The DiCAD Design Methodology focuses on the development of a fine-tuning digital controlled oscillator (DCO) using a digital controlled artificial dielectric (DiCAD). The methodology provides a structured step-by-step guide for designing fine-tuning range DCOs for use in All-Digital Phase-Locked Loops (ADPLLs), addressing challenges in frequency stability, phase noise reduction, and tuning range precision.
This research builds upon previous work with coarse tuning DCOs, extending their capabilities to fine-tuning applications, which is critical for high-performance RF and microwave systems such as military-grade software-defined radios (SDRs).
As the Researcher & Lead Designer, I was responsible for:
• Developing the DiCAD-based DCO design methodology
• Simulating and validating the proposed fine-tuning technique
• Optimizing digital control mechanisms for frequency synthesis
• Analyzing oscillator phase noise and tuning stability
• Prototyping and testing the DiCAD structure using electromagnetic simulations
• Literature Review: Studied ADPLL architectures and noise reduction techniques
• Electromagnetic (EM) Simulations: Modeled DiCAD structures to optimize dielectric properties
• Phase Noise Analysis: Investigated the impact of oscillator noise sources
• Fine-Tuning Mechanism Development: Designed switchable transmission line structures for precision tuning
• Performance Benchmarking: Compared DiCAD tuning with traditional varactor-based approaches
• Electromagnetic Simulation: Sonnet, Agilent ADS
• Circuit Design & Modeling: Cadence Virtuoso, FreePDK45nm Design Kit
• Data Analysis & Automation: MATLAB, Perl scripting for model generation
The DiCAD Design Methodology focuses on the development of a fine-tuning digital controlled oscillator (DCO) using a digital controlled artificial dielectric (DiCAD). The methodology provides a structured step-by-step guide for designing fine-tuning range DCOs for use in All-Digital Phase-Locked Loops (ADPLLs), addressing challenges in frequency stability, phase noise reduction, and tuning range precision.
This research builds upon previous work with coarse tuning DCOs, extending their capabilities to fine-tuning applications, which is critical for high-performance RF and microwave systems such as military-grade software-defined radios (SDRs).
As the Researcher & Lead Designer, I was responsible for:
• Developing the DiCAD-based DCO design methodology
• Simulating and validating the proposed fine-tuning technique
• Optimizing digital control mechanisms for frequency synthesis
• Analyzing oscillator phase noise and tuning stability
• Prototyping and testing the DiCAD structure using electromagnetic simulations
• Electromagnetic Simulation: Sonnet, Agilent ADS
• Circuit Design & Modeling: Cadence Virtuoso, FreePDK45nm Design Kit
• Data Analysis & Automation: MATLAB, Perl scripting for model generation
• Literature Review: Studied ADPLL architectures and noise reduction techniques
• Electromagnetic (EM) Simulations: Modeled DiCAD structures to optimize dielectric properties
• Phase Noise Analysis: Investigated the impact of oscillator noise sources
• Fine-Tuning Mechanism Development: Designed switchable transmission line structures for precision tuning
• Performance Benchmarking: Compared DiCAD tuning with traditional varactor-based approaches
The DiCAD Design Methodology focuses on the development of a fine-tuning digital controlled oscillator (DCO) using a digital controlled artificial dielectric (DiCAD). The methodology provides a structured step-by-step guide for designing fine-tuning range DCOs for use in All-Digital Phase-Locked Loops (ADPLLs), addressing challenges in frequency stability, phase noise reduction, and tuning range precision.
This research builds upon previous work with coarse tuning DCOs, extending their capabilities to fine-tuning applications, which is critical for high-performance RF and microwave systems such as military-grade software-defined radios (SDRs).
