Circulators and isolators
are very handy (and necessary) devices for use when it is essential to keep RF signal
flow in one direction only. Think of them loosely as a steering diode array that directs
energy from one port to a specific other port (or ports). Circulators and isolators (an
isolator is basically a circulator with the third port terminated in the characteristic
impedance) are fundamentally 3-port devices with 120° between ports. Ferrites with special
properties (known only to the sworn circulator designer brotherhood) affect the directional
control. Here is a brief circulator application note from MECA Electronics.
One important thing to keep in mind is that specified values for isolation are only
guaranteed at 50+j0 ohms, or whatever the characteristic impedance of the attenuator
model happens to be (50 and 75 ohms most common). The farther away from the characteristic
impedance the connected ports are, the farther from the spec the isolation value will
| +49 7191 9659 0 | Germany
Microwave components including circulators, isolators,
waveguide and coaxial components, phase shifters, ferrites, thin film technology.
Advanced Technical Materials
(ATM) | 631-289-0363 | Patchogue, NY
Attenuators, bias tees, coaxial
cables, couplers, DC blocks, isolators, circulators, line stretchers, noise sources,
phase shifters, power dividers/combiners, switches, terminations, waveguide, adapters,
| 662-332-5035, 311-4448 | Thailand
Coaxial, drop-in, lump, drop-in lump, flange mount
circulators & isolators, 88 MHz - 18 GHz.
Cernex | 408-541-9226
| Sunnyvale, CA
Amplifiers, antennas, couplers, isolators, circulators, filters, diplexers,
oscillators, noise sources, switches, phase shifters, transition & adapters, mixers,
waveguide products, attenuators, terminations, detectors, subsystems.
| 805-482-7280 | Camarillo, CA
Coaxial and waveguide isolators, circulators, ISO-adapters,
integrated assemblies, filters, terminations.
| 727-549-8999 | Largo, FL
Electromechanical switches, attenuators, isolators, terminations,
circulators, power dividers, couplers.
| 724-940-7556 | Corry, PA
Dielectric resonators, bandpass filters, LC filters, VCOs,
PLLs, patch antennas, power dividers, connectorized lumped element power dividers, directional
couplers, isolators/circulators, high power hybrids, diplexers & multiplexers, attenuators,
switches, cavity filters, waveguides, standard gain horn antennas.
| 559-255-7045 | Fresno, CA
Connectorized single and dual junction ferrite
isolators and circulators for the space and defense markets. COTS and Hi-Reliability
products available covering 700 MHz to 31 GHz.
| 206-574-0900 | Seattle, WA
Planar, horn, 8.2 GHz to 110 GHz antennas, waveguide
isolators & circulators, switches, adapters, connectors.
EM Design, LLC
| 541-878-3927 | Shady Cove, OR
Specializes in the design and fabrication of RF and
microwave components, systems and sub-systems including antennas, antenna polarizers,
circulators, isolators, waveguide loads, coaxial loads, microwave pulse compressors,
waveguide windows, waveguide seals, waveguide shorts, waveguide couplers and microwave
| 800-796-2875 | Phoenix, AZ
RF peripherals devices from 30 MHz to 2.8 GHz. Design,
manufacture and systems' engineering for RF isolators, amplifiers & BDAs, filters
- band pass & band reject, mobile & base station duplexers, combiners - cavity
ferrite & hybrid ferrite, RX multicouplers and accessories including LNAs.
603-881-5234 | Hudson, NH
Circulators, isolators, transmitters.
Filtel | 450-455-6082
Couplers, power dividers, isolators, coaxial & waveguide circulators.
| +82-32-816-1456 | Incheon-City, Korea
A wide selection of RF & microwave components
as well as power dividers, power splitters, arrestors, bias-Ts, attenuators, terminations,
directional couplers which cover the frequency range from DC to 18 GHz. Waveguide filters,
diplexer, adaptor, couplers up to 40 GHz, custom designs are available to support applications
for the military and commercial industries.
Instruments for Industry (IFI)
| 631-467-8400 | Ronkonkoma, NY
Amplifier configurations such as tetrode tubes, TWTs,
klystrons, and solid state devices. Standard horn antennas and TEM cells.
Kete Microwave Electronics
| +86-595-22597735 | China
Ferrite RF isolator & circulators, high power RF
resistors & terminations, fixed & variable/step attenuators, multilayer High-Q
chip ceramic& feedthrough capacitor (EMI filters), directional couplers, power dividers
/ combiners, 3dB hybrid couplers.
| 888-236-9828 | Rolling Meadows, IL
Manufacturer of RF and microwave devices including
filters, isolators & circulators, directional couplers, power divider/combiners,
hybrid, termination and etc. Our R&D team provides outstanding services to quickly
bring your product concepts into prototype, and turn the prototype into products.
MCLI | www.800-333-6254
| St. Petersburg, FL
Power dividers, couplers, isolators, circulators, waveguide components,
oscillators, filters, hybrids, attenuators, switches, terminations, amplifiers.
