Mounting Pad Research Articles

A low-cost 24 GHz single-stage amplifier using SICL based stepped impedance matching network

This paper presents a single-stage amplifier using substrate-integrated coaxial line (SICL) technology. It is implemented with a low-cost PCB technique at 23.35–24.05 GHz. The size of the proposed amplifier is 4.9λg×1.1λg where λg is the guided wavelength at the center frequency. In this circuit, a SICL-based bias-tee network is designed where the mounting pads are introduced for the integration of the components, such as transistor and capacitor. Next, with the help of de-embedding techniques, the input and output matching networks are designed in the SICL environment at 24 GHz. The proposed amplifier circuit exhibits 9.2 dB of peak gain with less than 1 dB of gain ripple and more than 10 dB of input/output return losses in the operating frequency band of 23.35–24.05 GHz. Moreover, the elementary blocks of the amplifier are presented in the circuit. Based on the appropriate modeling of the amplifier’s elementary blocks, the simulated and measured results are in good agreement.

A low‐cost broadband millimeter‐wave bias tee network using SICL technology

AbstractThis article presents a substrate integrated coaxial line (SICL)‐based low‐cost bias tee network operating in K‐ and Ka‐band (20–29 GHz). A butterfly stub is introduced in the direct current (DC) circuit path for the radiofrequency (RF) isolation. A single‐layer ceramic capacitor is used along the RF mainline to provide the DC isolation. The size of the proposed circuit is , where is the guided wavelength at the center frequency of 24.5 GHz. The proposed design exhibits 0.5–1 dB insertion loss in 20–25 GHz and 1–2 dB insertion loss in 25–29 GHz, along with more than 30 dB isolation between RF and DC circuits with good impedance matching. The isolation is improved by adding a series of butterfly stubs. Moreover, a design method for realizing a mounting pad to connect the surface‐mount device (SMD) capacitor with the SICL line is proposed. The proposed method helps integrate SMD component in the SICL environment. The parasitic effects of the pad are analyzed with the help of an equivalent circuit. This circuit is most suitable for 5G FR2 (millimeter‐wave) band application.

밀폐형 한돈 사육환경 내 전자 기판의 부식 양상과 개선을 위한 컨포멀 코팅 적용 효과 연구

Purpose: This study aimed to analyze the corrosion pattern on the circuit board of an environmental measurement instrument in a closed Korean pig breeding environment and to verify the effectiveness of conformal coating applied to the circuit board as a corrosion mitigation method. The closed Korean pig breeding environment was associated with factors such as humidity, dust, and corrosive gases in a complex manner, which can lead to corrosion and malfunction of the electronic measuring device. Thus, it was necessary to ensure the reliability of the device.<BR>Methods: A printed circuit board (PCB), which is a core element of electronic devices, was selected as the experimental material. Experimental specimens were divided into those coated with a conformal coating and those without conformal coating. The specimens were placed in a breeding environment to examine the corrosion patterns and effect of the coating. The corroded specimens were analyzed using cross-sections and scanning electron microscopy and energy-dispersive X-ray spectroscopy methods.<BR>Results: In specimens without conformal coating, corrosion of the PCB occurred in the solder, component mounting pads, and through-vias (except for the photo solder resist), and sulfur was detected in the oxides and corroded parts. No corrosion was detected in the specimens coated with conformal coating.<BR>Conclusion: In an environment such as that found in the closed Korean pig breeding area, it is necessary to protect sensitive electronics from external environmental factors, such as hydrogen sulfide, that can cause PCB corrosion of solder, component mounting pads, and through-vias. The application of conformal coating to the PCBs of electronic devices is expected to be an effective solution to prevent corrosion.

Mechanical Engineering of Leg Joints of Anthropomorphic Robot

The problem of design engineering of anthropomorphic robot legs is considered. An overview of the existing anthropomorphic robots and an analysis of servomechanisms and bearing parts involved in the assembly of robot legs are presented. We propose an option for constructing the legs of the robot Antares under development. A two-motor layout, used in the knee, ensures higher joint power along with independent interaction with the neighboring upper and lower leg joints when bending. To reduce the electrical load on the main battery of the robot, the upper legs are provided with a mounting pad for additional batteries powering servos. Direct control of the servos is also carried out through the sub-controllers, responsible for all 6 engines installed in the articular joints of the robot legs.

Wasteless Splitting of Metal Round Bars Basing on Cross-Wedge Rolling Process

This paper presents research works on a new method of wasteless splitting of metal round bars. This method is connected with rolling on the bar circumference of a groove in the shape of letter V, and, later, on repeated rotary bending of the bar separate part, leading to the metal cracking. Special tools sets, in which a flat-wedged rolling mill LUW-2 used at the Lublin University of Technology was equipped with, were applied in the splitting process. A typical set includes: mounting, cutting knife and bending pad. Laboratory tests confirmed the effectiveness of the worked out splitting method. This process was also analyzed theoretically, basing on finite element method (FEM). In calculations, the influence of process basic parameters on the cracking process was analyzed: knife forming angle, rolled groove depth, bending angle and length of the cut bar part. The possibility of brittle fracture (on the basis of Saint-Venant hypothesis) and ductile fracture (on the basis of Cockroft-Latham) presence was analyzed.

