Millimeter-wave Radiation Research Articles

Analysis and Performance of Lumped-Element Kinetic Inductance Detectors for W-Band

Lumped-element superconducting resonators are a promising technology for their use in millimeter-wave observations and quantum computing applications that require large arrays of extremely sensitive detectors. Among them, lumped-element kinetic inductance detectors (LEKIDs) have shown good performance in the submillimeter band in several earth-based telescopes. In this work, LEKIDs for their use as millimeter-wave receivers of astronomical applications are presented. LEKID arrays using a thin bilayer of superconducting titanium/aluminum (Ti/Al), deposited on the silicon substrate, have been designed and fabricated. The design of a dual-polarization LEKID with the goal of detection at the W-band for two orthogonal polarizations is described and a fabricated array has demonstrated absorption at ambient temperature. Also, an approximate design methodology of the coupling parameter for LEKIDs' readout, essential for dynamic range optimization of the detector under millimeter-wave radiation, is proposed. In addition, the resonance characteristics and coupling factor of the fabricated superconducting resonators using high-quality internal factor Q <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">i</sub> under cryogenic temperatures have been analyzed. The design guidelines in this work are applicable to other LEKID arrays, and the presented superconducting Ti/Al thin-film LEKIDs can be used in future receiver arrays in the millimeter bands.

Application of Millimeter-Wave Radiation for Manufacture of Ceramic Items Using Additive Methods

Application of Millimeter-Wave Radiation for Manufacture of Ceramic Items Using Additive Methods

Low-Loss Transmission Line for a 3.4-kW, 93-GHz Gyro-Traveling-Wave Amplifier

In this article, a transmission line system for the propagation of millimeter-wave radiation is presented. The full system includes a TE11-to-TE01 mode converter, waveguide tapers, miter bends, and many straight sections. The design of each of these components is described, and the optimized simulation results are given. The mode converter shows a greater than 96% mode conversion efficiency that can be achieved over a 2% bandwidth at the ${W}$ -band. The miter bends demonstrate a transmission loss of 0.04 dB each over the same bandwidth when they are configured to introduce a mixture of higher order waveguide modes before the reflecting surface. An example transmission line system with a propagation length of 20 m, inclusive of four 90° bends with an oxygen-free high conductivity (OFHC) copper waveguide material, was studied over a 90–96-GHz frequency range and showed a 0.84-dB transmission loss at 93 GHz.

Wireless Soft Actuator Based on Liquid-Gas Phase Transition Controlled by Millimeter-Wave Irradiation

We propose a wireless soft actuator controlled thermally by millimeter-wave irradiation. The actuator is composed of low boiling point liquid sealed in a soft bellows. By irradiating high-power millimeter-waves, the liquid can be evaporated to generate a strong mechanical force. We characterize the force and work extracted from the bellows as a function of the liquid volume and temperature. We then demonstrate the wireless actuation by irradiating a millimeter-wave on the bellows. We also evaluate its dynamic response by modulating the millimeter-wave. Our approach provides novel usage and design space of soft actuators.

β-BBO, LBO, AND KTP Nonlinear Crystals as Sources of Millimeter-Wave Radiation

The refractive indices and the absorption coefficients of β-BBO, LBO, and KTP nonlinear optical crystals have been measured in the wavelength range of 0.5–3 mm at temperatures of 298 and 78 K. The absorption coefficients of all crystals at a wavelength of 1 mm do not exceed 3.5 cm–1 and fall with cooling. The anisotropy of the absorption coefficients of crystals increases significantly with decreasing wavelength ( 2 mm, it almost disappears. Upon cooling, the absolute values of the absorption coefficients fall below 0.2 cm–1. Based on the measured refractive indices, the collinear phase-matching curves are simulated numerically. The theoretical feasibility of IR (1.064 μm) laser radiation conversion into the millimeter-wave range is demonstrated.

