Radix-2 Technologies
Simulation to Measured Hardware SBA-Certified SDVOSB

Engineering Case Studies

For Radix-2 Technologies, simulation is not an end product. Each engineering study follows the complete technical chain from mathematical formulation and full-wave electromagnetic or algorithmic modeling through physical hardware implementation and laboratory measurement.

Standard Radix-2 Case Study Methodology
01
Problem
02
Requirements
03
Analysis
04
Design
05
Simulation
06
Fabrication
07
Measurement
08
Result
Designing and Fabricating a Microwave Microstripline Filter: From HFSS Simulation to PCB Testing – Part 2
Flagship Simulation-to-Hardware Case Study 5.5 GHz Microwave Filter & Spurious Harmonic Suppression

Designing and Fabricating a Microwave Microstripline Filter: From HFSS Simulation to PCB Testing – Part 2

Problem: Distributed bandpass filters suffer from harmonic spurious passbands (particularly at 2f₀ and 3f₀) that allow mixer image and intermodulation products to leak into receiver front-ends.
Analysis & Implementation: Hammerstad & Jensen analytical synthesis → 5-pole folded Hairpin bandpass + 9th-order radial-stub Butterworth lowpass cascade → Full-wave 3D Ansys HFSS Optimetrics → PTFE PCB fabrication → Scalar S21/S11 bench characterization.
Measured / Verified Result: Achieved < 1.5 dB passband insertion loss at 5.5 GHz with > 40 dB out-of-band harmonic suppression up to 20 GHz, validating simulated vs. measured S-parameters on low-cost PTFE laminate.
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Clash of the Telecom Codes: Zadoff-Chu vs. Gold Sequences
Waveform & SatCom PHY Case Study LEO Satellite Synchronization Under High Doppler Shift

Clash of the Telecom Codes: Zadoff-Chu vs. Gold Sequences

Problem: High radial velocities in Low Earth Orbit (LEO) satellite passes induce severe carrier frequency offsets that degrade correlation peaks and introduce delay-Doppler range-rate coupling.
Analysis & Implementation: Mathematical derivation of periodic/cyclic autocorrelation & cross-correlation bounds → Bit-true IQ time/frequency modeling → Delay-Doppler ambiguity surface evaluation across ±2.0 FFT frequency bins.
Measured / Verified Result: Quantified the exact Doppler collapse threshold of Gold codes versus Zadoff-Chu CAZAC sequences and demonstrated why ZC root selection governs range-Doppler sidelobe floors.
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Designing and Fabricating a Microwave Microstripline Filter: From HFSS Simulation to PCB Testing
EM Simulation & Hardware Verification 5.5 GHz Interdigital Bandpass Filter & Shielding Cavity Analysis

Designing and Fabricating a Microwave Microstripline Filter: From HFSS Simulation to PCB Testing

Problem: Translating ideal lumped/distributed filter synthesis to real PCB manufacturing tolerances while accounting for SMA launch discontinuities, via-stitching inductance, and metallic enclosure detuning.
Analysis & Implementation: Prototype dimensioning → Parametric 3D Ansys HFSS modal wave-port simulation → FreeCAD shielded enclosure modeling → KiCad controlled-impedance layout → Signal Hound BB60C / TG124A scalar S-parameter verification.
Measured / Verified Result: Characterized passband frequency shift, shield-induced dielectric loading, and return-loss trade-offs between unshielded and enclosed microwave PCB assemblies.
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GPS Quadrifilar helix antenna model
3D Antenna Modeling Case Study L1 GNSS Quadrifilar Helix (QFH) Antenna Synthesis

GPS Quadrifilar helix antenna model

Problem: Receiving circularly polarized L-band satellite transmissions from horizon-to-zenith without mechanical tracking requires wide-beamwidth hemispherical RHCP gain and precise quadrature phase excitation.
Analysis & Implementation: Reverse-engineering physical Vaisala GPS sonde geometry → 3D parametric helical modeling in Ansys HFSS → Far-field radiation pattern, axial ratio, and impedance sweep characterization.
Measured / Verified Result: Validated omnidirectional upper-hemisphere gain pattern and resonance sensitivity to helical pitch and loop diameter.
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balanced dipole fed by unbalanced coax
Electromagnetic Physics Case Study Coaxial Feedline Radiation & Balun Current Choking

balanced dipole fed by unbalanced coax

Problem: Feeding a balanced dipole directly from unbalanced coaxial cable excites common-mode currents along the outer shield surface, distorting the radiation pattern and detuning feedpoint impedance.
Analysis & Implementation: Skin-depth and three-conductor transmission line analysis → 3D Ansys HFSS surface current density modeling with and without a quarter-wave sleeve balun.
Measured / Verified Result: Demonstrated common-mode shield current suppression and restoration of symmetric dipole radiation patterns.
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Active Engineering & Laboratory Pipeline

Recent & Upcoming Engineering Studies

Representative areas of recent hardware, simulation, and signal-processing work available for client briefings and upcoming publication.

Antenna Synthesis & Validation

915 MHz ISM Antenna Design, Optimization & Measured vs. Simulated Characterization

Parametric HFSS optimization, impedance matching, fabrication, and VNA/spectrum bench correlation.

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Microwave Filter Engineering

Cavity & Interdigital Filter Coupling Matrix and Bandwidth Optimization

Coupling coefficient extraction, resonator spacing sensitivity, and Q-factor trade studies.

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Automated RF Test & Measurement

Automated Receiver & Component Characterization with Signal Hound BB60C & VSG60A

Programmatic vector signal generation, real-time spectrum capture, and repeatable calibration workflows.

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FPGA vs. Host Signal Processing

AMD Kria FPGA Acceleration vs. Optimized Host DSP: Quantitative Partitioning Benchmarks

When custom VHDL/FPGA logic outperforms—and when it loses to—vectorized host CPU processing once PCIe/AXI transfer overhead is measured.

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Array Processing & Direction Finding

Coherent Multi-Channel Receiver Architecture & Angle-of-Arrival (AoA) Estimation

Phase-coherent SDR front-ends, calibration, and subspace/interferometric AoA algorithm performance.

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Weather Radar & Remote Sensing

NEXRAD Doppler Weather Radar Signal Processing & Atmospheric Retrieval

Base reflectivity/velocity moment estimation, clutter suppression, and quantitative meteorological sensing.

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