Rajana Rama Satya Sai Durga Prasad

Research

Semiconductor fabrication, THz devices, photonics & quantum technologies

Terahertz Antennas · Semiconductor Fabrication · Silicon Photonics · Superconducting Circuits · Quantum Computing

MS thesis

Design and Analysis of Planar Log-Periodic Sawtooth Antennas for Terahertz Applications

May 2025 – ongoing · IIT Delhi · Supervisor: Prof. Santanu Manna, Department of Electrical Engineering.

Design & simulation

Full-wave Ansys HFSS simulation of planar log-periodic sawtooth antennas with a seven-parameter geometry space spanning 0.1–1.2 THz, evaluated on S11 impedance bandwidth, directivity, gain, and radiation pattern.

HFSS0.1–1.2 THzParametric Design

Graphene modeling

Graphene sheet impedance computed from a Python Drude model and applied as a surface-impedance boundary; a 1.5–10 THz simulation set establishes electron-beam-lithography scaling limits for on-chip THz detection.

Drude ModelSurface ImpedanceEBL Limits

Automated layout flow

Python-driven GDSII generation with KLayout verification replaces manual AutoCAD drafting — parameterized geometries produced directly from the simulation model.

Python GDSIIKLayoutDesign Automation

Fabrication & measurement

Gold antenna patterns on Si/SiO2; THz detection via graphene integrated at the antenna feed point, characterized in the IIT Delhi cleanroom and measurement labs.

Gold on Si/SiO2Graphene DetectorTHz Measurement

Cleanroom processing & THz device fabrication — ELP830

With Prof. Samaresh Das · Class 1000 cleanroom, IIT Delhi

Hands-on process flow: wafer cleaning and handling, thermal oxidation, diffusion, mask/maskless lithography, etching, and sputtering; 2D-material transfer by mechanical exfoliation; microscope inspection. Fabricated working MOSFETs and gold antenna patterns on Si/SiO2 with graphene feed-point integration for THz detection.

LithographyOxidation & DiffusionEtchingSputteringMOSFET2D-Material Transfer

Conferences & workshops

  • SAMDeV 2025, IIT Kharagpur (Dec 2025) — poster on THz antenna design and simulation
  • Quantum Devices Conference, QDC–QCSA (June 2026) — Josephson junctions, EM simulation & quantum technology
  • Quantum Design Workshop, UCLA — transmon geometry bounds on single-shot readout fidelity
  • QMD Hands-On Workshop, IIT Delhi — superconducting qubit design and silicon photonic filter design

Interests

Research directions

Terahertz devices & systems

Broadband antennas, graphene-based detectors, THz measurement chains, and spectroscopy for 6G wireless and sensing applications.

Fabrication & processing

Class 1000 cleanroom practice: lithography (mask & maskless), oxidation, diffusion, etching, sputtering, and 2D-material integration.

Silicon photonics

Ge-on-Si and III-V/SI electro-absorption modulators, carrier-depletion Mach–Zehnder modulators, ring-resonator filters on CMOS-compatible platforms.

Superconducting quantum circuits

Transmon qubits, readout resonators, energy-participation-ratio analysis, and dispersive-readout fidelity optimization.

Quantum computing tooling

Open-source development across the Qiskit ecosystem — Qiskit Metal, pyEPR, SQuADDS, scqubits, QuTiP — and cryogenic instrument automation.

Atomistic device simulation

Nanomaterial and nanodevice modeling with RESCU (DFT+DFPT), NanoDcal (DFT+NEGF), and QTCAD Poisson–Schrödinger electrostatics.

RF, microwave & analog IC

HFSS/ADS EM analysis plus Cadence Virtuoso analog design — LNAs, Schmitt triggers, PVT-aware verification on TSMC 65 nm.

Measurement automation

PyVISA/SCPI instrument control (Keithley SMU, spectrometer), custom measurement PCBs in Altium/KiCad, and cryogenic piezo nanopositioning from 300 K to 4 K.

In the lab

Research in pictures

Antenna GDS layout
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Parametric sawtooth antenna layout — generated via the Python GDSII flow.
Fabricated device under microscope
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Gold antenna pattern on Si/SiO2 with graphene feed point.
Cryostat measurement setup
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Closed-cycle cryostat with piezo nanopositioning for THz characterization.

Toolbox

Methodologies & expertise

Simulation & modeling

EM/RF: Ansys HFSS, Keysight ADS, Lumerical (CHARGE/MODE).
Quantum/device: QTCAD, RESCU, NanoDcal, Cadence Virtuoso.
Analysis: Python, MATLAB, OriginPro.

HFSSADSLumericalQTCADRESCUNanoDcalVirtuoso

Cleanroom fabrication

Wafer cleaning and handling, thermal oxidation, diffusion, mask/maskless lithography, etching, sputtering, mechanical exfoliation of 2D materials, and optical microscopy inspection.

PhotolithographyOxidationEtchingSputteringExfoliation

Instrumentation & automation

Keithley 2401 SMU I–V characterization with Ge photodetector readout; HRS750 spectrometer control; TCP/IP piezo nanopositioners inside a closed-cycle cryostat (300 K → 4 K); PyVISA/SCPI automation.

Keithley SMUCryostatNanopositionersPyVISA/SCPI

EDA, layout & programming

KLayout, AutoCAD, Python GDSII scripting, Altium Designer, KiCad PCB design; Python, C/C++, MATLAB, Bash, Linux, Git/GitHub; Verilog/SystemVerilog with UVM verification.

KLayoutAltiumKiCadPythonGitUVM

Output

Community & facilities

Conference activity

SAMDeV 2025 poster at IIT Kharagpur; QDC–QCSA participation (Josephson junctions, EM simulation, quantum tech); hands-on quantum design workshops at UCLA and IIT Delhi.

Collaboration & community

Member of Prof. Santanu Manna's research group; Qiskit Advocate contributing to the global quantum computing community; cross-group cleanroom collaboration with the Prof. Samaresh Das lab.

Facilities at IIT Delhi

Class 1000 cleanroom (NRF) with lithography, deposition, and etching tools; characterization labs with probe stations, spectrometers, and VNAs; closed-cycle cryostats for low-temperature THz measurements.

Teaching

Teaching Assistant (2024–2026): Introduction to Electrical Engineering (ELL101) and Laboratory (ELP101), Digital Electronics (ELL201, ELL1401), Electromagnetics (ELL212).