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ABSTRACT A novel superstrate‐based Vivaldi antenna design characterized by high‐gain and wideband performance is presented. The proposed design configuration features a Vivaldi antenna positioned between high dielectric superstrate (Rogers 6010, εr = 10.2) with copper etched off on both sides and an FR4 substrate that has copper etched on one side only. The introduction of a high permittivity dielectric material above and a reflector below the Vivaldi antenna enables favorable resonance conditions for achieving high‐gain operation. The measured antenna exhibits a peak gain of 17 dBi at 10 GHz, covering an operating frequency range of 6–20 GHz. It also features a narrow half‐power beamwidth and low side lobe level radiation patterns. Unlike existing studies, which rely on metamaterials, electromagnetic bandgap structures, and frequency selective surfaces for gain enhancement, our design employs high‐dielectric constant superstrates. This approach increased the antenna's peak gain by 10 dB. Also, the proposed configuration act as a radome protecting the antenna from Environment. [ABSTRACT FROM AUTHOR]

In the field of electronics, technological advancements bring about alterations in electronic devices. With the fast-paced advancements in the era of communication, the frequency bands are becoming congested. One of the frequencies utilized by Wi-Fi-6, 6 GHz, has garnered its share of attention in these changes. This study proposes the design of a Butterworth Bandpass Filter that can be utilized in the IEEE C Band, employing both lumped elements and microstrip transmission lines. The methodology for determining the length and width of the transmission lines, as well as the considerations taken into account during their modification, is provided. A composite filter comprising of both elements and lines is also presented. The combined filter design is aimed at resolving issues arising from the increasing frequency. During the design process, an 8th-order lowpass filter is generated using the Butterworth normalized table, and a bandpass filter with a 200 MHz bandwidth and a 6 GHz center frequency is obtained through the use of a resonant circuit. The dimensions of the transmission lines are determined using theoretical formulas and verified through Matlab files and the MWO-AWR optimization tool. The voltage gain graphs generated demonstrate that the designs created on an FR4 substrate are suitable for use in the IEEE C Band for Wi-Fi-6. [ABSTRACT FROM AUTHOR]

The manuscript represents a metamaterial-inspired superstrate patch antenna with a multiband response. The design consists of three superstrate layers over the patch antennaand SRRloaded over parasitic patches. The performance observation is carried out for 2–10 GHz. The simulation and fabrication are taken into consideration, and comparisonsbetween both of them are included. FR4 is used as a substrate material which helps reduce the structure's cost. The metamaterial approach is incorporated over superstrate regions for the improvement of results. The superstrate approach helps for enhancing the strength and Bandwidth of the design. Impedance response is analyzed for different resonating frequencies to check the metamaterial response. Two types of Parametric Analysis are considered to achieve the targeted goal, like changing feed position and the gap among superstrate layers. The presented work shows eight bands of reflectance response with a minimum value of − 44.83 dB with a Bandwidth of 3.139 GHz, peak directivity of 3.16 dB, a gain of 8.02 dB at 9.04 GHz, maximum E-field distribution of 1.160 × 105 v/m at 6.52 GHz. Presented work compared with other design structures to identify the improvement. Many wireless communication-related applications like military, WiMAX, and Maritime mobile services. [ABSTRACT FROM AUTHOR]

This article proposes an empirical methodology for accurately estimating the relative permittivity ${\varepsilon _r}$εr of FR4 boards, which is essential for designing microstrip antennas at S and C frequency bands. As the relative permittivity of dielectric materials changes with frequency, the proposed method involves selecting a known starting value of ${\varepsilon _r}$εr for an FR4 board and then simulating the reflection coefficient S11 parameters of an antenna design. These simulated parameters are then compared to the measured S11 parameters of a fabricated antenna. A value of ${\varepsilon _r}$εr = 4.55 is accurately determined when the two S11 parameters converge close to the desired design frequency. With the FR4 ${\varepsilon _r}$εr value obtained from this methodology, a slot patch antenna is designed for a frequency of 4 GHz, obtaining a reflection coefficient of |Γ| = 0.035, a bandwidth BW = 117 MHz, and a standing wave ratio (SWR) of 1.0746. The proposed methodology can be used as a tool to estimate the ${\varepsilon _r}$εr of various substrates that are not characterized at high frequencies. [ABSTRACT FROM AUTHOR]

