Multilayer coupler design and implementation for RFID systems and energy harvesting applications

Design, simulation, and implementation of multilayer microstrip type directional couplers for RFID systems operating in the ultra high frequency (UHF) range is presented. The two-line multi-layer microstrip directional coupler is integrated to the front end of an RFID system to provide the required isolation between transmitter and receiver, preventing signal leakage. Several configurations of two-line multi-layer microstrip couplers have been designed, simulated, built and tested. Microstrip couplers have been implemented using several different materials. It has been shown that analytical, simulation, and measurement results are all in agreement. The presented technique can be also used for design of passive components in energy harvesting applications.