There is a natural trade-off between spacecraft size and functionality in all current satellite applications, independently of orbit and mission. Therefore, advances in both miniaturization and integration technologies are required to increase satellites’ lifetime and performance, simultaneously reducing their cost. In case of the next generation of Earth Observation satellites, one of the key development areas is synthetic aperture radar (SAR) antennas, where expected progress will be to increase the operating bandwidth - requiring, for instance wideband true-time delay (TTD) beamformers - and miniaturization, drastically reducing the mass and volume compared to current implementations. In this scenario, the use of photonic integrated circuits (PIC) technology in the beamforming network, in combination with an optical fibre harness, are obvious key enabling technologies for future SAR instruments. Optically implemented TTD beamforming structures achieve orders-of-magnitude improvements in size and mass compared with coaxial cable and RF switch based alternatives. Photonic technology also brings easy routing thanks to wavelength-division multiplexing, antenna and RF system integration due to the EMI -free characteristic of the optical fibre and a reduction of the risks associated with the in-orbit antenna deployment. Additionally, the inherent broadband characteristic of photonic technology, related to the transport and processing of RF signals, simplifies the beamforming network and signal distribution design for different frequencies, applications and missions. In the H2020 RETINA project (H2020-SPACE-2018-821943) a consortium formed by DAS Photonics, Airbus Italia, AMO GmbH, STFC Rutherford Appleton Laboratory and Universitat Politècnica de València is developing a miniaturised photonic front-end for next-generation X-band space SAR applications. In this article we present advances in design and fabrication of PIC for TTD, the design and predicted performance of multi element, dual polarisation antenna building blocks and photoreceivers for phase and amplitude controlled optical to RF conversion.
TeraSCREEN is an EU FP7 Security project aimed at developing a combined active, with frequency channel centered at 360 GHz, and passive, with frequency channels centered at 94, 220 and 360 GHz, imaging system for border controls in airport and commercial ferry ports. The system will include automatic threat detection and classification and has been designed with a strong focus on the ethical, legal and practical aspects of operating in these environments and with the potential threats in mind. Furthermore, both the passive and active systems are based on array receivers with the active system consisting of a 16 element MIMO FMCW radar centered at 360 GHz with a bandwidth of 30 GHz utilizing a custom made direct digital synthesizer. The 16 element passive receiver system at 360 GHz uses commercial Gunn diode oscillators at 90 GHz followed by custom made 90 to 180 GHz frequency doublers supplying the local oscillator for 360 GHz sub-harmonic mixers. This paper describes the development of the passive antenna module, local oscillator chain, frequency mixers and detectors used in the passive receiver array of this system. The complete passive receiver chain is characterized in this paper.
Naomi Alexander, Byron Alderman, Fernando Allona, Peter Frijlink, Ramón Gonzalo, Manfred Hägelen, Asier Ibáñez, Viktor Krozer, Marian Langford, Ernesto Limiti, Duncan Platt, Marek Schikora, Hui Wang, Marc Andree Weber
The challenge for any security screening system is to identify potentially harmful objects such as weapons and explosives concealed under clothing. Classical border and security checkpoints are no longer capable of fulfilling the demands of today’s ever growing security requirements, especially with respect to the high throughput generally required which entails a high detection rate of threat material and a low false alarm rate. TeraSCREEN proposes to develop an innovative concept of multi-frequency multi-mode Terahertz and millimeter-wave detection with new automatic detection and classification functionalities. The system developed will demonstrate, at a live control point, the safe automatic detection and classification of objects concealed under clothing, whilst respecting privacy and increasing current throughput rates. This innovative screening system will combine multi-frequency, multi-mode images taken by passive and active subsystems which will scan the subjects and obtain complementary spatial and spectral information, thus allowing for automatic threat recognition. The TeraSCREEN project, which will run from 2013 to 2016, has received funding from the European Union’s Seventh Framework Programme under the Security Call. This paper will describe the project objectives and approach.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.