The paper depicts a microstrip hairpin bandpass filter design, simulation, fabrication and test. The proposed microstrip filter's design is comprised of five hairpin structures separated by a tenth of a mm distance for which various parametric studies have been conducted. The simplicity of design provides inexpensive and undemanding filter. The filter is fabricated with suitable parametric results. The design is based on Chebyshev's values for the prototype, with N (the order of filter) number being equivalent to five. The final fabricated version of the project is based upon FR4 dielectric substrate with the input return loss being below -10 dB and insertion loss above – 2 dB. Approximate values of the input reflection coefficient and insertion loss are -33.34 dB and - 1.72 dB respectively. Furthermore, the frequency range for the proposed geometry is between approximately 2.6 GHz and 3.6 GHz. The proposed filter is fabricated and the results measured in real life are highly correlated to the results simulated in the software. The proposed microstrip hairpin bandpass filter can be utilized in wireless internet access and communication. [ABSTRACT FROM AUTHOR]

In this study, a compact U-slot patch antenna design based on dielectric measurement approach of Flame Retardant 4 (FR4) material is presented for X band space applications. In accordance with the design method, the measured frequency dependent dielectric constant and tangent loss values of the FR4 material at X-band using the waveguide method is applied to the HFSS design tool to be used in antenna designs. Then, the functional performance of the design method on antennas is verified by comparing the simulation and measurement results of a conventional antenna design in the literature. In the light of the verified results, a new U-slot patch antenna design with lateral side slots for X-band space applications is presented with a feed line by using the proposed design method. The presented compact antenna design provides 1.77 dB gain at the center frequency (9.5 GHz) and the frequency bandwidth from 8.53 GHz to 10.63 GHz. [ABSTRACT FROM AUTHOR]

A comparative analysis of a compact planar Square patch Microstrip Multiband antenna on three different substrates is proposed. The proposed design has a C-shaped slot etched on the square radiating part and the antenna is energized using microstrip feed line. RT Duroid (𝜺r = 2. 2), Taconic (𝜺r = 3. 2) and FR4 (𝜺r = 4. 4) substrates are used for simulation analysis. The flow of current is modified by the C-shaped slot making the antenna to resonate at 3/4 and 6 bands for RT Duroid/Taconic and FR4 substrates respectively suitable for 5G sub GHz applications. The antenna has a compact dimension of 32 × 32 × 1. 6mm3 and exhibits a return loss, S11 of less than -10dB for all the resonating frequencies for all three substrates. The analysis has been done by considering the S11 (Return loss <-10 dB), Directivity, Antenna Gain, VSWR and surface current distribution. Table II provides the comparison of parameters for different substrate material. [ABSTRACT FROM AUTHOR]

Summary The paper reports an experimental investigation of an 8 × 8 MIMO antenna fabricated on a commercially available FR4 substrate. A fractal printed monopole radiator is introduced as a good prospect for super‐wideband (2.85–20.0 GHz) multiple‐input‐multiple‐output (SWB‐MIMO) configuration. The MIMO antenna is printed on both the planes (Plane A and Plane B) where four antennas are printed on Plane A and remaining on Plane B which are fed asymmetric to achieve wider impedance bandwidth. An inverted‐L type strip is embedded in a rectangular elliptical slotted ground to match the impedance. Also, a circular ring is embedded on both planes with a novel stub connected to each antenna ground providing isolation of more than 30 dB. The diversity performance of the antenna is also investigated with measured envelope correlation coefficient (ECC) < 0.025, directive gain (DG) > 9.995 dB, total active reflection coefficient (TARC) < −40 dB, and channel capacity loss (CCL) < 0.30b/s/Hz in the entire operating band. [ABSTRACT FROM AUTHOR]

A novel double-layer multiband, low-profile frequency selective surface (FSS) for IMT-Advanced (4G) mobile communication system is presented in this article. On aspired to a minimum transmission coefficient of -10 dB for surface materials when the frequency bands targeted for blocking are stopped. For this project, we chose the dielectric substrate FR4 (loss-tangent = 0.02; dielectric constant = 4.54) and a thickness of 1 mm. Dodecagonal rings, upright bars, and square frame make up the FSS unit cell. The desired frequency responses of the FSS were intended to avoid being changed according to the angle of incidence of the electromagnetic waves. The FSS design is proposed as a symmetrical structure to make it polarization-independent and is aimed to stop 800, 900, 1800, 2100, and 2600 MHz frequencies to prevent harmful effects to human health and interference effects at these frequencies. With a cell size of 0.17λ, the planned FSS is quite small and, thus, has a low sensitivity at the angle of the incident wave. In addition, FSS geometry was manufactured by a printed circuit board (PCB) and measured in a non-reflective environment after being studied in Ansys high-frequency structure simulator (HFSS) software. By comparing the analysis and measurement results of the design, the success of the FSS to the frequencies to be stopped has been verified. The effect of each patch on different frequencies has been examined by drawing the surface current density graphs of the design. [ABSTRACT FROM AUTHOR]

