Ehsan Afshari (Cornell University, Ithaca, USA)
Abstract: There is an increasing interest in low cost THz systems for medical imaging, spectroscopy, and high data rate communication. Recent results in the lower THz frequencies (<800 GHz) suggests that a standard CMOS process can compete with compound semiconductors for some applications. In this talk, we present a few “real” applications for the CMOS THz systems as well as a few “fake” ones. Next, we discuss major challenges in realizing these systems in CMOS. Moreover, we show several novel methods to overcome these challenges to generate mW-level powers at 300-500 GHz with relatively low noise using oscillators, amplifiers, and frequency multipliers. Finally, we show how we can realize more complicated systems such as 2-D phased arrays and coherent imaging systems in silicon.
Goutam Chattopadhyay (JPL, California Institute of Technology, Pasadena, USA)
"Terahertz Radar and its Capabilities for Stand-Off Imaging"
Abstract: Demand for new surveillance capabilities for usage in airport screenings and battlefield security check-points has led to the development of terahertz imagers and sensors. There are several advantages of imaging at terahertz frequencies compared to microwave or infrared: the wavelengths in this regime are short enough to provide high resolution with modest apertures, yet long enough to penetrate clothing. Moreover, unlike in infrared, the terahertz frequencies are not affected by dust, fog, and rain.
Several groups around the world are working on the development of terahertz imagers for various applications. One option is to use passive imaging techniques, which were very successful at millimeter-wave frequencies, by scaling in frequencies to terahertz range. However, the background sky is much warmer at terahertz frequencies due to high atmospheric absorption. Since passive imagers detect small differences in temperatures from the radiating object against the sky background, at these frequencies passive imagers do not provide enough scene contrast for short integration times. On the other hand, in an active imager, the object is illuminated with a terahertz source and the resulting reflected/scattered radiation is detected to make an image. However, the glint from the background clutter in an active terahertz imager makes it hard to provide high fidelity images without a fortunate alignment between the imaging system and the target.
We have developed an ultra wideband radar based terahertz imaging system that addresses many of these issues and produces high resolution through-clothes images at stand-off distances. The system uses a 675 GHz solid-state transmit/receive system in a frequency modulated continuous wave (FMCW) radar mode working at room temperature. The imager has sub-centimeter range resolution by utilizing a 30 GHz bandwidth. It has comparable cross-range resolution at a 25m stand-off distance with a 1m aperture mirror. A fast rotating small secondary mirror rapidly steers the projected beam over a 50 x 50 cm target at range to produce images at frame rates exceeding 1 Hz.
In this talk we will explain in detail the design and implementation of the terahertz imaging radar system. We will show how by using a time delay multiplexing of two beams, we achieved a two-pixel imaging system using a single transmit/receive pair. Moreover, we will also show how we improved the signal to noise of the radar system by a factor of 4 by using a novel polarizing wire grid and grating reflector.
The research described herein was carried out at the Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California, USA, under contract with National Aeronautics and Space Administration.
"Silicon Micromachined Compact Terahertz Instruments for Outer Planets"
Abstract: High‐resolution terahertz planetary instruments rely on heterodyne receivers for detection and measurements. In such instruments, the incoming radio frequency (RF) signal from the telescope is mixed with an on‐board generated local oscillator (LO) signal. The beat signal, known as the intermediate frequency (IF), is much lower in frequency than the signal, is then processed for data. All information in the incoming signal is present in the IF signal.
Space‐based terahertz heterodyne radiometry‐spectrometry has already been established as an important technique for planetary, terrestrial, and interstellar remote sensing. Heterodyne techniques at these frequencies have proven useful for measuring trace constituent abundances and physical properties under all climate conditions, including high dust loading. The terahertz transitions of polar molecules permit detection of numerous trace species at parts per trillion to parts per billion sensitivity. As an emission measurement, observations are carried out continuously in a passive mode without the need for any time restricted event such as a solar occultation. At these wavelengths, a moderate‐sized antenna (30‐cm effective) can yield high spatial resolution measurements (λ/D ≈ 1.8x10‐3 at 550 GHz), while ultrahigh spectral resolution (λ/Δλ > 106) provides clear line separation and well‐defined line profiles. Terahertz measurements are an ideal complement to infrared measurements of thermal inertia.
