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As well as largely exploited for microwave high-power applications, aluminum gallium nitride (AlGaN)/GaN high electron mobility transistor (HEMT) technologies have demonstrated promising results for the design of low-noise, high dynamic range, and highly robust amplifiers. In this manuscript, we describe the design and characterization of a Ku-band monolithic microwave integrated circuit low-noise amplifier for telecom space applications, exploiting an industrial AlGaN/GaN 0.25-μm HEMT on silicon carbide process. In the frequency band 12.75-14.8 GHz, the LNA features over 20 dB linear gain with a noise figure around 1.8 dB. Input and output return losses are nearly 10 dB. Power dissipation is 700 mW in linear operation. An innovative transistor model based on electromagnetic analyses and small-signal and noise measurements has been developed to improve the predictions of the foundry model on source-degenerated devices. A systematic radio frequency (RF) life stress test campaign performed on the designed low-noise amplifier demonstrated a safe operating area of 15 dBm of overdrive input power.

In nowadays CAD environments for integrated microwave circuit design, dedicated tools for the implementation of user defined component models are becoming more and more important. These tools are mainly oriented to the definition of equivalent circuit models. However, the need for more accurate prediction of nonlinear electron device performance pushes the modelling community towards the research of new, often nonconventional, modelling approaches (e.g., frequencydomain, behavioural, integral models, look-up-table based, state-space based, etc.). In such a context, the model implementation tools usually available may result not sufficiently flexible. The paper provides useful hints and points out the main limitations which can be encountered in the implementation of non-conventional electron device models. As an example, the implementation of a Nonlinear Discrete Convolution model will be considered by using three different advanced tools: the Model Wizard of AWR Microwave Office, the Model Development Kit and Verilog- A Language of Agilent ADS.

A new procedure is presented for the analytical representation of electron device characteristics on the basis of function samples. The proposed formula relies on the analogy with the reconstruction theory of sampled signals. Full analytical developments are provided in the paper along with practical application examples based on actual 0.25 μm GaAs PHEMT characteristics. The proposed function approximation is shown to provide excellent predictions under different signal operations, when used in association with accurate nonlinear models of microwave electron devices. Comparisons with other typical interpolation procedure are also provided.

We present a new netlist-compatible interface for entering and implementing nonlinear dynamic models into circuit simulators. The interface is completely general and allows to implement nonlinear models with nonlinear memory starting from model equations either in Volterra Series expansion and/or from state-space equations. A detailed description of the interface is included in the paper as well as two application examples using two different nonlinear non quasi-static models.

Electron device modelling requires accurate descriptions of parasitic passive structures connecting the intrinsic electron device to the external world. In conventional approaches, the parasitic phenomena are described by a network of lumped elements. As an alternative, a distributed description can be conveniently adopted. This choice has been proved very appropriate when dealing with device scaling and very high operating frequencies. In this paper, a distributed parasitic network is adopted in association with a nonlinear electron device model. In particular, it is shown how an equivalent intrinsic device and a suitably-defined distributed parasitic network can be accurately defined and modelled on the basis of standard measurements and easy electromagnetic simulations. Wide experimental validation based on GaAs and InP PHEMTs will be provided, showing accurate prediction capabilities both under small- and large signal conditions. The proposed model is shown to perform optimally even after periphery scaling.

Besides the well known outstanding characteristics in terms of power density and thermal behavior, which are largely exploited for microwave high power applications, AlGaN/GaN HEMT technologies have demonstrated promising results for the design of low noise, high-dynamic-range and highly rugged amplifiers. In this paper we describe the design, implementation and characterization of a Ku-band MMIC Low Noise Amplifier for telecom Space applications, exploiting an industrial AlGaN/GaN 0.25 μm HEMT on SiC process. In the frequency band 12.8-14.8 GHz, the LNA features a linear gain over 20 dB with a Noise Figure below 1.85 dB. Input and output return losses are better than -9 dB in the same band. Power dissipation is 840 mW in linear operation. The LNA delivers about 25 dBm of output power at 1 dB compression point and it has been tested to survive without performance degradation 25 dBm of CW input power. © 2013 European Microwave Association.

