To help customers with filter selection, we generally provide a lot of information on what our filters can do. But in this new Filter Basics Series, we are taking a step back to cover some background information on how filters do what they do. Regardless of the technology behind the filter, there are several key concepts that all filters share that we will dive into throughout this series. By providing this detailed fundamental filter information, we hope to help you simplify your future filtering decisions. 

To kick-off this series, our first post breaks down the basic properties impacting capacitor and inductor performance including resistance, capacitance, inductance, and impedance.

When an electrical device fails, oftentimes, the root cause can be traced to a field failure of a capacitor. While it is rare for the failure to be caused by a capacitor defect that was introduced during manufacturing, it can happen. This is especially true when multi-layer ceramic capacitors (MLCCs) are used versus other more simplistic capacitor types such as single-layer capacitors (SLCs) since the manufacturing process involves stacking many layers of dielectric and electrodes on top one another.

At this point, you’ve likely seen a slew of mainstream news articles about 5G causing safety concerns around air travel. In fact, ahead of the rollout of new 5G services from major US telecom companies including Verizon and AT&T on Jan. 19, 2022, many international airlines canceled or delayed flights to major US airports where they believed 5G signals could possibly interfere with the radar signals required to properly operate landing equipment on their planes.

In recent years, multilayer ceramic capacitors (MLCCs) have emerged as an excellent capacitor option for the high-power electrical systems needed in electric vehicle (EVs) due to their small physical size, low inductance, and ability to operate at higher temperatures. However, EV engineers are facing two big challenges with using MLCCs including DC bias that can cause capacitance loses of 80 to 90 percent of their quoted value and self-heating issues from AC ripple that can lead to inefficiencies in circuits as well as increased cooling demands. 

At Knowles Precision Devices, we truly do love all things RF. While we are focused on using our expertise in ceramics and thin film manufacturing to innovate on our high-performance filters, our engineers also enjoy keeping up with the trends impacting the entire RF “ecosystem.” This includes dedicating time to experimenting with various open-source RF modeling and analysis tools that we think our potential non-design engineer customers might find useful. One open-source RF and microwave network analysis tool we have been playing around with lately that we feel does a particularly good job is scikit-rf, which is based on the Python programming language.

The advent of fifth generation (5G) communications brings an increased interest in Millimeter Wave (mmWave) technologies. One of the biggest technology challenges engineers face with 5G is how to implement sufficiently high-performance RF filtering in mmWave applications. Given the frequencies involved a distributed element planar approach, such as using Microstrip or Stripline, is often ideal for constructing resonators and filters.

This year, Knowles Precision Devices acquired Integrated Microwave Corporation (IMC), a leader in the design and manufacture of custom precision RF microwave filters and multiplexers for the aerospace, defense, and communications industries. This acquisition was particularly exciting as our two companies share deep expertise in engineering high-performance ceramics for RF and microwave applications. And, like Knowles Precision Devices, IMC also has a long heritage of supplying highly reliable components for mission critical space devices that includes applications such as the MARS Orbiters, MARS Landers, and MARS Rovers.

Throughout the COVID-19 pandemic, Knowles Precision Devices has stayed focused on our primary goal of helping our customers address their most challenging application needs by providing high-performance components and innovative solutions. While 2021 did offer some unique challenges, overall, it was an exceptional year for our business. This is because even though all the unprecedented circumstances we saw in 2020, we were able to quickly adapt our business, making us really well positioned heading into 2021. As a result, this year was one of our best growth years to date.

Many power electronics today are being designed for use in high-temperature, high-voltage environments, such as inside electric vehicles (EVs). However, size, weight, and power (SWaP) are also key factors driving electronic product development. These conflicting design criteria are an issue for many electrical engineers because space is not available to simply add a cooling system, as this will add weight and increase the product’s overall footprint. Therefore, many of these electronic components are susceptible to “running hot” at the high temperatures and high voltages used in these tiny spaces.

From systems that diagnose, like a magnetic resonance imaging (MRI) machine, to implantable devices that treat patients, like pacemakers and implantable cardioverter-defibrillator (ICDs), highly reliable electronic components are necessary. While the functionality of these devices is quite different, the challenges associated with designing these devices, such as selecting failsafe electronic components designed for lifetime reliability and ensuring supplier partners can meet industry-specific standards, are shared. Let’s look more closely at some of the industry-wide challenges associated with electronic component selection for medical devices as well as some of the application-specific decisions medical device designers need to make to ensure these devices function consistently and reliably for the long term.