ДОСЛІДЖЕННЯ ПО ВПЛИВУ ЕЛЕКТРОМАГНІТНОГО ПОЛЯ КВЧ ДІАПАЗОНУ НА НАСІННЯ КУЛЬТУРНИХ РОСЛИН

У сучасних умовах для збільшення врожайності культурних рослин використовують передпосівний обробіток насіння з використанням хімічних і біологічних препаратів. У зв’язку з орієнтацією передових країн світу на екологічно безпечні технології виробництва сільськогосподарської продукції все більше уваги приділяється розвитку електротехнологічним методам обробки. Головна перевага електромагнітної технології по передпосівній обробці насіння низькоенергетичним випромінюванням КВЧ діапазону полягає в можливості поліпшення їх зростання і розвитку за рахунок мобілізації внутрішніх резервів самого насіння, пришвидшення дифузії молекул через клітинну мембрану, швидкості хімічних реакцій та викликає збільшення волого поглинання, що в свою чергу прискорює розвиток рослини і сприяє підвищенню врожайності без хімічних або біологічних препаратів або методів генної інженерії. Технологія обробки насіння ЕМП КВЧ дозволяє зберегти в насінні всі поживні речовини, вітаміни та мінерали, що при обробці іншими методами домогтися досить складно. Дослідження спирається на аналіз літературних джерел та експериментальні дослідження енергетичних і спектральних характеристик діодного генератора в КВЧ діапазоні довжин хвиль, судячи з яких можна зробити висновок, що підвищення врожайності рослин можливо на основі застосування інформаційного електромагнітного випромінювання міліметрового діапазону для передпосівної обробки насіння. У статті пропонується методика дослідження енергетичних характеристик напівпровідникового шестидіодного генератора на лавинно-пролітних діодах для передпосівної обробки насіння культурних рослин.Результатом розробленої методики слідує висновок, що одним з основних елементів установки для передпосівної обробки насіння є випромінювач ЕМ енергії, який повинен сформувати необхідну діаграму спрямованості і забезпечити достатній рівень щільності потоку потужності на зерні.

Complex Permittivity Estimation From Millimeter-Wave Radiometry

Millimeter-wave (MMW) radiation characteristic has been used in object classification and recognition. Complex permittivity is a key factor affecting the radiation characteristic. Previous study has shown that estimation values of complex permittivity based on multipolarization measurements spread around a special curve (called “C-curve”). In this letter, we analyzed the influence of complex permittivity on MMW radiation. We find that “C-curve” is the manifestation of the solution instability and can be avoided by our new estimation method based on the measurements of multiple incident angles. The simulation and experiment have proved the validity of our method. During research, we also find that objects whose complex permittivities are near the “C-curve” are hard to distinguish by MMW radiometry, unless we measure their radiation of vertical polarization near the Brewster angle. This finding has the guiding significance for object classification, recognition, and information acquisition.

Biological Risks of Using Non-Thermal Non-Ionizing Electromagnetic Fields

Electromagnetic pollution of the environment has become a significant environmental factor. The intensity of technogenic electromagnetic fields far exceeds the background indicators to which organisms have adapted in the course of evolution, in particular by their biorhythms. Much data on the biological effects of low-intensity (non-thermal) extremely high-frequency electromagnetic fields (EHF-EMF) at different levels of the organization has been accumulated. There are many possible explanations for these impacts, but the mechanism of action is not established. The purpose of this work is to analyze the negative effects of the use of non-thermal coherent electromagnetic radiation of extremely high frequencies. In particular, the use of microwave therapy is considered. A review of reports on the harmful effects of non-ionizing electromagnetic and magnetic fields among the population and professional groups has been made; the presence of the problem of hypersensitivity to such fields was shown. Information on the development of the direction of study of the resonant biological influence of EHF-EMF by Ukrainian specialists was provided. Particular attention is paid to the use of non-thermal microwaves for physiotherapy procedures, pain relief, correction of psycho-emotional disorders, ulcer healing, in particular stomach and duodenum, etc. It is noted that the so-called therapeutic frequencies of EHF-EMF, even if controlled, can cause negative effects, although they are not perceived as damaging. Changes in objective vital signs in the case of targeted exposure by low-intensity millimeter-wave radiation, namely, hemodynamics, temperature increase in the exposure zone, muscle activity, and the speed of the passage of a nerve impulse, an encephalogram were established. Precautionary recommendations based on the scientific and practical experience of using microwave acupuncture methods in the conditions of medical institutions are formulated. The synergistic effect of various influences, in particular electromagnetic fields, may not be a direct trigger of the disease, but a factor of not compensated stress. Therefore, clinical studies conducted many years ago cannot simply be dismissed on the grounds that the millimeter radiation penetrates only the outer layer of the skin. Skin cells can also secrete mediators that cause changes in ionic calcium channels and the level of calcium in the cells. The interest in these works is justified by the fact that currently the sources of monochromatic millimeter radiation will be spread with new communication systems. The risks of their biological action should be taken into account when emitters are installed.

