Compact patch antenna with space for integrating sensors for an RFID-sensor-node

Sensor applications for RFID systems received lot of attention in the last year. Here a compact planar patch antenna that provides space for sensor elements and their connection network is presented. The antenna built up from a standard patch, shortened by via holes and has an opening for the sensor elements. Placed on a metal surface the antenna behaves as a patch antenna, and in free space it has the radiation pattern of a dipole antenna.