Microwave Journal
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High Power Couplers Offer Breakthrough Performance

September 14, 2015

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Maury Microwave’s LLC series of bidirectional airline couplers represents a breakthrough in high power coupler technology. Combining precision machining with stellar electrical characteristics, the LLC series couplers offer unmatched performance: high power handling, high directivity, low insertion loss and broadband performance. The LLC18-7 handles 500 W CW or 2 kW peak to 18 GHz, and the LLC34-35 handles 150W CW or 500 W peak to 34 GHz. Unlike other models that are rated at breakdown, Maury defines power handling capability as the power at which there is no discernible change in the performance of the coupler. This level of power handling enables the couplers to be integrated in high power applications such as amplifiers and base stations, as well as test and measurement applications such as power amplifier and load-pull testing.

High directivity, the difference between coupling and isolation, enables highly accurate measurements by isolating the direct and coupled measurement pathways. This is especially important in a calibrated system where changing coupler characteristics due to poor directivity can invalidate the calibration and result in erroneous measurements. Low insertion loss is critical for high power applications to avoid power loss and eliminate drift due to heating. Compared with microstrip couplers that suffer losses and self-heating from metal resistivity and dielectric permittivity, the LLC series airline couplers have no added dielectric. LLC couplers have typical insertion losses of 0.15 dB at 8 GHz and 0.25 dB at 18 GHz for the LLC18-7 and 0.25 dB at 26.5 GHz and 0.3 dB at 34 GHz for the LLC34-35. When used as part of a vector-receiver load-pull setup, low insertion loss maximizes the tuning range when combined with an impedance tuner.

The broadband nature of the coupler allows it to be used for wideband applications. The LLC18-7 is rated between 0.6 and 18 GHz, yet is useable from 0.1 GHz with increased coupling. The LLC34-35 is rated between 2 and 34 GHz and is also useable from 0.1 GHz with increased coupling.

Maury Microwave
Ontario, Calif.
www.maurymw.com