A Novel Loop Antenna Easily Matching with Radio Frequency Integrated Circuit Chips

A novel loop antenna whose input impedance can match directly with that of a radio frequency integrated circuit (RFIC) chip is presented. Specifically, the antenna can be constituted so that resistance and reactance of its input complex impedance may simultaneously become 100 Ω or more. This feature has been realized by the structure winding a loop doubly. In this presentation, the antenna has been tuned to match with the RFIC chip whose complex impedance is 131-j91 Ω at 920 MHz. The performance of the antenna has been achieved with 16% or more in the −10 dB impedance bandwidth, 2.26 dB in the maximum gain and 99% in the radiation efficiency.