Rogers Corporation announces an extension of the thickness range for AquaPro® 37™ – the material of choice for long-lasting protection of sensitive electronics and enclosed devices.

Especially well-suited for critical applications in which sealing against water ingress is vital, this softer AquaPro 37 foam is constructed of closed cells with an open cell sub-segment. Working in tandem with hydrophobic raw materials the combination delivers superior water-sealing performance and reliability when compared to traditional sealing solutions, consistent with the high standards of the PORON® family of polyurethane materials.

Available in standard thicknesses ranging from 0.020” to 0.039”(0.50mm to 1.0mm), the AquaPro 37 formulation requires the lowest compression force of any PORON water-sealing material in achieving a tight seal. It performs reliably in a broad temperature range, is low outgassing, and provides dependable water sealing for thin applications – guaranteeing that design engineers never have to settle when a high-performing water seal is required.

Recent developments in eMobility (electro mobility or advanced mobility) have led to increasing options for clean and efficient vehicles that rely on electric powertrain technologies, in-vehicle information, communication technologies, and connected infrastructures.  The systems within these vehicles pose unique sealing and vibration management challenges vs cars with traditional combustion engines.

Rogers’ advanced materials are used in a wide variety of eMobility platforms, including gaskets and vibration management foams for airbag sensors, sound systems, and batteries. Let’s take a closer look at the challenges of vibration management and gasketing / sealing in EVs and hybrid vehicles.

Learn how Rogers advanced materials are used in a wide variety of eMobility platforms.

High performance gaskets are found in Exterior Lighting Seals; On-board EV Charging Seals; Roof Mounted Antenna Seals; Sensors; Back Up Camera Seals; Drive Train PCB Isolation Pads; EV & HEV Battery Isolation/Battery Separator & Compression Pads; Heat Shields; Buzz, Squeak and Rattle Isolation (BSR) Pads; Noise, Vibration & Harshness Isolation Pads; and Tolerance and Gap Pads.

Vibration management foams are found in Dampers/Isolators for Shock, Vibration, Noise & Impact; Gas Tank Isolator Pads; Airbag Sensor Arm Rest Pads; Door Handle Isolation Pads; Infotainment Display Seals; Isolation Pad Interior Trim for Cup Holders and Bin Liners; and Sunroof Control Panels.

High Performance Materials

Rogers’ Elastomeric Material Solutions group provides a wide range of high performance materials, from soft foams for automotive fuel tank isolator pads and camera window gaskets to very firm foams for enclosure gaskets. The company’s foams – PORON® polyurethane material and BISCO® silicone materials – provide solutions for door panels, air bags, instrument panels, battery systems, and more.

Vibration Management

Automotive interiors and exteriors are subjected to a variety of extreme environmental conditions. Safety is also a concern as severe damage – electrical shock or explosion – is possible if the vehicle’s battery pack is not properly sealed. Batteries need to be packaged to absorb internal impact energy. Vibration must be managed both within the pack and between the pack and the surrounding vehicle.

  • BISCO® Silicone Compression Set Resistance (C-set) withstands collapse due to the stresses of compression and temperature over time. This extends the life of the vehicle part by continuing to seal and absorb shock.
  • In EV / HEV batteries, cushions/springs hold components firmly in place and, if needed, firmly in contact with each other. PORON® polyurethane materials have a unique ability to produce a very consistent level of force across a range of compressions. This allows the system designer to predict the material’s behavior across varied dimensional tolerances.

Gasketing, Sealing, and Gap Filling

Like most vehicles, EVs and HEVs need to withstand the elements and function in all environments. Gaskets and gap fillers protect sensitive electronics – often in the presence of extreme temperatures – and seal out air, water, dust, light, and electromagnetic interference (EMI).

  • Gaskets made from BISCO® silicone materials seal the interface, such as where a battery is plugged into the electrical grid, and provide exceptional UV resistance and cold temperature flexibility.
  • PORON® polyurethane materials are low-outgassing and non-fogging. They contain no plasticizers or residual chemicals to contaminate devices. Wherever it is used, the material will not become brittle and crumble, and is non-corrosive to metal.

This post authored by John Coonrod, Technical Marketing Manager, and team originally appeared on the ROG Blog hosted by Microwave Journal.

Woven glass is incorporated into printed-circuit-board (PCB) materials to provide structural strength. It aids the mechanical stability of a laminate, but what does it do to its electrical behavior? One of the classic concerns regarding woven glass reinforced laminate PCBs is that the “glass weave effect” can have negative impact on the electrical performance of high-speed or high-frequency circuits fabricated on these laminates. In this blog post, we examine some of the factors affecting the glass weave effect phenomenon.