A Rotman lens antenna array with advantages of self‐packaging, low cost, and broadband is proposed by using substrate integrated suspended line technology at K band. The proposed lens‐fed antenna is designed to be low cost by using only FR4 material on all substrates. Meanwhile, patterned substrate and double metal layers with metalized via hole connecting are utilized to reduce its loss. To evaluate the proposed method, two Rotman lenses with different port numbers are designed, fabricated, and measured. For verification of switch beam property, the quasi‐Yagi antenna array is designed for broadband operation and low profile to integrate with the Rotman lens. The experimental results show that the scanning range is ±24° and ±30° of the two lenses, respectively. [ABSTRACT FROM AUTHOR]

The internal charging effect may lead to electrostatic discharges (ESDs) for Geostationary Earth Orbit (GEO) and Middle Earth Orbit (MEO) satellites. This is due to the high-energy electrons that deposit in the dielectrics of satellites. The properties of the dielectrics such as permittivity and dark conductivity dominate this effect. This may contribute to the ESD risk of long-lifetime satellites if these properties change with the increase of electron dose. Two general materials, Polyimide (PI) and FR4 Epoxy Glass Cloth (FR4), were chosen as samples to study by experiments with different doses. The results show that the permittivity of PI and FR4 decreased as the dose increased while the dark conductivity increased. Numerical simulation evaluates the electron dose and the ESD risk of dielectrics under the electron environment of a specific MEO electron spectrum. The results show that the decrease of permittivity and the increase of dark conductivity will shorten the time constant of internal charging. The quicker build-up of electric field will increase the ESD risk if it exceeds the breakdown threshold. [ABSTRACT FROM AUTHOR]

In the paper, the model of micron-level crosstalk interconnections was constructed based on FR4 substrate. By changing the input variables of the length and the spacing, this prediction model could provide useful information for Crosstalk intensity. With the increase of the length of the interconnect, the crosstalk intensity of the proximal end and the distal end increased. When the interconnect spacing increased, the trend of crosstalk was not changed, but the intensity decreased gradually. Which provided an experimental reference for future methods of reducing crosstalk from the perspective of physical structure. [ABSTRACT FROM AUTHOR]

In this article, a new approach is proposed for the measurement of the uniaxial anisotropic dielectric constant of different planar samples by means of a single sensor. The sensor is based on a couple of straight-line coupled resonators in microstrip technology that can be excited in odd and even propagation modes. This sensor is designed on an isotropic substrate at the design frequency. Due to the electric field configuration specific for each mode, it is possible to relate these modes to the dielectric constant in two different directions (parallel and perpendicular) of a dielectric material placed on top of the sensor. This technique is used for the successful characterization of the dielectric constant anisotropic of anisotropic dielectrics (FR4, Rogers 4350B, and Arlon Diclad 880), and the isotropic material PTFE. [ABSTRACT FROM AUTHOR]

Abstract: The design of an FR4‐based UHF RFID portable quasi‐isotropic reader antenna with a circular polarization is reported. This low‐cost small size antenna consists of two crossed dipoles with dimensions of 50 × 80 × 1.6 mm3. A 3‐dB axial ratio bandwidth of 10 MHz can be obtained and a quasi‐isotropic radiation pattern is achieved. The designed antenna performances are investigated for 6 prototypes using the same substrate and different boards. A performances comparison and analysis between the different realizations are presented in this article. Results demonstrate that inaccuracies in FR4 characteristics have effects on the antenna performances. Therefore, the key parameters of this type of antennas are identified. [ABSTRACT FROM AUTHOR]

