Technology achievements and projections for communication satellites of the future

Multibeam systems of the future using monolithic microwave integrated circuits to provide phase control and power gain are contrasted with discrete microwave power amplifiers from 10 to 75 W and their associated waveguide feeds, phase shifters and power splitters. Challenging new enabling technology areas include advanced electrooptical control and signal feeds. Large scale MMIC's will be used incorporating on chip control interfaces, latching, and phase and amplitude control with power levels of a few watts each. Beam forming algorithms for 80 to 90 deg. wide angle scanning and precise beam forming under wide ranging environments will be required. Satelllite systems using these dynamically reconfigured multibeam antenna systems will demand greater degrees of beam interconnectivity. Multiband and multiservice users will be interconnected through the same space platform. Monolithic switching arrays operating over a wide range of RF and IF frequencies are contrasted with current IF switch technology implemented discretely. Size, weight, and performance improvements by an order of magnitude are projected

Development of a broadband and squint-free Ku-band phased array antenna system for airborne satellite communications

Novel avionic communication systems are required for various purposes, for example to increase the flight safety and operational integrity as well as to enhance the quality of service to passengers on board. To serve these purposes, a key technology that is essential to be developed is an antenna system that can provide broadband connectivity within aircraft cabins at an affordable price. Currently, in the European Commission (EC) 7th Framework Programme SANDRA project (SANDRA, 2011), a development of such an antenna system is being carried out. The system is an electronically-steered phased-array antenna (PAA) with a low aerodynamic profile. The reception of digital video broadcasting by satellite (DVB-S) signal which is in the frequency range of 10.7-12.75 GHz (Ku-band) is being considered. In order to ensure the quality of service provided to the passengers, the developed antenna should be able to receive the entire DVB-S band at once while complying with the requirements of the DVB-S system (Morello & Mignone, 2006). These requirements, as will be explained later, dictate a broadband antenna system where the beam is squint-free, i.e. no variation of beam pointing direction for all the frequencies in the desired band. Additionally, to track the satellite, the seamless tunability of the beam pointing direction of this antenna is also required. In this work, a concept of optical beamforming (Riza & Thompson, 1997) is implemented to provide a squint-free beam over the entire Ku-band for all the desired pointing directions. The optical beamformer itself consists of continuously tunable optical delay lines that enable seamless tunability of the beam pointing direction

K-Band GaAs MMIC Doherty Power Amplifier for Microwave Radio With Optimized Driver

In this paper, a Doherty power amplifier for K-band point-to-point microwave radio, developed in TriQuint GaAs um PWR pHEMT monolithic technology, is presented. Highly efficient driver stages on both the main and auxiliary branches have been designed and optimized to boost gain with minimal impact on power-added efficiency. The selected architecture enables a modular combination to reach higher power levels. Matching network structures have been designed, according to simple equivalent circuit approaches, to obtain the desired 10% fractional bandwidth. The fabricated power amplifier (PA) exhibits, at 24 GHz in continuous-wave conditions, an output power of 30.9 dBm, with a power-added efficiency of 38% at saturation and 20% at 6 dB of output power back-off, together with a gain of 12.5 dB. System-level characterization at 24 GHz, in very demanding conditions, with a 28-MHz channel 7.5-dB peak-to-average ratio modulated signal, showed full compliance with the standard emission mask, adopting a simple predistorter, with average output power of 23.5 dBm, and average efficiency above 14%. The measured performance favorably compare with other academic and commercial K-band PAs for similar applications

A 4W Doherty power amplifier in GaN MMIC technology for 15GHz applications

This letter presents an integrated Doherty power amplifier (PA) in 0.25- μm GaN on SiC process. Designed for 15-GHz point-to-point radios, the PA exhibits an output power of 36 ± 0.5 dBm between 13.7 and 15.3 GHz, while at 14.6 GHz, it shows a 6-dB output back-off efficiency higher than 28%. Modulated signal measurements applying digital predistortion demonstrate the compatibility of the amplifier with point-to-point radio requirements. To the best of our knowledge, this PA has the highest back-off efficiency for the 15-GHz band, and is the first GaN Doherty in the Ku-band

