NAL technicians at work at its lab on Frequency Selective Surface (FSS) Radome

Significant advancements have been made in the detailed analysis and CAD modelling of the AMCA Frequency Selective Surface (FSS) Radome, which is crucial for enhancing the performance of the Advanced Medium Combat Aircraft (AMCA). This progress is part of ongoing efforts to optimize the aircraft's design and capabilities.

Importance of Frequency Selective Surfaces (FSS):

Frequency Selective Surfaces (FSS) are thin, repetitive surfaces that can absorb, transmit, or reflect electromagnetic fields based on the frequency of the field. They are made of metallic grids or arrays of elements placed on a dielectric substrate. FSSs are used in a variety of applications, including:

Antennas: FSSs are used as reflectors in antenna applications.
Wireless communication: FSSs are used to separate signals from disruptions caused by neighbouring devices.
Radar: FSSs can screen radar emitters and transmitters from hostile emissions.

FSSs work by allowing certain frequencies of electromagnetic waves to pass through while blocking others. The output radiation after striking the FSS varies in both amplitude and phase.

FSS are engineered structures that selectively transmit or reflect electromagnetic waves, making them ideal for use in Radomes, which protect radar systems from environmental factors while allowing radar signals to pass through with minimal distortion. This technology is particularly relevant for stealth applications, as it can help reduce radar cross-section and improve overall aircraft survivability.

Various coupon-level mechanical tests including static & fatigue were conducted to explore the suitability of advanced composite materials for AMCA. A series of tests were conducted on the flaperon test box of AMCA to qualify for flaperon internal structures, joints and other design features. Static strength testing of Frequency Selective Surface (FSS)-based planar GFRP laminate proposed to be used in AMCA was carried out.

Combat aircraft simulation facilities were extensively utilized to assess control laws for LCA and AMCA.

CSIR-NAL continued its research efforts on the development of various algorithms for multi-target tracking/fusion using onboard sensors such as Infrared Search & Track (IRST), Missile Approach Warning System (MAWS), Radar, and Radar Warning Receiver (RWR) for LCA Mk 2 and AMCA aircraft programs. In this context, a multi-target tracking algorithm for MAWS was developed and angle-only target tracking of aerial targets and homing missiles was conducted using a Global Nearest Neighbourhood (GNN)-based multi-target tracking algorithm. Five missile guidance laws were developed in the simulation environment. Target tracking algorithms were validated for homing missiles with these guidance laws using the real datasets from DRDO.

The National Aerospace Laboratories (NAL) has reported substantial advancements in the CAD modelling and analysis of the AMCA's FSS Radome. This involves intricate simulations that account for complex electromagnetic interactions within the Radome environment, ensuring that the design meets stringent performance criteria.

The modelling process typically begins with creating a unit cell of the FSS, which is then expanded into larger arrays to simulate real-world conditions. This approach allows engineers to evaluate how different configurations perform under various operational scenarios, including interactions with both plane wave and antenna excitations.

As the project progresses, further refinements in design will likely focus on optimizing material properties and structural configurations to enhance performance metrics such as bandwidth, transmission efficiency, and durability against environmental stresses.

The detailed analysis and CAD modelling of the AMCA Frequency Selective Surface Radome represent a critical step forward in developing advanced radar technologies for modern combat aircraft. Continued research and development in this area will play a significant role in achieving superior stealth capabilities and operational effectiveness for the AMCA program.