Reductions in printed circuit board line spacing and via diameters and the increased density of vias with higher aspect ratios (ratio between the thickness of the board and the size of the drilled hole before plating) are making electronic products increasingly more susceptible to material and manufacturing defects. One failure mechanism of particular concern is conductive anodic filament (CAF) formation, which typically occurs in two steps: degradation of the resin/glass fiber bond followed by an electrochemical reaction. Bond degradation provides a path along which electrodeposition occurs due to electrochemical reactions. The path can result from poor glass treatment, from the hydrolysis of the silane glass finish, or from mechanical stresses. Once a path is formed, an aqueous layer, which enables the electrochemical reactions to take place, can develop through the adsorption, absorption, and capillary action of moisture at the resin/fiber interface. This paper describes the concerns with CAF and the methods used for analyzing low-resistance failures. A case study is then given which highlights problems that arose on a commercial circuit board material used by a major telecommunications provider. [ABSTRACT FROM AUTHOR]

This article presents the long-term (1,000 h) behavior of two printed-circuit boardmaterials (Panasonic R1755V, a high-TG glass-epoxy composite and Arlon 85N, a polyimide-based laminate) stored at high temperature (190°C). Tests are performed in air and in nitrogen atmospheres. Electrical and physical measurements are performed regularly (once per week). Almost no degradation is observed for both materials when stored in nitrogen. On the contrary, the board stored in air shows the consequences of ageing. This is especially true for the glass-epoxy material, which becomes unusable after 2 w, because of large swelling. [ABSTRACT FROM AUTHOR]

In this work, two previously reported low-cost design techniques for high-gain microstrip antennas are compared based on detailed parameter study. Both of these methods exploit a combination of a spacer and a layer of FR4 epoxy. The distinguishing feature of the said methods is the position of the metallization. A parameter study is performed on the thickness of the FR4 layer and its effect on the antenna gain, efficiency and pattern symmetry is reported. Capability of these methods is designing high-gain arrays is studied and specific design examples are provided. It is shown that the first method has superior performance in the sense of gain and efficiency. Especially, the first method supersedes the second one for high-gain arrays. As well, it is shown that the first method is a pure microstrip alternative to another previously reported technique wherein a CNC milled waveguide structure is exploited as the feed network. [ABSTRACT FROM AUTHOR]

This work presents a novel multi voltage level non-overlapping clock phase generation architecture with a differential clock driver. It has a compact fully integrated power management, including LDOs and bandgap reference circuit. It is capable of controlling the PVT variation via SPI programming. It is functional from 50 MHz up to 1 GHz, to be used for pipelined ADCs. The core chip achieves SNR jitter around 72 dB from 50 MHz to 150 MHz, and above 68 dB from 150 MHz to 400 MHz, above 60 dB up to 1 GHz clock signals. The core section consumes 19 mA at 1 GHz from an external supply of 3 V. The chip occupies 1235 μm × 1300 μm, in a SiGe BiCMOS 0.13 μm process. The clock generation system occupies 400 μm × 360 μm silicon area, excluding I/O pads and interface circuits. It is packed in a 5 mm × 5 mm QFN32 package and assembled onto an FR4 board. [ABSTRACT FROM AUTHOR]

In this Letter ultra‐low frequency probes for measuring time‐varying magnetic field produced in gradient coils were designed, fabricated, and tested. A 1 cm radius induction loop antenna followed by an instrumentational amplifier with a gain of 40 dB and a cutoff frequency of 30 KHz was designed to measure the magnetic field. The probe was fabricated on a single‐sided PCB, FR4 of thickness 1.57 mm and copper of thickness 35 μm was employed in a dB/dt exposure system within a saline phantom using 3D printed waterproofed cover. Simulation and measurement results of the magnetic field were in good agreements. [ABSTRACT FROM AUTHOR]

The mechanical properties of the glass-epoxy composite material known as “G-10,” which is primarily used for electrical insulation purposes in electromechanical systems, have long been a topic of uncertainty and controversy. In the present paper, we demonstrate the application of an experimental methodology that exploits the Direct Strain Imaging (DSI) full field method to fully assess the elastic anisotropic mechanical properties of G-10. Tension and compression experiments were conducted for three distinct inclinations of the specimen orthotropic axes relative to the loading directions, while strain and displacement were monitored at relevant locations on the specimens via digital image capturing and subsequent application of DSI. Based on these experiments, we present the stress-strain experimental data, the associated data post processing, the engineering properties, the anisotropic compliance matrix and the ultimate strength properties of the G-10 composite material. Confidence bounds on the material properties based on the results from repeated tests on identical specimens are also reported. [ABSTRACT FROM AUTHOR]

