The paper describes the design, realization and characterization of a set of hybrid medium-power RF power amplifiers, based on a commercial packaged GaN HEMT and developed through a low-cost microstrip process. Two different design solutions suitable for wireless applications are presented: the first, intended for a constant-envelope modulation (with reference to the GSM standard), is a Class F...

A novel algorithm for class-A/AB power amplifiers (PA) enhancement is fully described. The principle is to find a combination of base current (gate voltage), collector voltage (drain voltage) and input power for each output power level so that the linearity/efficiency specifications of the application are satisfied. Based on a 1tone static characterization of the amplifier, the algorithm uses a...

An operational amplifier is one of the key functional blocks and is widely used in analog and mixed-signal circuits. For lowpower consumption, many techniques such as class AB and slew-rate enhancement have been proposed. Although phase compensation is related to power consumption, it has not been clearly discussed from the viewpoint of the power consumption. In this paper, the conventional and...

In this study, multi-harmonic voltage reflections are analyzed for compact power amplifiers that can be integrated into micro-sized radio units. By combining impedances at DC and harmonic frequencies throughout the transmission lines of power amplifier circuits, this method is used to reduce analytically the footprint of these circuits. Further, a cost function that takes the occupied area and ...

This paper presents the use of a new structure of active inductor named cascoded flippedactive inductor (CASFAI) in a T-type high-pass tunable output matching network of a class-E RF power amplifier (RFPA) to control the output power and enhance the efficiency. The designed CASFAI behaves as an inductor in the frequency range of 0-6.9 GHz, and has reached to a maximum quality factor of 4406, in...

In this paper, we present the design and evaluation of a software-based wireless power transfer platform that enables the development of a prototype involving various openand closed-loop power control functions. Our platform is based on a loosely coupled planar wireless power transfer circuit that uses a class-E power amplifier. In conjunction with this circuit, we implement flexible control fu...

A phase-alignment system is used fully integrate a power amplifier, Cartesian feedback linearization circuitry, and a phasealignment system. The phase-alignment system employs a new technique for offset-free analog multiplication that enables it to function without manual trimming. This paper demonstrates how the phase-alignment system improves the stability margins of the fully integrated Cart...

A fully integrated differential class-AB power amplifier has been designed in a 0.25um CMOS technology. It is intended for medium output power ranges such as Bluetooth class I, and has an operating frequency of 2.45GHz. By using two parallel output stages that can he switched on or off, a high efficiency can be achieved for both high and low output power levels. The simulated maximum output pow...