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It is challenging to accurately characterize the three-dimensional distribution of horizontal wind vectors (known as 3D winds). Feature-matching satellite cloud top or water vapor fields have been used for decades to retrieve atmospheric motion vectors, but this approach is mostly limited to a single and uncertain pressure level at a given time. Satellite wind lidar measurements are expected to provide more accurate data and capture the line-of-sight wind for clear skies, within cirrus clouds, and above thick clouds, but only along a curtain parallel to the satellite track. Here we propose Vientos—a new satellite mission concept that combines two or more passive water vapor sounders with Doppler wind lidar to measure 3D winds. The need for 3D wind observations is highlighted by inconsistencies in reanalysis estimates, particularly under precipitating conditions. Recent studies have shown that 3D winds can be retrieved using water vapor observations from two polar-orbiting satellites separated by 50 min, with the help of advanced optical flow algorithms. These winds can be improved through the incorporation of a small number of collocated higher-accuracy measurements via machine learning. The Vientos concept would enable simultaneous measurements of 3D winds, temperature, and humidity, and is expected to have a significant impact on scientific research, weather prediction, and other applications. For example, it can help better understand and predict the preconditions for organized convection. This article summarizes recent results, presents the Vientos mission architecture, and discusses implementation scenarios for a 3D wind mission under current budget constraints.

This study presents a simulated simultaneous retrieval of mass mean cloud ice particle effective diameter, ice water content, water vapor, and temperature profiles using a combination of a 94-GHz cloud radar and multifrequency (118, 183, 240, 310, 380, 664, and 850 GHz) millimeter- and submillimeter-wave radiometers from a space platform. The retrieval capabilities and uncertainties of the combined radar and microwave radiometers are quantified. We show that this combined active and passive remote sensing approach with SmallSat technologies addresses a gap in the current state-of-the-art remote sensing measurements of ice cloud properties, especially deriving vertical profiles of ice cloud particle sizes in the atmosphere together with the ambient thermodynamic conditions. Therefore, this new approach can serve as a plausible candidate for future missions that target cloud and precipitation processes to improve weather forecasts and climate predictions. ©2019. The Authors.

We present deep CCS and HC$_7$N observations of the L1495-B218 filaments in the Taurus molecular cloud obtained using the K-band focal plane array on the 100m Green Bank Telescope. We observed the L1495-B218 filaments in CCS $J_N$ = 2$_1$$-$1$_0$ and HC$_7$N $J$ = 21$-$20 with a spectral resolution of 0.038 km s$^{-1}$ and an angular resolution of 31$''$. We observed strong CCS emission in both evolved and young regions and weak emission in two evolved regions. HC$_7$N emission is observed only in L1495A-N and L1521D. We find that CCS and HC$_7$N intensity peaks do not coincide with NH$_3$ or dust continuum intensity peaks. We also find that the fractional abundance of CCS does not show a clear correlation with the dynamical evolutionary stage of dense cores. Our findings and chemical modeling indicate that the fractional abundances of CCS and HC$_7$N are sensitive to the initial gas-phase C/O ratio, and they are good tracers of young condensed gas only when the initial C/O is close to solar value. Kinematic analysis using multiple lines including NH$_3$, HC$_7$N, CCS, CO, HCN, \& HCO$^+$ suggests that there may be three different star formation modes in the L1495-B218 filaments. At the hub of the filaments, L1495A/B7N has formed a stellar cluster with large-scale inward flows (fast mode), while L1521D, a core embedded in a filament, is slowly contracting due to its self-gravity (slow mode). There is also one isolated core that appears to be marginally stable and may undergo quasi-static evolution (isolated mode)., Comment: ApJ accepted

