S Band Hybrid Power Amplifier in GaN Technology with Input/Output Multi Harmonic Tuned Terminations

n this paper, the design, fabrication, and measurements of an S band multi harmonic tuned power amplifier in GaN technology is described. The amplifier has been designed by exploiting second and third harmonic tuning conditions at both input and output ports of the active device. The amplifier has been realized in a hybrid form, and characterized in terms of small and large signal performance. An operating bandwidth of 300 MHz around 3.55 GHz, with 42.3 dBm output power, 9.3 dB power gain and 53.5% power added efficiency PAE (60% drain efficiency) at 3.7 GHz are measured

Microwave and Radar Week (MRW 2020): Selected Papers

The 9th Microwave and Radar Week (MRW 2020) was held in Warsaw the capital of Poland, on 5–7 October 2020 [...

A contribution to linearity improvement of a highly efficient pa for WIMAX applications

This paper describes the design of a highly efficient and linear GaN HEMT power amplifier which may be used in WiMAX application. To improve linearity of highly efficient power amplifiers, a technique using diodes in the gate DC path was applied to TL and 2HT amplifier. This solution using diodes offers a good manner to improve linearity near saturation zone compared to the approach using only a DC gate resistor for TL (tuned load) case as well as for 2HT (second harmonic tuning approach). A 2.5 GHz 2HT power amplifier circuit was built, and measured data confirm the linearity improvement, particularly near saturation zone, as predicted by simulation, maintaining higher power performances. An output power of 36.8 dBm has been measured with an associated power added efficiency of 46.5% and carrier to third order intermodulation (C/I3) of 53.4 dBc. A 2HT PA also exhibits good performances across the full (2.3-2.7) GHz band. An output power ranging from (35-36.9) dBm with an associated gain of $12.9±0.9 and a power added efficiency ranging from (40-46)% are measured across the full (2.3-2.7) GHz band.Our acknowledgment to the financial support provided by the Spanish Ministry of Science and Innovation (MICINN) through projects TEC2008-06684-C03-01 and CONSOLIDER-INGENIO 2010 CSD2008-00068

Space-Compliant Design of a Millimeter-Wave GaN-on-Si Stacked Power Amplifier Cell through Electro-Magnetic and Thermal Simulations

The stacked power amplifier is a widely adopted solution in CMOS technology to overcome breakdown limits. Its application to compound semiconductor technology is instead rather limited especially at very high frequency, where device parasitic reactances make the design extremely challenging, and in gallium nitride technology, which already offers high breakdown voltages. Indeed, the stacked topology can also be advantageous in such scenarios as it can enhance gain and chip compactness. Moreover, the higher supply voltages and lower supply currents beneficially impact on reliability, thus making the stacked configuration an attractive solution for space applications. This paper details the design of two stacked cells, differing in their inter-stage matching strategy, conceived for space applications at Ka-band in 100 nm GaN-on-Si technology. In particular, the design challenges related to the thermal constraints posed by space reliability and to the electro-magnetic cross-talk issues that may arise at millimeter-wave frequencies are discussed. The best cell achieves at saturation, in simulation, 3 W of output power at 36 GHz with associated gain and efficiency in excess of 7 dB and 35%, respectively

The Doherty Power Amplifier

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3-Way Doherty Power Amplifiers: Design Guidelines and MMIC Implementation at 28 GHz

This article presents the design strategy and the implementation of a three-way Doherty power amplifier (DPA3W) to enhance the efficiency at deep power back-off. Theoretical design equations are derived, based on which design charts are drawn to explore the available design space, accounting for practical constraints related to the available technology and selected application. The proposed design strategy is demonstrated by the design, fabrication and experimental characterization of a three-way multistage Doherty amplifier optimized for efficiency peaks at 6 and 12 dB back-off. The amplifier is realized on the WIN Semiconductors 150 nm GaN-SiC high-electron-mobility transistor (HEMT) monolithic process at 28 GHz, targeting 5G applications. The prototype achieves saturated output power in excess of 34 dBm and power added efficiency of the order of 15% from 6 to 12 dB back-off, demonstrating competitive performance and a good agreement between simulations and measurements, thus validating the approach

The Switched Mode Power Amplifiers

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Full-band oversized turnstile-based waveguide four-way power divider/combiner for high-power applications

Very high-power and high-efficiency microwave applications require waveguide structures to combine/divide the power from/to a variable number of high-power solid-state devices. In the literature, among the different waveguide configurations, those capable of providing the maximum output power show a limited relative bandwidth. To overcome this limitation, in this paper a full-band (40%) waveguide power divider/combiner specifically designed for high-power applications (up to several kW) is presented. The proposed structure uses an evolved turnstile junction with a standard rectangular waveguide common port, rotated 45°, with respect to its central axis, to divide/combine the signal to/from the four output/input rectangular ports. The inclusion of an oversized central cavity together with circular and rectangular waveguide impedance transformers at the common port allows the achievement of a full-band operation with excellent electrical performance, while maintaining a very simple and compact configuration. Only two layers of metal are required for the physical implementation of this structure in platelet configuration. A prototype has been designed covering the full Ka-band (26.5-40 GHz), showing an excellent measured performance with around 30 dB of return loss, 0.18 dB of insertion loss, and less than 1.5° of phase imbalance

Renormalization group evaluation of exponents in family name distributions

According to many phenomenological and theoretical studies the distribution of family name frequencies in a population can be asymptotically described by a power law. We show that the Galton-Watson process corresponding to the dynamics of a growing population can be represented in Hilbert space, and its time evolution may be analyzed by renormalization group techniques, thus explaining the origin of the power law and establishing the connection between its exponent and the ratio between the population growth and the name production rates.Comment: 8 pages, no figures, many typos correcte