When designing a ceramic capacitor, the type of dielectric used will influence the characteristics of the capacitor and define its electrical behavior. At a high level, there are two types of dielectrics made with ceramics – paraelectric and ferroelectric. Dielectrics containing paraelectric (or non-ferroelectric) ceramics are known as Class I dielectrics. These dielectrics show a linear relationship of polarization to voltage and are formulated to have a linear temperature coefficient. Capacitors using a Class I dielectric have high stability across various temperatures, but have low permittivity, which means the capacitor will offer low capacitance.

Achieving high capacitance means going big. But how do you do that while still maximizing board space? At Knowles Precision Devices, we’ve developed a new method for building customizable large capacitor assemblies that capitalize on the vertical space above the circuit board. While stacked capacitor assemblies have been around for many years, these parts do not have very good bump and vibration withstand due to the thin leads used in their construction. These new assemblies from Knowles Precision Devices offer a ruggedized construction capable of withstanding high levels of shock and vibration. This offers a unique combination of capability, durability, high capacitance, and very high voltage in a smaller area, making these capacitors ideal for automotive, military, and aerospace applications.

The millimeter wave (mmWave) part of the electromagnetic spectrum is at the high end of the microwave region, which spans ~300 MHz to 300 GHz, and is usually taken to mean frequencies from ~30 GHz to 300 GHz and wavelengths in the range of 1mm to 1cm (Table 1). This dramatically increases available bandwidth, thus expanding achievable data rates, which makes these frequencies extremely interesting to teams around the world working on fifth generation (5G) communications.

As complex electronic systems become more prevalent in our daily lives, the demand for high-temperature, high-reliability components continues to increase. Standard electronic components have an operating temperature of -55 °C to 125 °C, but the number of applications requiring functionality above 125 °C is growing. Components in these applications, like capacitors, must maintain their functionality and take the heat (literally and figuratively) while powered. To meet the brief, material and design of these high-temperature components must deviate from today’s standard.

At Knowles Precision Devices, we thrive on working with companies who want to take technically challenging ideas and work through the details to figure out how to turn their seemingly impossible ideas into reality. This is because we are not limited to volume production and have extensive experience making specialty and custom parts. We are also familiar with the challenges associated with delivering high-reliability components as we supply many industries and applications that depend on the consistent functionality of custom-shaped parts. For example, we provide numerous space grade components and we are the only manufacturer who has developed planar array ceramic parts for the International Space Station. 

Many critical military operations around the world are increasingly relying on a variety of electronic warfare devices for a range of threat suppression, detection, and neutralization activities. This means that numerous devices operating across the RF spectrum including low-frequency devices in the VHF band and mmWave devices in the Ka band are necessary. As shown in Figure 1, when many electronic warfare devices are in use, a large number of signals are being sent and received and crossing paths. Therefore, it’s easy for any one of these devices to experience issues with interference if proper filtering techniques are not in place.

We are pleased to announce that the Knowles Corporation recently 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. With this acquisition, the Knowles Precision Devices Microwave group can now offer a complete range of RF and microwave filtering solutions that support applications from the VHF to the Ka band. In addition to the small, temperature-stable filters our customers have come to know us for, we can now deliver ceramic and cavity filters for lower frequency and/or higher power applications. The full range of the IMC filter technologies we now offer is shown in the graphic below.

To provide a better understanding of build-to-print in general and the breadth of our offerings, as well as how our thin-film technology can benefit your applications, we’ve put together a Build-to-Print Basics series. In this final post of our Build-to-Print Basics series, we discuss the quality standards we follow to ensure our components are qualified for military and space grade applications as well as the additional testing or spec design we can perform as needed by our customers.

As early adopters of beamforming technology in the 1960s, aerospace and defense organizations have a lot of experience using the initial large-scale active electronically scanned arrays (AESAs) for military radar tracking applications. But these arrays aren’t as convenient for some applications today as the operational frequencies of the targets of interest for many military applications are increasing. This means the wavelengths of the signals that need to be monitored are getting shorter and these radar applications need denser arrays since antenna spacing needs to be set at one half the wavelength. For example, at 25GHz, the wavelength in free space is approximately 12mm (0.47”), leading to half-wave spacing for antennas of 6mm (0.24”). Also, as arrays become denser, the new challenge for RF system designers is avoiding interference in these tighter spaces, especially when transmitting signals.

To provide a better understanding of build-to-print in general and the breadth of our offerings, as well as how our thin-film technology can benefit your applications, we’ve put together a Build-to-Print Basics series. In part 14 we discuss a range of non-standard testing services our facilities can provide when needed by our build-to-print customers.