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Progress in Differential Amplifiers. Óscar García-Pérez FG-IGN oscar.perez@oan.es José A. López-Fernández, Daniel Segovia-Vargas, Enrique García-Muñoz, Vicente González-Posadas, José L. Vázquez-Roy, José M. Serna-Puente, Timothy Finn.
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Progress in Differential Amplifiers Óscar García-Pérez FG-IGN oscar.perez@oan.es José A. López-Fernández, Daniel Segovia-Vargas, Enrique García-Muñoz, Vicente González-Posadas, José L. Vázquez-Roy, José M. Serna-Puente, Timothy Finn 4th SKADS Workshop, Lisbon, 2-3 October 2008 Progress in differential amplifiers Oscar Garcia-Perez
Overview • DS4-T4 • Differential amplifiers: • First prototypes circuit schematics • Characterization procedure • 50ohms measurements • Source-pull measurements • Conclusions and future lines • Feeding network • Implementation • Measurements • Array system • Noise and gain simulation 4th SKADS Workshop, Lisbon, 2-3 October 2008 Progress in differential amplifiers Oscar Garcia-Perez
Task DS4-T4 • DS4-T4 establishes that the FG-IGN will be responsible for the design, development, construction and characterization of a 1m2 ultra wide band aperture array. • This design should be: • Low cost • Dual polarized • RF performance from 300MHz to 1GHz • Noise figure as low as possible 4th SKADS Workshop, Lisbon, 2-3 October 2008 Progress in differential amplifiers Oscar Garcia-Perez
Differential amplifiersFirst prototypes (I) • Balanced topology: Low Noise PHEMTs ATF34-143 (Avago Tech.) Resistor in series (10ohm) Power supply network: avoiding current peaks Several shock inductors (with several magnitude order values) in series : good isolation in the whole bandwidth 4th SKADS Workshop, Lisbon, 2-3 October 2008 Progress in differential amplifiers Oscar Garcia-Perez
Differential amplifiersFirst prototypes (II) • Fully-differential topology: Low Noise PHEMTs ATF34-143 (Avago Tech.) Several shock inductors (with several magnitude order values) in series : good isolation in the whole bandwidth RLC network: impedance matching and stability control Current source: inductors in series to increase the impedance 4th SKADS Workshop, Lisbon, 2-3 October 2008 Progress in differential amplifiers Oscar Garcia-Perez
Differential amplifiersCharacterization procedure Characterization by using input/output baluns. Measurements must be corrected in order to eliminate all the balun influence in our measurement. Some methods described in the literature: [A. A. Abidi et al., 1999] M/A-COM ETC1-1-13 1:1 TL Transformer 4.5-3000MHz [A. A. Abidi et al., 1999]:A. A. Abidi, and J. C. Leete, “De-Embedding the Noise Figure of Differential Amplifiers,” IEEE Journal of Solid-State Circuits, vol. 34, no. 6, pp. 882-885, Jun. 1999. 4th SKADS Workshop, Lisbon, 2-3 October 2008 Progress in differential amplifiers Oscar Garcia-Perez
Differential amplifiers50ohm measurements Balanced Fully-differential Gain > 39dB Noise < 170K CMRR = n/a Gain > 19dB Noise < 300K CMRR > 26.5dB Resonance (shock inductors self-resonance frequency) near to our band is increasing the noise at high frequencies. Solution: Higher Q-factor inductors in next prototype. 4th SKADS Workshop, Lisbon, 2-3 October 2008 Progress in differential amplifiers Oscar Garcia-Perez
Differential amplifiersSource-pull measurements Noise and gain measurements by using an impedance tuner at the input. It allows to estimate the gain and noise properties of our amplifier when connecting it with the antenna (normalized to 150ohm diff.) as source. Impedance tuner: 1819A (Maury Microwave Corporation) 4th SKADS Workshop, Lisbon, 2-3 October 2008 Progress in differential amplifiers Oscar Garcia-Perez
Differential amplifiersSource-pull measurements Characterization at 300MHz, 650MHz and 1000MHz. Balanced Fully-differential Gain > 29dB Noise < 150K Gain > 19dB Noise < 59K (f={300,600MHz}) Future lines for next prototype: Trying to improve the noise at high frequencies. Future lines for next prototype: Replacing the shock inductors by other ones with higher Q-factor. 4th SKADS Workshop, Lisbon, 2-3 October 2008 Progress in differential amplifiers Oscar Garcia-Perez
Differential amplifiersConclusions • First prototypes using two different topologies have been manufactured and characterized. • Good gain level in all the bandwidth. • Good noise operation at low and intermediate frequencies. • We are currently working towards the improvement of these first designs. • Definitive circuit boards are projected to be ready in the beginning of 2009. 4th SKADS Workshop, Lisbon, 2-3 October 2008 Progress in differential amplifiers Oscar Garcia-Perez
Feeding networkImplementation 1/8 Powersplitter 1/4 Power splitter Connections between amplifiers and boards, and between boards and other boards by using coaxial cable sections with SMA connectors. 4th SKADS Workshop, Lisbon, 2-3 October 2008 Progress in differential amplifiers Oscar Garcia-Perez
Feeding networkMeasurements S21 > -19dB (-15dB nominal) S11 < -17dB 4th SKADS Workshop, Lisbon, 2-3 October 2008 Progress in differential amplifiers Oscar Garcia-Perez
Array systemGain and noise simulation Noise and gain simulations, including all the array system components: Antenna + DLNA + BFN Balanced Fully-differential Gain > 40dB Noise < 60K Gain > 23dB Noise < 90K 4th SKADS Workshop, Lisbon, 2-3 October 2008 Progress in differential amplifiers Oscar Garcia-Perez
Progress in Differential Amplifiers Óscar García-Pérez FG-IGN oscar.perez@oan.es José A. López-Fernández, Daniel Segovia-Vargas, Enrique García-Muñoz, Vicente González-Posadas, José L. Vázquez-Roy, José M. Serna-Puente, Timothy Finn 4th SKADS Workshop, Lisbon, 2-3 October 2008 Progress in differential amplifiers Oscar Garcia-Perez