As the Researcher & Lead Designer, I was responsible for:
• Developing the DiCAD-based DCO design methodology
• Simulating and validating the proposed fine-tuning technique
• Optimizing digital control mechanisms for frequency synthesis
• Analyzing oscillator phase noise and tuning stability
• Prototyping and testing the DiCAD structure using electromagnetic simulations
• Electromagnetic Simulation: Sonnet, Agilent ADS
• Circuit Design & Modeling: Cadence Virtuoso, FreePDK45nm Design Kit
• Data Analysis & Automation: MATLAB, Perl scripting for model generation
• Literature Review: Studied ADPLL architectures and noise reduction techniques
• Electromagnetic (EM) Simulations: Modeled DiCAD structures to optimize dielectric properties
• Phase Noise Analysis: Investigated the impact of oscillator noise sources
• Fine-Tuning Mechanism Development: Designed switchable transmission line structures for precision tuning
• Performance Benchmarking: Compared DiCAD tuning with traditional varactor-based approaches
Objectives
• Develop a high-frequency, fine-tuning range DCO with improved noise characteristics
• Create a structured methodology for designing DCOs using DiCAD technology
• Demonstrate feasibility for use in ADPLLs for RF and military applications
• Optimize tuning step resolution while maintaining oscillator stability
Constraints:
• Switching-induced noise—Minimizing frequency jumps due to DiCAD state changes
• Dielectric material variations—Ensuring consistency in the artificial dielectric properties
• Integration with CMOS processes—Maintaining manufacturability within standard semiconductor fabs
• Computational complexity—Managing the trade-offs between simulation accuracy and time
• University of Minnesota Research Faculty – Guidance and validation of the research
• Semiconductor & RF Engineers – Industry relevance and feedback
• Military & Defense Applications – Potential implementation for SDR and secure communications
Challenges:
• Traditional DCO designs lacked fine-tuning resolution, limiting their precision.
• Varactor-based tuning introduced phase noise, degrading oscillator performance.
• Existing coarse-tuning DiCAD DCOs did not allow small frequency adjustments.
The Impact:
• DiCAD fine-tuning extends the usability of DCOs in high-performance RF applications.
• Lower phase noise improves frequency synthesis for ADPLLs in SDR systems.
• Step-by-step design methodology ensures repeatability for future semiconductor designs.
Step 1: Define the DiCAD Tuning Mechanism
• Developed a switchable DiCAD structure to dynamically adjust effective dielectric properties.
• Designed metal strip configurations to control phase delay and frequency shifts.
Step 2: Electromagnetic Modeling & Simulation
• Created test structures in FreePDK45nm for CMOS implementation.
• Ran Sonnet EM simulations to analyze phase delay and resonance behavior.
Step 3: Circuit Integration & Validation
• Implemented spice models derived from S-parameters for system-level simulations.
• Built a switchable 4-port DiCAD model using Perl scripts for automated circuit generation.
Step 4: Performance Evaluation & Optimization
• Simulated DCO fine-tuning across different duty cycles and analyzed frequency stability.
• Compared tuning resolution against varactor-based oscillators to validate DiCAD’s superiority.
• Designed a CMOS-compatible DiCAD structure for fine-tuning in DCOs
• Implemented a switchable model to dynamically control oscillator frequency
• Optimized phase noise performance by minimizing switching-induced jitter
• Developed a 10-step design methodology for repeatable implementation
Key Success Metrics:
• Achieved fine-tuning resolution of 1.21 MHz per duty cycle adjustment
• Demonstrated stable oscillator operation with reduced phase noise
• Developed a structured methodology for designing high-performance DCOs
• Validated feasibility for use in ADPLL-based SDR applications
Long-Term Impact:
• Reduced oscillator phase noise improves signal integrity in RF systems
• Increased tuning precision allows for higher performance ADPLL designs
• Methodology serves as a foundation for future research in digitally controlled oscillators
• DiCAD technology enables precise frequency control for RF applications.
• Fine-tuning DCOs require a balance between stability and flexibility.
• Switching-induced noise is a key limitation that must be mitigated.
• This research contributes to the evolution of ADPLL design methodologies.
• DiCAD-based tuning offers a scalable approach for military and commercial RF applications.
• Structured methodology ensures practical implementation beyond academia.
• The learnings from this project and my senior honors project paved the way for the start of my career at Broadcom - Principle IC Design Engineer
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