Low-cost antennas are suggested for 5.8 GHz narrow-band, low-power and dual-polarized wireless bridges based on pure microstrip flat reflectarrays. A single layer of the cheapFR4 epoxy is exploited as the substrate for both of the feed and reflector. Detailed design procedure for the feed is reported. Three different elements are used for designing the reflector including rectangular dipole, unbalanced cross and square patch. Using method of moments, performance of the designs is compared from various aspects, including reflector diameter, computational cost, gain, half-power beamwidth and polarization purity. [ABSTRACT FROM AUTHOR]

In the present study, the capabilities of different chip materials for acoustic particle manipulation have been assessed with the same microfluidic device architecture, under the same actuator and flow conditions. Silicon, glass, epoxy with fiberglass filling (FR4), polydimethylsiloxane (PDMS) and polymethyl methacrylate (PMMA) are considered as chip materials. The acoustophoretic chips in this study were manufactured with four different fabrication methods: plasma etching, chemical etching, micromachining and molding. A novel chip material, FR4, has been employed as a microfluidic chip material in acoustophoretic particle manipulation for the first time in literature, which combines the ease of manufacturing of polymer materials with improved acoustic performance. The acoustic particle manipulation performance is evaluated through acoustophoretic focusing experiments with 2 μ m and 12 μ m polystyrene microspheres and cultured breast cancer cell line (MDA-MB-231). Unlike the common approach in the literature, the piezoelectric materials were actuated with partitioned cross-polarized electrodes which allowed effective actuation of different family of chip materials. Different from previous studies, this study evaluates the performance of each acoustophoretic device through the perspective of synchronization of electrical, vibrational and acoustical resonances, considers the thermal performance of the chip materials with their effects on cell viability as well as manufacturability and scalability of their fabrication methods. We believe our study is an essential work towards the commercialization of acoustophoretic devices since it brings a critical understanding of the effect of chip material on device performance as well as the cost of achieving that performance. • Selection of chip material is critical in micro-acoustofluidics. • Manipulation performance of several different chip materials are investigated. • FR4 chip material combines the advantages of polymer acoustically hard chip materials. • For the first time in the literature, the effect of choice of chip material isF investigated through electrical, vibration, thermal and cell viability perspectives as well as ease of manufacturing and scalability. [ABSTRACT FROM AUTHOR]

A hybrid fractal multiband antenna is designed by integrating Koch curve and meander antenna. Scripting method (*.vbs) is adopted to obtain the hybrid fractal structure using IFS and MATLAB. Final structure is obtained by perturbing the reference fractal shape. Proposed antenna exhibits multiband characteristics capable of operating in four different wireless frequency bands including very popular Bluetooth (2.4 GHz), WiMAX (3.4-3.7 GHz), WLAN 802.11 a/b/g (5.3-6.1 GHz) and Aeronautical radionavigation (8.68-9.05GHz). The antenna has a planar structure, compact size of 39 mm × 32 mm × 1.58 mm and is suitable for wireless applications. Prototype of the proposed structure is developed on easily available and low cost FR4 substrate. The antenna has acceptable values of return loss, VSWR and gain. Measured characteristics are in good agreement with the simulated one. [ABSTRACT FROM AUTHOR]

Anisotropic conductive adhesive films (ACF) have been widely studied for numerous applications. However, their resistance to corrosion in highly corrosive environments has been studied only very little. This study investigated the reliability and behaviour of ACFs in corrosive salt spray environment. ACF was used to attach flip chip (FC) components on FR4, liquid crystal polymer (LCP) and polyimide (PI) substrates and the FC packages were subjected to a salt spray test lasting 3000 h. The FC packages had daisy chain structures which were measured continuously in real time during testing. After testing cross sections of the tested packages were examined using an optical microscope and a scanning electron microscope (SEM). Most components failed during the test and the results showed significant differences between the various substrate materials. The LCP substrate performed considerably better than the other substrates and the PI substrate proved to have the poorest reliability. Corrosion of the pads on the substrates as well as open joints was seen in all substrate materials. The corrosion behaviour as well as the differences between the substrates showed that the substrate structure and material are critical factors in corrosive environments and should be carefully considered. The reliability of the ACF FC package with the LCP substrate was found to be good, as the test was very severe and no failures occurred during the first 625 h of testing and only 20% failed during the first 1000 h. [ABSTRACT FROM AUTHOR]