Morphological Changes in H1299 Human Lung Cancer Cells Following W-Band Millimeter-Wave Irradiation

Efficiently targeted cancer therapy without causing detrimental side effects is necessary for alleviating patient care and improving survival rates. This paper presents observations of morphological changes in H1299 human lung cancer cells following W-band millimeter wave (MMW) irradiation (75–105 GHz) at a non-thermal power density of 0.2 mW/cm2, investigated over 14 days of subsequent physiological incubation following exposure. Microscopic analyses of the physical parameters measured indicate MMW irradiation induces significant morphological changes characteristic of apoptosis and senescence. The immediate short-term responses translate into long-term effects, retained over the duration of the experiment(s), reminiscent of the phenomenon of accelerated cellular senescence (ACS), and achieving terminal tumorigenic cell growth. Further, results were observed to be treatment specific in an energy (dose)-dependent manner and were achieved without the use of chemotherapeutic agents, ionizing radiation, or thermal ablation employed in conventional methods, thereby overcoming the associated side effects. Adaptation of the experimental parameters of this study for clinical oncology concomitant with current developmental trends of non-invasive medical endoscopy alleviates MMW therapy as an effective treatment procedure for human non-small cell lung cancer (NSCLC).

Inexpensive Millimeter-Wave Communication Channel Using Glow Discharge Detector and Satellite Dish Antenna

A full proof of concept for low-cost millimeter wave (MMW) communication link is demonstrated in this study. The suggested MMW channel is based on a very inexpensive commercially available off-axis dish antenna usually used for TV satellites, two Arduino Uno micro controller boards, and glow discharge detectors (GDD). The GDD is a robust and inexpensive room-temperature plasma device which was found to be a sensitive MMW radiation detector. The Arduino micro controllers are used to encode a text message into serial bits and also decode it. Those serial bits were used to modulate the MMW radiation in On-Off keying. The detection of MMW radiation was performed using a simple and inexpensive GDD. The suggested MMW channel can be used as point to point backhaul wireless communication for the 5th generation of cellular communication.

Development of a Ka-Band Circular TM01 to Rectangular TE10 Mode Converter

The output/input circuit is a core component in all high-power millimeter-wave (MMW) radiation sources, and its performance specifications and reliability directly impact upon the performance of the radiation source device. Central to achieving high power is the development of efficient mode converters. Here, we report on the development of a compact Ka -band circular TM01 to rectangular TE10 mode converter. The present mode converter adopts an all-metal waveguide structure and facilitates notable improvement in the system power capacity and is capable of realizing high-power propagation. The mode converter realizes effective mode conversion between high-order and fundamental modes, as well as allowing longitudinal and transverse transmission. Our simulation and empirical findings have shown mode purity ≥99.5% in the frequency range of 32.7–34.6 GHz, and the mode conversion efficiency is more than 96% at a center frequency of 32.9 GHz with a return loss ${S}_{{11}}$ of −19.3 dB. The bandwidth of the converter is 2.4 GHz with transmission coefficient ${S}_{{21}}\ge -{1}$ dB.

A millimeter-wave Bell Test using a ferrite parametric amplifier and a homodyne interferometer

A combined ferrite parametric amplifier and millimeter-wave homodyne interferometer are proposed as an ambient temperature Bell Test. It is shown that the non-linear magnetic susceptibility of the yttrium iron garnet (YIG) ferrite, on account of its narrow line-width Larmor precessional resonance, make it an ideal material for the creation of entangled photons. These can be measured using a homodyne interferometer, as the much larger number of thermally generated photons associated with ambient temperature emission can be screened out. The proposed architecture may enable YIG quantum technology-based sensors to be developed, mimicking in the millimeter-wave band the large number of quantum optical experiments in the near-infrared and visible regions which had been made possible by use of the nonlinear beta barium borate ferroelectric, an analogue of YIG. It is illustrated here how the YIG parametric amplifier can reproduce quantum optical Type I and Type II wave interactions, which can be used to create entangled photons in the millimeter-wave band. It is estimated that when half a cubic centimeter of YIG crystal is placed in a magnetic field of a few Tesla and pumped with 5 Watts of millimeter-wave radiation, approximately 0.5 × 1012 entangled millimeter-wave photon pairs per second are generated by the spin-wave interaction. This means an integration time of only a few tens of seconds is needed for a successful Bell Test. A successful demonstration of this will lead to novel architectures of entanglement-based quantum technology room temperature sensors, re-envisioning YIG as a modern quantum material.

