Essential oil analysis and antibacterial activity of Ferula assa-foetida L. aerial parts from Neishabour mountains

Abstract Background and objectives: Ferula assa-foetida (asafoetida) is a native Iranian species which grows in different regions and climates in Iran. The plant is well known in Iranian Traditional Medicine as well as folk medicine for treatment of diseases. Several studies have been carried out on the essential oil of this species collected from different areas of Iran. This study is the first report about the essential oil of the plant collected from Neishabour mountains that is a potent area for growing this valuable plant species. Methods: Essential oil of the aerial part of Ferula assa-foetida which was collected from Neishabour, Iran, was analyzed by gas chromatography-mass spectroscopy (GC/MS). The minimum inhibitory concentrations of the essential oil was investigated against both Grampositive (Staphylococcus epidermidis, Staphylococcus aureus, Bacillus subtilis) and Gram-negative (Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumonia) bacteria using microdilution method. Results: Twenty three components representing 97.06% of the total oil were identified. (E)-1-propenyl sec-butyl disulfide (53.77%), (Z)-1-propenyl sec-butyl disulfide (35.6%) and α-pinene (3.4%) were identified as major components. The MIC of the essential oil ranged from 12-24 mg/mL against all tested bacteria. Conclusion: The results indicated that among various compounds identified in the essential oil of F. assa-foetida L. from Neishabour mountains, disulphide compounds were the major constituents of the oil. In comparison to other reports of this plant around the country, disulphide compounds could be the reason of its moderate antibacterial effect

A flexible phased array system with low areal mass density

Phased arrays are multiple antenna systems capable of forming and steering beams electronically using constructive and destructive interference between sources. They are employed extensively in radar and communication systems but are typically rigid, bulky and heavy, which limits their use in compact or portable devices and systems. Here, we report a scalable phased array system that is both lightweight and flexible. The array architecture consists of a self-monitoring complementary metal–oxide–semiconductor-based integrated circuit, which is responsible for generating multiple independent phase- and amplitude-controlled signal channels, combined with flexible and collapsible radiating structures. The modular platform, which can be collapsed, rolled and folded, is capable of operating standalone or as a subarray in a larger-scale flexible phased array system. To illustrate the capabilities of the approach, we created a 4 × 4 flexible phased array tile operating at 9.4–10.4 GHz, with a low areal mass density of 0.1 g cm^(−2). We also created a flexible phased array prototype that is powered by photovoltaic cells and intended for use in a wireless space-based solar power transfer array

Dynamic Polarization Control of Integrated Radiators

Dynamic Polarization Control (DPC) ensures polarization matching to the receiving antenna regardless of its polarization or orientation in space. A fully integrated 105.5 GHz 2×1 DPC multi-port driven radiator array with beam steering radiates linear polarization across the full polarization angle range of 0° to 180° maintaining axial ratios above 10 dB, and controls the axial ratio from 2.4 dB (near circular) to 13 dB (linear) in various directions of radiation and a maximum EIRP of 7.8 dBm

Dynamic Polarization Control

Dynamic polarization control (DPC) is the method of setting the polarization of the far-field electric field generated by a radiating antenna entirely electronically in order to maintain polarization matching with the receiving antenna regardless of its polarization or orientation in space. This work implements a fully integrated 2 × 1 phased array radiator in 32 nm CMOS SOI at 105.5 GHz with DPC. The system consists of a central locking oscillator that phase locks oscillators within the core of each antenna followed by three amplification stages with variable gain that drive the antennas. By controlling the amplitude and phase of two orthogonal polarized subparts of each multi-port antenna, various far-field polarizations can be realized. The array is capable of beam steering, controlling the polarization angle across the entire tuning range of 0° to 180° while maintaining axial ratios above 10 dB, and controlling the axial ratio from 2.4 dB (near circular) to 14 dB (linear) in various directions of radiation. It radiates a maximum EIRP of 7.8 dBm with a total radiated power of 0.9 mW. To the best of the authors’ knowledge, this work presents the first integrated radiator with dynamically controllable polarization

An Integrated Slot-Ring Traveling-Wave Radiator

Electromagnetic duality is used to design a multi-port traveling-wave slot-ring antenna with on-chip driver circuitry to create a fully integrated radiator. By creating a slot version of the multi-port driven antenna, the required exclusive use area of the antenna is significantly decreased, while still being able to perform impedance matching, power combining, and power transfer off chip through electromagnetic radiation in a single step. The driver core consists of an oscillator followed by three amplification stages. A split path inductor design was utilized to reduce the radiator's dependence on process variation in the metal stack while ensuring proper isolation between the four quadrature paths. The slot radiator has a simulated antenna efficiency of 39% and a measured single-element effective isotropic radiated power of 6.0 dBm with a total radiated power of -1.3 dBm at 134.5 GHz

An integrated traveling-wave slot radiator

A traveling-wave integrated slot radiator is designed using electromagnetic duality theory based off of the ring portion of a radial multi-port driven radiator to minimize the area required exclusively for the antenna. It is designed in 32 nm SOI CMOS and driven by a buffered quadrature VCO at 4 points to create the traveling wave that radiates out of the backside of the chip. It is measured to have a maximum EIRP of 6.0 dBm at 134.5 GHz with a total radiated power of -1.7 dBm while drawing 168 mW DC power

Proximal-field radiation sensors

Proximal-Field Radiation Sensors (PFRS) are introduced as a new set of tools to enable extraction of far-field radiation properties of integrated antennas from the surface waves inside their dielectric substrates. These sensors allow self-characterization, self-calibration, and self-monitoring of the radiation performance for both printed circuit board (PCB) antennas and integrated circuit (IC) antennas without any need to additional test equipment. In this paper, we explain how these sensors can be implemented and demonstrate how the far-field radiation properties can be determined from them. A PCB prototype consisting of two transmitting patch antennas and four integrated PFRS antennas is fabricated and tested to verify the concept and demonstrate the implemented sensors' capabilities to capture the radiation properties such as gain pattern, radiated polarization, and the steering angle of the antenna array as a few examples of radiation sensors applications