Quadrature Hybrid Coupler. The layout for a round quadrature hybrid coupler at 24 GHz is shown in Figure 6(a).
Quadrature Hybrid Coupler. The properties of the radar coupler are crucial for the performance of the overall system.
Measurement results in Figure 15 and Table 1 show that the four quadrature phase shifts between 24 and 24.25 GHz can be obtained with only 2[degrees] deviation, which is due to the optimal phase shift performance of the quadrature hybrid coupler.
A circuit simulation with Agilent Advanced Design System has been performed in order to estimate the theoretical accuracy of the radar front-end due to the imperfections of the Sixport network and the quadrature hybrid coupler used as radar coupler.
The scaled version of the VCA, like its lower frequency prototype, incorporates two of the quadrature hybrid couplers
discussed above and two arrays of three shunt-mounted PIN diodes, arranged in conventional balanced fashion.