Rapid consolidation of hydroxyapatite using intense millimeter-wave radiation

Hydroxyapatite powder compacts have been sintered to a relative density of about 95% using rapid 24 GHz microwave heating at rates 10–100 °C/min to 1300 °C with zero hold time. An optical system based on an infrared camera has been developed to measure shrinkage and temperature distributions over the surface of the samples. Ultra-rapid localized consolidation of hydroxyapatite powder, with application prospects in additive manufacturing, has been achieved using heating by a focused beam of 263 GHz millimeter-wave radiation.

Absorption of 5G Radiation in Brain Tissue as a Function of Frequency, Power and Time

The rapid release of 5G wireless communications networks has spurred renewed concerns regarding the interactions of higher radiofrequency (RF) radiation with living species. We examine RF exposure and absorption in ex vivo bovine brain tissue and a brain simulating gel at three frequencies: 1.9 GHz, 4 GHz and 39 GHz that are relevant to current (4G), and upcoming (5G) spectra. We introduce a highly sensitive thermal method for the assessment of radiation exposure, and derive experimentally, accurate relations between the temperature rise (ΔT), specific absorption rate (SAR) and the incident power density (F), and tabulate the coefficients, ΔT/ΔF and Δ(SAR)/ΔF, as a function of frequency, depth and time. This new method provides both ΔT and SAR applicable to the frequency range below and above 6 GHz as shown at 1.9, 4 and 39 GHz, and demonstrates the most sensitive experimental assessment of brain tissue exposure to millimeter-wave radiation to date, with a detection limit of 1 mW. We examine the beam penetration, absorption and thermal diffusion at representative 4G and 5G frequencies and show that the RF heating increases rapidly with frequency due to decreasing RF source wavelength and increasing power density with the same incident power and exposure time. We also show the temperature effects of continuous wave, rapid pulse sequences and single pulses with varying pulse duration, and we employ electromagnetic modeling to map the field distributions in the tissue. Finally, using this new methodology, we measure the thermal diffusivity of ex vivo bovine brain tissue experimentally.

A study of flames with millimeter-wave radiation

It is a valuable issue to explore whether a flame can radiate microwaves, in spite of the electric field formed in the flame. Presented herein is an experimental study on a series of flames with millimeter-wave radiation in the combustion of pyrotechnic films. The pyrotechnic films were composed of ultra-fine red phosphorus (P), sodium nitrate (NaNO3), Polyvinyl Alcohol (PVA) and some additives such as chopped carbon fibers (CFs) and aluminized glass fibers (GFs). The combustion temperatures and millimeter-wave radiation signals of the flames were measured, the millimeter-wave emissivity and spectral radiant exitance were calculated to describe the millimeter-wave radiation intensity. The results demonstrate that the flame of the pyrotechnic films based on P/NaNO3/CFs can radiate millimeter waves, and different materials and their proportion have a great effect on the millimeter-wave radiation intensity.

Additive Manufacturing of Ceramic Products Based on Millimeter-Wave Heating

Additive manufacturing of ceramic articles making use of concentrated energy flows attracts the research interest worldwide. While the application of laser beams faces serious problems associated with high temperature of sintering and low thermal conductivity of ceramics, layer-by-layer sintering by focused millimeter-wave radiation appears to be a promising method of additive manufacturing. This paper describes the studies of fast millimeter-wave sintering of yttria-stabilized zirconia and hydroxyapatite ceramics. Coefficients of the millimeter-wave absorption have been determined in broad frequency and temperature ranges. Rapid sintering of compacted ceramics samples was accomplished using volumetric microwave heating in a work chamber of a 24 GHz / 5 kW gyrotron system. In addition, using a 263 GHz / 1 kW cwgyrotron millimeter-wave source and a purposely designed electrodynamic focusing structure, radiation intensities of up to 20 kW/cm2could be achieved, which was sufficient for fast localized heating of ceramic layers to the solidification temperature. The results of a study of the microstructure and mechanical properties of the sintered ceramics are presented.