Depending on the particular resin system of a woven-glass laminate, the dielectric constant (Dk) of the material can vary by location, in extremely small and periodic ways. These small areas with different Dk values can be due to the glass weave pattern, where the woven-glass fabric has areas of glass bundles and areas that are openings between the glass bundles (see the figure). The Dk of the glass bundles is typically about 6, while the Dk of the laminate in open areas between the bundles is much lower, typically around 3. The variation in Dk value has been a concern for circuit designers working with woven-glass laminates, since the impedance of high-speed / high-frequency transmission lines is highly dependent upon Dk.

As an example of how the glass weave effect can have an impact on a microstrip transmission-line circuit, consider a laminate with top and bottom copper layers (signal conductor and ground plane for microstrip) with a Dk of 3.0 in the z-axis (thickness) at 10 GHz. Dk variation in the circuit material typically will affect performance more at higher frequencies, such as millimeter-wave frequencies (30 GHz and above). At 77 GHz, for example, the one-quarter wavelength of signals propagating through the circuit is about 0.024 in., which would make the one-eighth wavelength about 0.012 in. In theory, when an electromagnetic (EM) wave encounters any kind of Dk change in its propagating medium that is larger than one-quarter wavelength of the frequency of interest, propagation will be disrupted and resonances can occur.

Practical experience has shown that even anomalies as small as one-eighth wavelength can cause wave propagation issues. Circuit laminates with openings in the glass or glass bundles that are one-eighth wavelength or larger at a frequency or frequencies of interest could suffer performance irregularities because of the distribution of glass bundles (and corresponding variations in Dk). Given the various styles of glass used to reinforce different circuit laminates, it is not unusual for several of these glass types to have window openings that are one-eighth wavelength or larger at 77 GHz (0.012 in.).

As multiple plies of woven glass are stacked to form a laminate, it is less likely for glass bundles and openings to align. As a result, it is less likely for discrete Dk variations due to the location of glass bundles and window openings. Therefore, the impact of the glass weave effect at millimeter-wave frequencies is decreased for woven-glass circuit materials using two or more layers of glass fabric.

Greater concern regarding the glass weave effect is for high-speed and high-frequency circuits using a laminate with a single layer of woven-glass fabric. Using a microstrip circuit as an example, fabricated on a laminate with one glass weave layer, one concern has to do with the randomness of the glass weave effect when using woven-glass circuit materials and trying to achieve repeatable performance in high-volume production. Variations due to the glass weave effect can result in circuit-to-circuit performance variations. The random location of the woven-glass pattern as it relates to the circuit pattern can result in microstrip impedance variations that cause shifts in the phase angles of propagating high-frequency waves, resulting in degradation of any phase-sensitive signal characteristics, such as phase-based modulation.

While a laminate using multiple layers of a woven-glass fabric may help mitigate the glass-weave effect for high-speed and high-frequency circuits, multiple coupled or differential conductors on a single-layer circuit can expose additional problems with the glass weave effect. The degradation in conductor phase characteristics noted earlier can also impact coupled circuits or differential lines. Because such circuits have well-defined relationships between or among the conductors, each conductor requires the same wave propagation medium. If each conductor in a coupled pair has a different medium, they will not couple as expected. In pairs of differential lines, the phase angles will vary if the Dk values of the wave propagation medium varies between the pairs of lines. The end result is a slowing of the propagation of one signal wave versus the other, resulting in skew. Particularly in high-speed digital circuits, skew caused by the glass weave effect can significantly degrade performance due to changes in signal timing.

Changes in Dk due to the glass-weave effect can be moderated by fabricating a laminate with a filled resin system rather than an unfilled resin system. The filler typically has a different Dk value than the resin or the glass, and it fills the open spaces between the glass. The use of a filler results in a material with less-drastic changes in Dk in the small isolated areas between the glass bundles, with an effective averaging of the Dk values with the combinations of glass fabric, resin, and filler.

Another method is the use of spread/flat glass fabric along with minimizing the relative glass content in the laminate with respect to the filler and resin. This combination provides the mechanical benefits of glass reinforcement while minimizing the Dk variation along the signal propagation path.

