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.
This paper presents the development of heterodyne receiver configurations based on EBG technology. The basic required
building blocks, waveguides and cavities are first described. A subhamonic EBG receiver design is finally presented.
We report here the performance improvement of frequency doublers using substrate transfer technique, the method by
which the diodes/MMIC circuits made on GaAs substrate have been subsequently transferred on to a host substrate like
Quartz and Aluminium Nitride. These host substrates have low loss and high thermal conductivity at mm-wave and sub
millimeter wave frequencies. The substrate transfer technique on RAL doubler circuits designed at 160 GHz gives a
conversion efficiency ~ 30% and 3 dB BW >15%, which is a significant performance improvement compared to the
same diodes on GaAs substrate. The efficiency and bandwidth at a constant input power has been studied using doubler
diodes of different anode areas and the results are presented in this paper. The measured data is compared to simulations,
and the test results agree closely to predictions.
Most parts of the electromagnetic spectrum are well understood and exploited, but the terahertz region between the microwave and infrared is still relatively under developed. Potential receiver applications are wide-ranging and cross-disciplinary, spanning the physical, biological, and medical sciences. In this spectral region, Schottky diode technology is uniquely important. InP MMIC amplifiers are generally limited to frequencies less than ~200 GHz, above which their noise performance rapidly deteriorates. Superconducting circuits, which require cooling, may not always be practical. Either as varistor diodes (heterodyne mixing), or varactor diodes (sub-millimetre power generation), Schottky technology underpins terahertz receiver development.
We report upon the development of a 190 GHz MMIC frequency doubler and 380 GHz sub-harmonic mixer using
foundry planar Schottky diodes. The devices have been fabricated by the company UMS using their BES process, and
post-processed afterwards to transfer the GaAs circuit membranes onto a quartz substrate. This novel substrate transfer
technique is presented. Preliminary measurements give a doubler output power over 3 mW in the frequency range 170-205 GHz.
We present a design concept for a new state-of-the-art balloon borne atmospheric monitor that will allow enhanced limb sounding of the Earth's atmosphere within the submillimeter and far-infrared wavelength spectral range: TELIS, TErahertz and submm LImb Sounder. The instrument is being developed by a consortium of major European institutes that includes the Space Research Organization of the Netherlands (SRON), the Rutherford Appleton Laboratory (RAL) will utilize state-of-the-art superconducting heterodyne technology and is designed to be a compact, lightweight instrument cpaable of providing broad spectral coverage, high spectral resolution and long flight duration (~24 hours duration during a single flight campaign). The combination of high sensitivity and extensive flight duration will allow evaluation of the diurnal variation of key atmospheric constitutenets sucyh as OH, HO2, ClO, BrO togehter will onger lived constituents such as O3, HCL and N2O. Furthermore, TELIS will share a common balloon platform to that of the MIPAS-B Fourier Transform Spectrometer, developed by the Institute of Meteorology and Climate research of the over an extended spectral range. The combination of the TELIS and MIPAS instruments will provide atmospheric scientists with a very powerful observational tool. TELIS will serve as a testbed for new cryogenic heterodyne detection techniques, and as such it will act as a prelude to future spaceborne instruments planned by the European Space Agency (ESA).
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