Speaker
Mr
Rosario Martorana
(Finmeccanica Società per Azioni)
Description
The Synthetic Aperture Radar (SAR) are essential instruments for Earth Observation.
Use of Ka-band SAR instruments imaging has been proven in various airborne demonstrators and instruments but, so far, it has not been utilized for SAR from space.
The need of a Ka-band High Power Amplifier (HPA) with capabilities beyond what is currently available on the market has been pointed out by an ESA internal study on
the feasibility of a Ka-band SAR instrument and interferometer.
The key issue relevant to the Ka-band SAR is the availability of a vacuum tube amplifier given the high output power required.
Main characteristic and design driving requirements of the HPA in subject are:
• Carrier frequency: 35.75 GHz
• Transmitted Peak Power: 3.5 kW (4 kW goal)
• Operating bandwidth: 350 MHz minimum.
• Duty cycle: 13%
The feasibility study has been focused on the definition of a possible solution, starting from the available vacuum tubes technologies and defining the required
development plan to achieve a space qualification for the identified one.
From a review of the existing devices for both space, avionic and ground application, it resulted that there is not a technological limit in the vacuum tube technology to
achieve the
required performances in terms of peak power and bandwidth.
Nevertheless the development of a new vacuum tube is needed in order to get a space power
device and to achieve the challenging performances required for the Ka-band SAR.
Moreover, since no European product is available to the purpose, either space or avionic/ground, export restrictions can be an issue, thus the opportunity to develop an
European device for such application has been looked at as a further objective.
Starting from the driving requirements, a trade-off between the TWT and the EIK was carried out resulting in the baseline where the preferred technology is the klystron
one.
All aspects related to the application, like the multipaction, the extended lifetime both in terms of operative hours and switching cycles and thermal control issues have
been investigated to achieve a design baseline that will be the starting point for the following development.
An updated technical requirement specification has been issued and a detailed development plan has been proposed to achieve the space qualification of the baseline
HPA.
Primary authors
Mr
Alberto Battisti
(Selex ES (IT))
Mr
Aurelio Borella
(Selex ES (IT))
Mr
Carlos Gahete
(AURORASAT (ES))
Mr
Carlos VICENTE
(AURORASAT (ES))
Mr
Marcello Gambarara
(Selex ES (IT))
Mr
Paolo Galantini
(Selex ES (IT))
Mr
Roberto Dionisio
(Selex ES (IT))
Mr
Rosario Martorana
(Selex ES (IT))
