This letter presents the design of a broadband power amplifier (PA) that achieves, over the 0.45-3.4-GHz frequency band, an output power between 41.5 and 44.3 dBm and a power added efficiency (PAE) higher than 54%. A four-section transformer has been adopted as the output-matching network in order to target the impedance region defined by a simplified prediction of the power and efficiency contours. The designed PA can find application in flexible hardware for 5G applications, as well as in broadband radar and countermeasure systems.

This paper describes a large-signal single-sweep characterization system based on vector network analyzer receivers for on-wafer harmonic load/source pull measurements up to 110 GHz using passive tuners, and waveform measurements up to 100 GHz using an oscilloscope as a phase meter. The calibration and measurement procedures are described and validated with thru structures and on GaAs HEMTs at Ka-band demonstrating the capability to offer an important insight for both technology developers and designers of millimetre-wave transistors and amplifiers.

This paper analyzes the dependence vs. gate bias voltage of the coefficients of the Cardiff model in the admittance form. The load-pull measurement data used to extract the model, inclusive of input power sweep, is taken on a GaAs pseudomorphic high electron mobility transistor (pHEMT) at the frequency of 36 GHz. The gate bias is swept in class C and in class AB and a different set of coefficients is extracted at each bias point.It is observed that the model coefficients can be fitted vs. bias using a linear function within the class C and class AB ranges. This allows to predict the model coefficients within a range of bias voltages with load-pull measurements at only a few bias points, significantly reducing the measurement effort. Using the predicted coefficients, the model shows a global error lower than -31 dB for the DC and fundamental output current.