Review Article
A Review of Over-the-Horizon Radar Systems: Global Perspectives on Design, Operational Principles, and Performance
Ajay Prudhvi Raj*
,
Sahebgowda Patil,
Anthonysamy Arockia Bazil Raj,
Kamla Prasan Ray
Issue:
Volume 14, Issue 1, June 2026
Pages:
1-16
Received:
28 November 2025
Accepted:
31 January 2026
Published:
16 March 2026
Abstract: This paper presents a comprehensive global review of over-the-horizon radar (OTHR) systems, spanning both skywave and surface-wave designs across operational, research, and historical contexts. The review integrates technical descriptions of system architectures, operating frequency ranges, waveform designs, signal processing methods, and performance characteristics, supported by corrected historical attributions and consolidated references. Major operational systems-including JORN, ROTHR, Nostradamus, the Russian 29B6 ”Container,” and Iran’s Sepehr-are examined alongside research networks such as SuperDARN and large-scale high-frequency surface-wave radar arrays used for oceanographic monitoring. Historical and retired systems, including the Soviet Duga, Cobra Mist, and the U.S. OTH-B network, are analyzed for the technical lessons they provide regarding antenna siting and noise suppression. A comparative table summarizes key parameters across all systems, offering a unified reference framework. Applications in defense surveillance, maritime domain awareness, environmental monitoring, and ionospheric research are outlined. Furthermore, this survey highlights emerging trends critical to the next generation of OTHR, such as multi-frequency agility for ionospheric resilience, machine learning-based clutter suppression, and the integration of spaceborne or UAV-borne sensors for enhanced data fusion. By linking historical technical challenges with modern adaptive signal processing and compact deployable architectures, this survey serves as both a strategic technical reference and a forward-looking roadmap for the continued evolution of high-frequency radar technology.
Abstract: This paper presents a comprehensive global review of over-the-horizon radar (OTHR) systems, spanning both skywave and surface-wave designs across operational, research, and historical contexts. The review integrates technical descriptions of system architectures, operating frequency ranges, waveform designs, signal processing methods, and performan...
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Research Article
On the Radar Absorbing Material Reflectivity and Electromagnetic Interference Shielding Effectiveness
Tarek Abdulrahman Sallam,
Abdel Rahman Mohammad Sallam*
Issue:
Volume 14, Issue 1, June 2026
Pages:
17-23
Received:
21 September 2026
Accepted:
4 October 2026
Published:
11 November 2026
DOI:
10.11648/j.ajea.20261401.12
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Views:
Abstract: The goal of this work is to examine radar absorbing material (RAM); which -in the simplest case- is composed of a single metal-packed coating layer, reflectivity (R) through a frequency (f) range from 0.5 GHz to 40 GHz; this range covers applications of long-range radar, missile detection, surface target tracking, and airborne precision ground radars. Variation of nonmagnetic, homogeneous, and non-dispersive RAM R is reformed to facilitate calculations. Effect of dielectric parameters; permittivity and permeability (ϵ and μ) on R for one layer-metal-packed RAM with two different thicknesses (they influence the electromagnetic wave absorption due to attenuation and matching models) are given. Electromagnetic interference shielding effectiveness (EMISE) which characterises the behaviour of a material depends on material conductivity (σ), relative permittivity (ϵ_r) and relative permeability (μ_r). reflection loss (R), absorption loss (A), and internal loss (M) for one and two layers located between two semi-infinite free space media are derived. Attenuation (α) variations with f, ϵ, μ, and layer thickness for single and double layers are examined. Results indicate that most waves are reflected from inside interfaces of RAM also high conductivity, high permeability, and increasing thickness are necessary to configure good absorbent. Calculations and graphs are carried on using MATLAB R2013a.
Abstract: The goal of this work is to examine radar absorbing material (RAM); which -in the simplest case- is composed of a single metal-packed coating layer, reflectivity (R) through a frequency (f) range from 0.5 GHz to 40 GHz; this range covers applications of long-range radar, missile detection, surface target tracking, and airborne precision ground rada...
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