In this paper we discuss the latest developments of the STRIP instrument of the “Large Scale Polarization Explorer” (LSPE) experiment. LSPE is a novel project that combines ground-based (STRIP) and balloon-borne (SWIPE) polarization measurements of the microwave sky on large angular scales to attempt a detection of the “B-modes” of the Cosmic Microwave Background polarization. STRIP will observe approximately 25% of the Northern sky from the “Observatorio del Teide” in Tenerife, using an array of forty-nine coherent polarimeters at 43 GHz, coupled to a 1.5 m fully rotating crossed-Dragone telescope. A second frequency channel with six-elements at 95 GHz will be exploited as an atmospheric monitor. At present, most of the hardware of the STRIP instrument has been developed and tested at sub-system level. System-level characterization, starting in July 2018, will lead STRIP to be shipped and installed at the observation site within the end of the year. The on-site verification and calibration of the whole instrument will prepare STRIP for a 2-years campaign for the observation of the CMB polarization.

We present deep CCS and HC$_7$N observations of the L1495-B218 filaments in the Taurus molecular cloud obtained using the K-band focal plane array on the 100m Green Bank Telescope. We observed the L1495-B218 filaments in CCS $J_N$ = 2$_1$$-$1$_0$ and HC$_7$N $J$ = 21$-$20 with a spectral resolution of 0.038 km s$^{-1}$ and an angular resolution of 31$''$. We observed strong CCS emission in both evolved and young regions and weak emission in two evolved regions. HC$_7$N emission is observed only in L1495A-N and L1521D. We find that CCS and HC$_7$N intensity peaks do not coincide with NH$_3$ or dust continuum intensity peaks. We also find that the fractional abundance of CCS does not show a clear correlation with the dynamical evolutionary stage of dense cores. Our findings and chemical modeling indicate that the fractional abundances of CCS and HC$_7$N are sensitive to the initial gas-phase C/O ratio, and they are good tracers of young condensed gas only when the initial C/O is close to solar value. Kinematic analysis using multiple lines including NH$_3$, HC$_7$N, CCS, CO, HCN, \& HCO$^+$ suggests that there may be three different star formation modes in the L1495-B218 filaments. At the hub of the filaments, L1495A/B7N has formed a stellar cluster with large-scale inward flows (fast mode), while L1521D, a core embedded in a filament, is slowly contracting due to its self-gravity (slow mode). There is also one isolated core that appears to be marginally stable and may undergo quasi-static evolution (isolated mode)., Comment: ApJ accepted

In this paper we discuss the latest developments of the STRIP instrument of the “Large Scale Polarization Explorer” (LSPE) experiment. LSPE is a novel project that combines ground-based (STRIP) and balloon-borne (SWIPE) polarization measurements of the microwave sky on large angular scales to attempt a detection of the “B-modes” of the Cosmic Microwave Background polarization. STRIP will observe approximately 25% of the Northern sky from the “Observatorio del Teide” in Tenerife, using an array of forty-nine coherent polarimeters at 43 GHz, coupled to a 1.5 m fully rotating crossed-Dragone telescope. A second frequency channel with six-elements at 95 GHz will be exploited as an atmospheric monitor. At present, most of the hardware of the STRIP instrument has been developed and tested at sub-system level. System-level characterization, starting in July 2018, will lead STRIP to be shipped and installed at the observation site within the end of the year. The on-site verification and calibration of the whole instrument will prepare STRIP for a 2-years campaign for the observation of the CMB polarization.

In this paper, we study the feasibility of using CMOS circuit blocks for designing future light weight, small in size atmospheric remote sensing receivers. A compact CMOS down-converter is designed which operates from 160 to 188 GHz and includes a sub-harmonically pumped I/Q resistive mixer, two IF amplifiers and a voltage controlled oscillator (VCO) with LO buffer. A measured down-conversion gain of +2.6 dB is achieved with a total dc power consumption of 152 mW using the nominal supply of +1.2 V. The measurement results show a 3 dB IF bandwidth from 1 to 5 GHz and the VCO tuning range is from 85 to 89 GHz. The designed CMOS MMIC down-converter including the probing pads occupies a silicon area of 0.575 mm^2.

