RF / Microwave
Custom-designed and off-the-shelf microwave components including filters, power dividers and couplers.
Featured RF/MW Filters
Knowles RF/MW filters provide high-performance signal selection for demanding RF and microwave systems. Available as standard catalog parts or fully custom designs, they enable compact, reliable solutions for applications where predictable RF performance and SWaP‑C optimization are critical.
Key Highlights:
- Wide operating frequency range from 300MHz to 75GHz. Supports diverse RF and microwave system requirements with coverage spanning VHF through V-Band.
- Multiple filter topologies (bandpass, lowpass, highpass, bandstop) Enables precise signal selection and interference control tailored to specific system architectures.
- Advanced ceramic and thin-film manufacturing. Delivers highly stable, repeatable RF performance suitable for demanding environments and long-life systems.
- High rejection, high selectivity, and low insertion loss options. Improves system accuracy and reduces noise, supporting applications such as GPS and complex RF front-ends.
- Available and standard catalog or fully custom designs. Allows optimization for size, weight, power, cost (SWaP-C), and performance, particularly valuable in radar, aerospace, and defense systems.
Featured Power Dividers
Knowles power dividers are passive microwave components designed to split or combine RF signals with low insertion loss, high isolation, and excellent phase and amplitude balance. Available in common multi-way configurations and compact surface-mount or chip-and-wire formats, they simplify RF signal routing while preserving performance across wide bandwidths. These devices are ideal for radar, satellite communications, telecom infrastructure, and test systems.
Key Highlights:
- Low-loss, high-permittivity dielectric materials. Maintains efficient signal splitting/combining with small size and stable RF performance over temperature.
- Available in surface-mount (SMT) and chip-and-wire (WB) formats. Supports flexible integration into compact RF modules or hybrid microwave assemblies.
- Thin-film precision resistors integrated into the design. Provides accurate, repeatable power division essential for maintaining amplitude and phase balance.
- Wide operational bandwidth, from 0.3GHz to 18GHz depending on model. Enables use across diverse RF and microwave systems requiring consistent performance across broad frequency ranges.
- Compact, temperature-stable construction. Minimizes performance drift and supports SWaP-C (size, weight, power, cost) optimization in radar, satellite, telecom, and test equipment.
Featured Couplers
Knowles RF couplers enable precise signal sampling, splitting, and combining for monitoring and measurement within high-frequency systems. Designed for low loss and dependable isolation, they are available in compact formats that integrate easily into modern RF layouts. These couplers support accurate power measurement and signal management across applications including radar, electronic warfare, satellite communications, and test and measurement equipment.
Key Highlights:
- High-permittivity, low-loss ceramic materials. Supports compact layouts and maintains stable coupling performance with minimal variation over temperature.
- Low insertion loss for efficient signal sampling. Preserves signal integrity when routing or monitoring high-frequency RF paths.
- Dependable isolation between coupled ports. Enables accurate measurement of incident and reflected power in sensitive RF subsystems.
- Available in compact SMT and chip-and-wire formats. Integrates easily into modern microwave assemblies and hybrid modules where space is limited.
- Stable performance across wide frequency ranges. Ensures predictable coupling behavior in radar, EW (electronic warfare), satellite, communication, and test environments.
Featured Gain Equalizers
Knowles gain equalizers compensate for frequency-dependent gain roll-off, helping improve overall passband flatness in RF and microwave signal chains. Built using thin-film ceramic technology, these compact components reduce the need for complex discrete equalization networks and support miniaturized module designs. They are well suited for front-end modules, amplifiers, radar systems, and satellite and telecom infrastructure.
Key Highlights:
- Thin-film construction on high-permittivity ceramic materials. Ensure stable, repeatable microwave performance and precise control of frequency-dependent attenuation.
- Monolithic design with integrated precision resistors. Provides a near-ideal R-C response, outperforming stacked-chip discrete equalization networks.
- Compact, pick-and-place-ready format. Simplifies assembly and supports miniaturized RF module designs without sacrificing performance.
- Improves passband flatness by compensating gain slope. Enhances signal chain accuracy in broadband RF and microwave systems.
- Suitable for demanding front-end, radar, satellite, and telecom applications. Delivers stable equalization performance required in high-reliability and high-frequency signal paths.
Featured Resonators
Knowles ceramic resonators provide high-Q frequency control in compact surface-mount formats. Available in multiple configurations and dielectric options, they enable precise frequency setting and stable performance for oscillators, filters, and timing-critical RF circuits. These resonators are commonly used in wireless communications, GPS, aerospace, and high-reliability microwave systems.
Key Highlights:
- High-Q performance across UHF, VHF, L, S, C, and microwave bands. Provides stable, low-loss frequency control essential for precision RF designs.
- Compact coaxial and surface-mount formats. Enables dense RF layouts and size-constrained module designs without compromising performance.
- Multiple configurations including quarter-wave and half-wave styles. Supports flexible circuit integration for frequency standards, filters, and resonant structures.
- High-stability ceramic dielectric materials. Ensures predictable behavior over temperature and frequency, improving oscillator and filter consistency.
- Pretuned to customer-specific frequencies with selectable tolerances. Reduces system-level tuning effort and speeds development of timing-critical RF architectures.
