Browsing by Author "Samoska, L."

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An MMIC low-noise amplifier design technique
(IEEE, 2016-03) Varonen, M.; Reeves, R.; Kangaslahti, P.; Samoska, L.; Kooi, J. W.; Cleary, K.; Gawande, R. S.; Akgiray, Ahmed Halid; Fung, A.; Gaier, T.; Weinreb, S.; Readhead, A. C. S.; Lawrence, C.; Sarkozy, S.; Lai, R.; Electrical & Electronics Engineering; AKGİRAY, Ahmed Halid
In this paper we discuss the design of low-noise amplifiers (LNAs) for both cryogenic and room-temperature operation in general and take the stability and linearity of the amplifiers into special consideration. Oscillations that can occur within a multi-finger transistor are studied and verified with simulations and measurements. To overcome the stability problem related to the multi-finger transistor design approach a parallel two-finger unit transistor monolithic microwave integrated circuit LNA design technique, which enables the design of wideband and high-linearity LNAs with very stable, predictable, and repeatable operation, is proposed. The feasibility of the proposed design technique is proved by demonstrating a three-stage LNA packaged in a WR10 waveguide housing and fabricated using a 35-nm InP HEMT technology that achieves more than a 20-dB gain from 75 to 116 GHz and 26-33-K noise temperature from 85 to 116 GHz when cryogenically cooled to 27 K.
Open Access
A multioctave 8 GHz-40 GHz receiver for radio astronomy
(IEEE, 2023-04) Kooi, J. W.; Soriano, M.; Bowen, j.; Abdulla, Z.; Samoska, L.; Fung, A. K.; Manthena, R.; Hoppe, D.; Javadi, H.; Crawford, T.; Hayton, D. J.; Malo-Gómez, I.; Gallego-Puyol, J. D.; Akgiray, Ahmed Halid; Gabritchidze, B.; Cleary, K. A.; Jacobs, C.; Lazio, J.; Electrical & Electronics Engineering; AKGİRAY, Ahmed Halid
Accurate measurement of angular positions on the sky requires a well-defined system of reference, something that in practice is realized by the International Celestial Reference Frame (ICRF) with observations of distant (typical redshift similar to 1) Active Galactic Nuclei (AGN). At such great distances a subset of these objects exhibit as little as 10-50 mu as/year observed parallax or proper motion, thus giving the frame excellent spatial and temporal stability. Until fairly recently the majority of AGN centered imaging was accomplished in the S (2.3 GHz) and X (8.4 GHz) radio frequency bands, however S-band observations for reasons such as sensitivity "plateauing", increased source structure (jets), and radio frequency interference (RFI) have become less productive. Following spacecraft telemetry moves to higher frequencies and a desire to strengthen JPL's leadership in defining the next-generation of celestial reference frames has motivated the development of a "Quad-band" prototype receiver that operates in X, Ku, K, and Ka band in both right hand (RCP) and left hand (LCP) circular polarization. The goal of this receiver is to achieve less than a 20 % increase in noise over the Jansky Very Large Array (JVLA, NRAO) performance specification, which in such a wide bandwidth represents a revolutionary capability. To evaluate the various technical developments of the 8 GHz-40 GHz receiver the feedhorn optical beam was designed to interface to the US based Very Long Baseline Array (VLBA). The receiver's intermediate frequency (IF) spans 4 GHz-8 GHz, giving rise to up to eight 4 GHz IF channels for a fully populated instrument. This paper outlines the technical development of a 21/2 octave wide (8 GHz-40 GHz) X-Ka band prototype receiver, fulfilling a need for super broadband technology within the VLBI network. An important additional benefit of the wideband receiver approach is its simplicity and low cost of operation.
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X- To Ka- Band cryogenic LNA module for very long baseline interferometry
(IEEE, 2020) Fung, A.; Samoska, L.; Bowen, J.; Montanez, S.; Kooi, J.; Soriano, M.; Jacobs, C.; Manthena, R.; Hoppe, D.; Akgiray, Ahmed Halid; Lai, R.; Mei, X.; Barsky, M.; Electrical & Electronics Engineering; AKGİRAY, Ahmed Halid
We report a new result of a packaged low noise amplifier (LNA) module with wide bandwidth of 5 to 35 GHz and low noise temperature performance of 10 -18 K, while operated at 10 K ambient. The LNA used 3-stages of sub-50 nm gate length, 100% indium channel content indium phosphide (InP) high electron mobility transistors (HEMTs). Wideband cryogenic LNAs are important for future radio astronomy observatories. To our knowledge these results represent the lowest noise achieved in a wideband amplifier from 5-35 GHz.