Miniature Antenna as Optimal Load for High Efficiency Integrated Active UHF Microsystems

This paper describes an electrically small active antenna optimized to deliver the maximum power within 800-1000 MHz band, being implemented in CMOS technology. The antenna plays the roll of an optimum load for the active device (PA), minimizing the total size and improving the system performance. The proposed antenna as a stand-alone element, with dimensions of lambda 0 /15timeslambda 0 /15timeslambda 0 /200, reaches efficiency values of 50% and bandwidth 14.5 MHz. Experimental results for the active element (PA) show a power-added efficiency (PAE) close to 30%. The PAE for the active antenna is measured by combining the calorimetric method with the measurement of the received power