In this work, we describe the complete design flow of a 1.3–3.3-GHz active balun, exploited to generate a high-voltage swing differential local oscillator (LO) signal driving a highly linear doubly balanced resistive ring mixer. Both the LO active balun and the mixer are integrated into a -band single chip monolithic microwave integrated circuits (MMIC) downconverter for the state-of-the-art telecom satellites. System performance has been maximized designing the different circuits by a holistic approach, which considers a non 50- environment. The experimental validation is carried out by means of an ad hoc time-domain load–pull test bench and shows that the LO active balun provides two quasi-sinusoidal, 180 out-phased, signals with 2.4-V peak-to-peak voltage to the input ports of the mixer over a very high-impedance loading condition.

In this paper, a single-chip front-end (SCFE) operating in Ku-band (12–17 GHz) is presented. It is designed exploiting a GaN on SiC technology featured by 150 nm gate length provided by UMS foundry. This MMIC integrates high power and low noise amplification functions enabled by a single-pole double-throw (SPDT) switch, occupying a total area of 20 mm2. The transmitting chain (Tx) presents a 39 dBm output power, a power added efficiency (PAE) higher than 30% and a 22 dB power gain. The receive path (Rx) offers a low noise figure (NF) lower than 2.8 dB with 25 dB of linear gain. The Rx port output power leakage is limited on chip to be below 15 dBm even at high compression levels. Finally, a complete characterization of the SCFE in the Rx and Tx modes is presented, also showing the measurement of the recovery time in the presence of large-signal interferences.

A X-band GaN monolithic microwave integrated circuits (MMIC) High Power Amplifier (HPA) suitable for future generation Synthetic Aperture Radar systems is presented. The HPA delivers 14 W of output power, more than 38% of PAE in the frequency bandwidth from 8.8 to 10.4 GHz. Its linear gain is greater than 25 dB. For the first time an MMIC X-band HPA has been designed by directly measuring the transistor behavior at the current generator plane. In particular, optimum device load-line has been selected according to the chosen performance tradeoffs.

The present manuscript details a wideband high power amplifier design, based on a 5-mm GaN power bar. In particular, a broadband input large-signal matching condition has been realized, that ensures optimal power transfer under actual device operation. The measured performance of the PA perfectly matches the expected predictions based on large-signal measurements carried out on a 1.25-mm GaN elementary cell.

Electron device modelling at very high frequencies needs, as a preliminary step, the identification of suitable parasitic elements mainly describing the passive structure used for accessing the intrinsic device. However, when dealing with device modelling at millimetre-wave frequencies conventional lumped parasitic networks necessarily become less adequate in describing inherently distributed parasitic phenomena. In this paper, a distributed approach is adopted for the modelling of the parasitic network and a new identification procedure, based on electromagnetic simulation and conventional S-parameter measurements, is proposed. The intrinsic device, obtained after de-embedding from the distributed parasitic network, is particularly suitable for the extraction of accurate nonlinear models. Preliminary validation results are provided in the paper. © 2006 EuMA.

In the context of the European Union TARGET Network of Excellence (NoE) a specific interest has been oriented to the comparison of different electron device models in order to choose the most suitable for a particular application (e.g. highly linear amplifiers, low phase noise oscillators). To this purpose different metrics have been defined to compare the models behavior under different operating conditions (i.e. dc, ac small- and large-signal). In this paper we apply different metrics proposed under the TARGET NoE in order to compare two models, the Nonlinear Discrete Convolution (NDC) model, based on a table-based black-box approach, and the EEHEMT1 model, based on the classic equivalent circuit approach. The goal is to provide a set of practical criteria for carrying on reliable model comparisons.