Publications
255 results found
Otter WJ, Ridler NM, Yasukochi H, et al., 2017, 3-D printed 1.1 THz waveguides, Electronics Letters, Vol: 53, Pages: 471-473, ISSN: 0013-5194
Abstract:For the first time, 3D printed metal-pipe rectangular waveguides (MPRWGs) have been demonstrated in the WM-380 (500-750 GHz) and WM-250 (750 GHz-1.1 THz) waveguide bands. The ultra-high spatial resolution offered by the new RECILS additive manufacturing technology enables the precision fabrication of these prototype MPRWGs at such high frequencies. This enabling technology avoids the need for access to expensive microfabrication resources and, thus, opens up the terahertz spectrum to the low-cost manufacture of passive components.
Muller AA, Sanabria-Codesal E, Moldoveanu A, et al., 2017, Extended Capabilities of the 3-D Smith Chart with Group Delay and Resonator Quality Factor, IEEE Transactions on Microwave Theory and Techniques, Vol: 65, Pages: 10-19, ISSN: 0018-9480
This paper extends the capabilities of the 3D Smith chart for representing positive and negative differential-phase group delay and the associated loaded resonator quality factor, displayed simultaneously with scattering (S)-parameters. Here, mathematical concepts, inspired from elementary differential geometry and topology, are used to implement 3D projections. It is shown that a condition for a circuit to exploit negative differential-phase group delay is that its S-parameter winding number should be ≥ 0 (relative to its origin). Finally, exemplar network responses that exhibit both positive and negative differential-phase group delay and loaded resonator quality factor are shown with the 3D Smith chart. The convenience of being able to simultaneously display a wider range of parameters on one visualization platform, with the 3D Smith chart, may help to speed-up the design and analysis of microwave circuits by the user.
Hanham SM, Ahmad MM, Lucyszyn S, et al., 2017, LED-switchable High-Q Packaged THz Microbeam Resonators, IEEE Transactions on Terahertz Science and Technology, Vol: 7, Pages: 199-208, ISSN: 2156-342X
This paper describes the design, fabrication and experimental characterization of photonic crystal microbeam cavity resonators for the terahertz band implemented using suspended dielectric rectangular waveguide (DRW) in high resistivity silicon. Electrical quality factors of up to 11,900, combined with small modal volumes of 0.28 mm3 and 0.077 mm3, are demonstrated for devices operating at 100 and 200 GHz, respectively. The devices are found to be extremely light-sensitive, opening up new opportunities for light-controlled switching devices at terahertz frequencies. It is shown that the quality factor of the resonator can be tuned and the resonance extinguished through photo-illumination with an infrared light-emitting diode (IR LED). Additionally, the questions of thermal tunability and thermal stability of the resonators are examined. The demonstrated resonators are inherently suited to integration with DRW and by silicon bulk micromachining represent an attractive approach for realizing microphotonic integrated circuits for terahertz systems-on-a-substrate.
Dhillon S, Vitiello M, Linfield E, et al., 2017, The 2017 terahertz science and technology roadmap, Journal of Physics D: Applied Physics, Vol: 50, Pages: 1-49, ISSN: 1361-6463
Science and technologies based on terahertz frequency electromagnetic radiation (100 GHz–30 THz) have developed rapidly over the last 30 years. For most of the 20th Century, terahertz radiation, then referred to as sub-millimeter wave or far-infrared radiation, was mainly utilized by astronomers and some spectroscopists. Following the development of laser based terahertz time-domain spectroscopy in the 1980s and 1990s the field of THz science and technology expanded rapidly, to the extent that it now touches many areas from fundamental science to 'real world' applications. For example THz radiation is being used to optimize materials for new solar cells, and may also be a key technology for the next generation of airport security scanners. While the field was emerging it was possible to keep track of all new developments, however now the field has grown so much that it is increasingly difficult to follow the diverse range of new discoveries and applications that are appearing. At this point in time, when the field of THz science and technology is moving from an emerging to a more established and interdisciplinary field, it is apt to present a roadmap to help identify the breadth and future directions of the field. The aim of this roadmap is to present a snapshot of the present state of THz science and technology in 2017, and provide an opinion on the challenges and opportunities that the future holds. To be able to achieve this aim, we have invited a group of international experts to write 18 sections that cover most of the key areas of THz science and technology. We hope that The 2017 Roadmap on THz science and technology will prove to be a useful resource by providing a wide ranging introduction to the capabilities of THz radiation for those outside or just entering the field as well as providing perspective and breadth for those who are well established. We also feel that this review should serve as a useful guide for government and funding agencies.
