At Knowles Precision Devices, we are well known for our expertise delivering high-performance mmWave filtering options. But did you know we also excel at providing a wide variety of lower frequency filtering options using a lumped element filter construction? In this blog post, we explore the basics of lumped element filter design, general lumped element filter characteristics, and how we can push lumped element filter design limits to develop a wide variety of high-performance low-frequency filtering options.

Satellite communication (satcom) systems have undergone a revolutionary transformation in recent years. The industry has shifted from multi-billion-dollar GEO satellites to million-dollar LEO satellites, reducing costs by three orders of magnitude while exponentially increasing the number of satellites in orbit.

Quadrature hybrid couplers are basic building blocks for many RF and microwave systems. For these couplers, the input splits into two output signals, of equal magnitude, with a 90 degree phase difference. Quadrature hybrid couplers provide improved input match for unbalanced loads. Energy splits evenly between outputs, and some energy is reflected back due to mismatch. For example, in Figure 1, there is a 90 degree phase difference between the two outputs, so the energy reflected at point A is 180 degree out of phase and cancels at the input port. At point B, the energy is in phase and sums at the isolated port, which is terminated.

The Wilkinson Power Divider, designed by Ernest Wilkinson in the 1960s, uses quarter wave transformers to split an input signal into two equal phase output signals. Since the design is reciprocal, Wilkinson Power Dividers can also be used as a power combiner. With this flexibility, they are widely used in many RF and microwave communication systems, including those with multiple channels or complex feed networks.

The performance of a resonant circuit comes down to its components. Two key factors, Q factor and capacitor equivalent series resistance (ESR), determine how efficiently energy moves through a resonator and how selectively it responds at its designed frequency.

Semiconductor manufacturing is one of the most advanced industrial processes on Earth, requiring precise control of energy and materials at the nanometer scale. Behind that precision lies an invisible backbone: the power electronics systems that deliver, shape, and regulate every watt of energy that drives chip production.

Radio frequency (RF) generators produce alternating current (AC) at specific frequencies ranging from kilohertz to gigahertz.

Common Data Link (CDL) is a secure U.S. military communications protocol. Established by the Department of Defense (DoD) in 1991, CDL is the primary standard for intelligence, surveillance, and reconnaissance (ISR) data transmission, enabling full-duplex, jam-resistant digital communications between airborne platforms, ground stations, and naval vessels. CDL supports real-time distribution of video, imagery, and sensor data critical for modern military operations.

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.  

Engineers designing for medical imaging and high-frequency applications need components that ensure minimal power loss, high signal integrity, and zero magnetic interference.

Knowles’ new FM2 range of Non-Magnetic X7R Low Loss Multilayer Ceramic Capacitors (MLCCs) is engineered to deliver superior RF efficiency and uncompromised reliability. These MLCCs provide lower equivalent series resistance (ESR)/higher Q factor compared to standard X7R capacitors, making them ideal for MRI systems and low-noise amplifier (LNA) applications.