National Instruments Corporation

Michael Joseph Seibel

Marcus Kieling daSilva

Daniel S Wertz

Justin R Magers

A reflectometer may include two directional couplers configured in parallel by being disposed across from each other on opposite sides of a shared section of a signal line. One of the couplers may couple, to a first port of the reflectometer, a portion of the signal power of a first signal flowing from the first end of the shared through-line to the second end of the shared through-line, and the other coupler may couple, to a second port of the reflectometer, a portion of the signal power of a second signal flowing from the second end of the shared through-line to the first end of the shared through-line. The reflectometer benefits from reduced size and signal loss relative to a serial coupler configuration. When used in vector network analyzer (VNA) systems, this results in higher output power and higher dynamic range of the VNA.

Dual directional asymmetric coupler with a shared through-line

A reflectometer may include two directional couplers in a parallel configuration, sharing the same section of a signal line or through-line. For example, two directional couplers may be disposed across from each other on opposite sides of the shared through-line. One of the directional couplers may couple, to a first port of the reflectometer, a portion of the signal power of a first signal flowing from the first end of the shared through-line to the second end of the shared through-line, and the other directional coupler may couple, to a second port of the reflectometer, a portion of the signal power of a second signal flowing from the second end of the shared through-line to the first end of the shared through-line. The reflectometer benefits from reduced size and signal loss with respect to reflectometers having a serial configuration. When used in vector network analyzer (VNA) systems, this results in higher output power and higher dynamic range of the VNA.

Measurements, e.g. S-parameter measurements may be performed by obtaining a complex ratio of at least two signals, using a single signal-receiver while eliminating noise problems traditionally associated with single receiver systems. A Vector Signal Generator (VSG) may be used to generate the input stimulus (signal), making it possible to share the local oscillator (LO) signal of the VSG with a single vector receiver, such that the phase noise of the LO signal is common to both the VSG and the vector receiver. When the stimulus signal from the VSG is observed with the vector receiver, the LO phase noise is unobservable, resulting in a significant reduction of the phase noise in the measured signals in both the numerator and the denominator, which in turn leads to a significant reduction in the phase noise of the ratio while retaining the benefits of a simple, single receiver.

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Michael Joseph Seibel