Otter WJ, Lucyszyn S, 2016, 3-D printing of microwave components for 21st century applications, IEEE MTT-S International Microwave Workshop Series on Advanced Materials and Processes for RF and THz Applications (IMWS-AMP 2016), Publisher: IEEE
Additive manufacturing using 3-D printing is anemerging technology for the production of high performancemicrowave and terahertz components. Traditionally, thesecomponents are made by (micro-)machining. However, recentadvances in rapid prototyping technology have led to its use increating high performance and low weight RF components. In thisreview paper ten state-of-the-art exemplars are described,covering a wide variety of applications (absorbers, waveguides,antennas and lenses) operating over a broad range of frequencies,from 8 to 330 GHz.
Gillatt BTW, D'Auria M, Otter WJ, et al., 2016, 3-D printed variable phase shifter, IEEE Microwave and Wireless Component Letters, Vol: 26, Pages: 822-824, ISSN: 1531-1309
This letter presents the first fully 3-D printed microwave variable phase shifter. The design methodology for a 3-D printable dielectric flap metal-pipe rectangular waveguide variable phase shifter is described. The ABS building material was independently characterized, revealing a dielectric constant of 2.34 and loss tangent of only 0.0015 at 10 GHz. The predicted and measured performance is given, demonstrating a maximum relative phase shift of 142 degrees at 10 GHz, with a near uniform relative phase shift across the whole of X-band and a low variation in differential-phase group delay.
Klein N, Watts C, Hanham SM, et al., 2016, Microwave-to-terahertz dielectric resonators for liquid sensing in microfluidic systems, Conference on Terahertz Emitters, Receivers, and Applications VII, Publisher: Society of Photo-optical Instrumentation Engineer, ISSN: 0277-786X
The microwave-to-terahertz frequency range offers unique opportunities for the sensing of liquids based on the degree of molecular orientational and electronic polarization, Debye relaxation due to intermolecular forces between (semi-)polar molecules and collective vibrational modes within complex molecules. Methods for the fast dielectric characterization of (sub-)nanolitre volumes of mostly aqueous liquids and biological cell suspensions are discussed, with emphasis on labon- chip approaches aimed towards single-cell detection and label-free flow cytometry at microwave-to-terahertz frequencies. Among the most promising approaches, photonic crystal defect cavities made from high-resistivity silicon are compared with metallic split-ring resonant systems and high quality factor (Q-factor) whispering gallery-type resonances in dielectric resonators. Applications range from accurate haemoglobin measurements on nanolitre samples to label-free detection of circulating tumor cells. © (2016) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Mitcheson PD, Lucyszyn S, Pinuela M, et al., 2016, RF energy harvester, US9837865B2
Disclosed herein is an antenna apparatus for use in harvesting ambient radio frequency, RF, energy. The apparatus comprises one or more RF antenna components arranged to receive RF energy for producing electricity. The one or more RF antenna components comprise a plurality of frequency filtering components, each frequency filtering component being arranged to filter a respective frequency band of the received RF energy. Also disclosed herein is an apparatus comprising a rectifying circuit arranged to convert a variable electrical signal received at an input from an associated antenna into a direct current electrical signal for supplying to an electrical energy storage unit, the antenna for use in harvesting ambient radio frequency, RF, energy. The apparatus also comprises a power management module having an input arranged to receive the direct current and control supply of the direct current to the electrical energy storage unit. The rectifying circuit comprises a plurality of transmission lines, wherein the input of the rectifying circuit and the input of the power management module are connected via the plurality of transmission lines. The power management module is arranged at least partially within a boundary defined by the plurality of transmission lines.
Hanham SM, Watts C, Otter WJ, et al., 2016, Probing the THz response of biological cells using photonic crystal resonators, Energy Materials Nanotechnology (EMN) Meeting on Terahertz
Hu F, Lucyszyn S, 2016, Advances in Front-end Enabling Technologies for Thermal Infrared ‘THz Torch’ Wireless Communications, Journal of Infrared, Millimeter, and Terahertz Waves, Vol: 37, Pages: 881-893, ISSN: 1866-6892
The thermal (emitted) infrared frequency bands (typically 20-40 THz and 60-100 THz)are best known for remote sensing applications that include temperature measurement (e.g., noncontactingthermometers and thermography), night vision and surveillance (e.g., ubiquitous motionsensing and target acquisition). This unregulated part of the electromagnetic spectrum also offerscommercial opportunities for the development of short-range secure communications. The ‘THzTorch’ concept, which fundamentally exploits engineered blackbody radiation by partitioningthermally-generated spectral radiance into pre-defined frequency channels, was recentlydemonstrated by the authors. The thermal radiation within each channel can be independently pulsemodulated,transmitted and detected, to create a robust form of short-range secure communicationswithin the thermal infrared. In this paper, recent progress in the front-end enabling technologiesassociated with the ‘THz Torch’ concept is reported. Fundamental limitations of this technology arediscussed; possible engineering solutions for further improving the performance of such thermalbasedwireless links are proposed and verified either experimentally or through numericalsimulations. By exploring a raft of enabling technologies, significant enhancements to both data rateand transmission range can be expected. With good engineering solutions, the ‘THz Torch’ conceptcan exploit 19th century physics with 20th century multiplexing schemes for low-cost 21st centuryubiquitous applications in security and defence.