Using newly developed silicon micromachining technology that enables low‐mass and highly integrated receivers, we are developing a state‐of‐the‐art terahertz radiometer/spectrometer instrument for planetary orbiter missions to Mars, Venus, Titan, and the Galilean moons. Our flexible receiver architecture provides a powerful instrument capability in a light‐weight, low power consuming compact package which offer unprecedented sensitivity performance, spectral coverage, and scalability to meet the scientific requirements of multiple missions. The instrument will allow a large number of chemical species, such as water, NO2, N2O, NH3, SO2, H2S, CH4, and HCN, among others, in the atmospheres of Mars, Venus, and Titan to be detected at concentrations below a part per billion. It will also be able to pinpoint their location in latitude, longitude, and in altitude. The low‐power, low‐mass, and low‐volume terahertz instrument is a combined radiometer and spectrometer. It features a dual‐polarized, sideband separating, and balanced mixer receiver backed by a high‐speed digital spectrum analyzer. In exploring planets and their moons from orbit, this instrument will gather data on the thermal structure, dynamics and composition of planetary atmospheres and surfaces.
The maturation of this terahertz instrument will have an immediate impact on other areas such as multi‐pixel focal plane heterodyne arrays for astrophysics and terahertz imagers and radars for a variety of national security applications.
The research described herein was carried out at the Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California, USA, under contract with National Aeronautics and Space Administration.
Songcheol Hong (KAIST Institute, Republic of Korea)
Abstract: 26Ghz and 79Ghz UWB frequency bands are allowed to use in short-range radar applications for automobile . The single chip front-end ICs for both frequency bands are presented. The pulsed oscillator at 26 Ghz can produce UWB short pulses, which consumes powers only during short duty cycles. This allows a power-efficient radar. A stereo radar which has synchronized two radars is demonstrated with the ICs. Hybrid beam forming techniques based on base band delay are also demonstrated. The pulsed front-end architecture of the proposed 79Ghz UWB pulse radar is discussed, which is expected to reduce power consumption. The performances of some circuit elements are also introduced.
Wei Hong (Southeast University, Nanjing, China)
Abstract: People think 5G should have the features of 1000× capacity enhancement, extremely improved cost and energy efficiency etc. Continuously improving the spectrum efficiency at lower frequency band is not enough to reach the goal. Consequently, people pay close attention to the huge spectrum resource of millimeter waves for 5G applications. In this talk, we’ll introduce some 5G research activities at millimeter wave band in China, especially in the SKLMMW, including the consideration of candidate millimeter wave frequency bands, measurement of channel characteristics, IC design, demo systems etc. The advances in the new standard IEEE 802.11aj (45GHz) and Q-LINKPAN in China will also be presented.
Tian-Wei Huang (Faculty of National Taiwan University, Taipei, Taiwan)
Abstract: In our daily life, we have smart phones, smart TVs, or even auto-pilot smart cars in the future. In our engineer career, we have smart antenna, smart baseband chips, but we still need auto-calibration smart RFICs. Especially for millimeter-wave RFICs with giga-hertz bandwidth, the narrow-band baseband calibration cannot compensate the broadband AM/AM or AM/PM non-ideal properties. For future multi-band multi-standard radio, auto-band-switching is an essential function to optimize RF performance and to simplify the system control interface. A Miller-divider-type frequency sensor can be used to detect the frequency of input signal and perform auto-band-switching inside RFIC without any system control bits. For parametric sensitive 3rd-order nonlinearity, we need parametric-insensitive calibration methods to compensate the non-ideal behavior within RFIC. For millimeter-wave phase array system, the phase error comes from not only phase shifters but also other functional blocks, like variable gain amplifier (VGA), during phase shifting and gain compensation. We need a phase-error calibration method to compensate the phase error from all RFIC blocks. To optimize system EVM performance, IQ modulator/demodulator are the key components to compensate IQ mismatch at RF frequency, which is also the enabling technology for gigabit high-QAM wireless links. For IQ self-calibration at RF frequency, the phase compensation has more design challenges than the amplitude calibration, so composite right/left-handed transmission line, switching capacitor array, and phase shifters have been proposed in the IQ phase calibration. All above built-in self-calibration and auto-switching functions are innovated to pave the road to the next-generation millimeter-wave 5G mobile smart RFIC.
