet of Things and artificial intelligence by embedding intelligence in wireless devices to improve accuracy and reduce energy consumption. His work has been published in notable journals such as Nature Electronics, highlighting his involvement in innovative projects like programmable threshold sensing using Ising dynamics and the development of dual-mode, reprogrammable radio-frequency front ends.

Research topics

• Optoelectronics
• Materials science
• Electronic engineering
• Electrical engineering
• Engineering
• Nanotechnology
• Physics
• Composite material

Selected publications

• ScAlN-on-SiC K<i>ᵤ</i>-Band Sezawa Solidly-Mounted Bidimensional Mode Resonators

  IEEE Electron Device Letters · 2025-02-13 · 13 citations

  article1st authorCorresponding

  This letter reports on Solidly-Mounted Bidimensional Mode Resonators (S2MRs) exploiting a highly-optimized Sezawa mode in 30% Scandium-doped Aluminum Nitride (ScAlN) on Silicon Carbide (SiC) and operating near 16 GHz. Experimental results demonstrate mechanical quality factors (<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${Q}_{m}$ </tex-math></inline-formula>) as high as 380, Bode quality factors (<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${Q}_{\textit {Bode}}$ </tex-math></inline-formula>) approaching 500, electromechanical coupling coefficients (<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${k}_{t}^{{2}}$ </tex-math></inline-formula>) of 4.5%, an overall Figure of Merit (<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\textit {FOM} = {Q}_{m} \cdot {k}_{t}^{{2}}$ </tex-math></inline-formula>) exceeding 17, and power handling greater than 20 dBm for devices closely matched to <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$50~\Omega $ </tex-math></inline-formula>. To the best of the authors’ knowledge, S2MRs exhibit the highest Key Performance Indicators (KPIs) among solidly mounted resonators in the Ku-band, paving the way for the integration of nanoacoustic devices on fast substrates with high-power electronics, tailored for military and harsh-environment applications.

  PublisherDOI

• Black Box Neural Modeling of Micro- and Nanoacoustic Resonators

  2025-05-12 · 1 citations

  article1st authorCorresponding

  SummaryIn this work, a black box model for acoustic resonators is developed using artificial Neural Networks (NN), leveraging synthetic data generated from finite element analysis (FEA) simulations. The approach is demonstrated on Solidly-Mounted Bidimensional Mode Resonators (S2MR), utilizing an optimized Sezawa mode in Scandium Aluminum Nitride (ScAlN) on Silicon Carbide (SiC). Practical applications, including dispersion characteristic reconstruction, topology optimization, and fabrication variability analysis, are presented. While this implementation focuses on a specific resonator type, the proposed methodology is inherently technology-agnostic, making it adaptable to a broad range of resonator designs and scalable to higher-dimensional simulations or experimental datasets.

  PublisherDOI

• A Radiofrequency Threshold Temperature Sensor Using a Hf_0.5Zr_0.5O₂ Device and a Microacoustic Piezoelectric Resonant Sensor

  Journal of Microelectromechanical Systems · 2024-02-22 · 3 citations

  article

  This article presents the first prototype of a novel threshold sensing system operating in the radiofrequency (RF) range, capable of passively detecting and recording instances of temperature violations with high sensitivity and without the need of DC-biased memory devices. The system comprises a microfabricated hafnium zirconium oxide (HZO) ferroelectric varactor, a microfabricated lithium niobate (LiNbO3) shear-horizontal (SH0) Lamb wave microacoustic resonator used as a temperature sensor, and an inductor. All components have been soldered onto a printed circuit board for testing and characterization. Through this threshold sensing system, we also provide the first demonstration of ferroelectric switching in a HZO varactor triggered exclusively by an RF signal without requiring any DC voltages. The findings reported in this paper offer a promising pathway for future RF passive tags leveraging micro- and nanosystems to implement a programmable threshold sensing functionality with high sensitivity and with embedded memory capabilities. [2023-0215]

