NEW DELHI — May 31, 2026 : New technical details have emerged regarding the indigenous Active Electronically Scanned Array (AESA) radar being developed for India’s Advanced Medium Combat Aircraft (AMCA), indicating that the system will feature a 10.5 kW cooling capacity and approximately 1,540 Gallium Nitride (GaN)-based Transmit/Receive Modules (TRMs) designed to support the stealth fighter’s performance, thermal management, and operational efficiency requirements.
The radar is being developed by the Defence Research and Development Organisation (DRDO)’s Electronics and Radar Development Establishment (LRDE) as part of India’s wider effort to equip the AMCA with domestically developed mission systems and sensors. During Aero India 2025, LRDE displayed a 1:2 scale model of the radar, highlighting a GaN-based AESA configuration integrated with DRDO’s newly developed Vivaldi antenna technology.
Cooling Capacity and TRM Configuration
According to technical details now in circulation, the AMCA radar will incorporate a cooling capacity of 10.5 kW, equivalent to the Vapour Compression Machine developed for the Virupaksha AESA radar currently being designed for the Indian Air Force’s Su-30MKI upgrade programme.
However, while the Virupaksha radar is reported to feature around 2,400 TRMs, the AMCA radar is expected to integrate approximately 1,540 modules. The reduced TRM count is understood to reflect the stealth fighter’s design requirements, where compactness, thermal efficiency, and optimized integration within a fifth-generation airframe are prioritized.
The radar is expected to maintain high operational efficiency within the same thermal envelope due to the use of GaN semiconductor technology. Compared to older Gallium Arsenide (GaAs)-based systems, GaN TRMs provide higher power density and improved efficiency per module, enabling stronger performance with a comparatively smaller module count.
Vapour Compression Cooling System
Thermal management for the AMCA radar will rely on a closed-loop Vapour Compression System engineered to absorb and dissipate up to 10.5 kW of continuous heat load. The cooling system is intended to maintain stable thermal conditions for radar electronics, power supplies, and signal-processing units, particularly during prolonged missions and sustained high-power radar operation.
Maintaining thermal efficiency is considered particularly important for stealth aircraft because excessive localized heating can affect system performance and increase infrared detectability. By regulating temperatures across radar components, the system is intended to support both operational reliability and sustained mission effectiveness.
Tile-Based Radar Architecture
For the AMCA platform, LRDE is developing a tile-based radar array architecture in which GaN TRMs are arranged in a circular layout compatible with the aircraft’s stealth-oriented nose cone design. Unlike conventional approaches focused primarily on maximizing TRM numbers, the AMCA radar emphasizes efficiency, compactness, bandwidth, and integration within a limited internal volume.
The tile-based configuration is also modular in design. Individual tiles can be replaced independently in the event of failure, reducing maintenance complexity without requiring the complete radar array to be dismantled.
In parallel, LRDE is also developing phased-array and tile-array configurations for different aircraft categories. Available details indicate a tiered radar architecture strategy in which plank-based radar designs are intended for lighter fighter aircraft such as the Tejas family, while tile-based systems are being developed for larger and more advanced platforms, including the upgraded Su-30MKI and the AMCA, where bandwidth, range, and electronic resilience are operational priorities.
Vivaldi Antenna for Wideband Performance
A key feature of the AMCA radar is the incorporation of DRDO’s Vivaldi antenna, also known as a Tapered Slot Antenna (TSA). The antenna was selected to meet operational requirements involving bandwidth greater than 50 percent of the centre frequency and dual-polarisation capability.
According to available technical information, commonly used antenna types such as microstrip patches and printed dipoles were not suitable for these requirements. The Vivaldi antenna provides a symmetrical radiation pattern, high gain, and broad bandwidth, enabling transmission across a wide frequency range.
Its low-profile design and wideband characteristics are expected to support efficient signal transmission while improving resistance to interference and electronic countermeasures. Combined with GaN-based TRMs, the radar is expected to deliver a higher power beam than the Uttam AESA radar for Tejas Mk1A platform.
L-Band Antenna for Identification Friend or Foe
The AMCA radar suite will also incorporate a dedicated L-band TRM antenna for Identification Friend or Foe (IFF) functions. L-band frequencies operate at longer wavelengths, making them suitable for reliable identification and communication tasks in contested environments.
The dedicated IFF antenna is intended to complement the radar’s primary fire-control functions by supporting secure and efficient identification of friendly airborne and ground assets during operations.
Parallel Development with Virupaksha Radar
The AMCA AESA radar programme is progressing simultaneously with the development of the Virupaksha radar for the Su-30MKI upgrade programme. Both systems are being undertaken by DRDO’s LRDE and reflect a broader effort to establish an indigenous airborne radar ecosystem for India’s present and future combat aircraft fleet.
By advancing technologies such as GaN-based TRMs, tile-array radar architectures, Vivaldi antennas, L-band IFF integration, and high-efficiency thermal management systems, India is working toward a domestically developed radar capability tailored to both current-generation and fifth-generation combat platforms.
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