Senior RF / Electromagnetic (EM) Modeling Engineer

Role: Senior RF / Electromagnetic (EM) Modeling Engineer
Location: Mountain View, CA (Onsite / Hybrid)

About the Opportunity

We are is seeking an experienced Senior RF / Electromagnetic (EM) Modeling Engineer for an advanced semiconductor and chip design program with a leading technology company in the Bay Area.

This role focuses on electromagnetic modeling and characterization of on-chip passive components, particularly inductors, capacitors, transformers, and LC tanks used in RF circuits, oscillators, PLLs, and other high-performance analog/RF applications.

The ideal candidate will bring strong hands-on experience with Ansys HFSS and IC-focused electromagnetic simulation tools, along with a deep understanding of RF passive behavior, circuit modeling, and silicon correlation.

Key Responsibilities

• Develop and simulate electromagnetic models of on-chip passive components, including spiral inductors, transformers, baluns, T-coils, varactors, and MOM/MIM capacitors.
• Perform full-wave EM simulations using Ansys HFSS and IC-focused EM tools such as Cadence EMX, Ansys RaptorX, Keysight Momentum, Sonnet, or Clarity 3D.
• Extract and characterize key RF parameters, including inductance, quality factor (Q), self-resonant frequency (SRF), coupling coefficients, and S-parameters across relevant frequency ranges.
• Develop lumped-element equivalent circuit models, including pi-models, and broadband models suitable for circuit-level simulations.
• Collaborate with RF and analog circuit designers working on LC-VCOs, PLLs, LNAs, matching networks, and resonator-based circuits.
• Evaluate the impact of passive component quality factor, parasitic effects, and capacitor-bank configurations on phase noise, frequency tuning range, and overall circuit performance.
• Analyze electromagnetic coupling and parasitic effects associated with surrounding layout structures, including routing, metal fill, seal rings, substrate, package interconnects, and bumps.
• Correlate EM simulation results with silicon measurements using Vector Network Analyzers (VNAs), RF probe stations, and appropriate de-embedding techniques.
• Configure metal-stack technology files and PDK-related simulation environments for accurate passive component modeling.
• Automate simulation workflows, parameter sweeps, and model extraction processes using Python or similar scripting languages.

Required Qualifications

• Master's or PhD degree in Electrical Engineering, specializing in RF, microwave engineering, or electromagnetics. Bachelor's degree candidates with equivalent relevant industry experience will also be considered.
• 5+ years of relevant industry experience in RF electromagnetic modeling, simulation, or on-chip passive component characterization.
• Strong hands-on experience with Ansys HFSS, specifically for on-chip integrated circuit structures and passive components.
• Practical experience with at least one IC-focused EM simulation tool:
  • Cadence EMX
  • Ansys RaptorX
  • Keysight Momentum
  • Sonnet
  • Cadence Clarity 3D
• Strong understanding of RF passive components, LC tanks, and their applications in oscillators, PLLs, matching networks, and LNAs.
• Experience integrating EM-extracted models into circuit simulation environments such as Cadence Virtuoso with Spectre/SpectreRF or Keysight ADS.
• Strong understanding of S-parameters, Smith charts, impedance matching, and RF de-embedding techniques.
• Ability to interpret simulation results, troubleshoot model discrepancies, and collaborate effectively with circuit design teams.

Preferred Qualifications

• Experience with advanced semiconductor technologies, including CMOS, FinFET, or SiGe processes.
• Exposure to millimeter-wave (mmWave) design and modeling, particularly at frequencies of 28 GHz and above.
• Foundry, PDK, or process technology experience involving the development and characterization of on-chip inductor and capacitor models.
• Hands-on laboratory experience with Vector Network Analyzers, RF probe stations, and on-wafer measurements.
• Experience with silicon measurement correlation and de-embedding methodologies.
• Exposure to cryogenic RF electronics, superconducting resonators, or low-temperature electromagnetic modeling.

Technical Skills & Keywords

EM Simulation: Ansys HFSS, Cadence EMX, Ansys RaptorX, Keysight Momentum, Sonnet, Clarity 3D

RF Passive Components: On-Chip Inductors, Spiral Inductors, Transformers, Baluns, T-Coils, Varactors, MOM Capacitors, MIM Capacitors, LC Tanks

RF Characterization: S-Parameters, Quality Factor (Q), Self-Resonant Frequency (SRF), Coupling Coefficient, Smith Charts, De-embedding

Circuit Simulation: Cadence Virtuoso, Spectre, SpectreRF, Keysight ADS

RF Applications: LC-VCOs, PLLs, LNAs, Matching Networks, RF Front Ends, Resonators, Phase Noise

Automation & Measurement: Python, Parameter Sweeps, VNA, RF Probe Stations, Silicon Correlation