Dr Devy Kuswidiastuti ST MSc when presenting his dissertation on long-range radar in the Open Session of the Doctoral Promotion of the Department of Electrical Engineering ITS

ITS Campus, ITS News – The number of graduates with doctoral degrees from Institut Teknologi Sepuluh Nopember (ITS) has increased once more. This time, Dr. Devy Kuswidiastuti ST MSc of the Electrical Engineering Doctoral Study Program received her doctorate for her work on long-range radars that may reach a high resolution in angle, range, and speed. Her study was presented at the Doctoral Promotion Open Session on Tuesday (26/7).

According to Devy, a drawback of the standard phased array radar technology currently in use is that it can only broadcast signals in a limited number of directions. As the range is extended, she added, “The radar loses the ability to discriminate from which direction the beam is receiving the signal.”

Therefore, through her dissertation entitled Orthogonal Frequency Division Multiplexing (OFDM) Multiple-input Multiple-output (MIMO) Radar with Circulating Codes (CC), Devy focuses on overcoming radar problems in the specification of the direction of the signal and a narrow range.

In the study that resulted in the patent “Remote Radar System with Simultaneous Multiple Beams” in March 2022, Devy adapted OFDM signals, which are often used in the communications industry, to the radar technology she invented using the CC-OFDM MIMO Technique.

This OFDM signal will be paired with CC MIMO, which by applying a phase difference to the element emitting the signal, can form a beam that leads to a specific angle. The woman, who is also a lecturer at the ITS Electrical Engineering Department, added, “Each OFDM signal will be encoded with a particular code, so that when the signal is re-recorded by the signal receiver, it can be observed from whatever beam direction the signal comes from.

That way, she continued, the addition of the OFDM feature on the CC MIMO radar makes it possible to make 63 beams to be emitted simultaneously. This is what distinguishes it from conventional phased array radars, which only transmit signals in one particular direction. “So when the conventional radar is used to detect objects that are in another direction, it is necessary to have a rotor to rotate the radar,” she said.

Dr Devy Kuswidiastuti ST MSc at the Doctoral Promotion Open Session which was held in a hybrid manner and was also attended by representatives of the National Research and Innovation Agency (BRIN)

Devy asserts that altering the phase difference of each signal transmitter is necessary to modify the radar signal beam’s direction without using a rotor. The radar currently employs a phase shifter component to alter the phase difference. However, this German graduate of Hochschule Darmstadt remarked, “This phase shifter component is incredibly pricey.

She believes that another advantage of his radar design is that it can eliminate the use of the expensive phase shifter. This is because the phase difference needed to rotate the direction of the signal beam can be obtained from the OFDM signal. “That way, the price of radar using the CC-OFDM MIMO technique will be cheaper,” she assured.

With the advantages offered by his research, Devy managed to graduate with a doctor of Electrical Engineering. Devy hopes that this research can continue in the prototyping and commercialization stage. “That way, Indonesia can produce this OFDM-technology radar at a low cost,” she concluded optimistically. (ITS PR)

Reporter: Tyara Novia Andhin