Six-port precision directional coupler

Abstract

A design for a six-port, high phase and amplitude balance, stripline coupler is presented. Both the predicted and the measured performance of a hardware prototype show phase and amplitude balance better than 0.2 dB and 0.9 at the design frequency of 2.46 GHz when fabricated on an FR-4 substrate.Introduction: During the course of our investigations into phased array calibration the requirement arose for a six-port directional coupler with high coupled-port phase and amplitude balance. This design is based on edge-coupled striplines which have varied little since their conception and characterisation [1,2]. Since then other coupler configurations have been proposed [3,4]

Amplitude and phase mismatch calibration testbed for 2 x 2 tower-top antenna array system

“…-The 2x2 calibration coupler board (based on six-port precision couplers [14]) that was invented by Cooper [6] is used in this testbed design.…”

On the accuracy and hardware requirements of CORDIC-based phased array calibration

“…Thus, given an electromagnetic coupler with RMS error of, F c = 1.117° and d c = 0.3295 dB [3], the total error contribution (ε c ) to the RMS sidelobe level for a 25 element array is shown in figure 2. A 35 dB RMS sidelobe level specification is derived, limiting the total measurement error contribution to the shaded area of figure 2.…”

Wideband Substrate‐Integrated Waveguide Six‐Port Power Divider/Combiner

“…Rectangular waveguide couplers, due to their high manufacturing cost in the millimetre‐wave range, bulky three‐dimensional geometry, and difficult connection with planar structures, have been limited from being used in microwave integrated circuits. Moreover, microstrip circuits may suffer from high radiation loss and dispersion at millimetre‐wave frequencies . Substrate integrated waveguide (SIW) is a promising technique that combines relatively high Q‐factor and low insertion loss merits of traditional rectangular waveguides with the simplicity of fabrication and low‐cost integration of planar technology .…”