We report the bidirectional electrical tuning of electromagnetic energy harvesters using two different complex load topologies: capacitive load to tune in the lower frequency range and inductive load to tune in the higher frequency range respectively. A theoretical model has been developed to address the bidirectional tuning capabilities using complex loads and the model has been successfully validated against the experimental results. Four electromagnetic harvesters with different spring configurations and thus operating at different frequencies have been developed on FR4 using laser micromachining technique and a comparison of their untuned output performances has been reported. Varying the load capacitance, the resonant frequency has been tuned up to almost 1.8 Hz for both prototype 1 and 2 and up to almost 0.16 Hz for prototype 3 and 4 in the lower frequency directions. Similarly, varying the load inductance, the resonant frequency has been tuned up to 0.6 Hz for prototype 1 and 2 and up to 0.13 Hz for prototype 3 and 4 in the higher frequency directions. This tuning comes with the reduction in the output power; however the comparative experimental study shows that the tuning range can be further widened by using devices with larger electromagnetic coupling values. [ABSTRACT FROM AUTHOR]

Pulse-shaping techniques have been used for many years now in Kolsky bar testing of brittle materials. The use of pulse shapers allow the experimentalist to conduct high strain rate tests on brittle materials while ensuring that the sample will achieve a state of dynamic stress equilibrium before it fails, as well as to achieve a constant strain rate loading state for a large portion of the test. The process of choosing the appropriate pulse-shaper system has typically been one of trail-and-error, sometimes requiring many experimental trails to achieve optimal results. Advances in analytic modeling of Kolsky bar tests now make it possible, in an a priori fashion, to design a pulse-shaper system to produce a known constant strain rate experiment. This article describes the approach of coupling these analytic models to an optimization technique to quickly find a pulse-shaper system that will produce an experiment at a known constant strain rate. Experiments were conducted and the model predictions compared to resulting strain rate histories for a G10 material. Stress–strain curves for G10 are presented at three different strain rates in both the in-plane and out-of-plane loading configurations with respect to the laminate plys. The G10 material is not found to be rate sensitive in either its strength or failure properties. [ABSTRACT FROM PUBLISHER]

The current work investigates the use of liquid polydimethylsiloxane (PDMS), with a 10:1 ratio of prepolymer:curing agent =10:1 as the intermediate layer for adhesive bonding with Flame Retardant 4 (FR4). The spin coating of liquid PDMS on FR4 allows irreversible adhesive bonding with the solid PDMS. The strength of the proposed adhesive bonding technique has been investigated under different treatment temperatures: oven-heated at 60 °C, 70 °C, and 80 °C, cooled down in the room temperature of 25 °C, and exposed to direct sunlight at 35 °C. All the samples were left for 6h. Investigations were conducted to ana-lyze the effect of FR4 surface roughness on the strength and quality of the adhesive bond-ing. The standard procedure of American Standard Test Measurement (ASTM) D1002 was followed to verify the strength of PDMS-FR4 adhesive bonding. Strongest adhesive bond-ing, free from air bubbles, was obtained from a sample with smooth surface of FR4 that has undergone a cooling down treatment in the room temperature of 25 °C. FR4 was coated by solder mask to obtain smooth surface. The techniques reported in this paper are simple, straightforward, and effective to be implemented with FR4 as a base material for adhesive bonding with PDMS, thus eliminating expensive and complicated operating equipment as widely used in the oxygen plasma-assisted bonding treatment. Another benefit from this adhesive bonding technique is the fact that it avoids the use of expensive oven or hot plate. [ABSTRACT FROM AUTHOR]

This paper demonstrates the possibility and feasibility of an ultralow-cost antenna-in-package (AiP) solution for the upcoming generation of wireless local area networks (WLANs) denoted as IEEE802.11ad. The iterative design procedure focuses on maximally alleviating the inherent disadvantages of high-volume FR4 process at 60 GHz such as its relatively high material loss and fabrication restrictions. Within the planar antenna package, the antenna element, vertical transition, antenna feedline, and low- and high-speed interfaces are allocated in a vertical schematic. A circular stacked patch antenna renders the antenna package to exhibit 10-dB return loss bandwidth from 57–66 GHz. An embedded coplanar waveguide (CPW) topology is adopted for the antenna feedline and features less than 0.24 dB/mm in unit loss, which is extracted from measured parametric studies. The fabricated single antenna package is 9 mm\,\times\,6 mm\,\times\,0.404 mm in dimension. A multiple-element antenna package is fabricated, and its feasibility for future phase array applications is studied. Far-field radiation measurement using an inhouse radio-frequency (RF) probe station validates the single-antenna package to exhibit more than 4.1–dBi gain and 76% radiation efficiency. [ABSTRACT FROM PUBLISHER]

