Filtro en banda W con alto rechazo en banda imagen

This paper describes the design and implementation of a filter in the 81-99 GHz frequency band, aimed for the front-end module in a radio astronomy receiver where the image band rejection is very important. Classic formulation is used to design the filter. The fine adjustment process of the filter is based on manufacture considerations through Scattering parameters simulation. Design is based on waveguide resonant cavities topology. Therefore, image band rejection and in band losses are improved compared with micro-strip line technology. Measurements show a flat response with only 0.4 dB insertion losses and 20 dB return loss. Image rejection is very high, 40 dB relative to the pass band

Cryogenic broadband Q-band MMIC low-noise amplifier

The design of a broad-band monolithic cryogenic low-noise amplifier (MMIC LNA) in the Q band, aimed to be used in radio-astronomy receiver front-end modules is presented. A 70 nm gate-length GaAs mHEMT process from OMMIC foundry is used to manufacture the amplifier. An accurate model for the minimum noise bias point of the transistor has been obtained at room temperature. The amplifier design is based on a four stage monolithic common source transistor configuration. At 300 K, the amplifier shows an associated gain of 28 ± 1.1 dB and an average noise temperature of 145 K with a minimum noise temperature of 101 K at 45 GHz tested on wafer. When cooled down at 15 K, the average noise temperature is 18.4 K with a minimum of 13.5 K and 27.3 dB of associated gain. The DC power consumption is extremely low, 4.1 mW, at cryogenic temperatureThis work was supported by the Ministerio de Economía y Competitividad from Spain under the CONSOLIDER-INGENIO 2010 program CSD2010-00064 reference, and the research program FPI BES-2011- 046199

Ka-band full-hybrid cryogenic low- noise amplifier

This paper describes the design and implementation of a broad-band full-hybrid cryogenic lownoise amplifier (MIC LNA) in the 26 – 36 frequency band, aimed for the front-end module in radio-astronomy receivers. A metamorphic technology process (mHEMT) of 50 nm gate length is used to manufacture the transistor. Design is based on a three stage common source transistor configuration and surface mounted devices (SMD) with high quality factors. Therefore, gain and noise performance are improved compared with monolithic technology (MMIC). At room temperature the mean measured gain is G = 22.4 dB and the noise temperature is Tn = 175 K. When cooled to Tp = 13 K, insertion gain is Gi = 23.8 dB and the noise temperature is Tn = 26 K. The DC power consumption is extremely low, PDC = 5.7 mW at cryogenic temperatures.This work was supported by the Ministerio de Economía y Competitividad from Spain under the CONSOLIDER-INGENIO 2010 program CSD2010- 00064 reference, and the research program FPI BES- 2011-046199

Amplificador criogénico MMIC de bajo ruido en banda Q para aplicaciones de radioastronomía

The design of a broad-band monolithic cryogenic low-noise amplifier (MMIC LNA) in the Q band, aimed to be used in radio-astronomy receiver front-end modules is presented. A 70 nm gate-length GaAs mHEMT process from OMMIC foundry is used to manufacture the amplifier. An accurate model for the minimum noise bias point of the transistor has been obtained at room temperature. The amplifier design is based on a four stage monolithic common source transistor configuration. At 300 K, the amplifier shows an associated gain of 28 ± 1.1 dB and an average noise temperature of 145 K with a minimum noise temperature of 101 K at 45 GHz tested on wafer. When cooled down to 15 K, the average noise temperature is 18.4 K with a minimum of 13.5 K and 27.3 dB of associated gain. The DC power consumption is extremely low, 4.1 mW, at cryogenic temperature.Este trabajo ha sido financiado por el Ministerio de Economía y Competitividad bajo el programa CONSOLIDER-INGENIO 2010 referencia CSD2010-00064

Performance assessment of W-Band radiometers: direct versus heterodyne detections