Featured High Frequency RF Crossovers
Knowles' High Frequency RF Crossover allows RF signal paths to cross without the need for multilayer PCB routing, simplifying high-frequency board design. This compact surface-mount device supports broadband operation into millimeter-wave frequencies while maintaining strong isolation and return loss. It is ideal for dense RF layouts in aerospace, defense, and advanced communications systems.
Key Highlights:
- Broad DC-40GHz operating range. Supports wideband and mmWave system requirements without redesigning board stack-ups.
- Enables trace crossing without multilayer PCB routing. Reduces board complexity and cost by avoiding additional PCB layers previously required for RF crossover paths.
- Patented metallized ceramic channel construction. Provides strong isolation between crossed lines while maintaining controlled RF behavior.
- Compact surface-mount format. Integrates easily into dense RF layouts and supports modern assembly processes.
- Stable performance with adequate return loss and isolation. Maintains predictable signal integrity in high-frequency aerospace, defense, and advanced communications modules.
Featured Bias Networks
Bias filter networks are integrated R‑C devices that suppress unwanted RF energy on DC bias and control lines. By combining multiple passive functions into a single compact structure, they reduce parts count, simplify assembly, and help ensure stable biasing of sensitive RF devices. These networks are widely used in multichip modules and high-frequency designs where clean bias lines are essential.
Key Highlights:
- Broadband filtering from 10MHz to 40Ghz. Ensures clean bias and control lines across wide RF and microwave operating ranges.
- Integrated R-C structure using high-permittivity ceramics and thin-film resistors. Provides compact suppression of unwanted RF energy on DC lines.
- Reduces passive component count. Combines multiple bias-filtering functions into one device, simplifying design and PCB layout.
- Supports stable device biasing. Helps maintain reliable operating conditions for sensitive RF devices in high-frequency environments.
- Adaptable to multichip modules and dense RF assemblies. Enables cleaner bias distribution in tightly integrated microwave and mmWave systems.
Featured Single Layer Capacitors
Knowles single layer capacitors (SLCs) are high-frequency ceramic components designed for DC blocking, bypassing, coupling, tuning, and filtering. With broad capacitance and voltage options, tight tolerances, and compact footprints, they deliver stable performance across wide frequency and temperature ranges. SLCs are commonly used in telecom, industrial, medical, automotive, and instrumentation applications.
Key Highlights:
- Exceptional high-frequency performance up to 100GHz. Enables reliable operation in RF, microwave and mmWave circuits where signal integrity and resonance control are critical.
- Broad capacitance and voltage range. Supports values from sub-pF to >10,000pF with multiple voltage ratings, accommodating everything from precision tuning to robust bias and bypass functions.
- Low loss and stable dielectric options. Class I and Class II materials provide designers flexibility to balance temperature stability, capacitance density, and RF efficiency.
- Compact, customizable form factors. Small footprints, multiple geometries, and wire-bondable or solderable terminations support dense layouts, MMICs, and multichip modules.
- Commercial and high-reliability solutions. Available in standard commercial grades or screened high-reliability versions for telecom, industrial, medical, automotive, aerospace, and defense applications.
Featured Broadband Blocks
Knowles broadband blocks are surface-mount capacitors optimized for ultra‑low‑loss DC blocking across wide frequency ranges. Their resonance‑free behavior and low inductance help preserve signal integrity in broadband RF and microwave systems. Designed for easy integration and compact layouts, they are ideal for test equipment, satellite communications, fiber‑optic modules, and millimeter‑wave applications.
Key Highlights:
- Resonance-free DC blocking across ultra-wide bandwidths. Maintains clean signal paths without parasitic resonances that can distort broadband RF and microwave performance.
- Ultra-low insertion loss and low inductance. Minimizes signal degradation and preserves amplitude and phase integrity in wideband and high-speed designs.
- Broad frequency coverage for RF to mmWave systems. Supports operation from low frequencies into the tens of GHz, making a single solution viable across multiple bands.
- Compact, surface-mount form factors. Small SMT footprints enable easy integration into dense layouts, transmission-line designs, and broadband modules.
- Proven performance in demanding applications. Ideal for test and measurement equipment, satellite and space systems, fiber-optic and photonics modules, and broadband microwave/mmWave architectures.
Educational Resources
Switch Filter Banks for Agile RF Receiver Design in Radar
Enhancing Radar Performance: The Role of Gain Equalizers in RF Receivers
Examining the Definition of “Wideband” Through the Lens of Electronic Warfare Systems
The Role of Filters in Expanding Bandwidth for Electronic Warfare Receivers
The Essential Relationship Between Two Key RF Components
RF Filter Terminology and Specifications
RF/Microwave Products Catalog
SLC Capacitors Catalog
RF/Microwave Products for Space Applications
RF Components for Radar Systems
Filter Basics Ebook
Wilkinson Power Dividers and Feed Networks
RF Performance: Pole Count and Insertion Loss
Why Trust the Knowles Engineering Team?
Why do Ceramics Differ in Color?
Why is Alumina Costing You?
Is Temperature Stability Important?
Why Can't You Build Just One Filter?
Product Documentation
High Reliability Components for Satellite Communications
RF/MW Filter Technologies
SWaP-C Optimized Parts for Radar Systems
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