Of course, one way to overcome the glass weave effect altogether in a circuit laminate is to do without the woven glass. An example of such a material is RO3003™ laminate from Rogers Corp., with no woven glass fabric. It has become quite popular as a laminate solution for high-volume millimeter-wave circuits. RO3003 laminates are ceramic-filled PTFE composite materials with dielectric constant of 3.00. The dielectric constant is maintained within ± 0.04 across the circuit board and from lot-to-lot of circuit material. Such Dk consistency is vital for the small wavelengths of millimeter-wave circuits, but also for coupled lines as well as differential pairs in high-speed digital circuits. It is the type of Dk consistency that is difficult to achieve with woven-glass circuit materials, due to the glass weave effect.

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Download the ROG Mobile app to access Rogers’ calculators, including the popular Microwave Impedance simulation tool, literature, technical papers, and the ability to order samples of the company’s high performance printed circuit board materials.

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Do you have a design or fabrication question? Rogers Corporation’s experts are available to help. Log in to the Rogers Technology Support Hub and “Ask an Engineer today.

 

 

Over the years, battery technology has been slow to change. Li-Ion has dominated thus far because a lithium anode has a high energy density and is lightweight. Recent research demonstrates that new developments are showing promising results.

Fade, Capacity, and Size

As most mobile phone users know, batteries fade as they age. This “capacity fade” means the amount of charge a battery can supply diminishes with use. Researchers at the U.S. Department of Energy’s Argonne National Laboratory have identified the mechanism behind the scenes of fade in Lithium-ion batteries.

Other energy storage issues include capacity and size of the battery package. Researchers at Stanford have created an innovative mathematical model that will help develop new materials for storing electricity.

The high costs and technical challenges of battery storage have taken great leaps toward mainstream use, expanding exponentially along with renewable technologies. Further development and expansion of renewable energy infrastructure promises significant gains with the advent of grid-connected electrochemical battery systems. These systems will also provide a more flexible and reliable grid.

Hybrids & Electric Vehicles

A recent breakthrough in rechargeable zinc-based batteries may be able to store as much energy as lithium-ion batteries. Zinc-based devices could also end up being safer, cheaper, smaller, and lighter. Applications include microhybrids, electric vehicles, electric bicycles, and eventually, smartphones and power grid storage.

Pininfarina, designer of exotic cars from Ferrari, Maserati, and Alfa-Romero, has several new projects in the works with Hybrid Kinetic Group, a clean-energy auto company. The new vehicle designs feature high energy, high density “super batteries” that can recover energy. Micro-turbine generator range extenders recover almost 30% of the total energy stored and can extend the EV’s range to 1000 kilometers in one charge. The motors have a long lifespan, too, up to 50,000 hours of operation or 50 million kilometers.

A new, fast-charging, solid-state battery technology for EVs has been developed by John Goodenough, inventor of the lithium-ion battery. The new technology uses a glass electrode instead of a liquid one, sodium instead of lithium, and provides three times the energy density of Li-ion batteries.

Chemists at the U.S. Naval Research Laboratory (NRL) have announced a new safe, rechargeable battery technology that could end up in electric vehicles, bikes, or ships. Lithium-ion batteries are a problem because of the liquid inside them. If the battery or device gets too hot. in the form it usually takes inside alkaline batteries, zinc doesn’t cooperate with recharging. It’s prone to forming dendrites—tiny, problematic spikes. The NRL scientists reconstituted the zinc into another form, which makes the alkaline battery rechargeable without risking dendrite formation.

Power Electronics

In battery technology, semiconductors serve critical functions: boosting performance, reducing power losses, and optimizing thermal management.

Rogers’ ROLINX® busbars act as power distribution “highways.” These laminated busbars provide a customized power liaison for connecting battery cells or interconnecting between battery packs. The busbars can integrate both power and signal lines, including, for example, temperature measurement.

In IGBT and MOSFET power modules, substrates provide connections and cool components. curamik® ceramic substrates are able to carry higher currents, provide higher voltage isolation, and operate over a wide temperature range.

 

Part of being a conscious global citizen is realizing that it’s possible to make a difference. Rogers is well aware of the impact a company can have.

This year, Rogers Hungary chose to support an organization that serves a noble purpose and contributes to making the world a better place. Út a Mosolyért Alapítvány (The Smile Foundation) in Dunakeszi, Hungary, facilitates the curing of sick children. Our donation contributes to the foundation’s purchase of an intensive care bed, which will increase the survival rate of children taken to hospital.

József Sinkó Plant Manager represented Rogers Corp. at the donation ceremony. He said, “We are proud that through our business activities we can save the lives of children.”

About Út a Mosolyért Alapítvány

The foundation is focused on the education, employment, and health rehabilitation of disabled children and young adults in Hungary. The foundation provides programs that support equal opportunity and and help the disabled develop their skills and abilities so they can earn own livelihoods and improve their living conditions.

 
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