This work demonstrates the performance of conductor-backed coplanar waveguide (CBCPW) lines on FR408 for millimeter wave applications. These lines can be used as interconnects to integrate a CMOS IC with an antenna fabricated on FR408 for a low-cost system-in-package solution. To our knowledge, this is the first time coplanar lines on FR4 have been studied for millimeter-wave applications. Ansoft HFSS simulation results for 50 Ω coplanar lines show a return loss of 20 dB and an insertion loss of 0.5 dB/mm at 100 GHz. Measured results up to 67 GHz show that on average, the CBCPW lines have an attenuation constant of 0.22 dB/mm. [ABSTRACT FROM AUTHOR]

Purpose – The purpose of this paper is to highlight a novel manufacturing process for a biochip with a multi-electrode array (MEA) that is specifically designed for use in characterising cardio-active substances and to demonstrate a novel proposed solution prototype that has been constructed to meet the needs of end-users. Design/methodology/approach – Practical problems encountered with conventional MEA biochips are described and a novel biochip design to tackle these problems is presented. The manufacturing approach used to produce the prototypes of that design is described and depicted. Findings – The novel prototype MEA biochips were successfully manufactured using conventional electronics manufacturing approaches. Prototypes demonstrated limited successes in the early stages of testing. Further revisions of the feature geometry are required to implement an alternative MEA biochip that is suitably reliable. Research limitations/implications – Basic photolithography techniques have been used to construct a base substrate for proof-of-principle studies. Increased sophistication in manufacturing stages is required in future iterations of the proposed concept. Originality/value – This paper introduces a problem encountered by MEA system adopters that requires a suitable solution. The scale up of an electronics manufacturing process-based solution to the problems described holds much promise for the screening of new chemical entities. [ABSTRACT FROM AUTHOR]

A new technique to measure uniaxial anisotropy in planar substrates is described. The technique uses a single dual-mode resonator. Each mode of the resonator has a different distribution of horizontal (parallel to the substrate surface) and vertical (perpendicular to the substrate surface) directed fields. Using an electromagnetic analysis of the dual-mode resonator, the resonant frequencies of the modes are space mapped to the horizontal and vertical dielectric constants. The space mapping allows the anisotropic dielectric constants to be extracted from the measured resonant frequencies. It is also suggested that this technique can be applied to magnetic uniaxial anisotropy as well as to magnetic and electric loss tangent anisotropy. The dual and quad "RA" resonators are introduced in this paper. A measurement of FR4 (a common anisotropic epoxy-glass weave composite substrate) with a detailed error analysis illustrates the technique. [ABSTRACT FROM AUTHOR]

Abstract: A novel magnetic actuated polymer optical platform is integrated into lamellar grating and Michelson type Fourier transform spectrometers. The proposed advantages of the novel platform over existing approaches, such as MEMS spectrometers, or bulky FTIR systems, include millimeter range dimensions providing a large clear aperture and enabling conventional machining for device fabrication, a controllable AC and/or DC motion both in rotational and translational modes, and real-time measurement. The platform is capable of achieving ±250μm DC deflection (i.e., 20cm−1 frequency resolution) in ambient pressure in the translational mode. A spectral resolution of 0.89nm at 638nm is demonstrated using this platform in a Michelson interferometer configuration. In addition, an overview of system integration methods including an optical position feedback mechanism is also discussed. [Copyright &y& Elsevier]

This article examines the backplane connector technology for high frequency use and presents a novel concept for shielded enclosures without air vents. The experimental soldering of connections between a flexible printed circuit (flex, for short) and a FR4-board as part of a backplane connector is presented. A very high contact density is reached by soldering vias on the flex to pads on the FR4; this soldering was performed both with ordinary Sn/Pb solder material and as well with lead-free solder alloy. The solder joints were examined using a scanning electron microscope (SEM) and the electrical properties of the flex/solder joint structure were measured. [ABSTRACT FROM AUTHOR]