Mica Microwave (now
Mercury Systems) | 209-825-3977 | Manteca, CA
Circulators, isolators, mixers, equalizers,
| 888-736-8837 | Franklin, IN
Attenuators, terminators, directional couplers, filters,
isolators/circulators, cable assemblies, measurement equipment.
| 909-627-4125 | Chino, CA
Amplifiers, attenuators, circulators, isolators, frequency
multipliers, waveguide couplers, mixers, detectors, filters, pin switches, adapters.
Corporation (MTC) | +66-35-721-559 to 60 | Wang-noi, Thailand
passive components of isolators & circulators including coaxial from 80 MHz to 40
GHz. Drop-in or surface mounted from 400 MHz to 20 GHz. Waveguide is up to 40 GHz. Power
up to power rating 500 W. Additional product waveguide adaptor & termination.
| 800-241-6574 | Smyrna, GA
Chip multi-layer (1.0 2.5 GHz), chip dielectric (2450
GHz, Bluetooth), surface mount capacitors, thermistors/resistors, coil (inductors)/delay
lines, noise suppression products/EMI filters, resonators, piezoelectric sound components,
coaxial connectors, antenna/duplexers, isolators/circulators, PLL modules, VCOs, TCXO,
RF diode switches, DC-DC converters, sensors.
| +82-43-903-4828 | South Korea
SMD, drop-in, coaxial, waveguide isolators, circulators,
directional, hybrid couplers, 2way, 3way, 4way dividers, attenuators, terminations.
| 408-778-2746 | Clearwater, FL
RF ferrite circulators and isolators that connect,
protect and control critical commercial and military wireless telecomm systems. Standard
and custom design quality circulators and isolators from 380 MHz to 26.5 GHz.
| 866-727-8376 | Irvine, CA
Amplifiers to 2 GHz, attenuators 1 - 1000 W DC - 40 GHz,
circulators/isolators 1 - 26.5 GHZ w/SMA connectors, combiners/dividers 2 - 12 way 1
MHz - 18 GHz, couplers low & high power 0.5 - 18 GHz, switches manual & diode
DC - 18 GHz, terminations 1/2 - 100 W DC-40 GHz, waveguide 1.70 - 40 GHz.
| 310-320-1111 | Torrance, CA
Designs and manufactures
millimeter-wave products for communication, scientific, and test applications including
millimeter-wave products, microelectronic assembly, rapid prototyping, and mass customization.
oscillators, switches, attenuators,
circulators & isolators, filters,
and phase shifters, and
transceiver & radar subsystems.
Raditek | 408-266-7404
| San Jose, CA
Isolators, circulators, oscillators, synthesizers, couplers, splitters,
combiners, hybrids, adaptors, cable assemblies, connectors, terminations, attenuators,
bias tee's, lightning protectors.
| 978-772-7774 | Harvard, MA
Manufacturer of RF & microwave sub-systems and components
including isolators & circulators, dividers & combiners, waveguide components,
coaxial RF switches, switch matrices, base station equipment.
RF & Noise
Components Ltd | +44 (0) 5601 06 69 30 | Southend-on-Sea, Essex, UK
manufacturer of RF & microwave components including circulators, isolators, combiners,
couplers, dividers and power monitors. Specialising in custom designs to meet individual
customer requirements. ISO9001:2008 Approved.
613-592-6858 | Canada
Couplers, circulators, isolators, mixers, attenuators, coupler,
power amplifiers, LNA, VCO, switches, oscillators, connectors, adapters.
RTx Technology Co., Ltd
| +82-31-743-6275 | South Korea
Filters, duplexers, multiplexers (ceramic/cavity),
VCOs & PLL synthesizers, isolators & circulators, up/down converters, combiners &
dividers, directional couplers, SAW devices, attenuators, terminators.
| 888-283-8444 | Tampa, FL
Attenuators, circulators, isolators, comb generators, control
devices, couplers, delay line filters, GPS time & frequency, hybrids, IQ mod &
demod, mixers, multipliers, oscillators, phase shifters, splitters & combiners, synthesizers,
+61 3 9607 8357 | Melbourne , Australia
Waveguide components and assemblies, coaxial
components and antennas.
vidaRF | www.877-777-8432
| Huntersville, NC
Offering High performance isolators, circulators, power dividers,
couplers, RF connectors, adapters, custom cable assemblies, attenuators, and terminations.
Custom designs available. In-stock items shipped within 24 hours.
+1 818 547 5036 (USA) | +44 750 923 3838 (Intl Mobile)
System front-ends, mm-wave
test equipment, source modules, amplifiers, active multipliers, mixers, frequency converters,
frequency extension modules, radiometer front-ends, waveguide isolators, waveguide attenuators,
passive and active waveguide components and primary noise standards.
(now Ducommun Technologies) | 310-513-7200 | Carson, CA
Amplifiers, antennas, attenuators,
PIN diode switches, phase shifters, isolators/circulators, frequency converters, oscillators,
couplers, magic tees, coax power dividers, bandpass, low pass, high pass filters, waveguide
diplexers, transitions, waveguide to coax adapters, waveguide components, integrated