A novel passive phase modulator based on LH delay lines for chipless microwave RFID applications

This paper discusses novel techniques to overcome problems arising when porting the surface acoustic wave approach of building passive radio-frequency identification and measurement systems to the electromagnetic domain without the need of mechanical (acoustical) delay lines. These techniques include the utilization of left-handed artificial delay lines and the increase of information density by using a higher order modulation scheme. The benefit from the porting is a broader field of applications, e. g. RFID tags working at very high temperatures or in other harsh environments become possible.