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For a given feed position, newly derived equations are used to determine the dimensions of a circular‐polarized (CP) nearly square patch antenna. It is also shown that for a feed offset from one corner of the patch, the perturbation segment (ΔS) is increased, thereby reducing the effect of manufacturing errors. © 2005 Wiley Periodicals, Inc. Microwave Opt Technol Lett 46: 406–410, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21001

Based on the symmetric properties of the antenna, the design equations for the first four mode frequencies are derived. A design methodology for an antenna operating at 2.45 GHz is presented. Two antennas have been designed and tested, and good agreement among the predicted, simulated, and measured results is obtained. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 791–795, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22269

A high linearity and efficiency Doherty power amplifier is proposed and fabricated with inverted topology and uneven power drive. Its PAE achieves 33.1%, which performs 3.2% better than even drive case. The ACLR presents Ϫ47 dBc at 45 dBm output power, which is improved by 5 dB with 5-MHz two-tone test. The proposed amplifier has IMD3 of Ϫ44 dBc, which presents 2.5 dB improvement over the even case with appropriately cancellation of the carrier cell harmonics. The PAE maintains 30%, while 12 dB output back-off for low EVM. These experimental results clearly demonstrate the superior performance of the proposed Doherty power amplifier.

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