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Castel Guelfo di Bologna, Italy

Florian C.,University of Bologna | Resca D.,MEC Microwave Electronics for Communications | Biondi A.,MEC Microwave Electronics for Communications | Scappaviva F.,MEC Microwave Electronics for Communications
Microwave and Optical Technology Letters | Year: 2014

In this article, an X-band to Ka-band up-converter circuit designed for the transmitting chain of Satcom-on-the-move terminals is presented. The circuit is implemented using a 0.25 μm GaAs pHEMT microwave monolithic integrated circuit commercial process. It operates at fixed LO frequency of 22 GHz, IF input frequency within the band (8-9) GHz and corresponding RF output frequency within (30-31) GHz band. The up-converter circuit is composed of a resistive FET mixer, a K-band LO buffer amplifier, and a Ka-band medium power amplifier at the RF output. The bias operating condition of the entire multifunction chip is Vdd?=?2.8 V, Idq?=?322 mA, for a power consumption of 900 mW, when the Ka-band high power amplifier (HPA) operates in linear conditions. The chip dimensions are 3.4 × 2.8 mm2. The up-converter provides more than 12 dB conversion gain over the full bandwidth, when operated with LO input power of 0 dBm and IF fixed input power of -5 dBm. It also achieves 25 dBc of LO isolation at the RF output port. The high 1 dB compression point P1dB?>?19 dBm, along with an OTOI in excess of 29 dBm, make the circuit suitable to directly drive Ka-band high power amplifiers in very linear operating conditions. © 2014 Wiley Periodicals, Inc.

Resca D.,MEC Microwave Electronics for Communications | Cignani R.,University of Bologna | Florian C.,University of Bologna | Biondi A.,MEC Microwave Electronics for Communications | Scappaviva F.,MEC Microwave Electronics for Communications
International Journal of Microwave and Wireless Technologies | Year: 2015

A MMIC double-balanced subharmonic diode ring mixer was designed for broadband satellite communications exploiting a GaAs pHEMT process. The circuit implements the frequency conversion from Q (43.5-50 GHz) to Ku-K band (17-21.5 GHz). Besides the RF, LO, and IF baluns, the MMIC integrates a buffer amplifier for the local oscillator signal, which is designed between X and Ku bands (11-16.5 GHz), due to the subharmonic operation. The mixer measured conversion loss is between 8 and 12 dB along the bandwidth, with an LO power of 9 dBm. The input p1 dB and IP3 are 2 and 15 dBm, respectively. The balanced structure ensures an LO and 2 × LO leakages at the IF port lower than -25 and -35 dBm, respectively. Other spurious remain below -67 dBc. The chip dimensions are 2.4 × 2.4 mm2. © Cambridge University Press and the European Microwave Association 2014.

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