Heba A. Shawkey

Asynchronous switching for low-power Octagon network-on-chip

Asynchronous switching is proposed to achieve low power Network on Chip. Asynchronous switching reduces the power dissipation of the network if the activity factor of the data transfer between two ports αd is less than A αc + B αclk. Closed form expressions for power dissipation of Octagon topology are provided for both synchronous and asynchronous switching. The area of the asynchronous switch is 50% greater than the area of the synchronous switch. However, the power dissipation of asynchronous switching could be decreased by up to 73.6%. Asynchronous switching becomes more efficient as technology advances and network density increases. A reduction in power dissipation reaches 81.3% for 256 IPs with the same chip size. Even with clock gating, asynchronous switching achieves significant power reduction of 76.7% for 75% clock activity factor.

FM-UWB transmitter for wireless body area networks: Implementation and simulation

This paper describes an implementation of low power frequency modulated ultra-wideband (FM-UWB) transmitter in standard 130nm CMOS technology. The transmitter is designed to operate in the range of 3.328-4.608 GHz. A relaxation oscillator is used to generate the subcarrier signal which is calibrated by a phase-locked loop (PLL). The RF carrier is generated using a voltage-controlled oscillator (VCO). A proposed calibration scheme based on a PLL is utilized to calibrate both the upper and the lower frequencies of the operation band. The proposed FM-UWB transmitter consumes 835μW from a 1.2V supply at 500kbps achieving an energy efficiency of 1.67nJ/bit.

A Survey on FM-UWB Transceivers

his paper surveys the research on frequency modulated ultra- wideband (FM-UWB) transceivers. FM-UWB system uses low modulation index digital FSK followed by high modulation index analog FM to generate a constant envelope UWB signal with a flat power spectral density and steep spectral roll-off. FM-UWB can be seen as an analog implementation of a spread spectrum system with spreading gain equal to the modulation index. FM-UWB system is suitable for low data rate and short-range applications. The advantages of FM-UWB system such as low power consumption, very low radiated power (−41.3 dBm/MHz), good coexistence with other existing wireless technologies, and robustness to interference and multipath making it suitable for Wireless Body Area Network (WBAN) in medical applications.

Modeling of RLC interconnect lines

Simple uniform reduced order model is used to model an RLC interconnect line. Few number of sections are shown to achieve high accuracy of modeling the RLC interconnect. Waveform characterization is used to evaluate the accuracy of the adopted model. As compared to RC lines, five times the number of sections is sufficient to model RLC lines. The model is shown to be accurate for wide range of relative impedance of the driver, the line, and the load. The model provides a simple and quick mean to characterize an RLC interconnect which is necessary for performance evaluation in digital circuits.

Passive Front End for LTE TDD Transceiver

In this paper, a passive front end for a 3GPP Long Term Evolution (LTE) TDD transceiver comprising a microstrip antenna and filter is presented. The proposed antenna and filter operates in the LTE band 36 (TDD) which extends from 1930MHz to 1990MHz. A patch antenna and Hairpin filter is fabricated with a total area of 43x36mm for the antenna and 38.6x32.16mm for the filter. The proposed devices are fabricated using FR-4 material substrate and the measuring results show good agreement with the simulation results. The fabricated antenna has 2.67dBi directivity, 1.242dB gain, a minimum return loss of -31.85dB at resonant frequency 1950MHz and 150.3 MHz bandwidth at 6dB return loss, while the filter has -3dB BW of 90MHZ, a center frequency of 1950MHz and a fractional bandwidth of 4.615%.

Ultra-low power 3.5–4.5GHz FM-UWB transmitter

This paper presents a novel ultra-low power FM-UWB transmitter implemented in 130nm CMOS process. The transmitter operates in the range of 3.5-4.5GHz with 4GHz RF carrier frequency. The transmitter can accept input data rates up to 250kbps. It consists of a relaxation oscillator to generate the subcarrier signal and a VCO for RF carrier generation. The center frequency of the VCO is periodically calibrated by an integer-N phase-locked loop (PLL). The PLL takes only 300ns to complete the calibration. The simulated VCO phase noise is - 79dBc/Hz at 1MHz offset. The proposed FM-UWB transmitter consumes (power amplifier is not included) about 50μW for a 1.2V supply.

INTERCONNECT MODELING WITH THE EXISTENCE OF LINE INDUCTANCE

Simple uniform reduced order model is used to model an RLC interconnect line. Waveform characterization is used to evaluate the accuracy of the adopted models. As compared to RC lines, less than five times the number of sections is sufficient to model RLC lines. Look-up tables are provided to simplify the process of choosing the best interconnect section model to characterize an RLC interconnect line. The tables are shown to be accurate for wide range of relative impedance of the driver, the line, and the load. The tables provide a simple and quick mean to characterize an RLC interconnect which is necessary for performance evaluation in digital circuits. The presented model reduces the simulation time while keeping the simulation accuracy. The simulation time can be reduced by up to 72% with less than 10% reduction in accuracy using the provided tables.

Wideband inductorless CMOS RF front-end for LTE receivers

This paper presents a new design of inductorless wideband front-end receiver using 130 nm CMOS technology for LTE bands of 0.7 GHz to 3 GHz. The RF front-end receiver consists of the microstrip antenna, self-bias resistive feedback low-noise amplifier, active balun and folded mixer architecture. The miniature antenna provides good matching results for the entire band of interest. Optimization of low-noise amplifier using linearization technique followed by NMOS switches mixer stage are effectively used to achieve maximum gain, low noise figure, and low power consumption. The designed receiver exhibits a maximum gain of 22 dB, maximum noise figure of 7.5 dB, minimum 3rd order intercept point (IIP3) of −9.2 dBm, and DC power consumption of 22 mW at 1.2 V power supply. Using these optimizations, our proposed receiver can be a good candidate for LTE applications.

PLL based BFSK subcarrier generator for FM-UWB transmitter

This paper presents the implementation, the layout and the post-layout simulation of two main blocks of the FM-UWB transmitter; the voltage-controlled oscillator (VCO) and the subcarrier generator. A low power and linear ring VCO is proposed to generate the RF signal. A low power PLL based BFSK subcarrier generator is introduced. It includes a linear relaxation oscillator to produce the subcarrier signal. The circuits are implemented in 130nm CMOS technology. The data rate is 500kbps. Post-layout simulations show that the PLL consumes only 306μW while the VCO consumes 300μW from a 1.2V supply. The area of the PLL is 0.0124mm2.

Injection locking phase rotator for Outphasing transmitter

This paper presents a novel technique of implementing the amplitude information into out-phase mapping, which is a necessary block of the high-efficiency Outphasing transmitter architecture. The proposed technique is based on using injection locking ring oscillator and switching-based control circuit to implement phase rotator. The technique is compatible with digital implementation using DSP. Since, Outphasing transmitters use switching power amplifiers, this implementation is suitable for an all-digital and adjustable transmitter implementation. The modulator system is designed using UMC130nm CMOS technology; and is simulated at 1.8GHz operation frequency, as it is commonly used in multiple mobile applications requiring high power levels. Simulation shows an out-phasing error of 0.41?rms, across the whole input amplitude sweep of 45dB. The power consumption of the single phase rotator is 1.5mW from 1.2V supply.