Realization of high-order modulation schemes directly in the RF domain enables the generation of spectrally efficient 4 M quadrature-amplitude-modulated (4 M QAM) symbols using the vectorial summation of M quadrature phase-shift keying... more
This paper presents a theoretical study and design of two techniques used to reduce start-up time (TS) and energy (ES) of Pierce crystal oscillator (XO). An analytical study of precise injection on a crystal resonator is introduced, and... more
This work presents an energy-efficient electrocorticography (ECoG) array architecture for fully-implantable brain machine interface systems. A novel dual-mode analog signal processing method is introduced that extracts neural features... more
The analysis, design, and implementation of a 50-Gb/s transimpedance amplifier (TIA) in a 0.13-μm SiGe BiCMOS process are presented. The proposed TIA, designed for use in a single-channel optical communication network, is comprised of... more
This paper presents the design and implementation of a millimeter-wave (mm-wave) fundamental frequency circularly polarized radiator which employs a multi-port cavity as the core of a high-Q resonator, a power combiner, and an antenna. A... more
A novel high-speed wireless transmitter (TX) architecture is presented that directly transforms incoming data bits into high-order 4 M -quadrature amplitude modulation (QAM) constellation by adding multiple quadrature phase shift keying... more
A wideband, low-loss balun-based differential power splitter is studied. The use of lumped double-tuned baluns as key building blocks within a splitter leads to a wideband operation, while avoiding signal crossovers and the detrimental... more
A study of operating condition and design methods is presented that enables the amplifiers to achieve the upper limit of their power gain at frequencies close to the device f max .Using the gain-plane approach, the necessary and... more
A CMOS 170-GHz fundamental-frequency transmitter (TX) realizing the 8PSK modulation scheme directly in the RF domain is presented. The use of direct RF modulation obviates the need for high-resolution high-speed mixed-signal blocks. The... more
A Millimeter-Wave Partially Overlapped Beamforming-MIMO Receiver: Theory, Design, and Implementation
This paper presents an analysis and design of a partially-overlapped beamforming-MIMO architecture capable of achieving higher beamforming and spatial multiplexing gains with lower number of elements compared to conventional... more
This paper presents a 53-61GHz low-power chargepump integer-N type-II PLL, employing a class-D V-band VCO. Transistors in the VCO enter deep triode region to achieve low DC power and phase noise. Pros and cons of the triode region are... more
MedRadio 413-419 MHz inductorless transceiver (TRX) for an implantable brain-machine interface (BMI) in a 180 nm CMOS process is presented. Occupying 5.29 mm 2 of die area (including pad ring), this on-off-keying (OOK) TRX employs a... more
Two brain signal acquisition (BSA) front-ends incorporating two CMOS ultra-low power low noise amplifier arrays and serializers operating in MOSFET weak inversion region are presented. To boost the amplifier's gain for a given current... more
Conventional brain-computer interfaces (BCIs) are often expensive, complex to operate, and lack portability, which confines their use to laboratory settings. Portable, inexpensive BCIs can mitigate these problems, but it remains unclear... more
A 300 GHz frequency synthesizer incorporating a triple-push VCO with Colpitts-based active varactor (CAV) and a divider with three-phase injection is introduced. The CAV provides frequency tunability, enhances harmonic power, and... more
Recent studies show that peripheral circuit (including decoders, wordline drivers, input and output drivers) constitutes a large portion of the cache leakage. In addition, as technology migrates to smaller geometries, leakage contribution... more
This paper is concerned with the analysis and optimization of the ground bounce in digital CMOS circuits. First, an analytical method for calculating the ground bounce is presented. The proposed method relies on accurate models of the... more
This paper presents the design and analysis of a novel distributed CMOS mixer for ultrawideband (UWB) receivers. To achieve the UWB RF frequency range required for the UWB communications, the proposed mixer incorporates artificial... more
The design of a CMOS 22-29-GHz pulse-radar receiver (RX) front-end for ultra-wideband automotive radar sensors is presented. The chip includes a low-noise amplifier, in-phase/quadrature mixers, a quadrature voltage-controlled oscillator... more
Two monolithically integrated W-band frequency synthesizers are presented. Implemented in a 0.18 m SiGe BiCMOS with of 200/180 GHz, both circuits incorporate the same 30.3-33.8 GHz PLL core. One synthesizer uses an injection-locked... more
A CMOS distributed amplifier (DA) with distributed active input balun is presented that achieves a gain-bandwidth product of 818 GHz, while improving linearity. Each cell within the DA employs dual-output two-stage topology that improves... more