Pavia JP, Otter WJ, Lucyszyn S, et al., 2016, Design of a THz-MEMS frequency selective surface for structural health monitoring, International Conference on Metamaterials, Photonic Crystals and Plasmonics
This paper characterizes the relationship between applied force and reflectance/transmittance of a terahertz frequency selective surface for use as a sensor in structural healthmonitoring. Numerical modelling of both the mechanical and electromagnetics, solving the elasticityequation and Maxwell’s equations, respectively, has been undertaken for a 3 layer device.The unit cell comprises of a metal cross wire embedded within a (hard) silicon substrate, interleavedwith stacks of (soft) low density polyethylene.
Otter W, Hu F, Hanham S, et al., 2016, Terahertz metamaterial devices, International Conference on Semiconductor Mid-IR and THz Materials and Optics (SMMO2016)
Muller AA, Sanabria-Codesal E, Lucyszyn S, 2016, Computational Cost Reduction for <i>N+2</i> Order Coupling Matrix Synthesis Based on Desnanot-Jacobi Identity, IEEE ACCESS, Vol: 4, Pages: 10042-10050, ISSN: 2169-3536
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- Citations: 1
Otter WJ, Hanham SM, Klein N, et al., 2016, Millimeter-wave negative group delay network, URSI Asia-Pacific Radio Science Conference (URSI AP-RASC), Publisher: IEEE, Pages: 1205-1207
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- Citations: 2
Sun J, Hu F, Lucyszyn S, 2016, Predicting Atmospheric Attenuation Under Pristine Conditions Between 0.1 and 100 THz, IEEE ACCESS, Vol: 4, Pages: 9377-9399, ISSN: 2169-3536
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- Citations: 25
Muller AA, Lucyszyn S, 2015, Properties of purely reactive Foster and non-Foster passive networks, Electronics Letters, Vol: 51, Pages: 1882-1884, ISSN: 0013-5194
The mathematical concept of strongly real functions of positive and negative types is introduced to network theory for the first time. In this letter we show that the driving point reactance/susceptance of a pure Foster network, made up of only ideal positive inductance and capacitance element, is a strongly real function of real frequency of positive type. As a corollary, for a pure non-Foster network made up of only ideal negative inductance and capacitance elements, we show that the driving point reactance/susceptance is a strongly real function of real frequency of negative type. It is shown that a condition for a purely reactive passive network to exhibit a positive or negative reactance/susceptance-frequency gradient is that the driving point immittance should have alternating poles and zeros lying on the real frequency axis. Finally, it is shown that either purely Foster or non-Foster networks can be constructed by combining ideal Foster and non-Foster reactive elements.
D'Auria M, Otter WJ, Hazell J, et al., 2015, 3-D printed metal-pipe rectangular waveguides, IEEE Transactions on Components, Packaging, and Manufacturing Technology, Vol: 5, Pages: 1339-1349, ISSN: 2156-3985
This paper first reviews manufacturing technologies for realizing air-filled metal-pipe rectangular waveguides (MPRWGs) and 3-D printing for microwave and millimeter-wave applications. Then, 3-D printed MPRWGs are investigated in detail. Two very different 3-D printing technologies have been considered: low-cost lower-resolution fused deposition modeling for microwave applications and higher-cost high-resolution stereolithography for millimeter-wave applications. Measurements against traceable standards in MPRWGs were performed by the U.K.'s National Physical Laboratory. It was found that the performance of the 3-D printed MPRWGs were comparable with those of standard waveguides. For example, across X-band (8-12 GHz), the dissipative attenuation ranges between 0.2 and 0.6 dB/m, with a worst case return loss of 32 dB; at W-band (75-110 GHz), the dissipative attenuation was 11 dB/m at the band edges, with a worst case return loss of 19 dB. Finally, a high-performance W-band sixth-order inductive iris bandpass filter, having a center frequency of 107.2 GHz and a 6.8-GHz bandwidth, was demonstrated. The measured insertion loss of the complete structure (filter, feed sections, and flanges) was only 0.95 dB at center frequency, giving an unloaded quality factor of 152--clearly demonstrating the potential of this low-cost manufacturing technology, offering the advantages of lightweight rapid prototyping/manufacturing and relatively very low cost when compared with traditional (micro)machining.
