14 research outputs found
A GaN power amplifier for 100 VDC bus in GPS L-band
No full textAn innovative approach in RF GaN technology suitable for Global Positioning System (GPS) L-band transmitters is presented. The solution operates directly from the 100 VDC voltage bus without the need for a DC-DC step-down converter to typical 28 V or 50 V. It is based on a mature GaN HEMT process which is radiation tolerant and reliable for space applications. The prototype single stage amplifier reported in this paper operates at 100 V bias and achieves 100 W CW output power with 19 dB gain and high efficiency > 60% at the L1 frequency band of 1575 ± 50 MHz. Preliminary results at L2 and L5 GPS bands are also reported. The demo amplifier consists of a single die with 12 mm gate periphery in a hermetic package. Higher power can easily be attained by utilizing multiple chips in one package. The proposed technology reduces SWaP figure of merit and simplifies the design of transmitters for GPS satellites
200-W GaN PA Design Based on Accurate Multicell Transistor Modeling
No full textIn this paper, a model extraction technique suitable for GaN transistors with very large periphery is described. The technique is based on the accurate nonlinear model extraction of a reference size device that is then scaled to a larger periphery preserving its original accuracy. The proposed model has been extensively validated with microwave nonlinear load-pull measurements and with the design of a 200-W S-band power amplifier
I mosaici del Battistero di San Giovanni a Canosa di Puglia: analisi chimico-mineralogiche di materiali lapidei, cotti e strati preparatori
No full textI mosaici del battistero di San Giovanni a Canosa di Puglia: caratterizzazione dei materiali lapidei
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EDNRB gene variants and melanoma risk in two southern European populations
No full textEDNRB gene variants were reported to be associated with melanoma risk in French patients, with the S305N variant showing the highest frequency
EDNRB gene variants and melanoma risk in two southern European populations.
No full textBackground. EDNRB gene variants were reported to be associated with melanoma
risk in French patients, with the S305N variant showing the highest frequency.
Aim. To verify the S305N association with melanoma risk in an independent larger
French population (378 patients, 389 controls); to investigate the role of EDNRB
variants in melanoma risk in an Italian population (133 patients, 118 controls); and to
explore the association of CDKN2A or CDK4 mutations with the S305N EDNRB variant
in a subgroup of patients (59 French, 12 Italian) with a suspected hereditary
predisposition to melanoma (familial melanoma, sporadic multiple primary melanoma
or melanoma associated with pancreatic cancer).
Methods. The S305N variant was genotyped in the French population, while the
EDNRB gene in the Italian population was entirely sequenced.
Results. Overall, there was no significant difference in the frequency of the S305N
variant between patients with sporadic melanoma and controls in either the French or
the Italian population. However, a significantly higher S305N allele frequency was
detected in French patients with a suspected hereditary predisposition to melanoma
compared with controls (P = 0.04). In addition, in this subgroup of patients, the
S305N allele was also significantly associated with the presence of CDKN2A mutations
(P = 0.04).
Conclusions. Our results showed no evidence of association of the S305N EDNRB
polymorphism with sporadic melanoma risk in either the French or Italian populations,
but there was an indication that EDNRB might be a melanoma-predisposing gene in
French patients with a suspected hereditary predisposition to melanoma
CMOS MESFET Cascode Amplifiers for RFIC Applications
No full textabstract: There is an ever-increasing demand for higher bandwidth and data rate ensuing from exploding number of radio frequency integrated systems and devices. As stated in the Shannon-Hartley theorem, the maximum achievable data rate of a communication channel is linearly proportional to the system bandwidth. This is the main driving force behind pushing wireless systems towards millimeter-wave frequency range, where larger bandwidth is available at a higher carrier frequency. Observing the Moor’s law, highly scaled complementary metal–oxide–semiconductor (CMOS) technologies provide fast transistors with a high unity power gain frequency which enables operating at millimeter-wave frequency range. CMOS is the compelling choice for digital and signal processing modules which concurrently offers high computation speed, low power consumption, and mass integration at a high manufacturing yield. One of the main shortcomings of the sub-micron CMOS technologies is the low breakdown voltage of the transistors that limits the dynamic range of the radio frequency (RF) power blocks, especially with the power amplifiers. Low voltage swing restricts the achievable output power which translates into low signal to noise ratio and degraded linearity. Extensive research has been done on proposing new design and IC fabrication techniques with the goal of generating higher output power in CMOS technology. The prominent drawbacks of these solutions are an increased die area, higher cost per design, and lower overall efficiency due to lossy passive components. In this dissertation, CMOS compatible metal–semiconductor field-effect transistor (MESFETs) are utilized to put forward a new solution to enhance the power amplifier’s breakdown voltage, gain and maximum output power. Requiring no change to the conventional CMOS process flow, this low cost approach allows direct incorporation of high voltage power MESFETs into silicon. High voltage MESFETs were employed in a cascode structure to push the amplifier’s cutoff frequency and unity power gain frequency to the 5G and K-band frequency range. This dissertation begins with CMOS compatible MESFET modeling and fabrication steps, and culminates in the discussion of amplifier design and optimization methodology, parasitic de-embedding steps, simulation and measurement results, and high resistivity RF substrate characterization.Dissertation/ThesisDoctoral Dissertation Electrical Engineering 201
A study for achieving high power and efficiency based on high bias operation in C- and X-band GaN power amplifiers
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