Design and Manufacture of Traveling-wave Electro-optic Modulator for X-band LFM Signal Generation

In this paper, a photonic-based microwave system technology is described, and a traveling-wave electro-optic modulator is designed and manufactured as a key component. The fabricated modulator is composed of a metal diffusion waveguide for optical transmission and a planar waveguide electrode on lithium niobate substrate for microwave transmission. The electro-optic response bandwidth of I and Q channels in a fabricated dual parallel Mach-Zehnder modulator were measured for 27.67 and 28.11 GHz, respectively. Photonic four times up-converted X-band frequency and linear frequency modulated signal were confirmed using the fabricated electro-optic modulator by S-band input signal. The confirmed broadband signal can be applied to a microwave system for surveillance and high-resolution ISAR imaging.

Concentration of Metals in Native and Invasive Species of Fish in the Fluvial-Lagoon-Deltaic System of the Palizada River, Campeche

Aquatic organisms, such as fish, are important indicators of the bioavailability of metals in coastal environments, demonstrating the capacity of different species to bioaccumulate these metallic elements. The fluvial-lagoon system of the Palizada River is an important ecosystem for its terrestrial and aquatic biological diversity where fishing is an important productive activity in this system. The objective of this research was to evaluate the concentration of Pb and Cd in the muscle tissue of native and invasive fish species in this area. For this, the digestion of fish muscle samples was carried out with a CEM MARS 5 Digestion Microwave System, while the quantification of metals was performed with an atomic absorption equipment. All analysis muscle samples from native and invasive fish showed Pb and Cd in their content. By sampling site there was a statistically significant difference (p < 0.05), with a maximum Pb concentration of 7.760 µg g−1 at the LLAR site (Laguna Larga). In terms of species, the maximum Cd concentration was obtained in the Cyprinus carpio with 6.630 ± 0.127 and in Pterygoplichthus pardalis with 6.547 ± 0.873 µg g−1 (dry weight). The presence of metals such as Pb and Cd in muscle tissue of native and invasive fish species represents an important bioindicator of environmental exposure in the study area and a potential risk to public health, as these species are commonly consumed.

Breast tissue mimicking phantoms for combined ultrasound and microwave imaging

We present a new formulation for a breast tissue-mimicking phantom for combined microwave and ultrasound imaging to assist breast cancer detection. Formulations based on coconut oil, canola oil, agar and glass beads were used to mimic skin and fat tissues. First, 36 recipes were fabricated, and properties were measured to determine the relationship and possible interaction between ingredients with the ultrasound and microwave properties. Based on these results, the formulae were developed to mimic different tissues found in breast, including skin, fat, fibroglandular, and tumour tissues. All phantoms contained a base of agar and glass beads at different proportions depending on the tissue mimicked. Tumour and fibroglandular tissues were best mimicked by adding polyvinylpyrrolidone (PVP), while using coconut oil for skin and canola oil for fat produced the best results. Five final phantoms with different internal structures were fabricated and imaged using B-mode ultrasound and a microwave transmission system. Microwave permittivity maps were obtained from the microwave system and compared to ultrasound images. The structure and composition of the phantoms were all confirmed through this microwave and ultrasound imaging.

Evaluation of the use of the Microwave system and Calculation of Economic Efficiency

Cost-effectiveness calculations for computational irrigation options, costs of sugar beet productivity by macro and microelements, costs associated with the assembly of single added microsurgeons, cost of microwave system, expenditure on production of products according to options, etc. the experimental results of the experimental studies carried out in different regions of the country are proven by the fact that the use of microcirculation by drop irrigation method is well-aerated in the soil zone in the soil zone of the root system of plants, where normal biological activity of beneficial microorganisms is provided, it is ensured that the required amount of continuous fertilizer in the formulation of the solution provides optimal nutrient, water and air regimes in the soil, which in turn promotes biological and physical improvement of the plant and, consequently, increases productivity and improves product quality

A double layer FSS filter for sub-THz applications

This work presents the simulated and measured performance of single- and double-layer frequency selective surface filters for operation at sub-THz frequencies (250 GHz center frequency). They were composed of concentric square loops with a split as a unit cell resonator on top of a low dielectric permittivity, low thickness material (RT5880). Both a single layer filter and a cascaded two layer filter with varied distances were investigated. The simulated bandwidth for the cascaded filter was 27 GHz and 16 GHz and 9 GHz bandwidth measured with a THz-TDS and microwave system.

