Abstract: A platform for trapping atomic ions includes a substrate and a plurality of metallization layers that overlie the substrate. The metallization layer farthest from the substrate is a top layer patterned with electrostatic control trap electrodes and radio-frequency trap electrodes. Another metallization layer is a microwave layer patterned to define a microwave circuit. The microwave layer lies below the top layer. The microwave circuit is adapted to generate, in use, a microwave magnetic field above the electrostatic control and radio-frequency trap electrodes. The top metallization layer includes slots that, in use, are penetrated by microwave energy from the microwave circuit.