Compact Terahertz Instruments for Space Terahertz Astronomy

programme Is the Job related to staff position within a Research Infrastructure? No

Offer Description

BACKGROUND

In the Thz frequency range, they offer unprecedented solutions to study at the same time wind dynamics, abundancy of atmospheric contents and surface temperatures of the planets/comets atmospheres. On Earth, Aura's Microwave Limb Sounders-MLS has flown up to 2.5 THz to measure Earth's stratosphere (Ozone), and today ESA is considering direct observations of atomic oxygen, hydroxyl radical, carbon monoxide and nitrous oxide of the high atmosphere up to 4.7 THz (KEYSTONE).

Similarly, heterodyne receivers have been built to measure water and carbon monoxide emissions from comets (Microwave Imager for the Rosetta Orbiter-MIRO at 557 GHz); or Jupiter and its Icy moon's atmospheres and surfaces (JUICE-SWI) with two channels working at 0.6 and 1.2 THz (mainly water line and methane as wind tracers). These heterodyne front-end instruments are based on III-V THz Schottky technology for both the Detector (Mixer) and its Local Oscillators source (Frequency Multiplier Chain), today available respectively up to 2 THz and 1 THz (state-of-the-art demonstrated recently at JPL USA, ongoing work at LIRA France). In particular, these front-ends can operate at room temperature, with a relative bandwidth reaching 20 % and a spectral resolution of 10^7 across an instantaneous spectrum of up to ten's of GHz (IF).

Therefore, During the last 15 years, the THERA group at LIRA (former GEMO group at LERMA) associated with C2N, has developed a manufacturing process for Schottky diodes, becoming the main contributor to the detectors of the Submillimeter Wave Instrument (SWI) for the ESA JUICE mission launched in 2023. The mixers, fabricated with this process, define the world state-of-the-art at 600GHz and 1.2 THz, and, in the case of the lastest, have reached TRL8 maturity (space qualification and flight operation validation), which is a strong asset for building future space science missions (MADNESS for Mars, KEYSTONE for Earth) in France. However, despite of their success, maturity, and recent investments in Europe, Teraherz heterodyne instruments still suffer from their complexity and size to be deployed on a larger scale. They are still using single channels element per frequency bandwidth, require a complex bias scheme for their local oscillator tuning, and are order of magnitude away from a volume compacity required in focal plane array elements.

PROJECT

The mixer and frequency multipliers are built with the THz schottky technology that feature sub-micron anode size Schottky junctions (diodes) integrated in few millimeters long MMICs. They are, for every MMIC, integrated and packaged in separated mechanical blocks. The mixer block plus its LO multiplication chain (one block per multiplication element) are assembled together through waveguide interfaces, filling up a volume of typically 20x10x3 cm3 for the front-end receiver only. This makes it difficult to consider more than a single receiver element per channels and is still order of magnitude away from a volume compacity required in focal array elements. In addition, the receiver performance suffers from multiplicity of interfaces between elements, highly critical at THz frequencies. This thesis has the ambition to develop new integration paradigms that are required for Schottky-based heterodyne instruments at terahertz frequencies, where the transmission lines losses or excess noises in the junctions dominate the System Performances limits. Those paradigms will aim also at reducing drastically the front-end volume, in order to make it attractive for multichannels and/or multi-focal elements configurations.

The recruited student will first carry out a thorough literature review of existing packaging and interfacing solutions used in high frequencies hybrid technology low-noise systems. The differents elements influencing the performances will be analyzed. New technological approaches will be explored such as integrating the front-end receiver in a unique compact element, either by traditional mechanical manufacturing techniques, or by silicon machining and the technical limits will be identified. The study will encompass RF design exploration of new MMIC schemes, with Multi-harmonics Simulations, and strengthening performances through more elegant interfaces of the MMICs and their neighbouring stages (such as LNAs, thermal breaks, ESD and filter protection circuits). The theoretical study, design and RF measurements of the novel THz front-ends will be performed at LIRA under the supervision of Dr. Jeanne Treuttel and Dr. Yan Delorme. The PhD can also include period of stay at ETEC premises to collaborate with experts.

Where to apply

E-mail: jeanne.treuttel@observatoiredeparis.psl.eu

Requirements

Research Field: Engineering » Electronic engineering
Education Level: Master Degree or equivalent

Research Field: Astronomy » Astrophysics
Education Level: Undergraduate

Research Field: Physics » Solid state physics
Education Level: Master Degree or equivalent

Research Field: Physics » Electronics
Education Level: Master Degree or equivalent

Research Field: Physics » Electromagnetism
Education Level: Master Degree or equivalent

Skills/Qualifications

APPLICANTS: must have a solid background in high frequency electronics and electromagnetics theory. Strong problem-solving skills and an inquisitive mindset are required, as well as good writing skills and team spirit.

Specific Requirements

Advanced Design system, Ansys HFSS or other electronic sofware will be a plus. THz and RF measurement will be part of the PhD.

Languages: ENGLISH — Level: Excellent

Languages: FRENCH — Level: Basic

Research Field: Astronomy » Astrophysics; Engineering » Electronic engineering

Additional Information

Benefits

French PhD grants in partnership with ESA.

Eligibility criteria

Strong, genuine, motivation and previous educational background. Name and contact of referee is required.

Selection process

All the candidatures are evaluated. However, due to the large number of applications we receive, we will contact only the short-listed candidates.

Work Location(s)

Number of offers available: 1
Company/Institute: Observatory of Paris
Country: France
State/Province: Ile de France
City: Paris
Postal Code: 75014
Street: 61, avenue de l'observatoire

Contact

State/Province: Ile de France
City: meudon
Website: https://lira.observatoiredeparis.psl.eu/
Street: 5, place Jules Janssen
Postal Code: 92195
E-Mail: jeanne.treuttel@observatoiredeparis.psl.eu, yan.delorme@observatoiredeparis.psl.eu, martina.wiedner@observatoiredeparis.psl.eu