Increasing radiation power in half width microstrip leaky wave antenna by using slots technique

<p class="Default">The radiation power in the endfire is decreased while the main beam of half substrate integrated waveguide scan from broadside to endfire in a forward. The design of half-width microstrip leaky-wave antenna (HW-MLWA) has been presented in this work to increase the power radiation near endfire by using the slots technique in the radiation element. This slot leads to a decrease the cross-polarization. The proposed design comprises one element of HW-MLWA with repeated meandered square slots in the radiation element. One aspect of this antenna is generated by using a half substrate integrated waveguide with a full tapered feed line. The proposed antenna was terminated by load of 50 Ω, and feed on the other end of the antenna. Finally, the suggested design is simulated and acceptable results were found. The released gain is increased from 10.6 dBi to 12 dBi at 4.3 GHz. This design is suitable for unmanned aerial vehicle UAVs at C band application.</p>

Pseudospark-sourced beam and its application in high-power millimeter-wave generation

A pseudospark (PS) discharge can generate an electron beam with a high current density. The electron beam can be self-focused by an ion channel and transported over a long distance without the need for an external magnetic field. Such features make it attractive to drive millimeter-wave/THz interaction circuits for the generation of high-power radiation from a compact device. This paper presents the experimental results on the generation and transportation of the PS-sourced beam with different cross-sections, as well as the differences of the PS-sourced beam with and without post acceleration. Its application in millimeter-wave/THz sources was demonstrated by the operation of extended interaction oscillators (EIOs) at different frequencies is presented.

Physical layer key generation against MIMO eavesdropper by exploiting full-duplex technology

Generating a shared secret key from physical layer is an interesting topic with practical value. Inspired by the encouraging progress on full-duplex radio, a novel mechanism aiming at high and steady key generation rate with low cost is proposed in this paper. Legitimate users simultaneously send random bit sequences to actively interfere with each other. They extract those mutually jammed bits to form a secret key. A special digital modulation scheme, called Random Manchester coding is proposed. The proposed scheme achieves three goals. The first and the most important one is to prevent a MIMO eavesdropper from separating the superposed signal; the second one is to detect denial of service and key compromise attack to defend against an active attacker; the third one is to achieve design goal on low power radiation, computational complexity and memory cost. Theoretical analysis, numerical simulations and concept-proof experiments validate the effectiveness of our proposed scheme. Our solution is promising to facilitate key generation applications of nearby wireless devices such as ubiquitous smartphones, wearable devices.

Plasma Metabolomics in a Nonhuman Primate Model of Abdominal Radiation Exposure

The acute radiation syndrome is defined in large part by radiation injury in the hematopoietic and gastrointestinal (GI) systems. To identify new pathways involved in radiation-induced GI injury, this study assessed dose- and time-dependent changes in plasma metabolites in a nonhuman primate model of whole abdominal irradiation. Male and female adult Rhesus monkeys were exposed to 6 MV photons to the abdomen at doses ranging between 8 and 14 Gy. At time points from 1 to 60 days after irradiation, plasma samples were collected and subjected to untargeted metabolomics. With the limited sample size of females, different discovery times after irradiation between males and females were observed in metabolomics pattern. Detailed analyses are restricted to only males for the discovery power. Radiation caused an increase in fatty acid oxidation and circulating levels of corticosteroids which may be an indication of physiological stress, and amino acids, indicative of a cellular repair response. The largest changes were observed at days 9 and 10 post-irradiation, with most returning to baseline at day 30. In addition, dysregulated metabolites involved in amino acid pathways, which might indicate changes in the microbiome, were detected. In conclusion, abdominal irradiation in a nonhuman primate model caused a plasma metabolome profile indicative of GI injury. These results point to pathways that may be targeted for intervention or used as early indicators of GI radiation injury. Moreover, our results suggest that effects are sex-specific and that interventions may need to be tailored accordingly.

A wrap-gate CNT-MOSFET based SRAM bit-cell with asymmetrical ground gating and built-in read-assist schemes for limited-energy environments application

Today, designing low-power single-bit SRAM structures with the ability to operate regularly at low supply voltages and with high immunity against standard radiation particles impact is challenging for designers. In the present article, a novel design of a low-power radiation-hardened single-ended SRAM bit-cell (UPRHSE) based on gate-diffusion input (GDI) method using gate-all-around carbon nano-tube (CNT) MOSFETs (GAA CNT-MOSFETs) along with dual-chirality/multiple-diameter technique for CNTs with an asymmetric virtual ground gating and built-in read-assist schemes with inherent single-node event upset (SEU) preventive and self-correction capabilities and a high degree of robustness against multiple-node event upsets (MEUs) in the presence of more consumption area storage has been proposed. In order to investigate single/double upset injection circuit model using the structure of the T-connected pseudo resistors (TPRs) has been proposed. Also, based on the analytical-compact model, an equation for calculating the data-retention voltage (VDR) metric for the suggested bit-cell structure and an algorithm for facile estimate of VDR for other bit-cell architectures is presented. The results of extensive Monte-Carlo (MC) simulations to evaluate the proposed bit-cell indicate larger noise margins, acceptable yield, less sensitivity to process, voltage and temperature (PVT) variations, higher critical charge and consequence more robustness to soft errors with high reliability of data storage in standby mode in the presence of voltage conditions lower than the nominal power supply, and better results in other comprehensive figure of merits (FoMs) criteria compared to nanotechnology-based state-of-the-art radiation-hardened (rad-hard) bit-cell circuits with the same number of transistors in the 16 nm technology node. So, the proposed UPRHSE design can be a reasonable choice for applications that demands high stability, impact resistance to radiation particles and extremely low power in a radiation abundant environment with limited-energy sources. Finally, in order to use the suggested UPRHSE bit-cell in a real application with secure data transfer approach, the suggested structure is employed for storing. The results show the better performance of UPRHSE in terms of other comprehensive FoMs based on PSNR and MSSIM metric to evaluate the appropriate accuracy in pixel-by-pixel image compared to other well-known counterpart designs.

