Mustafa Lokhandwala | Indian Institute of Technology Bombay (original) (raw)

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Papers by Mustafa Lokhandwala

A novel Brain-Machine Interface (BMI) system based on a distributed network of implantable wirele... more A novel Brain-Machine Interface (BMI) system based on a distributed network of implantable wireless sensors was proposed. Small CMOS "Neurograin" chips (0.5x0.5 mm 2) with on-chip antenna are designed to harvest near-field RF energy at ~1 GHz, and backscatter 10 Mbps BPSK modulated data asynchronously and periodically. A "Skinpatch" software-defined radio (SDR) receiver is realized on a commercial USRP running GNU Radio programs. It down-converts the reflected waves from the Neurograins and performs data recovery. In this BMI prototype demonstration, 32 Neurograins will be wirelessly powered, while a Skinpatch USRP will recover their backscattered packets in real-time.

Transition metal atoms are one of the key ingredients in the formation of functional 2D metal org... more Transition metal atoms are one of the key ingredients in the formation of functional 2D metal organic coordination networks. Additionally, the co-deposition of metal atoms can play an important role in anchoring the molecular structures to the surface at room temperature. To gain control of such processes requires the understanding of adsorption and diffusion properties of the different transition metals on the target surface. Here, we used density functional theory to investigate the adsorption of 3d (Ti, Cr, Fe, Ni, Cu), 4d (Zr, Nb, Mo, Pd, Ag) and 5d (Hf, W, Ir, Pt, Au) transition metal adatoms on the insulating calcite (10.4) surface. We identified the most stable adsorption sites and calculated binding energies and corresponding ground state structures. We find that the preferential adsorption sites are the Ca-Ca bridge sites. Apart from the Cr, Mo, Cu, Ag and Au all the studied metals bind strongly to the calcite surface. The calculated migration barriers for the representative Ag and Fe atoms indicates that the metal adatoms are mobile on the calcite surface at room temperature. Bader analysis suggests that there is no significant charge transfer between the metal adatoms and the calcite surface.

This article presents a dual-band millimeter-wave front end in 45-nm CMOS silicon-on-insulator (S... more This article presents a dual-band millimeter-wave front end in 45-nm CMOS silicon-on-insulator (SOI) for 5G applications. The front end is composed of a low-noise amplifier (LNA), power amplifier (PA), and a single-pole doublethrow (SPDT) switch. A double-tuned PA is used and is based on a two-stage stacked amplifier with a reconfigurable load using SOI switches, so as to achieve an optimal load for both 28-and 39-GHz 5G NR bands. A wideband series-shunt switch is also developed with high power handling (P1dB > 22 dBm) and <1-dB insertion loss at 20-40 GHz. In the receive mode, the front end has a measured peak gain of 19.3 dB with a 3-dB bandwidth of 19.7-40 GHz, a noise figure (NF) < 4 dB at 18-40 GHz, and an IP1dB of 19 to 16 dBm. In the transmit mode and for lowband operation, the peak gain is 17.6 dB with a 3-dB bandwidth of 22.7-30.8 GHz. The P sat is >18.8 dBm and the peak PAE is 18% at 24-30 GHz and includes the switch loss and compression. For high-band operation, the gain at 36-40 GHz is 13.6 ± 1.5 dB with P sat > 18 dBm. To the best of our knowledge, this is the first front end that covers both the 24-28-and 37-40-GHz 5G bands with high output power and low-NF. Application areas are in multistandard base stations and small cells. Index Terms-5G, 45-nm CMOS silicon-on-insulator (SOI), front end, high efficiency, high power, low noise figure (NF), millimeter wave, wideband receiver. I. INTRODUCTION T HE 5G communication systems are being heavily investigated due to their potential to achieve high data rates in congested environments. At millimeter-wave frequencies, the path loss becomes severe and limits the link distances, and therefore, 16-to 512-element phased arrays are used for directional propagation and increased effective isotropic radiated power (EIRP). With an N × N antenna system, the EIRP is increased by 20log(N) compared with a single-channel transmitter, and the power per element becomes moderate even high EIRP levels. Most millimeter-wave systems operate at an Manuscript