  PublisherDOI

• Parametric Frequency Divider Based Ising Machines

  Physical Review Letters · 2024-04-02 · 6 citations

  article

  We report on a new class of Ising machines (IMs) that rely on coupled parametric frequency dividers (PFDs) as macroscopic artificial spins. Unlike the IM counterparts based on subharmonic-injection locking (SHIL), PFD IMs do not require strong injected continuous-wave signals or applied dc voltages. Therefore, they show a significantly lower power consumption per spin compared to SHIL-based IMs, making it feasible to accurately solve large-scale combinatorial optimization problems that are hard or even impossible to solve by using the current von Neumann computing architectures. Furthermore, using high quality factor resonators in the PFD design makes PFD IMs able to exhibit a nanowatt-level power per spin. Also, it remarkably allows a speedup of the phase synchronization among the PFDs, resulting in shorter time to solution and lower energy to solution despite the resonators' longer relaxation time. As a proof of concept, a 4-node PFD IM has been demonstrated. This IM correctly solves a set of Max-Cut problems while consuming just 600 nanowatts per spin. This power consumption is 2 orders of magnitude lower than the power per spin of state-of-the-art SHIL-based IMs operating at the same frequency.

  PublisherDOI

• A Millimeter Wave Ferroelectric Hafnium Zirconium Oxide-based Programmable Antenna

  2024-09-22 · 3 citations

  article

  In this work, we present an on-chip Hafnium Zirconium Oxide-based millimeter wave (mmWave) programmable antenna. The device exhibits a resonance frequency of 36.623 GHz, which can be programmed by varying the polarization state of a thin Hafnium Zirconium Oxide (HZO) layer enclosed in the structure of the antenna. By polarizing such HZO film, we demonstrate, for the first time, a variation in the resonance frequency for ferroelectrically programmable antennas without continuously applying a bias. In this regard, the non-volatile behavior of HZO allows to retain the polarization state of the film even after removing the DC voltage, therefore enabling the antenna's resonance frequency retention. The full ferroelectric switching of the HZO layer occurs approximately at ±3 V, resulting in a maximum resonance frequency shift of 3.019 GHz (8.3% fractional frequency change) between different programming voltages. The device's response to the applied programming voltage generates a ferroelectrically-induced hysteresis on its resonance frequency. In contrast to prior devices of this class, the proposed approach showcases a more compact size, full post-CMOS compatibility, low programming voltage, and non-volatile programmability.

  PublisherDOI

• SCANDIUM ALUMINUM NITRIDE OVERMODED BULK ACOUSTIC RESONATORS FOR FUTURE WIRELESS COMMUNICATION

  2024-06-02 · 2 citations

  articleOpen access

  This work reports on the modeling, fabrication, and experimental characterization of a 13 GHz 30% Scandiumdoped Aluminum Nitride (ScAlN) Overmoded Bulk Acoustic Resonator (OBAR) for high-frequency Radio Frequency (RF) applications, notably in 5G technology and beyond.The Finite Element Analysis (FEA) optimization process targets the top and bottom metal electrode thicknesses, balancing the electromechanical coupling coefficient and acoustic energy distribution to enhance device Figure of Merit (FOM).Experimental results on fabricated devices employing platinum and aluminum as bottom and top electrode, respectively, demonstrate a quality factor at resonance (Q s ) of 210 and a coupling coefficient (k 2 t ) of 5.2% at 13.3 GHz for the second bulk thickness overtone, effectively validating the simulation framework and hinting at the possible implementation of OBARs for advanced RF filters in 5G networks.

