“…Here, to increase the input power of the injection transistors, the transformer based balun is connected in between the input pads and the transistors, realizing the purpose of impedance matching. To generate a large harmonic current, the injection transistors work in the class-B mode [9,21,22,23], and the neutralization capacitor CN is specially added to enhance its gain performance [24,25]. To improve the ILFT working efficiency, a 3 rd harmonic LC tail filter is connected at the injection transistor source terminal [19,26,27,28,29,30].…”