Indium Phosphide MMIC LNAs are enabling new capabilities in instrument development. The development of arrays of hundreds of cryogenically-cooled millimeter wave receivers has previously been challenging, but is now achievable with highly repeatable MMIC processes and advances in cryogenic on-wafer testing of LNAs. We have developed InP HEMT LNA MMICs for the 67–90 GHz frequency band that is the last missing receiver system from the ALMA. These MMICs provided average performance of less than 22.5 K noise temperature over the frequency band and minimum noise temperature of 17.5 K at 72 GHz. These LNAs achieve NT=220K (NF=2.4dB) at 90 GHz for Earth remote sensing instrument on Sentinel-6. Our HRMR (High Resolution Microwave Radiometer) achieves NEDT < 0.05K enabling Sentinel-6 to measure coastal ocean topography at 3 km resolution with better than 1 cm accuracy.

In this work, we describe monolithic millimeter-wave integrated circuit (MMIC) Low Noise Amplifier (LNA) and mixer designs for U-Band, also known as the WR19 waveguide band (40–60 GHz). The LNAs were fabricated in NGC's 35 nm InP HEMT MMIC process. The MMICs were packaged in WR19 waveguide housings and tested for noise, both at room temperature and cryogenically. We present the results, including a comparison to the state-of-the-art, and discuss applications for amplifiers in this frequency range. To date, these are the first cryogenic 35 nm InP MMIC results covering the 40–60 GHz range. We achieved a noise temperature less than 30 K over the 40–60 GHz range, when the amplifiers were cryogenically cooled. These results are comparable with other results in the literature, and we believe are the lowest reported for MMICs in the 50–60 GHz range.

Wideband receivers for the 3-mm band were developed for CARMA, the Combined Array for Research in Millimeterwave Astronomy. Three cryogenic MMIC (monolithic microwave integrated circuit) amplifiers manufactured in InP 35- nm technology are combined in a block with waveguide probes and gain equalizers to cover the 80–116 GHz band. These are followed by a sideband-separating mixer that has two 17 GHZ wide outputs, for upper and lower sidebands. Each receiver has a feed horn followed by a circular-to-linear polarizer and orthomode transducer. The two polarizations are amplified by the cryogenic MMICs, and the outputs downconverted in sideband separating mixers, resulting in four 1–18 GHz channels that can be simultaneously correlated. The first receiver was tested in the lab, and on-sky tests conducted at CARMA. Measured noise temperatures were in the range 40–70 K, with a sideband rejection of about 15 dB.

We are building Argus, a 16-pixel square-packed focal plane array that will cover the 75-115.3 GHz frequency range on the Robert C. Byrd Green Bank Telescope (GBT). The primary research area for Argus is the study of star formation within our Galaxy and nearby galaxies. Argus will map key molecules that trace star formation, including carbon monoxide (CO) and hydrogen cyanide (HCN). An additional key science area is astrochemistry, which will be addressed by observing complex molecules in the interstellar medium, and the study of formation of solar systems, which will be addressed by identifying dense pre-stellar cores and by observing comets in our solar system. Argus has a highly scalable architecture and will be a technology path finder for larger arrays. The array is modular in construction, which will allow easy replacement of malfunctioning and poorly performing components.

We report on the development of Argus, a 16-pixel spectrometer, which will enable fast astronomical imaging over the 85–116 GHz band. Each pixel includes a compact heterodyne receiver module, which integrates two InP MMIC low-noise amplifiers, a coupled-line bandpass filter and a sub-harmonic Schottky diode mixer. The receiver signals are routed to and from the multi-chip MMIC modules with multilayer high frequency printed circuit boards, which includes LO splitters and IF amplifiers. Microstrip lines on flexible circuitry are used to transport signals between temperature stages. The spectrometer frontend is designed to be scalable, so that the array design can be reconfigured for future instruments with hundreds of pixels. Argus is scheduled to be commissioned at the Robert C. Byrd Green Bank Telescope in late 2014. Preliminary data for the first Argus pixels are presented.

