16, April 2020

ESA Open Invitation to Tender AO10270
Open Date: 27/03/2020
Closing Date: 26/05/2020 13:00:00

Status: ISSUED
Reference Nr.: 19.18I.08
Prog. Ref.: Fut.Mis.Prep.
Budget Ref.: E/E104-E5 – Fut.Mis.Prep.
Tender Type: C
Price Range: > 500 KEURO
Products: Satellites & Probes / Payloads / Instruments / RF and microwave Instruments / Microwave radiometers
Technology Domains: RF Systems, Payloads and Technologies / RF Technologies and Equipment / RF Equipment
Establishment: ESTEC
Directorate: Directorate of EO Programmes
Division: Future Missions & Instrument Division
Contract Officer: Tchoualack, Cendrine
Industrial Policy Measure: N/A – Not apply
Last Update Date: 27/03/2020
Update Reason: Tender issue

Stable, good quality calibration targets are essential for space borne radiometers. For European radiometers operating in the 90-230GHz range, calibration is typically based on the measurement of external, well known reference targets such as cold sky and on-board quasi-optical calibration targets. This type of calibration is called external or absolute calibration and is based on known physical noise temperatures of the calibration targets. This technique has been selected as the baseline in the MetOp-Second Generation radiometer instruments which are currently in the main development phase. There are limitations in using external references forcertain operational missions where implementing complex rotating mechanisms and large, bulky calibration targets may be prohibitivedue to accommodation aspects. In these cases it would be advantageous if the calibration could be done internally to the instrument without moving parts. Such a capability could be implemented using calibration sources based on semiconductor devices that generate cold and/or hot brightness temperatures while operating at ambient temperature. Active cold loads (ACL) are based on novel MMIC technologies and have already been developed in several previous ESA programs up to a frequency of about 90 GHz. Hot loads can be based on noise diodes up to some 150 GHz or on MMIC amplifiers at higher frequencies. The latter type of hot load is already being developed for advanced noise measurement set-ups in the vicinity of 200 GHz within an ESA frame contract. In connection with ACLs and hot loads, other key components for internal calibration capabilities are RF switches, directional couplers and passive terminations.ESA has developed semiconductor switches and ferrite switches up to about 90 GHz but few components are available above that frequency. This activity aims, through the development of a prototype, to provide a European source for internal calibration capability suitable for future high frequency radiometers operating in the 90-230GHz range, e.g. radiometers for future generation of altimeters with coastal/wide swath capabilities and for small satellite sounder missions.

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