A 3.1 W High Gain 51% Fractional Bandwidth GaN HEMT Power Amplifier Design for Far-Field Wireless Power Transfer (WPT) Applications

This paper presents the design of a high gain and efficient power amplifier (PA) that is capable of operating within the ultra-wideband (UWB) frequency range (3.1 - 10.6 GHz) for wireless power transfer (WPT) applications. Qorvo TGF2977 GaN HEMT transistor has been used for the proposed design since it is capable of operating in the desired UWB frequency range from DC to 12 GHz. An impedance matching technique has been proposed in this paper so that when the matching network elements are translated through the T-line elements, the impedance of the matching network incorporating the T-line elements is matched to the optimal source and load impedances of the transistor. An analytical model of the microstrip T-line has been developed in this paper so that proper impedance matching can be achieved by tuning and controlling the width of the T-line elements. The desired S-parameter response can be obtained by using this technique so that the target performances of the PA can be achieved. The proposed PA is chosen to operate in the class-C mode since this mode of operation can achieve a very high efficiency. The designed PA is capable of achieving a gain of 14.34 dB and has a
$-3dB$
gain bandwidth of 3.03 GHz (51% fractional bandwidth) from 4.22 – 7.25 GHz. The PA is able to generate the highest output power of 34.9 dBm
$(3.1W)$
at the
$P_{1dB}$
of 22 dBm input power at 6 GHz frequency. At the same frequency and the
$P_{1dB}$
input power, the proposed PA is able to achieve a power added efficiency (PAE) of 37.1% while the highest PAE of 45.6% is achieved at the 28 dBm input power.