We report on the development of W-band (75-110 GHz) heterodyne receiver technology for large-format astronomical arrays. The receiver system is designed to be both mass-producible, so that the designs could be scaled to thousands of receiver elements, and modular. Most of the receiver function- ality is integrated into compact Monolithic Microwave Integrated Circuit (MMIC) amplifier-based multichip modules. The MMIC modules include a chain of InP MMIC low-noise amplifiers, coupled-line bandpass filters and sub-harmonic Schottky diode mixers. The receiver signals will be routed to and from the MMIC modules on a multilayer high frequency laminate, which includes splitters, amplifiers, and frequency doublers. A prototype MMIC module has exhibited a band-averaged noise temperature of 41 K from 82-100 GHz and a gain of 29 dB at 15 K, which is the state- of-the-art for heterodyne multi-chip modules., Comment: The copyright owner is the European Microwave Association, EuMA

We report on the development of W-band (75-110 GHz) heterodyne receiver technology for large-format astronomical arrays. The receiver system is designed to be both mass-producible, so that the designs could be scaled to thousands of receiver elements, and modular. Most of the receiver function- ality is integrated into compact Monolithic Microwave Integrated Circuit (MMIC) amplifier-based multichip modules. The MMIC modules include a chain of InP MMIC low-noise amplifiers, coupled-line bandpass filters and sub-harmonic Schottky diode mixers. The receiver signals will be routed to and from the MMIC modules on a multilayer high frequency laminate, which includes splitters, amplifiers, and frequency doublers. A prototype MMIC module has exhibited a band-averaged noise temperature of 41 K from 82-100 GHz and a gain of 29 dB at 15 K, which is the state- of-the-art for heterodyne multi-chip modules., Comment: The copyright owner is the European Microwave Association, EuMA

In this paper, we describe the design, simulation, and on-wafer measurements of Submillimeter-wave Monolithic Integrated Circuit (S-MMIC) amplifiers having gain in the 400-500 GHz range. A single-stage amplifier and two three-stage amplifiers with similar topology are presented, and have been fabricated in Northrop Grumman Corporation's (NGC) 35-nm InP high electron mobility transistor (HEMT) process. The circuits were fabricated using different indium channel compositions on different wafers, and comparison of the results based on the indium content will be presented. We have performed on-wafer S-parameter calibration and measurements using newly developed WR2.2 waveguide wafer probes from 325-508 GHz. We measured approximately 5 dB of gain for the single stage amplifier at 437 GHz, and approximately 10 dB of gain at 474 GHz for a three-stage amplifier, with over 9 dB of gain at 490 GHz.

We discuss results of low noise amplifier Monolithic Millimeter-wave Integrated Circuits (MMICs), which were designed for specific frequencies in the range of 70-200 GHz. We report on room temperature and cryogenic noise performance for a variety of circuits. The designs utilize Northrop Grumman Corporation’s (NGC) 35 nm gate length InP HEMT technology. Some of the lowest reported noise figures to date have been observed with this process at cryogenic temperatures.

We report on the development of some of the key technologies that will be needed for a large-format Cosmic Microwave Background (CMB) interferometer with many hundreds of wideband W-band (75-110 GHz) receivers. A scalable threebaseline prototype interferometer is being assembled as a technology demonstration for a future ground- or space-based instrument. Each of the prototype heterodyne receivers integrates two InPMonolithic Microwave Integrated Circuit (MMIC) low-noise amplifiers, a coupled-line bandpass filter, a subharmonic balanced diode mixer, and a 90° local oscillator phase switch into a single compact module that is suitable for mass production. Room temperature measurements indicate bandaveraged receiver noise temperatures of 500 K from 85-100 GHz. Cryogenic receiver noise temperatures are expected to be around 50 K.

