An Alpha Defense Exclusive: Gallium Nitride based AESA for AMCA

-Subodh Sharma and Aman Routray

In a big development, the Electronics & Radar Development Establishment (LRDE) is all set to give India its first X Band, Gallium Nitride (GaN) based Active Electronically Scanned Array Radar. The radar will be based on the current Uttam AESA radar but will have GaN based Transmitter and Receiver Modules (TRM). GaN TRM are considered as next generation technology and can enhance the performance of Uttam AESA by manifolds.

Acknowledging the fact that Alphadefense.in has technical and non-technical readership. we have classified the article in technical and non-technical format. Firstly, we will cover the non-technical exclusive details with you and then the technical analysis of this upcoming platform. Although, as always we will simplify this technical topic for non-technical readers as well.

Exclusive details on AMCA from www.alphadefense.in

The LRDE in upcoming 18 months will provide India, its first X band AESA radar with GaN TR Modules. The GaN technology will enable this radar to detect the target at much longer distance, it will be capable of detecting stealthy aircrafts. Since the power required will be much lesser, the same aircraft will be capable of carrying radar with more TR modules, detecting and tracking more targets.

Looking at the timeline this radar could be for any platform that India is working but upon fabrication the certification of the platform will require couple of years. Thus, this Radar is likely being planned for the next generation Advance Medium Combat Aircraft (AMCA). This stealth aircraft equipped with stealth killer AESA technology will provide India decisive edge over its adversaries.

Technical Analysis of AMCA GaN AESA radar

Before we understand why Gallium Nitride (GaN) is a big thing, let’s understand the basics of RADAR Technology. In any RADAR, there are three important components

1. Transmitter – The system that transmits the signals towards the target.
2. Receiver – The system that receives the reflected signals from the target and
3. Signal Generator – The system that generates the signal, that transmitter transmits.

All these components use amplifiers for various purposes. These amplifiers are manufactured using the semiconductors. Today the semiconductor technology is rapidly shifting from Gallium Arsenide (GaAs) to Gallium Nitride (GaN). GaN and GaAs are both compound semiconductor materials, each composed of two elements. The materials are obtained in the form of ingots (TMT bars like structures), which are cut into thin wafers (see figure 1) upon which semiconductor devices, including passive circuit elements, are fabricated over these wafers by etching.

The GaAs MMICs are designed for operation at low voltages on other hand GaN is known as a power process, capable of fabricating active devices for amplifiers that can operate at voltages of +48 V dc and higher. With the higher-voltage capabilities of GaN devices and MMICs, they have become the active components of choice for such applications as power amplifiers.

The other advantages of GaN are as following:

1. Lower on-resistance giving lower conductance losses
2. Faster devices yielding fewer switching losses
3. Less capacitance resulting in fewer losses when charging and discharging devices
4. Less power needed to drive the circuit
5. Smaller devices taking up less space on the printed circuit board
6. Lower cost

Quad TRM Package:

As explained earlier in the article any radar has three major components: Transmitter, receiver, and signal generator. In transmitter and receiver, the components are almost same, just that they are used in reverse direction. Thus, to achieve the compactness, both transmitter and receiver are merged and termed as transceiver.

To further increase the compactness, these transceivers are further merged in a pack called “Quad”. This quad pack has four transceivers which results in much more compactness and ease of manufacturing.

Longer Range Radar

The Gallium Nitride based system will be capable of handling more peak power in comparison to the Gallium Arsenide TR modules. Thus, these systems will be sending more powerful signals towards the target. More powerful signal will ensure that the returned signal which usually gets attenuated, can travel longer distance before fading out completely. This will increase the detection range significantly.

Another advantage of Gallium Nitride based receiver units is that these units will have lower signal to noise ratio and higher gain. This will allow the receiver to pick up the very low signals as well. So, in case the target is at much longer distance and the radar signal reflection is significantly faded out due to distance between the radar and target, these receiver units still will be able to identify the target because of higher gain. 

Stealth Killer Radar for AMCA

Mature gallium nitride-based technology will be the significant threat to the fifth-generation fighter jet. The fifth-generation fighter jets or low observable fighter jets rely heavily on reduction in strength of the incoming radar radiation by deflecting it away from its body or absorbing it completely. In either case a small amount of radiation is anyways reflected towards the radar. This low energy signal can now be picked up by the receiver of a GaN based radar as they have low signal to noise ratio and higher gain. So, with those little reflection as well, these fifth-generation fighter jet can be detected making them vulnerable.

Conclusion

As this X band AESA radar has just started the fabrication, the final unit is at least 18 months away but the upcoming fighter jets like AMCA and Twin-engine Deck based fighter (TEDBF) can be equipped with these radars. This will enhance the capabilities of these aircrafts significantly.

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Interested about the previous updates on AMCA? Read here.