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 be.
AFT Microwave |
+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, horn antenna.
Aerotek Company |
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,
| 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.
Corry Micronics | 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
DiTom Microwave | 559-255-7045 | Fresno,
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 heating.
EMR Corporation | 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
Ferrite | 603-881-5234
| Hudson, NH
Circulators, isolators, transmitters.
Filtel | 450-455-6082
Couplers, power dividers, isolators, coaxial & waveguide circulators.
Innertron | +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
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,
MECA Electronics | 866-444-6322
| Denville, NJ
RF & microwave components for in-building, satellite,
radar, radio, telemetry, mobile radio, aviation & ATC. Attenuators, directional &
hybrid couplers, isolators & circulators, power dividers & combiners,
loads, DC blocks, bias-Ts and adapters & cables.
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,
Microwave Technology 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.
Murata Electronics |
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.
Nanowave | +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.
| 857-499-0071 | Cohasset, MA
Millimeter-wave waveguide components including
attenuators, detectors, diplexers, power amplifiers, mixers, isolators &
circulator, multipliers, antennas, switches, probe adapters, terminations, and
filters. Waveguide sections include straight, bends, twists, transitions, and
adapters. Patented "GuideLock" connector eliminates screws. Cryogenic components
available. Designed and manufactured at their Massachusetts facility.
QuinStar Technology |
310-320-1111 | Torrance, CA
manufactures millimeter-wave products for communication, scientific, and test
applications including millimeter-wave products, microelectronic assembly, rapid
prototyping, and mass customization.
oscillators, switches, attenuators,
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.
RF-Lambda | 613-592-6858
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.
Trak Microwave | 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, transformers.
Vector Telecom |
+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
VivaTech | +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
(now Ducommun Technologies) | 310-513-7200 | Carson, CA
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 assemblies.