This paper investigates a novel approach to implementation of multiband frequency synthesizer for cognitive multi-radio applications. The architecture here considered employs a dual-mode PLL (Phase Locked Loop) based frequency synthesizer for data applications, which is capable to switch between a fractional wideband high speed mode and an integer, narrowband and low spur mode after the settlin...

This work presents the optimization of radio frequency (RF) to direct current (DC) circuits using Schottky diodes for remote wireless energy harvesting applications. Since different applications require different wireless RF to DC circuits, RF harvesters are presented for different applications. Analytical parameters influencing the sensitivity and efficiency of the circuits are presented. Resu...

We analyze three different sources of noise in a sampling mixer working at radio frequency (RF) or intermediate frequency. External RF and intrinsic noise are analyzed using conventional frequency domain methods. External local oscillator (LO) noise is analyzed in time domain by solving a stochastic differential equation. We are able to take into account the timevarying aspect of the LO noise c...

Underwater acoustic channels are band-limited and reverberant, posing many obstacles to reliable, phase-coherent acoustic communications. In terrestrial wireless sensor networks, the nodes use radio frequency (RF) to build up the communication. In underwater environments, due to water absorption, radio wave does not work well. Compared to radio waves, sound has superior propagation characterist...

We report on our progress and development of high speed flexible graphene field effect transistors (GFETs) with high electron and hole mobilities (~3000 cm/V·s), and intrinsic transit frequency in the microwave GHz regime. We also describe the design and fabrication of flexible graphene based radio frequency system. This RF communication system consists of graphite patch antenna at 2.4 GHz, gra...

A measurement technique [1] is presented that allows measurement of MOSFET low frequency (LF) noise under large signal RF (Radio Frequency) excitation. Measurements indicate that MOSFETS exhibit a reduction in LF noise when they are cycled from inversion to accummulation and that this reduction does not depend on the frequency of excitation for excitation frequencies of up to 3 GHz. The measure...

This paper is concerned with radio resource allocation in multiple-chip-rate (MCR) DS/CDMA systems accommodating multimedia services with different information rates and quality requirements. Considering both power spectral density (PSD) over a radio frequency (RF) band and the effect of RF input filtering on the receiver in MCR-DS/CDMA systems, criteria for capacity estimation are presented an...

Abstract. Radio-frequency field inhomogeneity is one of the most common imperfections in NMR experiments. They can lead to imperfect flip angles applied radio-frequency (rf) pulses or a mismatch resonance conditions, resulting artefacts degraded performance In solid-state under magic angle spinning (MAS), radial component becomes time-dependent because rf irradiation amplitude and phase modulat...

In this paper, we have analyzed the Double-Pole Four-Throw Double-Gate Radio-Frequency Complementary Metal-Oxide-Semiconductor (DP4T DG RF CMOS) switch using S-parameters for 1 GHz to 60 GHz of frequency range. DP4T DG RF CMOS switch for operation at high frequency is also analyzed with its capacitive model. The results for the development of this proposed switch include the basics of the circu...