A novel Brain-Machine Interface (BMI) system based on a distributed network of implantable wirele... more A novel Brain-Machine Interface (BMI) system based on a distributed network of implantable wireless sensors was proposed. Small CMOS "Neurograin" chips (0.5x0.5 mm 2) with on-chip antenna are designed to harvest near-field RF energy at ~1 GHz, and backscatter 10 Mbps BPSK modulated data asynchronously and periodically. A "Skinpatch" software-defined radio (SDR) receiver is realized on a commercial USRP running GNU Radio programs. It down-converts the reflected waves from the Neurograins and performs data recovery. In this BMI prototype demonstration, 32 Neurograins will be wirelessly powered, while a Skinpatch USRP will recover their backscattered packets in real-time.

Transition metal atoms are one of the key ingredients in the formation of functional 2D metal org... more Transition metal atoms are one of the key ingredients in the formation of functional 2D metal organic coordination networks. Additionally, the co-deposition of metal atoms can play an important role in anchoring the molecular structures to the surface at room temperature. To gain control of such processes requires the understanding of adsorption and diffusion properties of the different transition metals on the target surface. Here, we used density functional theory to investigate the adsorption of 3d (Ti, Cr, Fe, Ni, Cu), 4d (Zr, Nb, Mo, Pd, Ag) and 5d (Hf, W, Ir, Pt, Au) transition metal adatoms on the insulating calcite (10.4) surface. We identified the most stable adsorption sites and calculated binding energies and corresponding ground state structures. We find that the preferential adsorption sites are the Ca-Ca bridge sites. Apart from the Cr, Mo, Cu, Ag and Au all the studied metals bind strongly to the calcite surface. The calculated migration barriers for the representative Ag and Fe atoms indicates that the metal adatoms are mobile on the calcite surface at room temperature. Bader analysis suggests that there is no significant charge transfer between the metal adatoms and the calcite surface.

This article presents a dual-band millimeter-wave front end in 45-nm CMOS silicon-on-insulator (S... more This article presents a dual-band millimeter-wave front end in 45-nm CMOS silicon-on-insulator (SOI) for 5G applications. The front end is composed of a low-noise amplifier (LNA), power amplifier (PA), and a single-pole doublethrow (SPDT) switch. A double-tuned PA is used and is based on a two-stage stacked amplifier with a reconfigurable load using SOI switches, so as to achieve an optimal load for both 28-and 39-GHz 5G NR bands. A wideband series-shunt switch is also developed with high power handling (P1dB > 22 dBm) and <1-dB insertion loss at 20-40 GHz. In the receive mode, the front end has a measured peak gain of 19.3 dB with a 3-dB bandwidth of 19.7-40 GHz, a noise figure (NF) < 4 dB at 18-40 GHz, and an IP1dB of 19 to 16 dBm. In the transmit mode and for lowband operation, the peak gain is 17.6 dB with a 3-dB bandwidth of 22.7-30.8 GHz. The P sat is >18.8 dBm and the peak PAE is 18% at 24-30 GHz and includes the switch loss and compression. For high-band operation, the gain at 36-40 GHz is 13.6 ± 1.5 dB with P sat > 18 dBm. To the best of our knowledge, this is the first front end that covers both the 24-28-and 37-40-GHz 5G bands with high output power and low-NF. Application areas are in multistandard base stations and small cells. Index Terms-5G, 45-nm CMOS silicon-on-insulator (SOI), front end, high efficiency, high power, low noise figure (NF), millimeter wave, wideband receiver. I. INTRODUCTION T HE 5G communication systems are being heavily investigated due to their potential to achieve high data rates in congested environments. At millimeter-wave frequencies, the path loss becomes severe and limits the link distances, and therefore, 16-to 512-element phased arrays are used for directional propagation and increased effective isotropic radiated power (EIRP). With an N × N antenna system, the EIRP is increased by 20log(N) compared with a single-channel transmitter, and the power per element becomes moderate even high EIRP levels. Most millimeter-wave systems operate at an Manuscript