Jeff Massman received the B.S.E. degree in electrical engineering from the U.S. Air Force Academy and the M.S.E.E. and Ph.D. degrees from the Air Force Institute of Technology. He is Chief Systems Architect, Phased Arrays at Analog Devices, where he leads the strategy, portfolio, and platform vision for phased-array systems. His work focuses on commercial AESA architectures, antennas, digital beamforming, calibration, and MIMO software for scalable radar and sensing platforms. He has more than 16 years of experience across defense and commercial RF systems, with contributions spanning RF seekers, space-based sensors, collaborative UAV platforms, and 5G mmWave products. He has authored numerous peer-reviewed publications, delivered invited workshops and technical talks, and holds multiple patents in antennas, RF systems, and array technologies.
Abstract:
Title: Spectral Regrowth Has an Angle: A Systems Perspective on Nonlinear Front Ends in Phased Arrays
Nonlinear RF front ends are often treated as channel-level design problems, with performance judged through compression, phase distortion, intermodulation, efficiency, and spectral regrowth. In an active electronically scanned array, those same effects are repeated across many transmit channels with controlled relative phase, where they can affect beam shape, pointing stability, sidelobes, null depth, polarization purity, and the spatial distribution of unwanted emissions. This talk looks at the connection between nonlinear microwave circuits and practical phased-array design from a systems perspective, drawing on real-world AESA architecture experience, industry use cases, and selected trends from the research literature. It will examine how drive-dependent gain and phase errors can perturb aperture weights, how memory effects and bias dynamics can create time-varying channel behavior, and how intermodulation or spectral-regrowth products may radiate with angle-dependent structure, potentially leading to nonlinear ghost-beam behavior. These observations raise a practical question for the nonlinear microwave community: What does linearization mean when unwanted emissions are spatially distributed? The talk will use that question to connect channel-level nonlinear behavior to aperture-level specifications, measurement approaches, calibration needs, and architecture tradeoffs across scan angle, waveform, thermal state, and subarray design. The aim is to give the nonlinear microwave community a practical aperture-level lens for next-generation AESA systems.