  PublisherDOI

• Characterization of Acoustic Losses in Interdigitated VHF to mmWave Piezoelectric M/NEMS Resonators

  2024-09-22 · 8 citations

  article1st authorCorresponding

  This work reports on a technology-agnostic and frequency-independent methodology combining a-priori modeling, Finite Element Analysis (FEA), and experimental results for the characterization of acoustic losses in interdigitated piezoelectric micro- and nano-electromechanical (M/NEMS) resonators. The proposed approach models the mechanical quality factor (Q<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">m</inf>) and its dependency on piezoelectric (Q<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">piezo</inf>) and metal (Q<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">metal</inf>) acoustic losses, as a function of the mode of vibration dispersion characteristics. The model is finally experimentally validated by exploiting the intrinsic on-chip multifrequency manufacturability of interdigitated devices.A broad range of available resonator technologies, frequencies, and piezoelectric materials are investigated for this purpose, including bulk X-cut Lithium Niobate (XLN) leaky surface acoustic wave resonators operating at Ultra High Frequency (UHF), thin film XLN Lamb Wave resonators spanning between Very High Frequency (VHF) and the K<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">u</inf> band, and Aluminum Nitride (AlN) and scandium-doped AlN (ScAlN) cross-sectional lamé mode resonators ranging from the K<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">u</inf> to K<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">a</inf> band (mmWave).

  PublisherDOI

• A Radiofrequency Threshold Sensing System Using a Hf0.5Zr0.5O2 Device and a Microacoustic Piezoelectric Resonant Sensor

  2024-01-17

  preprintOpen access

  The maximum value of the V bias V c (-) Coercive voltage required to switch the HZO varactor to its negative polarization state V c (+) Coercive voltage required to switch the HZO varactor to its positive polarization state V DC Generated DC voltage across the varactor due to rectification WSN Wireless Sensor Nodes VNA Vector Network Analyzer Y 11Input admittance relative to the Drive-Port

  PublisherOA PDFDOI

• Up-Scaling Microacoustics: 20 to 35 GHz ALN Resonators with f • Q Products Exceeding 14 THz

  2024-01-21 · 12 citations

  article

  This work presents an analysis of the first mmWaves-operating Cross-sectional Lamé Mode Resonators (CLMRs), investigating the intrinsic quality factor limit of the technology. By leveraging the Finite Element Modeling-simulated energy distributions in the piezoelectric and metal layer, an accurate matching of theoretical and experimental quality factor is achieved, thus identifying the main source of CLMR performance degradation in the 20 to 35 GHz frequency range. Furthermore, excellent quality factors are recorded, achieving the largest frequency and quality factor product (f <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">s</inf> • Q = 14.4 THz) ever demonstrated on sputtered thin-films and among the largest ever reported for the microacoustic technology. In conclusion, the present results explore the feasibility of enabling mmWaves-operating CLMRs to extend the use cases of the microacoustic technology to a virtually new spectrum territory, while outlining design trade-offs aiming to maximize their quality factors.

  PublisherDOI

• Optical camera communications for indoor positioning: high accuracy, low cost, and low power consumption

  2024-01-26 · 1 citations

  articleOpen access

  Optical Camera Communication (OCC) can be employed for indoor positioning and navigation, and it is suitable for environments where GPS signals are unavailable or unreliable. We developed a novel solution based on a network of Light Emitting Diode (LED) lamps placed on the ceiling, where each lamp emits a unique identification (ID) code made of a few simple sine waves. The code is detected by the camera sensor exploiting the rolling shutter and ad-hoc signal processing which does not need synchronization. The system only requires a single image to recognize different IDs captured by the camera, reducing the power consumption of the device. The position can operate in coarse and fine modes, with meter and centimeter accuracy, respectively. In both cases, a single LED lamp is enough for localization.

  PublisherOA PDFDOI

Frequent coauthors

• Matteo Rinaldi

  Scuola Normale Superiore

  49 shared

• Gabriel Giribaldi

  Northeastern University

  27 shared

• Gianluca Piazza

  University of Cambridge

  22 shared

• Pietro Simeoni

  21 shared

• Cristian Cassella

  Universidad del Noreste

  20 shared

• Michele Pirro

  Northeastern University

  19 shared

• Abhay Kochhar

  17 shared

• Giuseppe Michetti

  Northeastern University

  15 shared