Illustrative    

India’s Technology Development Fund (TDF), managed by DRDO, has introduced a significant new project under its priority Request for Information (RFI) aimed at developing shared aperture phased array antenna technology. This initiative seeks to revolutionise antenna integration across radar, electronic warfare (EW), and communication systems on modern military platforms.

The shared aperture concept addresses the growing challenge of platform congestion due to multiple independent antenna arrays used for radar surveillance, EW, and communications. By merging these functionalities into a single aperture, the system reduces structural clutter, minimises mutual interference, and improves electromagnetic compatibility across on-board systems, particularly critical for stealth platforms.

A key advantage of this integrated approach lies in its ability to significantly reduce radar cross-section (RCS). Traditional multi-antenna configurations contribute to higher reflectivity and signature exposure. The shared aperture antenna, conversely, enables a smooth electromagnetic profile, essential for low-observable platforms such as stealth UAVs, advanced fighter aircraft, and naval vessels requiring signature management.

The project proposes the development of two design verification modules (DVMs) operating across distinct wideband frequency ranges: 1–6 GHz and 5–18 GHz. These bands will collectively support multifunction capabilities required for radar surveillance, high-data-rate communications, and EW operations.

By incorporating shared aperture arrays, these systems will simultaneously handle detection, tracking, jamming, and data-link functions from one radiating surface.

Critical indigenous technologies identified for the project include wideband transmit/receive modules (TRMs), wideband antenna structures, wideband Radomes leveraging metamaterial or frequency selective surface (FSS) designs, and a unified exciter/receiver architecture. The integration of these subsystems is essential to achieve high-performance multi-band operation without compromising sensitivity or power distribution.

The unified exciter/receiver architecture lies at the core of this initiative, enabling seamless signal coordination across the shared aperture. It allows concurrent radar scanning, jamming, and communication transmissions through coherent beamforming and dynamic frequency management. Such integration promises agility in simultaneous multi-role operations, indispensable for next-generation air and maritime platforms.

The envisaged antenna modules will play a key role in multiple strategic programmes, including sea surveillance systems, ballistic missile defence (BMD) tracking arrays, High Endurance Autonomous Unmanned Vehicles (HEAUVs), and Airborne Early Warning and Control (AEW&C) platforms. The wider operational bandwidth will permit real-time networked coordination across these domains while maintaining low-profile installations.

The challenge lies in achieving ultra-wideband performance within compact architectures without mutual functional degradation. Realisation of efficient multi-band TRMs will require solid-state materials with linear gain characteristics and adaptive calibration mechanisms to maintain phase coherency across frequencies and functionalities.

The use of metamaterial or FSS-based Radomes will represent an additional technological leap. These advanced materials can selectively filter, transmit, or absorb signals within specific bands, ensuring that radar and communication beams experience minimal losses while suppressing unwanted spectral leakage. The result is enhanced sensitivity, radiation efficiency, and stealth compatibility.

This initiative directly supports India’s larger objective of achieving defence self-reliance in high-frequency electronic systems. By indigenising shared aperture antenna technology, DRDO aims to reduce dependency on imported hardware for radar and communication integration, fostering cross-domain modularity within indigenous military systems.

Once realised, this technology will underpin future integrated sensor networks across the Indian Armed Forces, enabling consolidated antenna architectures for platforms ranging from ground-based command centres to space-linked surveillance systems. It positions Indian defence electronics on par with global benchmarks in multifunctional aperture technologies vital for network-centric warfare.

Comparison: Shared Aperture Antenna Vs Existing Multi‑Antenna Systems (AEW&C, TEJAS MK-2)

ParameterExisting Multi‑Antenna Architecture (AEW&C / TEJAS MK-2)Proposed Shared Aperture Phased Array Antenna
System ConfigurationMultiple discrete antennas for radar, EW, and communication systems mounted separatelySingle integrated radiating aperture combining radar, EW, and communication functions
Frequency CoverageNarrow to medium band; each subsystem limited to its operating rangeUltra‑wideband operation covering 1–6 GHz and 5–18 GHz simultaneously
Physical FootprintHigh spatial requirement due to multiple arrays and feedsMinimal footprint with consolidated aperture design
Electromagnetic Interference (EMI)High potential for mutual interference and cross‑talkSignificantly reduced EMI due to unified and synchronised architecture
Radar Cross Section (RCS)Elevated RCS signature from multiple exposed radiatorsReduced RCS achieved through streamlined shared aperture surface
System Weight and CablingHeavy wiring, connectors, and RF cabling between independent unitsReduced structural mass, simplified interconnections, and integrated signal paths
Operational FlexibilityDedicated subsystems restrict parallel operations between radar, jamming, and communicationsConcurrent multi‑functional performance through unified exciter/receiver coordination
Maintenance and AlignmentComplex calibration and separate fault diagnostics for each antennaSimplified maintenance and self‑calibrating modules
Technology BaseMature but segmented legacy hardware; partial foreign contentIndigenous wideband TRMs, Radome materials, and unified signal processing modules under TDF
Stealth CompatibilityLimited stealth integration due to multiple protruding antennasHigh stealth efficiency from low‑profile conformal shared aperture
ApplicationsAEW&C, Tejas Mk2, Sukhoi upgrades, select naval radar systemsFuture AEW&C variants, BMD surveillance, HEAUVs, stealth UAVs, naval integrated masts
Development DriversPlatform‑specific antenna design with separate development cyclesCross‑domain modularity enabling reuse across diverse vehicle classes
Strategic OutcomeEfficient in niche roles but lacks multi‑role adaptabilityCore enabler for network‑centric warfare and indigenous sensor fusion capability

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