RESUMEN
In order to meet the application requirements of radar networks for high efficiency and high second harmonic suppression (SHS) of power amplifiers, this paper proposes a C-band 30 W power amplifier (PA) microwave monolithic integrated circuit (MMIC) based on 0.25 µm gallium nitride (GaN) high electron mobility transistor (HEMT) process. The proposed PA uses a two-stage amplifier structure to achieve high power gain. A topology with SHS is designed in the output-matching network. Besides, the large signal model load pull simulation and the harmonic control technology in the output stage are used to improve efficiency. The high-power additional efficiency (PAE) and high SHS of the PA MMIC are achieved simultaneously. In the 5-6 GHz frequency range, multiple indicator measurements of the proposed PA show that output power is over 45 dBm, the PAE is more than 57%, the SHS exceeds 45 dBc, the power gain is greater than 24 dB, which are conducted under the condition of 100 µs pulse width and 10% duty cycle. In addition, the size of the PA MMIC, including bonding pads, is 3.3 × 3.1 mm2.
RESUMEN
This paper introduces a miniaturized system in package (SIP) for a Ku-band four-channel RF transceiver front-end. The SIP adopts the packaging scheme of an inner heat-dissipation gasket and multi-layer substrate in the high temperature co-fired ceramics (HTCC) shell with a metal heat sink at the bottom. The gasket effectively solves the heat-dissipation problem of high-power transceiver chips, and the multi-layer substrate achieves the interconnection between multiple chips. Within the limited size of 14.0 × 14.0 × 2.5 mm3, the SIP integrates five bidirectional amplifier chips, an amplitude-phase control multi-function chip, and two power modulation chips to realize the Ku-band four-channel RF transceiver front-end. Transmitting power over 0.5 W (27dBm) and receiving noise figure of 3.4 dB are achieved in the Ku-band. The efficient heat dissipation, high air tightness, and excellent integration are simultaneously realized in this SIP. The measurement results show that the performance is stable in the receiving and transmitting states, and the SIP based on HTCC technology has specific prospects for radar transceiver application.
RESUMEN
A quantitative proteomics workflow was implemented that provides extended plasma protein coverage by extensive protein depletion in combination with the sensitivity and breadth of analysis of two-dimensional LC-MS/MS shotgun analysis. Abundant proteins were depleted by a two-stage process using IgY and Supermix depletion columns in series. Samples are then extensively fractionated by two-dimensional chromatography with fractions directly deposited onto MALDI plates. Decoupling sample fractionation from mass spectrometry facilitates a targeted MS/MS precursor selection strategy that maximizes measurement of a consistent set of peptides across experiments. Multiplexed stable isotope labeling provides quantification relative to a common reference sample and ensures an identical set of peptides measured in the set of samples (set of eight) combined in a single experiment. The more extensive protein depletion provided by the addition of the Supermix column did not compromise overall reproducibility of the measurements or the ability to reliably detect changes in protein levels between samples. The implementation of this workflow is presented for a case study aimed at generating molecular signatures for prediction of first heart attack.