The characterization of the intensity fluctuations of the cosmic microwave background (CMB) will be followed by the mapping of the polarization fluctuations of the CMB. Measurement of the polarization fluctuations requires highly sensitive instruments that are only possible by increasing the number of receivers. We are developing a large receiver array for the Q, U imaging experiment (QUIET) by building individual receivers that have noise temperatures close to the physical limit and that are simple, and low cost to build and operate. We developed these planar polarimetry receivers for Q-band by designing InP MMIC amplifiers with noise below 20 K, low loss and highly balanced phase switches and an entirely planar hybrid thin film circuit for the detection of the Stokes parameters Q and U. Our receivers achieve 25 K noise temperature over 8 GHz bandwidth and provide the I, Q and U parameters simultaneously. These planar modules have a simple plug in architecture that enables automated production of a large number of receivers and simple integration of large arrays of receivers.

Recent developments in millimeter-wave receiver have enabled new remote sensing capabilities. MMIC circuits operating at frequencies as high as 200 GHz have enabled low-cost mass producible integrated receivers suitable for array applications. We will describe several ground-based demonstrations of this technology including development of integrated spectral line receivers for atmospheric remote sensing, a synthetic thinned aperture radiometer for atmospheric sounding and imaging and polarimetric array radiometers for astrophysics applications.

Four low noise amplifiers for 94 GHz cloud radar are presented. One LNA is designed using coplanar waveguides and the others use microstrip lines. The designed amplifiers were manufactured with a metamorphic high electron mobility transistor (MHEMT) technology and the chip size is 2.1 mm x 1.1 mm. The four stage LNAs have either 2x25 µm or 4x25 µm size MHEMTs. The scattering parameters and the noise figures of the amplifiers were measured at W-band and the results are presented. The best measured gain at 94 GHz was 16 dB and the noise figure 5.7 dB using a 2.5 V supply voltage and a drain current of 15 mA per stage. Furthermore, one of the amplifiers was assembled in a package that has WR-10 waveguide interfaces. The packaged chip exhibited 10.8 dB of gain and the noise figure was 8 dB at 94 GHz.

Four low noise amplifiers for 94 GHz cloud radar are presented. One LNA is designed using coplanar waveguides and the others use microstrip lines. The designed amplifiers were manufactured with a metamorphic high electron mobility transistor (MHEMT) technology and the chip size is 2.1 mm x 1.1 mm. The four stage LNAs have either 2x25 µm or 4x25 µm size MHEMTs. The scattering parameters and the noise figures of the amplifiers were measured at W-band and the results are presented. The best measured gain at 94 GHz was 16 dB and the noise figure 5.7 dB using a 2.5 V supply voltage and a drain current of 15 mA per stage. Furthermore, one of the amplifiers was assembled in a package that has WR-10 waveguide interfaces. The packaged chip exhibited 10.8 dB of gain and the noise figure was 8 dB at 94 GHz.

Lisääntyvä langattoman tiedonsiirtokapasiteetin tarve johtaa yhä korkeampien taajuuksien käyttöön. Langattoman laajakaistaisen tiedonsiirtojärjestelmän 60 GHz radioetupäätä varten suunniteltiin matalakohinaisia etuvahvistimia. Vahvistimen kohina ja lineaarisuus vaikuttaa koko vastaanottimen suorituskykyyn. Lisäksi erityistä huomiota kiinnitettiin etuvahvistimien stabiilisuuteen. Diplomityössä on suunniteltu kaksi 4-asteista etuvahvistinta, joista toisessa käytettiin koplanaarista siirtojohtoa ja toisessa mikroliuskaa. Simulointituloksia vertailtiin. Vahvistimien kohinaluku on alle 4 dB ja lineaarinen lähtöteho 8-9 dBm. Suunnittelua varten tehtiin Pospieszalskin mallin mukainen kohinaparametrimalli. Aiemmin toteutetun 3-asteisen etuvahvistimen s-parametrit ja kohinaluku mitattiin suoraan sirulta mittakärjillä ja aaltoputkiliitännöillä. Kohinamittauksissa tutkittiin kolmea eri tasajänniteasettelua ja niiden vaikutusta kohinan määrään sekä vahvistukseen. Mittauksista saatua tietoa hyödynnettiin 4-asteisten etuvahvistimien suunnittelussa. Diplomityö on osa Tekesin ETX-ohjelman LALAMO-projektia.