10.5 GHz PLFM Phased Array RADAR System

  • Hardware
  • Signal Processing
  • Embedded
  • Open Source

In Progress · C/C++, Signal Processing, Phased Array, RF Hardware (10.5 GHz) …

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Executive Overview

An open-source, modular hardware and signal processing architecture for a 10.5 GHz Pulsed Linear Frequency Modulated (PLFM) phased-array radar system, enabling low-cost RF target detection, range resolution, and beamsteering experimentation.
The Challenge & Bottleneck

Core Problem

Commercial phased-array radar systems cost tens of thousands of dollars and utilize proprietary firmware, locking researchers and independent engineers out of hands-on RF signal processing experimentation. Building custom 10 GHz hardware requires addressing microstrip impedance matching, phase drift across antenna elements, and voltage-controlled oscillator (VCO) chirp non-linearities.

Engineering Approach

Architectural Solution

Designed and built an open-hardware architecture featuring microstrip patch antenna arrays, an analog RF front-end operating at 10.5 GHz, and a digital signal processing pipeline utilizing Fast Fourier Transforms (FFT) and phase-shift calculations in Python and C/C++ to steer beam patterns and calculate range-Doppler maps.

Quantified Outcomes

Measurable Impact

Successfully achieved target detection and range resolution at 10.5 GHz using accessible off-the-shelf components, with full schematics, simulation models, and signal processing scripts open-sourced under Ghosh-Sons.

System Architecture

Component topology, protocol boundaries, and data flow.

10.5 GHz PLFM Phased Array RADAR System System Topology
Architecture Flow
CLIENT CONSUMERWeb & API CallsHTTPS / REST PayloadsJSON Schema InputBOUNDARY GATEWAYNginx / Reverse ProxyTLS TerminationRate Limiting & AuthNSERVICE CORE LOGIC• Domain Services & Controllers• DTO Runtime Validation• AWS Secrets Manager Config• Health Readiness ProbesPERSISTENCEPostgreSQL / RedisACID TransactionsDocker / EKS Hosted

Reliability & Production Security

Features hardware thermal stabilization routines to prevent frequency drift during continuous transmission, calibration loops that periodically re-measure phase offsets between antenna elements, and hardware current limiting to protect sensitive RF mixer components.

Deployment & Infrastructure

Hardware reference design with open KiCad PCB schematics, FPGA/microcontroller control firmware, and a Python DSP analysis pipeline processing recorded I/Q data streams.
Engineering Post-Mortem & Insights

What I Learned

Technical trade-offs, battle-tested discoveries, and operational takeaways from this project.

1

High-Frequency RF Demands Extreme PCB Manufacturing Precision

At 10.5 GHz, millimeter trace length discrepancies translate directly into massive phase errors. Controlling substrate dielectric constants and impedance-matched microstrip routing is critical to prevent destructive standing waves.

2

VCO Chirp Linearity Directly Determines Range Resolution

Non-linearities in frequency chirps smear target reflection peaks in FFT spectra. Implementing digital pre-distortion lookup tables or closed-loop PLL frequency synthesis significantly cleans up the noise floor.

3

Phase Drift Between Elements Requires Dynamic Calibration

Temperature changes alter component phase responses over time, distorting the steered beam. Periodic self-calibration routines measuring phase differences against a known internal loopback are essential for beam pointing accuracy.

4

Modular RF Architecture Isolates High-Noise Digital Blocks

Placing high-speed digital clocks and microcontrollers on the same ground plane as sensitive RF mixers induces severe phase noise. Physically separating the digital control plane from RF microstrip sections preserves signal-to-noise ratios.

Future Roadmap & Architectural Evolution

  • →Implement real-time FPGA-accelerated FFT range-Doppler map generation for live tracking.
  • →Refine digital beamsteering control matrix to support 2D planar target acquisition.
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10.5 GHz PLFM Phased Array RADAR System | Siddhant Ghosh