A multi-layer coupled-line power divider

In this paper, a power divider configuration made of coupled microstrip line is proposed. This power dividing scheme allows a larger range in unequal power dividing ratio and is therefore suitable for array antenna feeds with serially connected elements. The proposed power dividing scheme is also attractive in reducing power loss in the feeding network due to reduced number in power dividers and transmission line lengths. The coupled-line power divider consists of three layers of traces and two slabs of substrates. The top and bottom layers are microstrip lines while the middle layer is the common ground. At the power divider location, elliptical patches present on both the top and bottom layers, and an elliptical aperture is cut on the ground. By adjusting the size of metal patches and the aperture, a controllable power dividing ratio can be achieved.