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A fully integrated push–push voltage controlled oscillator (VCO) working in K-band with a large tuning range and a low phase noise fabricated in a 0.18 μm SiGe BiCMOS technology is presented. Multi-coupled LC tanks are used to improve the tuning range, power consumption and phase noise. Digital tuning varactors are used to maintain a low VCO tuning sensitivity (K_VCO) and maximum frequency overlap. The VCO achieves a frequency tuning range (FTR) of 17% at 12 GHz, a phase noise of -106.62 dBc/Hz at 1 MHz offset and consumes 7 mW from 1.8 V supply.

In this paper, an offline bandwidth and frequency calibration method for an on–off LC oscillator-based ultra-wideband impulse radio (UWB-IR) transmitter is presented. Implemented in 0.18-$\mu$m CMOS, the offline calibration circuits consume very little power. This allows the transmitter to consume an ultra-low average power of 319$\mu$W over 3–5GHz at 2Mbps. The calibration is critical to ensure the FCC spectral mask compliance despite the process–voltage–temperature (PVT) variations. The transmitter can deliver a large differential output swing of 1.8–3V to a 100-$\mathrm{\Omega }$ load with minimal power efficiency of 7% at different data rates (2–30Mbps). It is suitable for WPAN application with localization and positioning capabilities.

In this paper, we describe a novel architecture to enable a secure communication among mobile devices using different wirelesstechnologies like wireless LAN, Bluetooth, cellular systems or even infrared. Making use of the combination of these technologies for the data transmission and for the signaling of the communication, we analyze several scenarios with increasing complexity. The complete picture appears in the last scenario where all technologies are involved and the network is composed of heterogeneous mobile nodes. The paper also presents a solution for the setup of a secured communication channel (i.e. a Virtual Private Network connection) between several heterogeneous mobile nodes controlled by the cellular network operator. The mobile nodes can be either cellular aware or non-cellular aware in this framework. We propose to setup the heterogeneous network communications via the cellular network using the cellular aware nodes.