Monolithic microwave integrated circuit (MMIC) amplifiers are widely used in defense radar systems. The industry recognizes them as a compact, high-performance option that’s reliable and easy to integrate. Whether they serve a receive (e.g., low noise amplifier (LNA)) or transmit (e.g., power amplifier (PA)) function, MMIC amplifiers rely on bypass capacitors to perform their core function to amplify microwave signals. 

Radio frequency (RF) and microwave applications involve the transmission and receipt of high-frequency electromagnetic signals. RF refers toalternating current (AC) signals at 3 kHz to 300 GHz, and microwave refers to a higher range, closer to 300 MHz to 300 GHz. Capacitance, and by extension impedance, varies with frequency, so capacitors play a variety of critical roles in these RF and microwave circuits. With many options for configuration, they function in energy storage and voltage regulation, DC blocking, impedance matching, filtering and more. 

DC link capacitors are commonly used in power converters as an intermediary buffer between an input source to an output load that have different instantaneous power, voltages, and frequencies. In electric vehicle (EV) applications, DC link capacitors help offset the effects of inductance in inverters, motor controllers, and battery systems. They also serve as filters that protect EV subsystems from voltage spikes, surges, and electromagnetic interference (EMI).

Battery energy storage systems (BESS) are named for their function. They capture, accumulate, and store energy in rechargeable batteries to be discharged later. Industrial facilities, homes, electric vehicles (EVs) and the like rely on these systems for backup power and operational efficiency.

Ongoing innovation in solar power electronics and rising interest in photovoltaic (PV) installations underscores the importance of robust and efficient electronic components. Capacitors play a key role in power conversion systems as they function to smooth and regulate power flow, protect against voltage surges and filter unwanted signals. 

In radar systems, power amplifiers serve an essential role in transmitting signals that probe the environment of interest. They boost signal strength and maintain its quality to achieve the intended range and resolution of the overall system.

When considering capacitor selection for a given circuit, whether you’re focused on power electronics or deep in the world of RF, it's important to remember that some of a capacitor’s fundamental roles are universal. 

In our review of today’s trends in power electronics, we discussed the growth in the renewable energy market and the resulting increased investment in renewable energy technologies, such as wind. As a result, global demand for wind power is surging. To keep pace, not only are there more wind turbines being installed onshore and offshore, but the generation capacity of each turbine is also growing substantially. This is changing the requirements for the power electronics needed for these systems. In this blog, we review some of the key wind power generation trends fueling the ability to provide increased capacity and driving changes in the power electronics required for these systems.

At Knowles, we closely monitor the trends and market conditions that impact our customers’ design needs. As a specialty components manufacturer with in-house ceramic and thin film manufacturing expertise, we can quickly adapt to these changing needs to make it easier for customers to find exactly what they are looking for. That’s why in 2023 we released numerous new off-the-shelf DLI brand microwave devices.

These components are made with our temperature stable ceramics, are incredibly small compared to other similar parts on the market, and cover a range of frequency bands, from the S band to the V band. Below is a summary of the capabilities of our latest microwave product offerings.

The electrical power systems in most modern technologies, like electric vehicles (EVs), are complex. In EVs specifically, power systems are responsible for performing many tasks such as converting AC to DC and DC to AC as well as managing changing power levels in DC/DC conversion. When performing these tasks, manipulating AC voltages and removing noise from DC voltage requires passive components such as capacitors, to perform many “jobs” inside the power system. But no single capacitor type can perform all these jobs since each one has different requirements for voltage, size, temperature, and reliability. Therefore, a variety of capacitor technologies, such as ceramic, film, and aluminum, are required to meet all these needs.