Preliminary Circuit Analysis of a $W$ -Band High-Power Extended Interaction Oscillator With Distributed Hollow Electron Beam

In this paper, the circuit synthesis concept is applied to support a novel extended interaction RF circuit for generating a high-power millimeter-wave radiation. Its novel configuration is constructed by parallel connecting multiple sheet-beam-extended interaction cavities arranged along the angular direction to form a distributed hollow electron beam (HEB) as a whole. The specific concept endows the proposed circuit features such as: 1) making the diameter of HEB flexible and hence extending the space to set more single-sheet beam cavity in angular direction for increasing power capacity and 2) offering the opportunity to adopt a mutual magnetic focusing system for the distributed HEB, which is critical for the feasibility of the circuit synthesis. The circuit analysis is carried out, and a ${W}$ -band extended interaction oscillator (EIO) based on this concept is proposed to preliminarily demonstrate the capability of circuit synthesis. The distributed HEB is produced with an immersed electron gun using a 0.8 T focusing magnetic field. Simulations using 3-D particle-in-cell (PIC) technology in Computer Simulation Technology (CST) predict a peak output power up to 10.0 kW around 103 GHz with the beam current of 4.2 A at 27 kV.

Power enhancement for millimeter-wave extended interaction radiation sources by using the TM31-mode scheme

The application of a TM31 mode scheme in extended interaction radiation sources permits the use of higher beam power and larger power capacity for power enhancement as compared with that of the conventional fundamental mode in the millimeter-wave band. To support this point, the effect of coupling cavities on the electromagnetic characteristics of the TM31 and fundamental modes is studied. This study shows that the TM31 mode can build up (1) a weaker TM11-like field in the gaps which has the same typical distribution pattern as that of a conventional fundamental mode at the same frequency and (2) two extra parts of field energy to support larger coupling cavities. To demonstrate this feature, we observe the field distribution and strength by injecting a certain wave power in two cavities, which are predicted to resonate in the TM31 and fundamental modes at the same frequency. The mode analysis and the beam-wave interaction are discussed to analyze the feasibility of the TM31 mode scheme. Through particle-in-cell simulations, the maximum output power over 26.3 kW is obtained at the desired frequency when the beam voltage and current are 61 kV and 3 A, respectively. The TM31 mode scheme could be a promising candidate for achieving high power in millimeter-wave extended interaction radiation sources.

Simulation and measurement of millimeter-wave radiation from Josephson junction array**Project supported by the National Natural Science Foundation of China (Grant No. 51002081), the Fundamental Research Funds for the Central Universities, China, the China Manned Space Advance Research Program, China (Grant No. 030201), and the Research Program of Application Foundation and Advanced Technology of Tianjin, China (Grant No. 15JCQNJC01300).

We report the circuit simulations and experiments of millimeter-wave radiation from a high temperature superconducting (HTS) bicrystal Josephson junction (BJJ) array. To study the effects of junction characteristic parameters on radiation properties, new radiation circuit models are proposed in this paper. The series resistively and capacitively shunted junction (RCSJ) models are packaged into a Josephson junction array (JJA) model in the simulation. The current-voltage characteristics (IVCs) curve and radiation peaks are simulated and analyzed by circuit models, which are also observed from the experiment at liquid nitrogen temperature. The experimental radiation linewidth and power are in good agreement with simulated results. The presented circuit models clearly demonstrate that the inconsistency of the JJA will cause a broad linewidth and a low detected power. The junction radiation properties are also investigated at the optimal situation by circuit simulation. The results further confirm that the consistent JJA characteristic parameters can successfully narrow the radiation linewidth and increase the power of junction radiation.

Measurement of stray millimeter-wave radiation from a 70-GHz ECH/ECCD system in Heliotron J

Stray millimeter-wave radiation from a 70-GHz electron cyclotron heating and current drive (ECH/ECCD) system has been measured in the Heliotron J helical device. Two rotatable diode detectors located at the outboard side ports are used to pick up the stray radiation: one is installed at the ECH launcher port and the other is installed at a toroidal angle of 135 deg far from the ECH launcher port. Both detectors are rotated to measure the polarization of the stray radiation. The results show that at the toroidal position far from the ECH launcher, the polarization is not fully randomized before plasma breakdown, whereas the polarization is uniform after a quasi-stationary plasma is generated. The polarization near the ECH launcher is not uniform even in a quasi-stationary plasma. Plasma experiments scanning the electron density indicate that the EC power absorption estimated from the stray radiation at the toroidal position far from the ECH launcher is correlated with the single-pass absorption rate calculated by the TRAVIS ray-tracing code. These results indicate that the diagnostic using a simple diode detector can be used as a real-time monitor of EC power absorption only when the plasma with finite density is produced and the detector is placed far from the ECH launcher port.