I am designing a GPS board with an SMT patch antenna (SGP.25cfrom Taoglas). I understand that the rf feed is 50Ohms impedance controlled track. But the datasheet shows 2 feeds - inner feed and outer feed. What are the 2 feeds. Does the inner feed mean that I can place the GPS on one layer and the antenna on the other layer and connect the RF track via the inner feed. In that case how is the impedance controlled through the via.