Mona Jarrahi (University of California Los Angeles, CA, USA)
Abstract: Although unique potentials of terahertz waves for chemical identification, material characterization, biological sensing, and medical imaging have been recognized for quite a while, the relatively poor performance, higher costs, and bulky nature of current terahertz systems continue to impede their deployment in field settings. In this talk, I will describe some of our recent results on developing fundamentally new terahertz electronic/optoelectronic components and imaging/spectrometry architectures to mitigate performance limitations of existing terahertz systems. In specific, I will introduce new designs of high-performance photoconductive terahertz sources that utilize plasmonic antennas to offer terahertz radiation at record-high power levels of several milliwatts – demonstrating more than three orders of magnitude increase compared to the state of the art. I will describe that the unique capabilities of these plasmonic antennas can be further extended to develop terahertz detectors and heterodyne spectrometers with single-photon detection sensitivities over a broad terahertz bandwidth at room temperatures, which has not been possible through existing technologies. To achieve this significant performance improvement, plasmonic antennas and device architectures are optimized for operation at telecommunication wavelengths, where very high power, narrow linewidth, wavelength tunable, compact and cost-effective optical sources are commercially available. Therefore, our results pave the way to compact and low-cost terahertz sources, detectors, and spectrometers that could offer numerous opportunities for e.g., medical imaging and diagnostics, atmospheric sensing, pharmaceutical quality control, and security screening systems. And finally, I will briefly highlight our research activities on development of new types of high-performance terahertz passive components (e.g., modulators, tunable filters, and beam deflectors) based on novel reconfigurable meta-films.
Stepan Lucyszyn (Imperial College London, UK)
Abstract: The thermal infrared ‘THz Torch’ concept was first introduced by Lucyszn et al., in 2011, for short-range secure wireless communications over a single (25 to 50 THz) channel. it fundamentally exploits engineered blackbody radiation, by partitioning thermally-generated spectral power into pre-defined frequency channels; the energy in each channel is then independently pulsed modulated. Within the past year, advances in the fundations, applications, source characterization and subsystems level analysis have been reported; incorporating frequency band multiplexing techniques across the 15 to 89 THz range. This technology offers many unique advantages over conventional coherent THz technologies; not least low cost. For this reason, the thermal infrared ‘THz Torch’ technology offers the potential for ubiquitous application, including spectroscopy, tagging and secure wirelee communications (key fobs, RFID and contactless payment).
Antti Räisänen (Aalto University School of Electrical Engineering, Espoo, Finland)
Abstract: A novel phase shifter based on high impedance surface (HIS) with carbon nanotube (CNT) membrane MEMS is proposed. The CNT MEMS HIS is integrated into a dielectric rod waveguide (DRW) so that the CNT membrane acts as a movable ground plane. We present a novel fabrication method of the phase shifter being significantly simpler than those previously used. The device performance is verified through numerical simulations that show a theoretical phase shift of 260° at 100 GHz with a 7 volt bias applied. So far we have experimentally demonstrated a CNT membrane varactor, where the distance of the CNT membrane and metal patches changed from 2 μm to 0.4 μm with a 10 volt bias.
