Nonlinear-Embedding Design Methodology Oriented to LDMOS Power Amplifiers

In this paper, we apply for the first time the nonlinear-embedding technique to the design of power amplifiers (PAs) based on laterally-diffused metal-oxide-semiconductor (LDMOS) field-effect transistors. Such a design technique is based on setting the transistor load line at the intrinsic current-generator plane, according to well-known theoretical guidelines. Then, the selected operating condition can be transposed at any design frequency at the extrinsic transistor terminals, by means of a model of the device nonidealities, such as the nonlinear intrinsic capacitances and the linear parasitic effects. A harmonically-tuned high-efficiency class-F and a wideband class-AB PAs operating within the FM broadcasting band 88 divided by 108 MHz based on a 10-W LDMOS are then designed and realized. To definitely assess the validity of the proposed approach for the LDMOS technology, we compare the measured performance on the fabricated PAs with the expected predictions.