This work deals with the selection and evaluation of new board materials that can enable microminiaturized, multilayered multifunctional system-level packaging such as system-on-package (SOP) pursued by the Packaging Research Center, Georgia Institute of Technology. The effect of board properties such as coefficient of thermal expansion (CTE) and high elastic modulus upon the increase in flip chip reliability performance was investigated and guidelines for optimum board properties for realizing SOP were suggested based on the reliability results. Three different types of carbon fiber reinforced composites boards and two different kinds of inorganic boards were tested to evaluate the improvement in flip chip reliability compared to conventional glass fabric-epoxy boards (FR-4). Short carbon fiber, unidirectional carbon fiber, and carbon fiber-cloth reinforced polymer composites with a CTE close to 3 ppm/° C and three to nine times higher modulus than conventional FR-4 were selected as polymer-based composite boards. Metal matrix composites with moderate CTE (Al/SiC; 8 ppm/° C) and ceramics with lower CTE (AlN, 4 ppm/° C) were selected as inorganic boards with high stiffness. The thermomechanical reliability of the electrical interconnections was evaluated with flip-chips assembled on five different boards by subjecting them to thermal shock treatments. Except AlN, all test vehicles fabricated with low CTE boards did not show any improvement in reliability even with underfill though they have matched CTE with Si. This is attributed to the higher dielectric stresses caused by the increased CTE mismatch between the boards and the build-up dielectric. The stress in dielectric leads to severe cyclic warpage of boards during heat cycle, resulting in dielectric fatigue cracking. With this mechanism, even underfill cannot improve the reliability. On the contrary, AlN board with highest modulus and matched CTE with Si significantly enhanced the reliability even without underfill because of its high modulus preventing cyclic warpage during thermal cycling. A new type of failure mechanism was proposed based on the optical microscopic failure mode analysis as well as analytical modeling of stress induced in the solder joints and dielectric layer. In-situ warpage of test vehicles during thermal cycling was measured in order to confirm the proposed failure mechanism. It can be concluded that to enhance the flip chip reliability without underfill, it is necessary to have high elastic modulus along with Si-matched CTE. Ultra-high stiffness is an important requirement for developing new board materials that can realize SOP concept. [ABSTRACT FROM AUTHOR]

A frequency selective surface for spatial filtering in the standardized Ultra-Wide Band (UWB) frequency range is proposed. A very large stop-band of 1.75–15.44 GHz has been obtained, with good polarization insensitivity and an angular stability of more than 60 ∘ and more than 50 ∘ in TE and TM incidence, respectively. Circuit models have been devised. The structure has been assessed by electromagnetic simulation and implemented on an FR4 substrate of 1.6 mm thickness, with an edge of the square-shaped unit cell of 15 mm. Tests in an anechoic chamber demonstrated good matching between simulation and experimental results and proper operation of the device. [ABSTRACT FROM AUTHOR]

ABSTRACT In this article, a novel microstrip antenna with EBG ground plane is proposed for broad bandwidth applications. A 27 mm × 27 mm patch is designed and a slot of 20 mm × 20 mm is made on it. Slots improve the bandwidth at the cost of introduction of side lobes in the radiation pattern. To absorb these side lobes and to enhance the gain, EBG mushroom structures were introduced. The whole structure when simulated provides a gain of 4.1 dBi and an impedance bandwidth of 721 MHz around 4.8 GHz and 1,200 MHz around 7.6 GHz. Measured results shows good agreement with the simulated results and thus validates this design. © 2016 Wiley Periodicals, Inc. Microwave Opt Technol Lett 58:555-557, 2016 [ABSTRACT FROM AUTHOR]

Multiband applications can be realized as a result of designing a double U-slot rectangular patch antenna. The equivalent circuit of a U-slot patch is presented and the return loss is theoretically derived, utilizing the [A] matrix formulation. CST Microwave Studio software was used to design the microstrip antenna with a transmission line feed and simulate return loss and radiation patterns. The antenna was fabricated in-house using a printed board CNC machine and was measured and compared for return loss using a portable network analyzer. The radiation patterns were measured using a laboratory antenna measurement system. The fabricated antenna was installed on a networked WiFi access point, and tested as far as average received power versus distance range. The antenna is simple, low-cost and easy to fabricate and measurements compared well with simulated results. [ABSTRACT FROM AUTHOR]

This paper presents a modified procedure to determine the microwave dielectric constant of substrate by two microstrip line method combined with EM simulation. The dielectric constant of substrate is mapped from the measured transmission phase with those of EM simulation, instead of using the closed form equations between the effective dielectric constant and dielectric constant. A tested example of dielectric constant of FR4 substrate is experimented and extracted to verify the proposed procedure. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 2199–2201, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21936 [ABSTRACT FROM AUTHOR]