W-Band radiometers using intermediate frequency down-conversion (super-heterodyne) and direct detection are compared. Both receivers consist of two W-band low noise amplifiers and an 80-to-101 GHz filter, which conforms to the reception frequency band, in the front-end module. The back-end module of the first receiver comprises a subharmonic mixer, intermediate frequency (IF) amplification and a square-law detector. For direct detection, a W-Band detector replaces the mixer and the intermediate frequency detection stages. The performance of the whole receivers has been simulated requiring special techniques, based on data from the experimental characterization of each subsystem. In the super-heterodyne implementation a local oscillator at 27.1 GHz (with 8 dBm) with a x3 frequency multiplier is used, exhibiting an overall conversion gain around 48 dB, a noise figure around 4 dB, and an effective bandwidth over 10 GHz. In the direct detection scheme, slightly better noise performance is obtained, with a wider bandwidth, around 20 GHz, since there is no IF bandwidth limitation (~15 GHz), and even using the same 80-to-101 GHz filter, the detector can operate through the whole W-band. Moreover, W-band detector has higher sensitivity than the IF detector, increasing slightly the gain. In both cases, the receiver performance is characterized when a broadband noise input signal is applied. The radiometer characteristics have been obtained working as a total power radiometer and as a Dicke radiometer when an optical chopper is used to modulate the incoming signal. Combining this particular super-heterodyne or direct detection topologies and total power or Dicke modes of operation, four different cases are compared and discussed, achieving similar sensitivities, but better performances in terms of equivalent bandwidth and noise for the direct detection radiometer. It should be noted that this conclusion comes from a particular set of components, which we could consider as typical, but we cannot exclude other conclusions for different components, particularly for different mixers and detectors.This research was funded by the Spanish Ministry of Science and Innovation through the grant: PID2019-110610RB-C22 and by the Spanish Ministry of Economy and Competitiveness, Program CONSOLIDER-INGENIO reference CSD2010-00064, CONSOLIDER-SPATEK Network of Excellence and University of Cantabria, Industrial Doctorate reference 12.DI05.648

Análisis de los efectos dispersivos en baja frecuencia de transistores HEMT a través de medidas de capacidad y conductancia

The analysis of low-frequency dispersive effects on semiconductors devices is a significant issue in order to characterize trapping states. This contribution shows a measurement set-up to test the gate-source capacitance and conductance of devices to study their frequency and bias dependence. Preliminary studies on trap characterization of High Electron Mobility Transistors (HEMT) are reported. The measurement set-up was performed assuming models in which the traps are present at the interface of the semiconductor heterojunction. The time constant and density of traps have been determined from measured data. The device under test has been also integrated into a cryogenic cycle where trap states becomes more significant

Amplificadores criogénicos de muy bajo ruido en microondas y ondas milimétricas

Cryogenic cooled very low noise amplifiers are critical components in radio astronomy receivers and other applications. A general description of these devices and their role in receivers is presented. Several examples of microwave and millimeter wave amplifiers covering bands from 4 GHz to 36 GHz are described. Noise temperatures of about 5 K in 4-12 GHz and 15 K in 25-34 GHz bands have been achieved in mHEMT technology based amplifiers

Multi-pixel Ka-band radiometer for the QUIJOTE experiment (Phase II)

This paper presents the configuration of the Ka-band radiometer developed for the Phase II of the QUIJOTE radio astronomy experiment, as well as the design of the different subsystems involved in the instrument. The new configuration, consisting of around 30 modified receivers working in the 26 - 36 GHz band, avoids the need of a rotating polar modulator at cryogenic temperatures, which is a source of mechanical and thermal difficulties. Moreover, the larger number of receivers will increase the instrument sensitivity. These two aspects are a clear advantage over the receiver developed for the experiment Phase I. The present paper also gives detailed information of some designed subsystems such as the feedhorn, the polarizer, the orthomode transducer, the cryogenic low-noise amplifiers and the back-end module.This work has been funded by the Ministerio de Ciencia e Innovación (Spain) under Astronomy and Astrophysics research programme, reference AYA2010-21766-C03-03, and the FPI grant BES-2011-046199

Polarímetro en banda W para aplicaciones de radioastronomía: diseño y simulación

This contribution presents and analyzes a polarimeter scheme for radio astronomy applications in W-band. The scheme is based on a sub-harmonic mixer thus enabling the reduction of W-band hardware design. The receiver functionality is analyzed theoretically and the design of some subsystems such as the feed-horn, the polarizer and the orthomode transducer is shown in detail. Finally, the whole scheme is simulated in an ideal way and then realistic data files are introduced in order to check the receiver functionality and the expected performance

Módulo posterior para la integración de polarímetros multi-pixel a 40 GHZ en radioastronomía

This work presents the design and future integration of the back-end module for the 40 GHz instrument of the QUIJOTE project, which is a project aimed to the measurement of the Cosmic Microwave Background’s polarization. This contribution focuses on the importance of the concept of modularity in order to facilitate the integration tasks and to enable the assembly of a high number of receivers (pixels) in the instrument, which improves the overall sensitivity. Performance measurements of each individual subsystem are provided and the foreseen whole integration in a metallic rack is presented.Los desarrollos de este trabajo se han financiado con la ayuda del Ministerio de Economía y Competitividad, Programa CONSOLIDER-Ingenio 2010 de referencia CSD2010-00064