241 results found
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
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: 2156-3950
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, 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 'THz Torch' Applications, JOURNAL OF INFRARED MILLIMETER AND TERAHERTZ WAVES, Vol: 36, Pages: 474-495, ISSN: 1866-6892
Hu F, Lucyszyn S, 2015, Modelling Miniature Incandescent Light Bulbs for Thermal Infrared 'THz Torch' Applications, JOURNAL OF INFRARED MILLIMETER AND TERAHERTZ WAVES, Vol: 36, Pages: 350-367, ISSN: 1866-6892
Sun J, Hu F, Lucyszyn S, 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
Sun J, Hu F, Wang Z, et al., 2015, Banknote Characterization using a Thermal Infrared 'THz Torch' Spectrometer, Asia-Pacific Microwave Conference (APMC), Publisher: IEEE
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
Otter WJ, Hanham SM, Ridler NM, et al., Terahertz photonic crystal technology, Workshop on THz
Lucyszyn S, Hu F, Over the THz horizon: The thermal infrared ‘THz Torch’, 8th IEEE Global Symposium on Millimeter-Waves (GSMM2015)
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
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
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
Otter WJ, Hanham SM, Ridler NM, et al., 2014, 100 GHz ultra-high Q-factor photonic crystal resonators, SENSORS AND ACTUATORS A-PHYSICAL, Vol: 217, Pages: 151-159, ISSN: 0924-4247
Otter WJ, Hu F, Hazell JF, et al., 2014, THz metal mesh filters on electrically thick fused silica substrates, Infrared Milliemter-Wave andTHz Waves Conference, Publisher: IEEE
This paper shows simulated and measured results of ultra-low cost metal mesh filters on electrically thick substrates for millimeter-wave and THz bands. It provides a broad overview of metal mesh filters currently available and suggest why it is worth moving to an electrically thick substrate for ultra-low cost applications. We demonstrate scalable traditional metal mesh filters on 525 μm thick fused silica substrates. In addition, trapped-mode excitation is exploited to improve out-of-band rejection at higher frequencies. The measured results prove that these filters are scalable in the THz range using cost-effective micromachining manufacturing. This work opens up the possibility of using electrically thick metal mesh filters for ultra-low cost applications.
Jose Sanchez-Martinez J, Marquez-Segura E, Lucyszyn S, 2014, Design of Compact Wideband Bandpass Filters Based on Multiconductor Transmission Lines With Interconnected Alternate Lines, IEEE MICROWAVE AND WIRELESS COMPONENTS LETTERS, Vol: 24, Pages: 454-456, ISSN: 1531-1309
Liang X, Hu F, Yan Y, et al., 2014, Secure thermal infrared communications using engineered blackbody radiation, Scientific Reports, Vol: 4, Pages: 1-7
The thermal (emitted) infrared frequency bands, from 20–40 THz and 60–100 THz, are best known for applications in thermography. This underused and unregulated part of the spectral range offers opportunities for the development of secure communications. The ‘THz Torch’ concept was recently presented by the authors. This technology fundamentally exploits engineered blackbody radiation, by partitioning thermally-generated spectral noise power into pre-defined frequency channels; the energy in each channel is then independently pulsed modulated and multiplexing schemes are introduced to create a robust form of short-range secure communications in the far/mid infrared. To date, octave bandwidth (25–50 THz) single-channel links have been demonstrated with 380 bps speeds. Multi-channel ‘THz Torch’ frequency division multiplexing (FDM) and frequency-hopping spread-spectrum (FHSS) schemes have been proposed, but only a slow 40 bps FDM scheme has been demonstrated experimentally. Here, we report a much faster 1,280 bps FDM implementation. In addition, an experimental proof-of-concept FHSS scheme is demonstrated for the first time, having a 320 bps data rate. With both 4-channel multiplexing schemes, measured bit error rates (BERs) of < 10−6 are achieved over a distance of 2.5 cm. Our approach represents a new paradigm in the way niche secure communications can be established over short links.
Hu F, Lucyszyn S, 2014, Emerging thermal infrared ‘THz Torch’ technology for low-cost security and defence applications, THz and Security Applications: Detectors, Sources and Associated Electronics for THz Applications, Editors: Sizov, Corsi, Publisher: Springer Netherlands, Pages: 239-275, ISBN: 978-94-017-8827-4
Carvalho NB, Georgiadis A, Costanzo A, et al., 2014, Wireless Power Transmission: R&D Activities Within Europe, IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES, Vol: 62, Pages: 1031-1045, ISSN: 0018-9480
Papantonis S, Ridler NM, Lucyszyn S, 2014, Rectangular waveguide enabling technology using holey surfaces and wire media metamaterials, SENSORS AND ACTUATORS A-PHYSICAL, Vol: 209, Pages: 1-8, ISSN: 0924-4247
Papantonis S, Lucyszyn S, Shamonina E, 2014, Dispersion effects in Fakir's bed of nails metamaterial waveguides, JOURNAL OF APPLIED PHYSICS, Vol: 115, ISSN: 0021-8979
Liang X, Hu F, Yan Y, et al., 2014, Link Budget Analysis for Secure Thermal Infrared Communications using Engineered Blackbody Radiation, 29th URSI General Assembly and Scientific Symposium (URSI GASS), Publisher: IEEE
Hu F, Liang X, Lucyszyn S, 2014, Multi-channel Thermal Infrared Communications using Engineered Blackbody Radiation for Security Applications, Conference on Optics and Photonics for Counterterrorism, Crime Fighting, and Defence X and Optical Materials and Biomaterials in Security and Defence Systems Technology XI, Publisher: SPIE-INT SOC OPTICAL ENGINEERING, ISSN: 0277-786X
Klein N, Hanham SM, Basey-Fisher TH, et al., 2014, Micro- and millimetre wave measurements of nanolitre biological liquids by dielectric resonators, IEEE MTT-S International Microwave Workshop Series on: RF and Wireless Technologies for Biomedical and Healthcare Applications (IMWS-Bio 2014), Publisher: IEEE
Hu F, Lucyszyn S, 2014, Noise Analysis for Multi-channel 'THz Torch' Thermal Infrared Wireless Communications Systems, 3rd Asia-Pacific Microwave Conference Proceedings (APMC), Publisher: IEEE, Pages: 1276-1278
Otter WJ, Hanham SM, Ridler N, et al., MM-wave photonic crystal technology, IET Colloquium on Millimetre-wave and Terahertz Engineering & Technology
Otter WJ, Hu F, Lucyszyn S, Scalable metal mesh filters for low cost THz applications, International Conference on Semiconductor Mid-IR Materials and Optics (SMMO2014)
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