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A dual-band Class-E power amplifier using composite right/left-handed transmission lines is proposed. Dualmode operation is achieved by the frequency offset and nonlinear phase slope of CRLH TL for the matching network of power amplifiers. The frequency ratio of two operating frequencies is not necessarily an integer. Two operating frequencies are chosen 836MHz and 1.95GHz in this work. The simulated results show that output power of 24.9 and 24.1 dBm was obtained at 836MHz and 1.95GHz, respectively. In terms of maximum PAE, we obtain 48.63% and 48.29% at two operating frequencies.

This paper deals with optimal design of notch and flux barrier in order to improve the characteristics of constant torque while minimizing the cogging torque. The position and width of the notch was calculated using the Fast Fourier Transform. The optimized model using the notch and barrier demonstrated a 60% decrease in the cogging torque, a 75.3% decrease in the torque ripple, and a 3% increase in the operating torque when compared with the basic model. Thus, the operating characteristics were significantly improved.

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