Sudhakar Rao (Northrop Grumman Aerospace Systems, Redondo Beach, CA, USA)
Abstract: 21st century has so far seen several new satellite services such as local-channel broadcast for direct broadcast satellite service (DBS), high capacity K/Ka-band personal communication satellite (PCS) service, hosted payloads, mobile satellite services using very large deployable reflectors, high power hybrid satellites etc. All these satellite services are driven by the operators need to reduce the cost of satellite and pack more capability into the satellite. Antenna sub-system design, mechanical packaging on the spacecraft, and RF performance become very critical for these satellites. This talk will cover recent developments in the areas of antenna systems for FSS, BSS, PCS, & MSS satellite communications. System requirements that drive the antenna designs will be presented initially with brief introduction to satellite communications. Typical block-diagrams of the satellite payload including antenna and repeater will be presented.
Naoki Shinohara (Research Institute for Sustainable Humanosphere, Kyoto University, Japan)
Abstract: We consider a system which consists of a wireless power transfer and high speed wireless communication at the same frequency of 60 GHz band. In this system, a rectenna, which consists of an antenna and a rectifier, is used to receive a RF power and to convert the RF power into DC power. As the frequency is higher, the RF-DC conversion efficiency generally decreases. This paper describes the development of a rectifier of 60 GHz band by adopting the technique of Monolithic Microwave Integrated Circuit (MMIC). We selected GaAs substrate of 100 micron thick ness and a microstrip line as a transmission line. We selected the diode and designed the Class-F load as an output filter in shingle shunt rectifier. We adopted bending the line as the way of decreasing the areaof circuit. We selected the loss less way of bending a line and analyzed the in fluence by coup ling of lines. The rectifier was improved in respect of efficiency by inserting a line between the anode terminal of the diode and the through hole of the substrate. We selected the length of the line achieves the highest efficiency. Then, we investigated the discontinuities of the microstrip line for the suppression of the surface wave. Finally, the designed rectifier achieved the efficiency of 44% when the input power was 28mW in the simulation. The size of the rectifier achieved 1280 umx740 um.
Andreas Stelzer (Johannes Kepler University, Linz, Austria)
Abstract: In the last years wireless sensor systems operating in the microwave and mm-wave range became more and more popular. Automotive radar sensors are still the driving force for a higher integration of mm-wave sensors and thus pave the way for applications even in completely new areas. Especially industrial and life-science applications require additional functionality, smaller size, higher accuracy, easier applicability and imaging capabilities, which leads towards flexible multi-channel multi-mode Systems-on-Chip (SoC) and Antenna-in-Package (AiP) solutions, with most RF-parts included. The lecture treats various aspects of radar and frontend concepts with respect to integration and begins with basic radar principles (FMCW, Pulse, PRN, OFDM) and realizations like mono-static or bi-static and their integration into a small package. The signal evaluation part covers a simple FMCW signal model, extended towards MIMO operation, and concepts for TDMA-, FDMA-, and CDMA-MIMO realizations. Furthermore, a simultaneously transmitting multi-beam sensor combining FDMA transmit phased array with a DBF receiver is introduced. Performance degradations caused by signal imperfections, e.g. due to noise or ramp non-linearity will be analyzed and performance bounds by means of the Crámer Rao Lower Bound stated. The integrated basic building blocks VCO, mixer, LNA, PA, realized SiGe-technology, form the core components of various integrated prototype systems. With advances in the packaging technology the handling of mm-wave components becomes much easier; a requirement for most new application areas. The introduced eWLB packaging technology serves as basis for the additional integration of the Antenna-in-Package (AiP). With the wide availability of commercial mm-wave chipsets, the antenna as interface to the measurement problem on one hand and the signal processing algorithms on the other hand remain as the main design tasks of the application engineer. Combining the MIMO principle with non-uniform antenna arrangements allows to increase the number of virtual receive antennas. Signal coupling, a major issue in highly integrated devices, generally degrades the performance. In that context a worst-case beam pattern estimation due to statistical errors will be shown. The last part of the lecture deals with realized systems of highly integrated SiGe-based sensors covering frequencies from 24 to 160 GHz and applications for 3D-surface monitoring in harsh environments, polarimetric edge detection, as well as low-cost AiP based mm-wave imaging at 160 GHz.