Mitcheson PD, Lucyszyn S, Pinuela M, et al., 2015, Inductive power transfer system, US9899877B2
An inductive power transfer system comprises a transmitter circuit comprising a transmitter coil and a receiver circuit comprising a receiver coil spaced from the transmitter coil. The transmitter circuit is in the form of a Class E amplifier with a first inductor and a transistor in series between the terminals of a power supply. A first transmitter capacitance is in parallel with the transistor between the first inductor and a power supply terminal, a primary tank circuit in parallel with the first transmitter capacitance, the primary tank circuit comprising the transmitter coil and a second transmitter capacitance arranged in parallel with the transmitter coil, and a third transmitter capacitance in series with the first inductor between the first transmitter capacitance and the primary tank circuit. The second transmitter capacitance is selected such that a resonant frequency of the primary tank circuit is not equal to the first frequency.
Hanham S, Watts C, Otter WJ, et al., 2015, Dielectric measurements of nanoliter liquids with a photonic crystal resonator at terahertz frequencies, Applied Physics Letters, Vol: 107, ISSN: 1077-3118
Hu F, Otter W, Lucyszyn S, 2015, Optically tunable THz frequency metamaterial absorber, 40th International Conference on Infrared, Millimeter, and Terahertz Waves (IRMMW-THz)
In this paper, we propose a metamaterial-based terahertz (THz) absorber with optically tunable absorbance. The unit cell of the structure consists of a cross-shaped resonator, a dielectric spacing layer for wave impedance matching and a high-resistivity silicon (HRS) substrate. Without illumination, the structure acts as a capacitive metal mesh filter that has minimum transmittance and maximum reflectance at its resonance frequency. When the HRS substrate is optically illuminated, its conductivity increases, effectively blocking transmission through the structure. Therefore, this device will have a low reflectance if the impedance is matched. The optimized structure shows a high absorbance of 98% at 0.25 THz in simulations. This concept can be used for the realization of dynamic control of absorbance and emissivity for applications in the THz and infrared (IR) range.
Hu F, Sun J, Brindley HE, et al., 2015, Systems Analysis for Thermal Infrared '<i>THz Torch</i>' Applications, JOURNAL OF INFRARED MILLIMETER AND TERAHERTZ WAVES, Vol: 36, Pages: 474-495, ISSN: 1866-6892
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- Citations: 10
Hu F, Lucyszyn S, 2015, Modelling Miniature Incandescent Light Bulbs for Thermal Infrared <i>'THz Torch'</i> Applications, JOURNAL OF INFRARED MILLIMETER AND TERAHERTZ WAVES, Vol: 36, Pages: 350-367, ISSN: 1866-6892
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- Citations: 8
Sun J, Hu F, Lucyszyn S, 2015, Challenges for the development of low cost thermal infrared 'THz Torch' spectrometers, BIT’s 4th Annual Conference and EXPO of AnalytiX-2015, Pages: 216-216
Otter WJ, Hanham SM, Ridler NM, et al., 2015, Terahertz photonic crystal technology, Workshop on THz
Lucyszyn S, Hu F, 2015, Over the THz horizon: The thermal infrared ‘THz Torch’, 8th IEEE Global Symposium on Millimeter-Waves (GSMM2015)
Jose Sanchez-Martinez J, Marquez-Segura E, Lucyszyn S, 2015, Synthesis and Design of High-Selectivity Wideband Quasi-Elliptic Bandpass Filters Using Multiconductor Transmission Lines, IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES, Vol: 63, Pages: 198-208, ISSN: 0018-9480
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- Citations: 13
Sun J, Hu F, Wang Z, et al., 2015, Banknote Characterization using a Thermal Infrared '<i>THz Torch</i>' Spectrometer, Asia-Pacific Microwave Conference (APMC), Publisher: IEEE
Papantonis S, Lucyszyn S, 2015, Lossy Spherical Cavity Resonators for Stress-Testing Arbitrary 3D Eigenmode Solvers, PROGRESS IN ELECTROMAGNETICS RESEARCH-PIER, Vol: 151, Pages: 151-167, ISSN: 1559-8985
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- Citations: 10
Muller AA, Sanabria-Codesal E, Moldoveanu A, et al., 2014, Apollonius unilateral transducer constant power gain circles on 3D Smith charts, ELECTRONICS LETTERS, Vol: 50, Pages: 1531-1532, ISSN: 0013-5194
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- Citations: 10
Papantonis S, Ridler NM, Wilson A, et al., 2014, Reconfigurable Waveguide for Vector Network Analyzer Verification, IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES, Vol: 62, Pages: 2415-2422, ISSN: 0018-9480
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- Citations: 1
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