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Jie Kao Ao (JQL) Electronics manufactures RF and microwave circulators, isolators, iso-adapters, ceramic filters, cavity filters, hybrid combiners, power splitters, couplers and low PIM terminations with excellent quality at a very reasonable price. Company brochure JQL

RF and Microwave Circulators and Isolators

Ferrite circulators are passive three-port devices in which an RF or microwave signal is transmitted from one port to the next port, but not to the third port. They are mainly used to protect amplifiers from reflected signals if there is a defect in the cable or antenna after the amplifier. Another usage is the separation of transmitted and received signals in systems which operate in the same frequency band for transmission and reception, e.g. RFID. The ports are matched inside the housing or on the microstip board to 50 Ohm. RF isolators have one port terminated with a power resistor.

JQL offers a complete spectrum of coaxial, drop-in, surface mount, microstrip, and waveguide ferrite circulators and isolators, from 100 MHz to 120 GHz, for all communications and radar bands: VHF, UHF, TETRA, GSM, ISM (868 MHz, 915 MHz, 2.4 GHz, 5 GHz, 24 GHz), UMTS, LTE, 5G, L-band, S-band, C-band, X-band, Ku-band, K-band, Ka-band, E-band, W-band.

JQL low IMD coaxial circulator Coaxial Circulators and Isolators

  • 100 MHz to 28 GHz
  • up to 500 W average power
  • single circulator and high isolation dual coaxial circulator and isolator designs
  • connector options: N, SMA, K-connectors
  • short lead times, also for custom designs

Drop-In Circulators and Isolators

  • 100 MHz to 40 GHz
  • up to 500 W average power, up to 6000 Watt peak power
  • single circulator and high isolation dual junction isolator designs

Surface Mount Circulators and IsolatorsJQL surface mount circulator

JQL microstrip RF isolatorMicrostrip Circulators and Isolators

  • 5 GHz to 36 GHz
  • up to 20 W average power
  • compact designs, small form factor (6.35 mm at X-band)
  • high isolation of 18 dB to 23 dB
  • ideal for Ka-band phased array radar and radio links

Waveguide Circulators and IsolatorsJQL waveguide circulator

  • 4.4 GHz to 100 GHz
  • up to 350 W average power
  • waveguide sizes: WR187, WR112, WR90, WR75, WR62, WR51, WR42, WR34, WR28, WR22, WR18, WR14, WR10
  • high isolation of up to 28 dB
  • low insertion loss of 0.3 dB at 30 GHz

Coaxial Cavity Filters


These coaxial filters use cavity resonances to achieve high Q and thus low insertion loss,JQL cavity filter bandpass steep skirts and high isolation. JQL offers various categories of cavity filters. All standard designs can be modified easily and quickly to meet customer specific requirements.

Bandpass Cavity Filters

200 MHz to 15 GHz, SMA- or N-connectors, as drop-in or with horizontal pins.
New: cavity filters for 915 MHz (datasheet)

Low Pass Cavity Filters

Band edge 450 MHz or 500 MHz

Coaxial Cavity Duplexers and Diplexers

JQL cavity filter duplexerFor center frequencies from 100 MHz to 40 GHz

Coaxial Cavity Triplexers

With three internal bandpass filters, for teh cellular frequency bands of GSM, UMTS and LTE

Coaxial Cavity Quadplexers

E.g. Quadplexer for EGSM900, UMTS2100, LTE800 and LTE2600

Cavity Multiplexers for 5 or 6 Cellular Frequency Bands

Cavity Filters for PIM Testing

Special high performance filters for test equipment which measures Passive InterModulation (PIM) distortion.
At 2 x 20 W the PIM value is <-171 dBc.

Coaxial Low PIM Terminations

Broadband (DC to 3GHz) terminations with low intermodulation distortions for power levels from 5 W to 100 W with SMA, N, 7/16 or 4.3-10 connectors. Datasheet J-4.3-10-50JR-50W JQL ceramic filter bandpass

Ceramic Filters

Ceramic Bandpassfilters

New: ceramic filter for C-band (datasheet)

Ceramic Duplexers and Diplexers

E.g. Diplexer for GSM900 and UMTS

Ceramic Triplexers JQL low PIM reactive power splitter

Ceramic Quadplexers

Coaxial Low-PIM Power Dividers

Reactive 500W RF power divider with low Passive InterModulation distortions (low PIM):
<-160 dBc at 2 x 20 W (2 x 43 dBm).
JQL low PIM bias tee

Low-PIM DC-Blocks

  • low PIM DC-Blocks for cellular frequency bands of  GSM, UMTS, LTE (698 MHz to 2.7 GHz)
  • 7/16- or N-connectors
  • low PIM: <-153 dBc at 2 x 20 W (2 x 43 dBm)
  • Broadband DC-Blocks (350 MHz to 5 GHz) with low PIM of <-150 dBc at 2 x 20 W (2 x 43 dBm)

Low-PIM Bias Tees

Bias Tees for cellular frequency bands  (690MHz to 2,7GHz) with low insertion loss (0.15dB) and low PIM (<-160dBc at 2x20W).

Coaxial Low-PIM Directional CouplersJQL coaxial low pim directional coupler

  • Directional couplers with low intermodulation distortions for DAS (Distributed Antenna Systems)
  • For PMR and cellular bands of TETRA, GSM, UMTS (3G), LTE (4G) and 5G
  • Frequency range 380MHz to 3.6GHz
  • Insertion loss less than 0.3dB
  • PIM < -140dBc at 2x20W
  • Coupling factors: 6dB, 10dB, 15dB, 20dB, 30dB, 40dB

Coaxial Low-PIM Terminations

JQL produces broadband (DC to 3GHz) coaxial terminations with low passive intermodulation distortions for RF power levels from 5 W to 100 W, with SMA, N, 7/16 or 4.3-10 connectors. Datasheet J-4.3-10-50JR-50W

Waveguide to Coax AdaptersJQL coax waveguide adapter

Adapters from waveguide to SMA-, N- or K-connector
7 GHz to 40 GHz

Power Dividers, Directional Couplers, Iso-Adapters

Catalog of JQL Standard Products