An integrated folded-patch chip-size antenna using high-resistivity polycrystalline silicon substrate

High-resistivity polycrystalline silicon (HRPS) wafers are utilized as low-loss substrates for three-dimensional integration of on-chip antennas in wafer-level chip-scale packages (WLCSP). Sandwiching of HRPS and silicon wafers enables to integrate complex RF passives with a spacing of >150 µm to the conductive silicon substrate containing the circuitry, while providing mechanical stability, reducing form factor and avoiding any additional RF loss. A folded-patch antenna with dimensions of 2.5x2.5x1 mm3, operating at 5.7 GHz was analysed considering a 10 kΩ-cm HRPS wafer. The antenna has a –10 dB return loss bandwidth of 50 MHz and an efficiency of 58 %, a performance comparable to glass substrates.Fundação Para a Ciência e Tecnologia (FCT) (SFRH/BD/4717/2001, POCTI/ESE/38468/2001, FEDER)

Advanced Silicon Avalanche Photodiodes on NASA's Global Ecosystem Dynamics Investigation (GEDI) Mission

Silicon Avalanche Photodiodes (APDs) are used in NASAs Global Ecosystem Dynamics Investigation (GEDI) which was launched in December 2018 and is currently measuring the Earths vegetation vertical structure from the International Space Station. The APDs were specially made for space lidar with a much lower hole-to-electron ionization coefficient ratio (k-factor ~0.008) than that of commercially available silicon APDs in order to reduce the APD excess noise from the randomness of the avalanche gain. A silicon heater resistor was used under the APD chip to heat the device up to 70C and improve its quantum efficiency at 1064 nm laser wavelength while maintaining a low dark current such that the overall signal to noise ratio is improved. Special APD protection circuits were used to raise the overload damage threshold to prevent device damage from strong laser return by specular surfaces, such as still water bodies, and space radiation events. The APD and a hybrid transimpedance amplifier circuit were hermetically sealed in a package with a sufficiently low leak rate to ensure multi-year operation lifetime in space. The detector assemblies underwent a series of pre-launch tests per NASA Goddard Environmental Verification Standard for space qualification. They have performed exactly as expected with GEDI in orbit. A detailed description of the GEDI detector design, signal and noise model, and test results are presented in this paper

On the design of 60 GHz integrated antennas on 0.13 µm SOI technology

International audienceThis work presents the performance of 0.13 µm Silicon on insulator technology in the design of 60 GHz fully integrated antennas. Three different types of antennas are considered and designed in order to study their ability to radiate efficiently at this frequency using specific IC technology in order to obtain good matching and higher radiation efficiency. A conductor backed coplanar waveguide is used to feed these antennas. The planar inverted F antenna, the slot antenna and the interdigitated dipole antenna show a good return loss and simulated radiation efficiency of 45%, 55% and 88% respectively. Backside substrate metallization has been used to improve radiation properties

60 GHz Slot antenna integrated on SOI

International audienceIn this paper, we propose a 60 GHz Slot antenna integrated on 0.13(m Silicon on Insulator (SOI) substrate. The antenna is composed of a CPW transmission line and the radiating slots. The design was based on electromagnetic simulations made using the CST Microwave Studio software package. The antenna exhibits a return loss of –12dB at 60GHz with a bandwidth of 10%. Backside substrate metallization has been used to improve radiation properties. The simulated radiation efficiency is 60 % with a gain around 3 dBi

Numerical optimization of integrating cavities for diffraction-limited millimeter-wave bolometer arrays

Far-infrared to millimeter-wave bolometers designed to make astronomical observations are typically encased in integrating cavities at the termination of feedhorns or Winston cones. This photometer combination maximizes absorption of radiation, enables the absorber area to be minimized, and controls the directivity of absorption, thereby reducing susceptibility to stray light. In the next decade, arrays of hundreds of silicon nitride micromesh bolometers with planar architectures will be used in ground-based, suborbital, and orbital platforms for astronomy. The optimization of integrating cavity designs is required for achieving the highest possible sensitivity for these arrays. We report numerical simulations of the electromagnetic fields in integrating cavities with an infinite plane-parallel geometry formed by a solid reflecting backshort and the back surface of a feedhorn array block. Performance of this architecture for the bolometer array camera (Bolocam) for cosmology at a frequency of 214 GHz is investigated. We explore the sensitivity of absorption efficiency to absorber impedance and backshort location and the magnitude of leakage from cavities. The simulations are compared with experimental data from a room-temperature scale model and with the performance of Bolocam at a temperature of 300 mK. The main results of the simulations for Bolocam-type cavities are that (1) monochromatic absorptions as high as 95% are achievable with <1% cross talk between neighboring cavities, (2) the optimum absorber impedances are 400 Ω/sq, but with a broad maximum from ~150 to ~700 Ω/sq, and (3) maximum absorption is achieved with absorber diameters ≥1.5λ. Good general agreement between the simulations and the experiments was found

The feed-in tariff in the UK : a case study focus on domestic photovoltaic systems

This paper explores the photovoltaic (PV) industry in the United Kingdom (UK) as experienced by those who are working with it directly and with consideration of current standards, module efficiencies and future environmental trends. The government's consultation on the comprehensive review for solar PV tariffs, proposes a reduction of the generation tariff for PV installations in the UK of more than 50%. The introduction of the Feed-In Tariffs scheme (FITs) has rapidly increased deployment of PV technologies at small scale since its introduction in April 2010. The central principle of FIT policies is to offer guaranteed prices for fixed periods to enable greater number of investors. A financial analysis was performed on two real-life installations in Cornwall, UK to determine the impact of proposed cuts to the FIT will make to a typical domestic PV system under 4 kW. The results show that a healthy Return on Investment (ROI) can still be made but that future installations should focus on off-setting electricity required from the national grid as a long term push for true sustainability rather than subsidised schemes. The profitability of future installations will have to be featured within in-service and end-of-service considerations such as the feed-in tariff, module efficiencies and the implications of costs associated with end-of-life disposal