Directional Couplers and Network Analyzers

Abstract

A directional coupler and network analyzer, the directional coupler includes two power splitters, the second port of one power splitter is coupled with the first port of another power splitter, and the power splitter is used for One signal energy input from the first port is divided into two signal energies, and the two signal energies flow to the second port and the third port respectively, and the signal energy flowing to the second port of the two signal energies is greater than the other signal energy flowing to the third port Signal energy; the power divider is also used to flow all the signal energy input from the second port to the first port, and output the signal energy through the first port, using the power divider between the second port and the third port The isolation achieves the directivity of the directional coupler, and realizes the ultra-high frequency bandwidth while realizing the dual-directional function through the connection of two power dividers.

Description

technical field [0001] The invention relates to the technical field of directional couplers, in particular to a directional coupler and a network analyzer. Background technique [0002] When the network analyzer completes the measurement of standing waves or S parameters, it will simultaneously collect the signal emitted by its own port and the reflected signal of the device under test, and perform arithmetic processing on these two signals to obtain the input standing wave and port impedance of the device under test, etc. Parameters, and the extraction of its own transmitted signal and reflected signal needs to be realized through the directional coupler at the front end of the network analyzer. The directional coupler mainly completes the separation of signals. It makes one of the coupling paths only complete the collection of the transmitted signal, but does not collect the reflected signal reflected by the transmitted signal through the DUT, and the other coupling path o...

AI Technical Summary

Problems solved by technology

[0004] There are two main ways to realize the directional coupler in the network analyzer: one is to use the principle of the balanced bridge, and use the combination of the coaxial line and the resistance device to simulate the balun realization, but the designed circuit must achieve a very good balance The directivity of the directional coupler can only be realized by the characteristics of the directional coupler, and the circuit design and debugging are undoubtedly very difficult; the second is to use a coupling attenuation network composed of resistors, combined with related software algorithms to realize the directivity of the directional coupler, but the direction realized by the algorithm The characteristic does not reduce the leakage of the signal. Both coupling channels will receive the transmitted signal and the reflected signal. When the transmitted signal and the reflected signal enter the coupling channel with the same phase, the signal amplitude will be superimposed and the power will increase by 6dB, causing the receiver of the coupling channel to The noise floor deteriorates by 6dB, which causes the dynamic range of the network analyzer to deteriorate by 6dB. In some test situations, such as testing the rejection of a filter stopband, the dynamic range of the network analyzer is required to be as high as 130dB or higher. The 6dB dynamic range appears to be particularly important