A Compact Wideband Active Two-Dipole HF Phased Array

The design and construction of an upgraded HF quarter-wavelength two-dipole active array with 90° difference feed was implemented in the course of a research project to perform a directional (azimuthal) investigation of interference at HF. The lack of affordable compact antennas to meet the project requirements was the incentive to develop a compact unidirectional antenna, with the maximum possible front-to-back ratio at frequencies of 20–30 MHz, where the dimensions of traditional passive antennas are enormous. By installing a low-noise very-high-input impedance amplifier in each dipole of the array, the effect of the mutual coupling between the two dipoles was reduced, improving the front-to-back (F/B) ratio over a wide frequency range. Electronic steering, easy polarization adjustment, and fast and easy deployment were the key requirements for the construction of the antenna. Therefore, a light and compact design was of the utmost importance to meet the space limitations at the monitoring site, which did not allow the deployment of a traditional HF directional antenna that employs a very long boom and elements.

An Efficient Conformal Stacked Antenna Array Design and 3D-Beamforming for UAV and Space Vehicle Communications

In this paper, a new conformal array structure and beamforming technique are proposed to provide efficient communication performance for unmanned aerial vehicles (UAVs) and space vehicles. The proposed array is formed by conformally stacking cylindrical, conical, and concentric circular (CSC4) arrays which are all coaxially aligned with the same axis of the conformed body and with uniform interelement spacing. The array elements are then fed by a weighting vector that has an adaptive cosine tapered profile where the maximum amplitude coefficient is oriented with the mainlobe direction to improve the scanning capabilities of the array and increase the array effective area. In addition, for very large, conformed body structures such as space vehicles, a frontal mainlobe-oriented partial CSC4 array beamforming technique is proposed to efficiently utilize the large CSC4 structure, reduce the processing requirements for mainlobe electronic steering, and to provide very low sidelobe levels with reduced backlobe levels. Simulation results show that the proposed CSC4 design can provide wide scanning angles of up to ±70° angular range in the θ-direction with only ±1° change in the beamwidth, without increasing array size and with achievable sidelobe level of −45 dB and backlobe levels less than −10 dB.

Design and Fabrication of a Focused Ultrasound Device for Minimallyinvasive Neurosurgery: Reporting a Second, Miniaturized and Mrcompatible Prototype with Steering Capabilities

Many surgeons are faced with inoperable or only partially operable brain lesions, such as tumors. Even when surgery is feasible, patient outcomes are greatly affected by blood loss or infection. This has led many physicians toward non- or minimally-invasive surgery, which demands specialized toolkits. Focused ultrasound has great potential for assisting in such procedures due to its ability to focus a few centimeters away from the surface of the transducer. In a prior study, we developed a focused ultrasound prototype that could fit within a BrainPath trocar, specifically made for minimally invasive brain surgery. Here, we present the design and fabrication of a second prototype that reduces size, is MR-compatible, and has electronic steering capabilities.

A Compact Ku-Band Active Electronically Steerable Antenna with Low-Cost 3D T/R Module

This paper presents a novel compact Ku-band active electronically steerable antenna array design with a low-cost and integrated T/R 3D module employed for airborne synthetic aperture radar (SAR) systems. The entire system adopts 3D multilayer technology with vertical interconnection to construct the hermetically packaging RF modules. By assembling different multifunctional modules into a whole multilayer board, the 3D T/R technique greatly improves the system integration and reduces implementation cost and size. Besides, a wideband circular polarized antenna array was designed in LTCC and connected to the proposed T/R modules to form a complete AESA. The whole proposed antenna system has been fabricated and experimentally investigated. Measurement results showed very good phased array performances in terms of gain, axial ratio, and radiating patterns. The low-cost, lightweight, and low-power features exhibited by the proposed design validate its applicability for weight and power constrained platforms with great electronic steering ability.

Loudness calculation procedure to study electronic steering column lock noise measurement

In the automotive field, the customer requirements for low interior noise and pleasant sound quality inside a vehicle are getting higher and higher. Various national and international regulatory authorities established and reviewed vehicle interior noise for the past years. Besides, lots of studies have shown that vehicle noise can influence the driver’s perceptions and also his or her driving capabilities. To succeed in this scenario, all manufacturers are investing in technology and research in order to improve their component performance. Working on the noise source so as to reduce the seriousness of these noise problems can be really effective. However, various engineering techniques are available to deal with noise and sound-measuring instruments, and systems can help to identify the nature of the problem and they can also be helpful in determining the right procedure to analyse the noise problem. This work proposes a procedure to evaluate the noise originated from an electronic steering column lock device which is used to lock and unlock the steering wheel according to European safety requirements. In particular, different standards and requirements for loudness evaluation have been discussed and the formulation of a straightforward procedure, which can be used to evaluate the loudness according to costumer’s requirements, is defined.