On-Board Ship Detection for Medium Resolution Optical Sensors

In recent years there has been an increased interest in ocean surveillance. The activity includes control and monitoring of illegal fisheries, manmade ocean pollution and illegal sea traffic surveillance, etc. The key problem is how to identify ships and ship-like objects accurately and in a timely manner. In this context, currently, many solutions have been proposed based on high resolution optical and radar remote sensing systems. Most often, these systems suffer from two major limitations viz., limited swath, thereby requiring multiple satellites to cover the region of interest and huge volumes of data being transmitted to ground, even though effective per-pixel information content is minimal. Another limitation is that the existing systems are either simulated on ground or built using the non-space qualified/Commercial Of-The-Shelf (COTS) components. This paper proposes an efficient on-board ship detection system/package connected with medium resolution wide swath optical camera. The methodology adopted has three major components, viz., onboard data processing for improving the radiometric fidelity, followed by a ship detection using modified Constant False Alarm Rate algorithm (CFAR) and a false alarm suppression module to mask false identifications. Finally, the package outputs only the locations of the ships, which is transmitted to the ground. The proposed system reduces the effective volume of data to be transmitted and processed on ground and also significantly cuts down the turnaround time for achieving the end objective. The system is built on radiation hardened Field Programmable Gate Array (FPGA) devices to meet the various engineering constraints such as real-time performance, limited onboard power, radiation hardness, handling of multiple custom interfaces etc. The system is tested with one of the medium resolution Multispectral Visual and Near Infra-Red (MX-VNIR) sensor having a spatial resolution of around 50 m and swath of around 500 Kms, which would be flown with one of the upcoming satellites. The systems performance is also verified on ground with Indian Remote Sensing (IRS) Satellite’s Resourcesat’s Advanced Wide Field Sensor (AWiFS) data and the results are found to be quite encouraging as well as meeting the mission objectives.

Antenna Array with TEM-Horn for Radiation of High-Power Ultra Short Electromagnetic Pulses

An antenna array with short shielded transverse electromagnetic horns (S-TEM-horns) for emitting high-power radiation of ultra-short electromagnetic pulses (USEMP) has been created and researched. The antenna unit consists of an ultra-wideband antenna array with four S-TEM horns, with each connected to a two-wire HF transmission line, and these four lines are connected to an antenna feeder. This feeder is connected to a semiconductor generator with the following parameters: a 50 Ohm connector, 10–100 kV high-voltage monopolar pulses, a rise time of about 0.1 ns, FWHM = 0.2–1 ns, and pulse repetition rates of 1–100 kHz. The antenna array was designed and optimized to achieve a high efficiency of about 100% for the antenna aperture by using a 2 × 2 array with S-TEM-horns, with shielding rectangular plates for the return current. The transient responses were studied by simulation using the electromagnetic 3D code “KARAT” at the time domain and experimentally with the use of our stripline sensor for measurement of the impulse electrical field with a 0.03 ns rise time and a 7 ns duration at the traveling wave. The radiators were emitting USEMP waves with a hyperband frequency spectrum of 0.1–6 GHz. The radiation with an amplitude of 5–30 kV/m of the E-field strength at a distance of up to 20 m was successfully applied to test the electronics for immunity to electromagnetic interference.

Diversity of non-palpable breast cancer. Timely diagnosis, adequate treatment and prevention

The goal. To show the variety of manifestations of non-palpable breast cancer, which create difficulties in diagnostics and the choice of treatment tactics, to focus on the need to accelerate the introduction of the latest organ-saving treatment and diagnostic technologies and prevention into the system of mammary cancer screening. The main provisions. The epidemiology of cancer, risk factors, positive trends in mammary cancer screening in Russia are presented. A description is given of the diversity of X-ray sonographic and molecular biological manifestations of non-palpable breast cancer based on the results of the analysis of a complex clinical X-ray sonographic pathomorphological and molecular genetic examination of 1,212 patients with clinically latent breast diseases, including 708 patients with non-palpable cancer of various molecular subtypes, manifested by a variety of options – a nodular growth (40.1%), an accumulation of microcalcifications (17.5%), a site of local heavy rearrangement of the structure (31.2%), cancer accompanied by pathological secretion (6.6%), X-ray negative cancer (4.6%). When distributed by stages, 70.3% had T1N0M0, 25% had TisN0M0 and microinvasive cancer. For differential diagnosis, high-tech radiological techniques were used – 3D X-ray and ultrasound tomosynthesis. Effective preoperative diagnostics allowed for adequate organ-saving treatment, including oncoplastic surgery, high-power radiation therapy and modern targeted drug treatment, timely rehabilitation and prevention. Conclusion. Non-palpable breast cancer has many faces. Knowledge of the variants of its manifestations and the use of modern diagnostic methods are necessary for mammary cancer screening, which creates the preconditions for adequate timely organ-saving treatment that preserves the life of patients and its quality.