Fabrication and Characterization of Flexible, Microfabricated Neural Electrode Arrays Made from Liquid Crystal Polymer and Polynorbornene

ABSTRACTThis paper reports the development of flexible, neural electrode arrays made from liquid crystal polymer (LCP) and a polynorbornene (PNB) known by its trade name AvatrelTM. Each array consists of a single flexible, polymeric structure composed of an 8 mm-wide pad supporting eight Pt contacts connected to an ASIC mounting pad by a 5 cm-long, 2 mm-wide shaft carrying eight, 50 μm-wide Pt interconnect lines. The Pt conductors sit atop a 50 μm-thick base layer and are isolated from the environment except at the contacts by a capping layer of the same material as the base. In both cases, the devices were fabricated using conventional microfabrication techniques adapted for the particular polymeric material. In the case of LCP, the base structure was fabricated on 50 μm-thick sheets that were laminated and etched into the final structure. In contrast to LCP, PNB is spin castable and photodefinable, which enabled conventional photolithographic patterning techniques to be employed in a straightforward manner. The PNB-based devices could readily be fabricated, however issues related to LCP etching necessitated the development of a multi-step etch process to form the vias that expose the contacts. Electrodes made from both polymers could support electrical loads typical of stimulation applications without failing. A simple cell culture test suggests that Avatrel™ may be biocompatible, at least for short term applications.

Investigation of accelerometer mass loading using a laser Doppler vibrometer

Laser Doppler vibrometer (LDV) measurements were used to quantify the effects of accelerometer loading and attachment methods on the response of a shaker driven submerged damped and stiffened plate. The complex plate transfer admittance over a frequency range from 5 to 40 kHz was first measured using the LDV without the accelerometers or the accelerometer mounting pads attached to the plate. The accelerometers and the mounting pads were then attached and the LDV measurements were repeated to determine their mass loading effects. With the accelerometers attached the complex plate transfer admittance was measured using both the accelerometer and the LDV outputs. These results were compared with the intention of developing a complex correction term to be applied to the accelerometer data to correct for data errors associated with accelerometer resonances and loading effects. This however was not carried out due to observed irregularities on the LDV measurement data possibly due to acousto-optic phase modulation of the laser signal.

The use of thick print copper and silver conductors for power applications

Thick printing Cu and Ag conductors have been developed specifically for use in power applications where excellent printing, thermal, electrical, wire bonding and soldering properties are prerequisite. Efficient thermal management can require fired films on alumina in excess of 150μm and often printed in large areas. In some designs the thickness of mounting pads alone for bare silicon dies may need to be built up locally. This approach enables a single substrate to comprise both thinner printed, dense circuitry for signal control and thick device mounting pads for efficient thermal management. The flexibility of thickness control, through hole connections and the ability to incorporate printed resistors using standard thick film processing can offer solutions which complement the other substrate technologies in many applications. This paper describes the advancements made in optimizing the performance of thick printing copper and silver conductors designed for use in power applications and their role in this demanding technology. The features of the materials, process guidelines, and performance characteristics will be discussed.

4967262 Gull-wing zig-zag inline lead package having end-of-package anchoring pins

A semiconductor package having a gull-wing, zig-zag, inline-lead configuration and end-of-package anchoring devices for rigidly af fixing the package to a circuit board such that each lead is in compressive contact with its associated mounting pad on the board. The anchoring devices of a first embodiment comprise anchoring pins (12) having fish-hook-type barbs (20) which lock against the under side of the board (13) when the pins are inserted through holes (15) in the board; a second embodiment utilizes anchoring pins (54) which are adhesively bonded in recesses (52) that have been drilled or molded into the board (52); a third embodiment utilizes anchoring pins (62), the ends of which can be bonded directly to planar peg-bonding regions on the surface of the board (63); and a fourth utilizes tapered anchoring pin (74) which may be inserted with an interference fit into holes (75) in the board. The invention eliminates the need for mechanical support of the packages during solder reflow operations used during board assembly and repair.

Analysis of Parameters Influencing Stresses in the Solder Joints of Leadless Chip Capacitors

The purpose of this study was to evaluate parameters such as solder joint standoff and fillet heights, termination cap length, chip eccentricity, chip rotation, etc. that influence stresses in the solder joints as well as the leadless chip capacitors. This analysis covers COG and X7R ceramic chip capacitors on multi-layer FR-4, and G-30 PWB or Alumina substrates. From the values of the stresses computed, it appears that (i) the stand-off height should be at least 100μm (.004 in.) (ii) the solder fillet height should be around half the chip thickness, (iii) the chip eccentricity on the mounting pad should be restricted to 8 percent of the chip length and (iv) chip rotation should be within 3.5 deg, while maintaining minimum solder stand-off height of 100μm (0.004 in.). The recommendations given here should be used only as preliminary design guidelines and not as a substitute for design and analysis or the requirements of manufacturing standards.

Vias‐in‐pads for Surface Mounted Components

The demand for higher density circuit packs, limited mounting space, faster switching times and cost‐effective designs has encouraged designers to take another look at placing vias directly in the mounting pads of reflow soldered surface mounted components. The standard reasons for not putting vias in pads (V‐I‐P) such as solder wicking and joint integrity were addressed and found to be surmountable. A study was performed to investigate the effects that a via in the mounting pad(s) has on the solder joint of both discrete components and gull and J‐leaded ICs. The size of the via was varied as well as the location along the centre axis of the pad. It was found that the via diameter is a critical parameter while the via location has no noticeable effect on the solder joint. Different assembly methods were also investigated. Several of the assembled test boards are being subjected to thermal cycling to determine the joint reliability. The results of this study are reported in this document.

4489365 Universal leadless chip carrier mounting pad

4489365 Universal leadless chip carrier mounting pad