Efficient electromagnetic transducers for spin-wave devices

This paper presents a system-level efficiency analysis, a rapid design methodology, and a numerical demonstration of efficient sub-micron, spin-wave transducers in a microwave system. Applications such as Boolean spintronics, analog spin-wave-computing, and magnetic microwave circuits are expected to benefit from this analysis and design approach. These applications have the potential to provide a low-power, magnetic paradigm alternative to modern electronic systems, but they have been stymied by a limited understanding of the microwave, system-level design for spin-wave circuits. This paper proposes an end-to-end microwave/spin-wave system model that permits the use of classical microwave network analysis and matching theory towards analyzing and designing efficient transduction systems. This paper further compares magnetostatic-wave transducer theory to electromagnetic simulations and finds close agreement, indicating that the theory, despite simplifying assumptions, is useful for rapid yet accurate transducer design. It further suggests that the theory, when modified to include the exchange interaction, will also be useful to rapidly and accurately design transducers launching magnons at exchange wavelengths. Comparisons are made between microstrip and co-planar waveguide lines, which are expedient, narrowband, and low-efficiency transducers, and grating and meander lines that are capable of high-efficiency and wideband performance. The paper concludes that efficient microwave-to-spin-wave transducers are possible and presents a meander transducer design on YIG capable of launching $$\varvec{\lambda = 500}\,$$ λ = 500 nm spin waves with an efficiency of − 4.45 dB and a 3 dB-bandwidth of 134 MHz.

Efficient Electromagnetic Transducers For Spin-Wave Devices

This paper presents a system-level efficiency analysis, a rapid design methodology, and a numerical demonstration of efficient sub-micron, spin-wave transducers in a microwave system. Applications such as Boolean spintronics, analog spin-wave-computing, and magnetic microwave circuits are expected to benefit from this analysis and design approach. These applications have the potential to provide a low-power, magnetic paradigm alternative to modern electronic systems, but they have been stymied by a limited understanding of the microwave, system-level design for spin-wave circuits. This paper proposes an end-to-end microwave/spin-wave system model that permits the use of classical microwave network analysis and matching theory towards analyzing and designing efficient transduction systems. This paper further compares magnetostatic-wave transducer theory to electromagnetic simulations and finds close agreement, indicating that the theory, despite simplifying assumptions, is useful for rapid yet accurate transducer design. It further suggests that the theory, when modified to include the exchange interaction, will also be useful to rapidly and accurately design transducers launching magnons at exchange wavelengths. Comparisons are made between microstrip and co-planar waveguide lines, which are expedient, narrowband, and low-efficiency transducers, and grating and meander lines that are capable of high-efficiency and wideband performance. The paper concludes that efficient microwave-to-spin-wave transducers are possible and presents a meander transducer design on YIG capable of launching λ=500nm spin waves with an efficiency of -4.45 dB and a 3 dB-bandwidth of 134 MHz.

Effect of Vertical and Horizontal Sample Orientations on Uniformity of Microwave Heating Produced by Magnetron and Solid-State Generators

In this study, the effect of different horizontal and vertical orientations of a model sample (cuboid gellan gel samples containing Maillard reactants) on microwave heat processing was investigated in the solid-state and magnetron microwave systems. To achieve this target, seven orientations inside both microwave cavities were defined. Two of the investigated sample orientations were in a vertical position with and without turntable rotation, and five in a horizontal position. Furthermore, samples at horizontal orientations were put at an angle position without turntable rotation. To analyze the microwave heating patterns, infrared (IR) pictures and photographs of the gellan gel samples were taken after processing to document IR-based thermal and Maillard color changes, respectively. Three main factors for improvement of the heating homogeneity were identified: first, processing samples in the solid-state microwave system; second, position variation of the sample by turntable activated; and third, horizontal orientation. In addition, it was observed that placing the gellan gel samples in a vertical position in the magnetron microwave system resulted in considerably more absorbed power and a more uniform microwave heat processing compared to other horizontal orientations in this system. This indicated a non-uniform microwave field distribution. The results of this study can also confirm the importance of designing suitable food packaging: a vertical shape for more microwave energy absorbance and thus, more energy efficiency, and a horizontal shape for more uniform microwave heat processing.

Thermoablation of thyroid nodules reveals excellent results with low morbidity

BACKGROUND: Thermoablation is an attractive treatment of thyroid nodules for its minimal-invasiveness. It remains unclear whether results and morbidity meet the patients’ expectations. OBJECTIVE: The aim of the presented study is to show data obtained after microwave thyroid ablation from a patients’ perspective. METHODS: Indications and preoperative diagnosis were chosen according to international guidelines. Thermoablation was achieved using a CE certified microwave system. The procedures heeded the published recommendations of the European Federation of Societies for Ultrasound in Medicine and Biology. Follow-up included ultrasound, laboratory parameters and a standardized questionnaire. RESULTS: Thirty patients were enrolled into the study. All patients reported an improvement of complaints following the procedure. Scar formation occurred in 3 cases (10%) with 0.5 ± 1.3 mm length and 0.4 ± 1.0 mm width. No cosmetic, neurological, vocal or pharyngeal complication occurred. Energy required for non-functioning nodules (n= 15, 50%) was 2.56 ± 3.41 kJ/mL, for autonomous adenoma (n= 8, 27%) 0.96 kJ/mL (p< 0.05, t-test). CONCLUSION: The presented data summarize an initial experience in selected patients and resemble excellent patient reported outcome with minimal morbidity. These preliminary data indicate the majority of patients satisfied with the procedure. Further trials will be required to endorse these findings.