Technologies directed to coupling structures for antenna feeds of phased array antennas are described. One circuit board includes a first layer with a first portion of a RF coupling structure, a second layer with a second portion of the RF coupling structure, and a first insulation layer located between the first layer and the second layer. The RF coupling structure is configured to electromagnetically couple a first conductive trace on the first layer and a second conductive trace on the second layer at RF frequencies. The circuit board also includes an RF shielding structure coupled to a ground connection on the second layer and located in the first insulation layer. The RF shielding structure is configured to operate as a RF short circuit between the ground connection and a third conductive trace on the first layer at RF frequencies.