DC and Low Frequency Noise Characteristics of SiGe n-MODFET’s.

This paper presents an investigation of the low frequency noise properties of SiGe based n MODFET’s through the characterization of both the gate current noise and the drain current noise including their correlation. Measurements versus bias and gate geometry have shown that this noise is generated through mobility fluctuations or carrier diffusion at the gate terminal and that carrier number fluctuations are involved in drain current fluctuations. Microwave residual phase noise measurements have shown that the up-conversion effect mainly occurs on the drain current noise

Design of autonomous multi-sensing passive UHF RFID tag for greenhouse monitoring

International audienceWhen it comes to management modernization of greenhouses, UHF RFID technology, with its passivecharacter and low-cost and power consumption, presents a very efficient solution. To this end, an EPCglobal C3 SL900A sensor tag is enhanced by integrating energy harvesting and multi-sensing capabilities.The challenge of using only the fundamental carrier as an energy-harvesting source without the needfor other auxiliary energy or battery source is considered and evaluated. The developed architectureuses a deep power consumption management strategy and operates autonomously under full passivemode for sensing the required parameters in the grown monitoring process. This architecture does notintegrate any chemical components or batteries, making it safe and more suitable for agriculture-relatedapplications. It can also be considered as an auto-adaptive data-rate sensor device, such as the rate changeaccording to the amount of harvested energy. Furthermore, this architecture can write all sensors’ datasimultaneously into the tag IC user memory. This latter is easily accessible by any standard UHF RFIDreader

Low frequency noise characterization and modeling of microwave bipolar devices: Application to the design of low phase noise oscillator

This paper addresses advanced low frequency noise measurements and modeling of SiGe HBTs. Results have been implemented into a non linear Gummel Poon model which has been validated through the design of a DRO made of an integrated SiGe negative resistance in the 10 GHz range. We have obtained phase noise of -105 dBc/Hz at 10 kHz offset, which is close to the state of the art, and we have demonstrated a design technique that provides an accurate phase noise prediction

Low frequency noise characterization and modeling of microwave bipolar devices : application to the design of low phase noise oscillator

This paper addresses advanced low frequency noise measurements and modeling of SiGe HBTs. Results have been implemented into a nonlinear Gummel Poon model which has been validated through the design of a DRO made of an integrated SiGe negative resistance in the 10 GHz range. We have obtained phase noise of -105 dBc/Hz at 10 kHz offset, which is close to the state of the art, and we have demonstrated a design technique that provides an accurate phase noise prediction

Geiger avalanche photodiodes as tentative light detectors for VHE gamma ray astronomy

International audienceDue to its sensitivity and speed, the detector still widely used in Cerenkov astrophysics experiments remains the PhotoMultiplier Tube (PMT). For instance, recent pathbreaking experiments in Very High Energy astrophysics (VHE), such as MAGIC and HESS, have used mainstream PMT technology (Aharonian et al, Astron Astrophys 492(1):L25-L28, 2008). Moreover the Cerenkov Telescope Array (CTA) which is now in its design phase, is also planed to be based on PMT's. However, there are some disadvantages to the PMT technology: the rather poor quantum efficiency, the use of high voltages, the high cost when used in large number in a matrix arrangement and the large weight. Hence, we have investigated the possibility to design future Cerenkov telescopes based on solid state technology, specifically Geiger avalanche photodiodes. In a preliminary developmen