P. Romanini

A C-band high-efficiency second-harmonic-tuned hybrid power amplifier in GaN technology

In this contribution, a C-band 2nd harmonic tuned hybrid power amplifier utilizing a PHEMT GaN device is presented, together with technological aspects, nonlinear device model and adopted design criteria. The amplifier has been realised in hybrid form, exhibiting a bandwidth larger than 20% around 5.5GHz, with a minimum output power of 33 dBm, and a drain efficiency of 60% at the centre frequency.

A C-band high efficiency second harmonic tuned hybrid power amplifier in GaN technology

In this paper, the design, fabrication, and test of high-efficiency, high-power C-band harmonic-tuned power amplifiers in GaN technology is reported. The amplifier has been designed utilizing second-harmonic tuning for high-efficiency operation, thus exploiting the high-breakdown voltage peculiarity of GaN-based devices. Realized in a hybrid form, the amplifier has been characterized in terms of small-signal, power, and intermodulation (IMD) performance. An operating bandwidth over 20% around 5.5 GHz, with 33-dBm minimum output power, and 60% drain efficiency at center frequency is demonstrated, together with low IMD

High power GaN-HEMT microwave switches for X-Band and wideband applications

In this article the design, fabrication and test of X-band and 2-18 GHz wideband high power SPDT MMIC switches in GaN technology are presented. Said switches have demonstrated state-of-the-art performance and RF fabrication yields better than 65%. In particular the X-band switch exhibits an on-state power handling capability of better than 37 dBm at the 1 dB insertion loss compression point and the wideband switch shows an insertion loss compression of 1 dB for input power higher than 34.3 dBm in the entire bandwidth.

GaN Device Technology: Manufacturing, Characterization, Modelling and Verification

Gallium Nitrides superior physical properties, in comparison with other semiconductors, make GaNHEMT active devices a prime candidate in the implementation of next generation transmitters for radar systems, 3G/4G base stations and WiMAX. In this contribution, the characterization, modelling and verification of different families of high efficiency, high- power devices manufactured at SELEX Sistemi Integrati are reported. Process, characterization and modelling phases are analyzed to improve and refine the technologys fabrication techniques, thermal degradation issues and dispersion phenomena.

MMIC Chipset for wideband multifunction T/R Module

This paper reports on the design, fabrication and test of key MMIC components developed for wideband Transmit/Receive Module applications in the framework of a bilateral Research Programme at System level between Italy and Sweden MoDs (M-AESA) with Technological Studies performed in order to guarantee the feasibility of main hardware critical aspects. The Chipset comprises a multi-function phase-amplitude control chip (“core-chip”) and two wideband HPA MMICs. In the 2–18GHz bandwidth the True Time Delay (TTD) core-chip enables a time delay up to 124ps with a LSB of 4ps and an unwrapped phase deviation from linear behaviour of ± 7deg. The two-octave bandwidth HPA operates in the 4.5–18GHz in CW and provides an output power of 33±1dBm. The other wideband HPA is focused on C and X band radar frequencies (5–12GHz) and operates in pulsed mode with an output power of 36±1dBm.

Design and Realization of GaAs Digital Circuit for Mixed Signal MMIC Implementation in AESA Applications

A complete design flow starting from the technological process development up to the fabrication of digital circuits is presented. The aim of this work is to demonstrate the GaAs Enhancement/Depletion (E/D) double stop-etch technology implementation feasibility for digital applications, aimed at mixed signal circuit integration. On the basis of the characterization of small E/D devices with different Gate peripheries, developed by the SELEX-SI foundry, and the analysis of several GaAs-based logical families, the most suitable logic for the available technology has been selected. Then, simple test vehicles (level shifters, NOR logic gates and D Flip-Flops) have been designed, realized, and measured to validate the design strategy applied to the GaAs E/D process. These logical circuits are preliminary to the design of a more complex serial-to-parallel converter, to be implemented onto the same chip together with RF analog blocks, such as stepped attenuators and phase shifters.

Wide bandgap technology: The right solution for Space and Defense market

The procurement of critical solid state electronic components has always been strategic for companies operating in the Defense and Space market. To-day the situation is even more stringent because of the increasing importance of Gallium Nitride device. An “ideal” Foundry is a sources that can satisfy all the basic requirements for the development and production of competitive edge RF products, avoiding ITAR restriction, and ensuring a right tradeoff between cost and performance.

Fabrication and nonlinear characterization of GaN HEMTs on SiC and sapphire for high-power applications: Research Articles

In this article, a linearity-improving technique for active antennas and arrays, based on spatial power combining, is presented. An auxiliary branch is employed to cancel the radiation pattern at the intermodulation distortion (IMD) components, either in the main-beam direction for a subarray or in all elevation angles for a single antenna element. The need for precise amplitude and phase control over the IMD currents in the array auxiliary elements is demonstrated, quantifying the possible degradation suffered in the carrier-to-intermodulation distortion (CIMD) ratio improvement obtained when this solution is applied. The potentialities of implementing the derivative-superposition technique in small- and large-signal regimes, both in an array and in an antenna element, are finally proposed.