This thesis presents the theory and analysis of IF polar receiver (PRX) architecture. By using new quantization techniques in the polar domain, the proposed receiver can boost the signal to quantization noise ratio (SQNR) compared to a... more
where the output voltage at the termination point of the transmission line may not reach its steady state value during the clock period, it is possible to reduce energy dissipation while meeting a DC noise margin by driver sizing. This is... more
This paper presents a spectrally-weighted balanced truncation technique for tightly coupled integated circuit interconnects, when the interconnect circuit parameters change as a result of statistical variations in the manufacturing... more
This paper investigates the impact of clock jitter induced by substrate noise on the performance of the oversampling 16 modulators. First, a new stochastic model for substrate noise is proposed. This model is then utilized to study the... more
This paper presents the design and implementation of a novel multi-antenna receiver front-end, which is capable of accommodating various multi-antenna schemes including spatial multiplexing (SM), spatial diversity (SD), and beamforming... more
CMOS Distributed Active Power Combiners and Splitters for Multi-Antenna UWB Beamforming Transceivers
This paper presents the design of the first CMOS distributed active power combiners and splitters with wideband variable delay and gain. These circuits are the key components for use in multi-antenna (MA) ultra-wideband (UWB)... more
This paper presents a W-band receiver chipset for passive millimeter-wave imaging in a 65 nm standard CMOS technology. The system comprises a direct-conversion receiver front-end with injection-locked tripler and a companion analog... more
This paper presents a W-band 2 2 focal-plane array (FPA) for passive millimeter-wave imaging in a standard 0.18 m SiGe BiCMOS process ( GHz). The FPA incorporates four Dicke-type receivers representing four imaging pixels. Each receiver... more
Design and implementation of a -band on-chip bowtie-shaped slot antenna fabricated in 180-nm BiCMOS process is presented, and its performance and limitations are discussed. This antenna has a measured impedance bandwidth ( dB) across the... more
A new second-order all-pass filter with maximum achievable delaybandwidth-product (DBW) is presented. The proposed circuit will be used as a wideband delay element in impulse radio ultra-wideband transceivers. Benefiting from a simple... more
An analysis of high-frequency noise in RF active CMOS mixers including single-balanced and doublebalanced architectures is presented. The analysis investigates the contribution of non-white gate-induced noise to the output noise power as... more
A comprehensive study of ultrahigh-speed currentmode logic (CML) buffers along with the design of novel regenerative CML latches will be illustrated. First, a new design procedure to systematically design a chain of tapered CML buffers is... more
A W-band direct-detection-based receiver front-end for millimeter-wave passive imaging in a 0.18-m BiCMOS process is presented. The proposed system is comprised of a direct-detection front-end architecture employing a balanced LNA with an... more
We propose to use the blind deconvolution and its modification to extract the point spread function (PSF) of layered metamaterials from a SNOM measurement. The measurement results are processed using the blind deconvolution algorithm to... more
We characterize the sensitivity of imaging properties of a layered silver-TiO2 flat lens to fabrication inaccuracies. The lens is designed for approximately diffraction-free imaging with subwavelength resolution at distances in the order... more
Imaging with a layered superlens is a spatial filtering operation characterized by the point spread function (PSF). We show that in the same optical system the image of a narrow sub-wavelength Gaussian incident field may be surprisingly... more
We compare the properties of subwavelength imaging in the visible wavelength range for metal-dielectric multilayers operating in the canalization and the resonant tunnelling regimes. The analysis is based on the transfer matrix method and... more
The technology of pre-saturated core fault current limiter (PCFCL) has a particular importance due to its instantaneous limitation of the fault current in electric power grids and keeping its value below the ratings of the switchgear or... more
Optical coherence tomography (OCT) is a non-invasive imaging modality which is widely used in clinical ophthalmology. OCT images are capable of visualizing deep retinal layers which is crucial for early diagnosis of retinal diseases. In... more
We propose a new method for training convolutional neural networks which integrates reinforcement learning along with supervised learning and use it for transfer learning for classification of glaucoma from colored fundus images. The... more