Ayush Bhatta

Mr. Ayush Bhatta

Kwangwoon University, Seoul, Republic of Korea
orcid

Research Focus & Metrics

Academic Career Length

5Years (2022-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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3 July 2023 in Sensors
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Journal Article
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ABAyush Bhatta
Ayush Bhatta
JPJeongsoo Park
Jeongsoo Park
Donghyun  BaekDonghyun Baek
Donghyun Baek
JKJeong-Geun Kim
Jeong-Geun Kim
A 28 GHz fully differential eight-channel beamforming IC (BFIC) with multimode operations is implemented in 65 nm CMOS technology for use in phased array transceivers. The BFIC has an adjustable gain and phase control on each channel to achieve fine beam steering and beam pattern. The BFIC has eight differential beamforming channels each consisting of the two-stage bi-directional amplifier with a precise gain control circuit, a six-bit phase shifter, a three-bit digital step attenuator, and a tuning bit for amplitude and phase variation compensation. The Tx and Rx mode overall gains of the differential eight-channel BFIC are around 11 dB and 9 dB, respectively, at 27.0–29.5 GHz. The return losses of the Tx mode and Rx mode are >10 dB at 27.0–29.5 GHz. The maximum phase of 354° with a phase resolution of 5.6° and the maximum attenuation of 31 dB, including the gain control bits with an attenuation resolution of 1 dB, is achieved at 27.0–29.5 GHz. The root mean square (RMS) phase and amplitude errors are <3.2° and <0.6 dB at 27.0–29.5 GHz, respectively. The chip size is 3.0 × 3.5 mm2, including pads, and Tx mode current consumption is 580 mA at 2.5 V supply voltage.

28 April 2022 in Applied Sciences
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Journal Article
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ABAyush Bhatta
Ayush Bhatta
Donghyun  BaekDonghyun Baek
Donghyun Baek
JKJeong-Geun Kim
Jeong-Geun Kim
This paper presents a 60 GHz CMOS I/Q receiver for the high-speed wireless communication system. It consists of a low noise amplifier, single-to-differential (S2D) amplifier, passive mixer, buffer amplifier with passive I/Q generator, and wideband baseband amplifier (BBA) stage. The measured conversion gain of 51 dB is achieved. The baseband bandwidth of 300 MHz is achieved from 57 GHz to 60 GHz. The 90° tandem coupler was implemented for I/Q signal generation, which has a phase error of <7° and an amplitude imbalance of <2 dB from 55 to 62 GHz. The Marchand balun is used to convert the I/Q signal to the differential, which has a phase error of <4°. A 60 GHz CMOS I/Q receiver is designed and fabricated, using a commercial 40 nm CMOS bulk process. The size of the receiver is 2.02 × 1.45 mm2, including the pads. The circuit is operated from a 0.9 V supply. The power consumption is 172 mW at maximum gain mode.

20 March 2024 in Sensors
Verified
Journal Article
Open access
PDF file
ABAyush Bhatta
Ayush Bhatta
MKMd Kamrojjaman
Md Kamrojjaman
SSsanghoon sim
sanghoon sim
JKJeong-Geun Kim
Jeong-Geun Kim
This paper presents a 5G new radio (NR) FR2 beamforming system with an integrated transceiver module. A real-time operating module providing enhanced flexibility and capability has been proposed. The integrated RF beamforming system with an integrated transceiver module can be operated in 8Tx-8Rx mode configuration simultaneously. A series-fed structure 8 × 7 microstrip antenna array for compact size and improved directivity is employed in the RF beamforming module. The RF beamforming module incorporates a custom 28 GHz, eight-channel fully differential beamforming IC (BFIC). An eight-channel BFIC in a phased-array beamforming system offers advantages in terms of increased antenna density and improved beam steering precision. The RF beamforming module is integrated with an RF transceiver module that enables the simultaneous up-conversion and down-conversion of the baseband signal. The RF transmitter module consists of a transmitter, a receiver, a signal generator, a power supply, and a control unit. The RF beamforming system can scan horizontally from −50° to +50° with a step of 10°. To achieve an optimized beam pattern, a calibration was conducted. The transmit and receive conversion gain of around 20 dB is achieved with the transceiver module. To verify the communication performance of the manufactured integrated RF beamforming system, a real-time wireless video transmission/reception test was performed at a frequency of 28 GHz, and the video file was transmitted smoothly in real time without interruption within a range of ±50°.