There are hundreds of filter applications operating across a wide range of frequencies, which presents a challenge for filter designers since most filter designs don't inherently operate across these wide ranges. Size, weight, power, and cost (SWaP-C) are also important considerations, so simply adding more filters to address different frequency ranges is not an attractive solution. There is, however, an alternative way of designing filters: combining filter technologies to meet the specific frequency, bandwidth, and size requirements of your application.

Bias filter networks and self-bias networks are two types of biasing components developed by Knowles Precision Devices for use in high-frequency microwave and RF applications.

To understand what an electromagnetic interference (EMI) filter is, and what it does, we need to first know what EMI is and why it needs to be filtered. EMI refers to undesirable electromagnetic emissions or disturbances generated either by electronic devices or natural sources in the environment that can interfere with the proper functioning of other nearby devices or systems. EMI noise can propagate through power supply lines and radiate into the environment, potentially causing disruptions or malfunctions in other electronic systems. For many devices, this could cause big issues, which is why many government organizations have developed regulatory standards for electromagnetic compatibility (EMC), or when two pieces of electronic equipment can function in the same environment without adversely impacting one another. 

The Knowles Precision Devices DLI brand of technologies are designed to address the complex challenges of implementing high-performance mmWave filters across the widest range of specifications. Our Microwave Product Catalog covers how to select the best catalog or custom components for your application needs, while our new Microwave Products Guide provides valuable information and recommendations for how to work with our DLI brand microwave products once you have the components in hand.

As the backbone of the X-ray machine, X-ray tubes produce the radiation that generates the electromagnetic waves known as the “X-ray.” This is done by using a high voltage to accelerate the electrons released by a hot cathode to a high velocity. Those electrons then collide with the anode, which is a metal target usually made of tungsten. This process requires an input voltage typically ranging from 180 to 480 VAC with a power supply that transforms and steps up the voltage to extremely high voltage outputs ranging from 10kV and 120kV DC. A high-level diagram of the power supply required to power the X-ray tubes is shown in Figure 1. 

As the demand for faster communications across consumer and commercial devices continues to increase, operating frequencies of RF devices are being pushed higher and higher. This creates a number of challenges for RF device designers, as filter size must be reduced to compensate for smaller device sizes and shorter wavelengths while also maintaining high levels of performance. While surface mount technology (SMT), and in particular microstrip implementations, are an excellent option to meet these demands, it is important to note that not every SMT microstrip filter is created equal. There are a variety of choices to discuss with your filter supplier, such as substrate type, plating technology, and topology that can dramatically reduce the size and increase the performance of an SMT microstrip filter. One particular choice that Knowles Precision Devices has guided customers through for decades is the decision to use thin film for these filters.

In this webinar we review and challenge how some aspects of microwave technology have advanced beyond traditional assumptions. Looking at several examples across different filter technologies and applications, we share some exceptions to the rules and how to spot an opportunity to challenge conventional thinking.

X2Y^® technology, which was originally developed by X2Y Attenuators, LLC, is based on a proprietary electrode arrangement embedded in passive components that can be manufactured using a variety of dielectrics. Using this innovative technology, Knowles Precision Devices manufactures high-performance multi-layer ceramic capacitors (MLCCs) that we then use to create a variety of off-the-shelf and custom bypass and noise decoupling capacitors and electromagnetic interference (EMI) filters. Let’s look at how building these components with X2Y is different than using a traditional ceramic MLCC and the resulting benefits.

Since our acquisition of Integrated Microwave Corporation (IMC) in 2020, we have extended our range of RF and microwave filtering solutions to include a wide variety of ceramic coaxial resonators, lumped element filters, and cavity filters from the VHF to the Ka band. During this time, we’ve also continued to innovate on and expand our product offering for one of our most popular filter types – the microstrip filter.  

To help our customers with filter selection, we generally provide a lot of detailed information on what our various filters can do. However, we thought it also might be really helpful for our customers if we took a step back and covered 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. Therefore, we decided it was time to bring together our top engineers so that we could compile their extensive filtering knowledge into a comprehensive Filter Basics ebook.