The quality factor (Q) of a resonator is expressed as the ratio of stored versus lost energy per oscillation cycle. Overall losses through a resonator increase as Q factor drops and will increase more rapidly with frequency for lower values of resonator Q. However, truly understanding how Q factor is determined is a bit more intricate. Let’s take a closer look.

The Knowles Precision Devices DLI brand of microstrip bandpass filters offers innovative filter topologies yielding excellent performance in a small footprint when fabricated on high DK temp stable ceramic substrate materials. Since our customers use our surface-mount filters in a wide range of applications, we’ve designed our devices so they can be used on most RF PCB materials. To ensure our customers achieve optimal performance and are successful with our filters, we have compiled a number of best practices and resources, which are outlined below.

Many microwave applications, such as repeaters, and electronic warfare equipment, require increased spectral resolution. This means these devices only need to look at a narrow slice of a given band. Filters that are optimized for the whole band, such us our planar microstrip devices, are too broadband for these applications. Likewise, traditional high Q filters, such as waveguide devices, are often too large to consider using in these types of applications.

With more than 2,000 satellites currently orbiting the Earth, and that number expected to quintuple in the next 10 years, the demand for space-ready components is exponentially increasing (Figure 1). At the same time, the technology needed to control and transmit satellite data has changed from mechanically controlled parabolic or dish technology to active electronically steered arrays (AESAs).

At Knowles Precision Devices, we support a wide variety of industries and applications with unique needs; the product catalog is constantly evolving to accommodate. We are often asked which frequencies we support. While our microwave products excel at higher frequencies, the catalog spans a wide range.

Today, surface-mount multilayer ceramic capacitors (MLCCs) are used in incredibly harsh applications, resulting in increased concern from end users over the likelihood of reliability issues such as mechanical cracking. Thus, at Knowles Precision Devices our engineers are often asked if our capacitors offer flexible termination that increases the mechanical strength of our components, which helps mitigate these potential issues. Our customers can rest assured that not only do we offer flexible termination in our capacitors, we were actually the creators of the first flexible termination technology for MLCCs.

At Knowles Precision Devices, our expertise in capacitor technology helps developers working on some of the world’s most demanding applications across the medical device, military and aerospace, telecommunications, and automotive industries.

The US MIL-STD-461 specification manages electromagnetic interference emissions by setting limits on the levels that can be emitted from electrical equipment. This specification also sets regulation to control equipment susceptibility to external noise sources and establishes guidelines for properly measuring the relevant equipment features.

EMI filtering plays an important role in reducing noise that could interfere with other devices; in medical or defense applications, for example, false alarms due to external interference could be detrimental. Here, we will continue our EMI filtering exploration with application and installation considerations. For earlier reading, review EMI filtering basics and filter performance.

To comply with international legislation such as the EU Directive on EMC or the FCC, EMI filtering is an essential element of equipment design. Here, we will continue to explore EMI filtering through insertion loss and filtering performance.

The insertion loss performance shows signal attenuation at any given frequency. As a metric, the insertion loss performance is most useful as a guide in the filter selection process; the actual performance in service can vary depending on circuit characteristics.