Josip Vukusic (Chalmers University of Technology, Göteborg, Sweden)
Abstract: Compact heterodyne receivers operating in the terahertz range are needed for earth observation instruments, space science missions (e.g. ESA’s “Jupiter icy moons explorer - JUICE”) and in the millimeter wave region for ground-based applications such as security scanners. Existing terahertz heterodyne receivers are usually bulky due to complex hybrid integration and there is a strong need for a terahertz monolithic integration circuit (“TMIC”) platform that allows for higher circuit functionality, ease of assembly, and low loss at terahertz frequencies. Moreover, this part of the electromagnetic spectrum, where optical and microwave techniques meet, call for an integration scheme that can support both active THz electronics & photonics. A possible solution is heterogeneous integration of THz devices (III-V, graphene) on a silicon carrier, which also allows for advanced micromaching of passive components and interconnects such as waveguides and antennas. This talk provides an overview of research on integrated diode circuits for terahertz applications. Progress on heterogeneous integration of HBV multipliers and Schottky diode mixers on silicon substrates (SOI) will be presented.
Jianping Yao (University of Ottawa, Canada)
Abstract: Microwave photonics is an area that studies the interaction between microwave and optical waves for the generation, distribution, control and processing of microwave signals by means of photonics. There are numerous applications of microwave photonics, such as optically controlled phased array antennas, fiber-fed wireless communication systems, radar, sensors, warfare systems, and instrumentation. In this lecture, an introduction to microwave photonics will be presented, then different topics of microwave photonics will be discussed, including:
* Photonic true time beamforming
* Photonic processing of microwave signals,
* Photonic generation of microwave signals and arbitrary microwave waveforms
* Radio over fiber and UWB over fiber
* Photonic-assisted instantaneous microwave frequency measurement
* Photonic analog-to-digital conversion
Challenges in implementing microwave photonics system and future research directions will also be discussed.
Herbert Zirath (Chalmers University of Technology, Göteborg, Sweden)
Abstract: The transmission rate of wireless data in the mobile networks is doubling every year due to the increased usage of mobile multimedia services like streaming video, music, television, data transfer in smartphones and laptop-computers etc. This tendency will require continuously improved telecom infrastructure regarding both base-stations and the backhaul communication links. Today, the E-band (71-76, 81-86, 92-95 GHz) is employed increasingly in the networks, allowing multi Gbps data rate. In a near future however, the E-band will be crowded and novel, higher frequency bands can to be employed as well. Several hundred Gigahertz bandwidth is available for new communication and sensing applications just waiting to be exploited at frequencies above 100 GHz. Until now, components for making such ‘THz-systems’ have been too expensive, too bulky, too power hungry and nonsufficient in terms of generating enough power for communication systems. With newly developed RFIC-processes, it is now possible to design multifunctional integrated circuits, realizing a full ‘frontend on a chip’ at frequencies well beyond 100 GHz. Recent results from ongoing projects aiming at enabling new applications for next generation mobile infrastructure, 5G, and imaging, up to 340 GHz will be reported. So far, critical building blocks such as LNA, PA, VCO, modulator and demodulator, frequency multiplier, power detector and mixer have recently been developed, and results will be reported. Multifunction front-end circuits such as complete receive and transmit RFICs, mixed signal designs for co-integrated baseband/frontend ICs, and radiometer ICs have also been developed and will be reported as well, including the newly developed D-band frontend chipset demonstrating state-of-the-art bitrate of beyond 40 Gbps.