The new radiation-hard optical links for the ATLAS pixel detector

The ATLAS detector is currently being upgraded with a new layer of pixel based charged particle tracking and a new arrangement of the services for the pixel detector. These upgrades require the replacement of the opto-boards previously used by the pixel detector. In this report we give details on the design and production of the new opto-boards.Comment: Presentation at the DPF 2013 Meeting of the American Physical Society Division of Particles and Fields, Santa Cruz, California, August 13-17, 201

Metamaterial-inspired electrically small antennas integrated into structural materials

© 2015 The Institute of Electronics, Information and Comm. An electrically small Egyptian axe dipole antenna has been designed and integrated into a glass fiber reinforced polymer (GFRP), a structural material now commonly found in most mobile platforms. The integration is accomplished by sewing the antenna with conductive threads into the GFRP prepreg and accounting for dimensional variations after curing under high temperature and pressure in an autoclave. The simulated and measured reflection coefficient values and radiated field patterns are in good agreement. These comparisons demonstrate that the antenna is nearly completely matched to the source without any matching circuit and radiates as an electric dipole

Investigation of microwave active elements embedded in composite structures

© 2016 IEEE. Multifunctional structures have become popular within the past decade as they allow for more efficient utilization of limited real-estate available on many civilian and military platforms. Taking structures and electromagnetics, one can marry these two fields to produce a weight optimized loadbearing microwave structure which may ideally be suited for unmanned aerial systems. This paper investigates the use of textile processes to develop loadbearing smart skins built into a class of structural conformal composite materials called pre-pregs (resin pre-impregnated fabrics). An example of an active UWB mini-circuits ERA-4SM+ (0-4 GHz) amplifier has been investigated within a 48 g.m-2 pre-preg structural glass material (HexPly914E). This amplifier has been embroidered and cured at 170°C in an autoclave at 700 kPa pressure. Its performance before and after curing has been examined

Microwave Doppler tomography of high impedance ground planes for aerospace applications

© 2016 IEEE. Recent developments in the areas of metamaterials and high impedance ground planes (HIGPs) have created new opportunities for the development of novel multi-functional aerospace materials. One niche application of such materials is the suppression of electromagnetic surface waves across the outer mold line (OML) of aerospace structures. Doppler tomographic imaging and spectral filtering techniques are used to characterize the performance of a simple numerically simulated HIGP. A tapered HIGP concept is introduced to improve the performance over a range of illumination angles. This tapered HIGP is to be embroidered in a commercial aerospace pre-preg material. Experimental results will be presented at the conference

Compact Crossed-Dipole Antennas Loaded with Near-Field Resonant Parasitic Elements

© 2016 IEEE. Two compact planar crossed-dipole antennas loaded with near-field resonant parasitic (NFRP) elements are reported. The NFRP and crossed-dipole elements are designed for the desired circularly polarized (CP) radiation. By placing the NFRP element over the driven element at angles of 0° and 45°, respectively, dual-band and broadband CP antennas are realized. All radiating elements of antennas are 35 mm × 35 mm × 0.508 mm (0.187 λ0 × 0.187 λ0 × 0.0027 λ0 at 1.6 GHz) in size. The dual-band CP antenna has a measured S11 <-10-dB bandwidth of 226 MHz (1.473-1.699 GHz) and measured 3-dB axial ratio (AR) bandwidths of 12 MHz (1.530-1.542 GHz) and 35 MHz (1.580-1.615 GHz) with minimum AR CP frequencies of 1.535 GHz (AR = 0.26 dB) and 1.595 GHz (AR = 2.08 dB), respectively. The broadband CP antenna has a measured S11 <-10-dB bandwidth of 218 MHz (1.491-1.709 GHz) and a 3-dB AR bandwidth of 145 MHz (1.490-1.635 GHz). These compact antennas yield bidirectional electromagnetic fields with high radiation efficiency across their operational bandwidths

Numerical Study of Wave Propagation in Uniaxially Anisotropic Lorentzian Backward Wave Slabs

The propagation and refraction of a cylindrical wave created by a line current through a slab of backward wave medium, also called left-handed medium, is numerically studied with FDTD. The slab is assumed to be uniaxially anisotropic. Several sets of constitutive parameters are considered and comparisons with theoretical results are made. Electric field distributions are studied inside and behind the slab. It is found that the shape of the wavefronts and the regions of real and complex wave vectors are in agreement with theoretical results.Comment: 6 pages, figure

Multi-functional composite metamaterial-inspired EEAD antenna for structural applications

© 2016 IEEE. An electrically small, load-bearing Egyptian axe dipole (EAD) antenna has been sewn into a low loss, pure quartz glass composite material to investigate its performance. Previous investigations of embroidered Egyptian axe dipole antennas indicated that the dielectric losses of the associated epoxy-based composite, in conjunction with the high effective surface resistance of the conductive textile threads, significantly degrade their performance. Simulations of the EAD antenna using a composite sandwich structure based on an advanced embroidery technique and the much lower loss quartz fabric have shown that a realized gain of 0.9 dBi is possible, a dramatic improvement over previous realizations

Tomographic Characterization of a Multifunctional Composite High-Impedance Surface

© 1963-2012 IEEE. The performance of a multifunctional composite high-impedance surface (HIS) has been evaluated using the coherent Doppler tomography (CDT) and finite-impulse response (FIR) filtering techniques. A combination of embroidery and advanced laser manufacturing processes were used to fabricate the conformable multifunctional glass fiber reenforced polymer HIS. The CDT method was utilized because it enabled the generation of a high-resolution tomographic map of the HIS reflectivity. Tomograms generated at high incidence angles (>80° from normal) were used to localize and FIR filter unwanted scattering associated with the ground plane edges and HIS transition regions. The resulting scattered fields from a defect (metallic block positioned in the center of the tomogram) were then used to gain a significantly distinctive insight into the HIS scattering properties. Furthermore, unlike traditional methods for characterizing HISs, the CDT and FIR methods presented herein are applicable to electrically large and conformal HISs

Towards Carbon Based Artificial Impedance Surfaces for Conformal Aerospace Applications

© 2018 European Microwave Association. Conformal load-bearing smart skins (CLSS) provide the unique ability to integrate complex electrical systems into aerospace composite materials. This paper provides a preliminary investigation into the patterning of Artificial Impedance Surfaces (AIS) on these materials as they are well suited to develop conformal meta-surfaces (MTS). In particular, a composite veil material has been patterned using laser ablation and has been transferred directly onto a resin pre-impregnated (pre-preg) structural glass material. The new patterning technique was found suitable for the creation of fine geometric features with a resolution of approximately mathbf{100} mumathbf{m}. The material has been characterized by a reflected magnitude and phase measurement

Radiation-hard ASICs for optical data transmission in the ATLAS pixel detector

We have developed two radiation-hard ASICs for optical data transmission in the ATLAS pixel detector at the LHC at CERN: a driver chip for a Vertical Cavity Surface Emitting Laser (VCSEL) diode for 80 Mbit/s data transmission from the detector, and a Bi-Phase Mark decoder chip to recover the control data and 40 MHz clock received optically by a PIN diode. We have successfully implemented both ASICs in 0.25 um CMOS technology using enclosed layout transistors and guard rings for increased radiation hardness. We present results from prototype circuits and from irradiation studies with 24 GeV protons up to 57 Mrad (1.9 x 10e15 p/cm2).Comment: 8th Tropical Seminar on Innovative Particle and Radiation Detectors, Siena, Italy (2002