More C-band applications, such UAV data link, 5G telecoms or Satcom links at higher data rates lead to a new generation of high power amplifiers: these HPA must have high efficiency over a wide range of output.
The paper describes a new high power envelope tracking amplifier based on 0.25um GaN technology in C-band. The design is focused on matching the input and output impedance to get the better trade-off for high efficiency over a wide range of output power and frequency, when sweeping the drain voltage of the HPA. A high efficiency GaN DC/DC converter is combined with such an amplifier to create an Envelope Tracking HPA
The measured HPA exhibits an average power-added efficiency (PAE) of 65% with an output power of 10W. The efficiency gain is about 25%.

We demonstrate a new class of amplifier (BJF-1) offering a continuum of waveforms between class J and class F-1, that relies on manipulation of the second harmonic of both current and voltage. By reducing the in-phase component of the second harmonic of the current, the phase difference between the fundamental components of the voltage and current is reduced. This increases the power factor and efficiency (upto 91%), beyond the theoretical efficiency of 78.5% of class J. These waveforms require a short at third and higher harmonics which is easily realized at high frequencies. The load at the second harmonic spans the entire |Γ|=1 circle, easing amplifier design. The fabricated amplifier using a GaN HEMT CGH40010F demonstrates 75.9% PAE and 42.2dBm output power at 2.6GHz, demonstrating the highest output power reported to date with comparable frequency weighted efficiency for this device.

ESA/ASI Agencies, and Leonardo Company itself, give great commitment to GaAs/GaN Foundry for GaN process/MMIC qualification from L- to K-Band. Particular attention to storage and life tests on passive components, active devices and MMICs (PRAGAN project), where technological drawbacks have been highlighted and solved. Two main projects oriented to C-Band T/R module in cooperation with University Tor Vergata and TAS-I are ongoing:
1) High Power GaN C-Band TRM Demonstrator, led by TAS-I, where HPA, Driver, LNA components are developed as separate MMIC functions. The TRM, conceived in support of future Copernicus missions by ESA, is capable of 40W pulsed operation in transmit mode enabling twice the RF power density with respect to current Sentinel-1 missions.
2) Single-Chip Front-End, where an integrated front-end includes all the single functionalities onto a single chip. The resulting chip, designed to operate in Sentinel C-Band, will be capable of delivering up to 50W (Tx mode).

The circuit demonstrator discussed in this paper is configured to operate in three power regimes whilst maintaining optimum circuit efficiency. This is achieved using the Load Modulated Balanced Amplifier (LMBA) technique where a control signal (CSP) is injected at the output coupler of a balanced amplifier to modulate the impedance of the balanced amplifier transistors. The circuit is implemented using GaN MMIC technology which integrates the balanced, driver and control signal amplifiers on a single chip. The amplifier can be configured to operate in three RF-output power regimes; from 1.5W to 14.1W for a constant input power of 22 dBm. Power added efficiencies above 37% are observed in all power regimes from 8 to 9 GHz under saturated conditions.

This paper presents investigations performed on GH25-10 in order to overcome the limitation linked to single event breakdown (SEB) under heavy ions observed on metal-isolator-metal (MIM) capacitor devices. Investigations were performed either at design or at technology level. Via circuit design, we could limit the maximum voltage swing seen by any MIM device, which was previously found to be directly linked to SEB. The fabricated MMICs were successfully stressed under Xe excitation with nominal drain bias conditions and RF large-signal at a compression level of 10dB. In a different approach, we modified the dielectric used for the MIM devices to investigate the impact of various parameters like thickness, composition or refractive index. Under Xe excitation, SEB on simple MIM devices could be shifted to a DC bias reaching 90V. The results were confirmed on complete MMICs under Xe excitation with DC bias of 45V and RF-signal up to 10dB compression.

This presentation is about an advanced behavioural modelling flow, used to simplify the design of complex RF and MW system architectures such as in 5G applications, satcom systems or active antenna arrays. The methodology presented here starts with the control of different test benches to perform measurements and extract the behavioural models of the circuits under tests (filters, mixers, amplifiers, passive elements). As a function of the system architecture, different circuit models will be concatenated into one standalone macro-model with its internal algebraic solver, which is able to represent different mismatch phenomena into the sub-system. This macro-model can be then exported into the leading commercial systems simulators to predict in advance the performances of a complex system. We will demonstrate these modelling capabilities in the design of an up-converter system using some circuits on the shelf, including a GaN Power amplifier exhibiting memory effects.