MMIC linear-phase and digital modulators for deep space spacecraft X-band transponder applications

The design concepts, analyses, and development of GaAs monolithic microwave integrated circuit (MMIC) linear-phase and digital modulators for the next generation of space-borne communications systems are summarized. The design approach uses a compact lumped element quadrature hybrid and Metal Semiconductor Field Effect Transistors (MESFET)-varactors to provide low loss and well-controlled phase performance for deep space transponder (DST) applications. The measured results of the MESFET-diode show a capacitance range of 2:1 under reverse bias, and a Q of 38 at 10 GHz. Three cascaded sections of hybrid-coupled reflection phase shifters were modeled and simulations performed to provide an X-band (8415 +/- 50 MHz) DST phase modulator with +/- 2.5 radians of peak phase deviation. The modulator will accommodate downlink signal modulation with composite telemetry and ranging data, with a deviation linearity tolerance of +/- 8 percent and insertion loss of less than 8 +/- 0.5 dB. The MMIC digital modulator is designed to provide greater than 10 Mb/s of bi-phase modulation at X-band

High linear power amplifier for multicarrier satellite communications

High linearity performance in transmitters is receiving continuously attention due to demands of higher data rates in satellite communication links. This paper presents a GaAs pHEMT MMIC high linear power amplifier intended for multicarrier operation at C-band. Junction temperature prediction methods are considered during the amplifier design to keep the temperature under control and achieve high reliability required for space applications. The design method is focused in high linearity optimizing the loads and using a non-linear transistor model to predict harmonic generation and intermodulation products. The amplifier was characterized in terms of S-parameters, single tone output power and two tone output power. The measured S-parameters shows a flattened gain over 25 dB between 3 and 6 GHz. The 1dB compression point is measured at 26.7 dBm and the output third order intercept point (OIP3) is above 40 dBm in the band reaching a maximum of 41.7 dBm at 4.5 GHz. The power consumption is lower than 2.5 W and the junction temperatures are calculated under 105 \ub0C

Low-Bias-Complexity Ku-band GaN MMIC Doherty Power Amplifier

This paper present a two-stage Doherty power amplifier designed to maximize the efficiency at 6 dB back-off while minimizing the complexity in terms of bias voltages. The amplifier has been manufactured on a GaN-SiC 150 nm monolithic microwave integrated circuit technology. The fabricated chip, measured in continuous wave conditions, maintains a linear gain higher than 13 dB, a saturated output power in excess of 34 dBm, with a power-added efficiency higher than 20% both at saturation and at 6 dB output back-off, over the 14.5 GHz-17.25 GHz band, favorably comparing with the present state of the art for similar applications

Disseny i desenvolupament de circuits d'altes prestacions en banda C per a la missió espacial CIMR (Copernicus Imaging Microwave Radiometer) de la ESA

