Knowles Syfer

Knowles Syfer or Knowles Precision Devices (KPD) is a division of the Knowles Corporation focusing on the design and production of a broad spectrum of precisely engineered Microwave to Millimeter-Wave components and Capacitors. 

The company’s product catalog has a wide range of applications across many high-tech industry segments essential to modern economies. These include critical use applications in medical devices, electric vehicles, 5G, aerospace, and defense market segments. 

Knowles Syfer is renowned as a critical player in the high-tech manufacturing field with expertise in multiple areas of highly complex technical fields beyond the capabilities of many other manufacturers, including extreme temperature environments, high performance, high reliability, and high frequency industrial end-user solutions. 

In the area of high-performance, multilayer ceramic capacitors, KPD particularly excels, with an unparalleled level of expertise in relation to performance-for-footprint mmWave filters and Surface Mount MLCCs.


A Brief History of Knowles Syfer 

Dielectric Laboratories, or DLI, were responsible for the invention of the Single Layer Capacitor in 1974. This company was acquired by the Dover Corporation in 1985, followed by the acquisition of Novacap in 1987, bringing together the expertise in capacitors from DLI with Novcap’s unique position in the specialization of MLCC products with applications space and military technology.

In 2000 Syfer, another company with unique MLCC expertise, joined the group, bringing their recent invention, the Flexicap, which prevents MLCC cracking and has since become an industry standard.

Voltronics, a leading manufacturer of high precision, variable capacitors, was acquired, adding expertise in multi-turn trimmer technology to the group’s portfolio of skills.  

In 2014 the Knowles Corporation became a publicly traded entity. Novacap, Syfer, Voltronics, and DLI were merged into the Precision Devices division known as Knowles Precision Devices (KPD) today. 

Other companies contributing unique value and expertise to KPD include Johanson Manufacturing (trimmer capacitors, microwave tuning element, and non-magnetic variable inductors), acquired in 2017, Compex (single-layer capacitors), acquired in 2018 and IMC (RF and microwave solutions), acquired in 2021.


What is a Surface Mount MLCC?

MLCC stands for multilayer ceramic capacitor and is characterized by a number of individual layers stacked together in parallel arrangement with contact achieved through the terminal surfaces of the component. In extremely large quantities, they are used extensively in the mass production of electronic devices and equipment. 

The KDP product line includes both standard surfaces mount MLCCs, together with radial lead packages, ribbon packages, and SMD case sizes in the 0402 to 8060 range. Voltages up to 12kV are supported for use in high-level application-specific screening, implantable medical devices, and many other settings. 

The Solution to MLCC Ageing

Over time the crystalline structure for barium titanate-based ceramic capacitors will age. It is therefore essential to know the rate at which a component will lose its capacitance. All Knowles Syfer capacitors are shipped within a determined tolerance with a standard reference age of at least 1000 hours. 

The unique ‘wet process’ used by KPD during manufacture enables their capacitors to operate with exceptionally narrow capacitance tolerances, as small as +/-0.05pF.


Knowles Syfer Products

5G mmWave Filter Products

  • mmWave Filters for 5G
  • 5G Band Offerings
  • Temperature stability from -55 to +125°C
  • Exceptionally High Repeatability via Precision Thin Film Fabrication
  • Surface Mount Assembly up to 42 GHz

Implantable Medical Devices

High Voltage Components for Electric Vehicle Drivetrains


  • SMD Capacitors
  • AEC-Q200
  • Broadband Blocks
  • Capacitor Assemblies
  • MLCCs 
  • Single Layer Capacitors
  • Discoidal Capacitors
  • Planar Capacitor Arrays


  • Air, sapphire, glass, and PTFE dielectrics
  • Multi-turn and Half/Single turn formats

Micro and Millimeter Wave Products

  • mmWave filters for Radar, 5G, and EW applications
  • Bandpass filters from 800MHz to 67GHz specification
  • Precision Thin Film Fabrication for extreme High Repeatability
  • Lowpass filters
  • Highpass filters
  • Cavity filters
  • Couplers
  • Gain equalizers
  • Power dividers
  • Resonators
  • Bias filter networks
  • Self bias networks

EMI Filtering

  • Surface Mount Filters
  • Panel Mount filters

Non-Magnetic High Performance Components

  • Multi-turn trimmer capacitors
  • Fixed and variable inductors
  • Multi-layer capacitors
  • Diodes

Other Products & Solutions

  • Heat sinks
  • Mounting shorts
  • Standoffs
  • Submounts


KDP products are used in various applications, including MRI equipment, aerospace, EVs, mobile phone base stations, satellites, pacemakers, radar equipment, and more. 

Knowles Syfer products are found performing crucial, high-reliability roles in every part of the globe from 8000ft below the earth’s surface to 250 miles above, in orbit, on the ISS. 


The revolution in the use of HEVs, EVs, and PHEVs has caused an enormous change in the requirements of control electronics. The higher temperatures occurring in modern control circuits mean that plastic film capacitors can no longer be withstanding these extreme environments. Ceramic MLCCs are the ideal replacement for these components with the additional advantage that they can be surface mounted directly onto boards which allows for shorter circuit tracks and lower inductance.


Whether you are in the telecoms, automotive, military, medical, or aerospace industries, Knowles Syfer products can provide the high-performance, extreme precision components and devices that you require. 

KDP single-layer capacitors easily support both mmWave and microwave applications up to 100GHz, making them ideal for use in devices such as Low Noise Amplifiers, DC Blocking, Oscillators, Filters, and High-Power Amplifiers. 


In the case of applications requiring high-performance, non-magnetic components, KDP offers a range of precision multilayer capacitors, variable and fixed inductors, diodes, and precision, multi-turn trimmer capacitors. Practical applications of this technology range from NMR and MRI medical scanning devices to base station antenna systems. 


The requirements for non-magnetic components in magnetic resonance industries are incredibly high, and KDP is one of few companies with the experience, expertise, and manufacturing capabilities to meet these. In addition, their extremely strict traceability and testing protocols ensure that you may have complete confidence in the reliability of their devices and components in this challenging field.


If you require any further information about the Knowles Syfer product range of MLCCs, non-magnetic components, diodes, or any other devices or if you would like to make an order for any of their specialized products, please don’t hesitate to contact us today.

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