D. Floriot

An active pulsed rf and pulsed dc load-pull system for the characterization of power transistors used in coherent radar and communication systems

This paper presents a new automated and vector corrected active load-pull system allowing the characterization of microwave power transistors under coherent pulsed RF and pulsed DC operating conditions. Measurements of an S band-Class C-8 Watt silicon bipolar amplifier are shown and demonstrate the ability of our system to accurately characterize power variations and carrier phase shift within the pulse. Source and load-pull measurements of an 8/spl times/30 /spl mu/m/sup 2/ GaInP/GaAs HBT (Thomson LCR) are also reported for different pulse widths.

State of the Art 58W, 38% PAE X-Band AlGaN/GaN HEMTs Microstrip MMIC Amplifiers

This paper presents the results obtained on X-Band GaN MMICs developed in the frame of the Kerrigan project launched by the European Defense Agency. A new step was achieved, 58 W of output power with 38% PAE in X-Band were obtained using an 18 mm 2 2-stages amplifier. To our knowledge, these results present a new state-of-the-art of X-Band MMIC power amplifiers.

43W, 52% PAE X-Band AlGaN/GaN HEMTs MMIC Amplifiers

This paper presents the results obtained on X-Band GaN MMICs developed in the frame of the Korrigan project launched by the European Defense Agency. GaN has already demonstrated excellent output power levels, nevertheless demonstration of excellent PAE associated to very high power in MMIC technology is still challenging. In this work, we present State-of-the-Art results on AlGaN/GaN MMIC amplifiers. An output power of 43W with 52% of PAE was achieved at 10.5 GHz showing that high power associated with high PAE can be obtained at X-band using MMIC GaN technology.

An active pulsed RF and pulsed DC load-pull system for the characterization of HBT power amplifiers used in coherent radar and communication systems

This paper presents a new automated and vector error-corrected active load-pull system allowing the characterization of microwave power transistors under coherent pulsed RF and pulsed DC operating conditions. In this paper, the use of this system is focused on the characterization of a 240-/spl mu/m/sup 2/ GaInP-GaAs heterojunction bipolar transistor (HBT) (Thomson CSP-LCR, Orsay, France). On one hand, source and load-pull measurements of such a transistor are reported for different pulsewidths. On the other hand, nonlinear simulations based on an electrothermal model of an HBT have been performed and are compared with experiments. Power variations and RF carrier phase shift within the pulse versus input power and junction temperature of the transistor are shown.

Fully monolithic Ku and Ka-band GaInP/GaAs HBT wideband VCOs

A family of fully monolithic VCOs utilizing GaInP/GaAs HBTs are presented for the first time. They operate at 14 GHz and 28 GHz with tuning bandwidths ranging from 10.7% to 19.6%. Output powers vary between -9 dBm and +3 dBm with an integrated 6 dB attenuator to reduce pulling. The fabrication yield is higher than 50%. On-wafer measurements show a very small dispersion, and good agreement with the small signal simulations.<<ETX>>

Power GaInP/GaAs HBT MMICs

GaInP/GaAs HBT technology is an excellent alternative to GaAlAs/GaAs HBTs. We present new X-Band power results both on discrete devices and on MMICs obtained using this new type of HBT. 12-2×30-¿m2 finger discrete devices show an output power of 1W at 10 GHz with a power added efficiency of 43% under near class A bias conditions. The dependence of the power gain on the HBT topology has been simulated and that predicts precisely the device performances. First power amplifier MMICs have been produced by Thomson-CSF. Those MMIC amplifiers achieve an output power above 1 W at 10 GHz under both CW and pulsed conditions. The power gain is higher than 12dB at 10 GHz. At the same RF frequency, the power added efficiency reaches 35% and 25% under pulsed conditions (3 ¿s, 10% duty cycle) and CW respectively. These first results are promising, and improved results are expected soon by tuning the output matching network and using higher gain devices.

Characterization and modeling of bias dependent breakdown and self-heating in GaInP/GaAs power HBT to improve high power amplifier design

It is usual to say that power GaInP/GaAs heterojunction bipolar transistors (HBTs) have many advantages for power amplification at microwave frequencies, because of their high gain and high power density. Furthermore, the possibility of controling the base biasing conditions (voltage, current, self-bias control) compared to a field-effect transistor offers additive degrees of freedom to make a tradeoff between linearity and power-added efficiency. Nevertheless existing devices are limited because of the relatively low breakdown voltage whereas high collector voltage swings are required to achieve high power. This drawback makes them not appropriate for use in the next generation of mobile communication base station or radar systems. Silicon technologies such as LDMOS and III-V devices (MESFET and HFET) present competitive performances in term of high power level but for medium power added efficiency. Important improvements have been made in recent years which make possible large breakdown voltages for GaInP/GaAs HBTs. Breakdown value close to 67 V has been achieved. The aim of this work is to significantly improve the modeling of the breakdown voltage on this type of transistor. Furthermore, the in depth characterization and modeling of self-heating effects have been greatly improved in order to improve thermal management solutions which enable us to enhanced design solutions of HBT high power amplifiers.

A non-quasi-static model of GaInP/AlGaAs HBT for power applications

A NonLinear (NL) model of HBT obtained from I(V) and S-parameters pulsed measurements is presented. Besides thermal effects, this model includes also two transcapacitances to take into account the Non-Quasi-Static (NQS) effects. It is shown that contrary to a Quasi-Static (QS) one, this model allows to predict accurately the behavior of the device in the whole power range as well as a broad frequency band.

Wideband 50W packaged GaN HEMT with over 60% PAE through internal harmonic control in S-band

This paper presents an internally-matched packaged GaN HEMT for achieving not only high-efficiency and high-power performances but also wide bandwidth and insensitivity to harmonic terminations in S-band. The internal matching circuits of the optimized package enable to reach a wider bandwidth and to confine the harmonic impedances seen by the internal GaN powerbar into high-efficiency regions whatever the external impedances presented to the package. In a 50Ω environment, the packaged GaN HEMT delivers 45 W output power with more than 55% PAE from 2.9 to 3.7 GHz (24% relative bandwidth). By optimizing source and load impedances at the 1st-harmonic, the packaged GaN HEMT demonstrates 50 W output power with more than 60% PAE over 21% bandwidth.

Industrial GaN FET technology

GaN technology has gained a lot of attention in Europe over the last few years for various domains including RF electronics. After a few years of active observation, United Monolithic Semiconductors (UMS) has taken the decision to introduce a GaN technology family in its portfolio. Based on its extensive experience of III–V technology and the intensive support and collaboration with partners and European research institutes, UMS has developed the capability to produce state-of-the-art GaN devices and circuits. The present paper will summarize the current status achieved and illustrate it with a few representative examples. Aspects covering material, devices, and circuits will be addressed.