The Arctic is region where deep changes are occurring which have direct repercussions on our weather and climate. CIMR, that stands for Copernicus Imaging Microwave Radiometer, is a mission that will carry a wide-swath conically-scanning multi-frequency microwave radiometer to provide observations of sea-surface temperature, sea-ice concentration and sea-surface salinity, among other sea-ice parameters. In particular, CIMR will highly respond to the requirements from Artic communities. Beyond the immensity of the project itself, SENER Aeroespacial has the chance to be part of such a great mission, together with great organisations such as Thales Alenia Space, OHB Italia and HPS Germany. In fact, SENER Aeroespacial is in charge of designing, prototyping and measuring the equipment that conform the receivers and the calibrators of the radiometer. These equipment are on-board satellite devices, thus a committed design and characterization must be considered regarding space conditions and variability. Through the development of this project, a straightforward explanation of the equipment that take part in the calibration and reception chain is proposed. Moreover, a high-performance design, analysis and prototyping of the receiver chain is proposed. In addition, a complete product development is designed from scratch to the manufacturing and testing of a characteristic prototype ready to be integrated in any RF chain.El Ártico es una región en la que se están produciendo cambios impactantes que repercuten directamente en el tiempo y en el clima. CIMR, cuyas siglas significan Copernicus Imaging Microwave Radiometer, es una misión que consiste en un radiómetro de microondas multifrecuencia de barrido cónico de gran alcance para proporcionar observaciones de la temperatura de la superficie del mar, la concentración de hielo marino y la salinidad de la superficie del mar, entre otros parámetros del hielo marino. En particular, CIMR responderá en gran medida a las necesidades de las múltiples comunidades del Ártico. Más allá de la inmensidad del proyecto en sí, SENER Aeroespacial tiene la oportunidad de formar parte de una misión tan importante, junto con distintivas organizaciones como Thales Alenia Space, OHB Italia y HPS Alemania. De hecho, SENER Aeroespacial se encarga de diseñar, prototipar y medir los equipos que conforman los receptores y los calibradores del radiómetro. Estos equipos son dispositivos embarcados en satélites, por lo que se debe considerar un diseño y caracterización comprometidos con las condiciones y variabilidad del espacio. Mediante el desarrollo de este proyecto se propone una explicación a grandes rasgos de los equipos que intervienen en la cadena de calibración y recepción. Además, se propone un diseño, análisis y prototipado de alto rendimiento de la cadena de recepción. Asimismo, se propone un desarrollo completo del producto desde su inicio hasta la fabricación y prueba de un prototipo característico listo para ser integrado en cualquier cadena de RF.L'Àrtic és una regió on s'estan produint canvis impactants que repercuteixen directament en el temps i el clima. CIMR, que significa Copernicus Imaging Microwave Radiometer, és una missió que consisteix en un radiòmetre de microones multifreqüència d'escombrat cònic de gran abast per proporcionar observacions de la temperatura de la superfície del mar, la concentració de gel marí i la salinitat de la superfície del mar, entre altres paràmetres del gel marí. En particular, CIMR respondrà en gran part a les necessitats de les múltiples comunitats de l'Àrtic. Més enllà de la immensitat del projecte en si, SENER Aeroespacial té l'oportunitat de formar part d'una missió molt important, juntament amb organitzacions distintives com Thales Alenia Space, OHB Italia i HPS Germany. De fet, SENER Aeroespacial s'encarrega de dissenyar, prototipar i mesurar els equips que conformen els receptors i els calibradors del radiòmetre. Aquests equips són dispositius embarcats en satèl·lits, per la qual cosa cal considerar un disseny i caracterització compromesos amb les condicions i la variabilitat de l'espai. Mitjançant el desenvolupament d'aquest projecte, es proposa una explicació a grans trets dels equips que intervenen a la cadena de calibratge i recepció. A més, es proposa un disseny, anàlisi i prototipat d'alt rendiment de la cadena de recepció. Així mateix, es proposa un desenvolupament complet del producte des del seu inici fins a la fabricació i prova d'un prototip característic llest per ser integrat a qualsevol cadena de RF

A high efficiency 10W MMIC PA for K-b and satellite communications

This paper discusses the design steps and experimental characterization of a monolithic microwave integrated circuit (MMIC) power amplifier developed for the next generation of K-band 17.3–20.2 GHz very high throughput satellites. The technology used is a commercially available 100-nm gate length gallium nitride on silicon process. The chip was developed taking into account the demanding constraints of the spacecraft and, in particular, carefully considering the thermal constraints of such technology, in order to keep the junction temperature in all devices below 160°C in the worst-case condition (i.e., maximum environmental temperature of 85°C). The realized MMIC, based on a three-stage architecture, was first characterized on-wafer in pulsed regime and, subsequently, mounted in a test-jig and characterized under continuous wave operating conditions. In 17.3–20.2 GHz operating bandwidth, the built amplifier provides an output power >40 dBm with a power added efficiency close to 30% (peak >40%) and 22 dB of power gain