power amplifiers (pas) are inherently nonlinear elements and digital predistortion is a highly cost-effective approach to linearize them. although most existing architectures assume that the pa has a memoryless nonlinearity, memory effects of the pas in many applications ,such as wideband code-division multiple access (wcdma) or orthogonal frequency-division multiplexing (ofdm), can no longer b...

Power amplifiers (PAs) are inherently nonlinear elements and digital predistortion is a highly cost-effective approach to linearize them. Although most existing architectures assume that the PA has a memoryless nonlinearity, memory effects of the PAs in many applications ,such as wideband code-division multiple access (WCDMA) or orthogonal frequency-division multiplexing (OFDM), can no longer b...

This paper presents a new procedure to design of high efficiency class E power amplifiers (PAs) using nonlinear transistors. The active device (MESFET-ATF34143) has been investigated and load harmonic networks have also been designed to match the requirement. By using the new procedure, the power added efficiency (PAE) of PAs could be increased to over 70%. The effect of the stabilized resistor...

Efficient RF power amplifiers used in third generation systems require linearization in order to reduce adjacent channel inter-modulation distortion, without sacrificing efficiency. Digital baseband predistortion is a highly cost-effective way to linearize power amplifiers (PAs). New communications services have created a demand for highly linear high power amplifiers (HPA's). Traveling Wave Tu...

Efficient RF power amplifiers used in third generation systems require linearization in order to reduce adjacent channel inter-modulation distortion, without sacrificing efficiency. Digital baseband predistortion is a highly cost-effective way to linearize power amplifiers (PAs), but most existing architectures assume that the PA has a memoryless nonlinearity. For wider bandwidth applications s...

This article is focused on GaN-based power amplifiers for applications up to 10 GHz. Several PAs developed in both MMIC and hybrid technologies for different RF and microwave frequency bands will be described. In particular, the designs of two ultra-wideband (UWB) PAs are reported together with experimental results. The first one is based on commercial GaN-on-SiC technology while the other one ...

Series stacking of multiple devices in power amplifiers is a promising technique that has been explored recently at millimetre-wave frequencies to overcome some of the fundamental limitations of metal–oxide–semiconductor (CMOS) technology. Stacking multiple devices improve the output power and efficiency by increasing the achievable output voltage swing. Switching power amplifiers (PAs), such a...

This paper deals with the design techniques of power efficient switching regulators intended for linear power amplifiers (PAs) employing envelope tracking techniques in wideband wireless standards. The bottlenecks involve a tradeoff between ripple voltage, slew rate and bandwidth. The slew rate limitation is identified as the main challenge; thus a ‘bang-bang’ slew-enhancement technique is prop...

Wide band code division multiple access (WCDMA) signals, transmitted by the base station high power amplifiers (HPAs), show high peak to average power ratios (PAPR), which results in nonlinear distortions. In this paper, using computer simulations effect of using a predistorted HPA on the symbol error rate (SER) of multi-user detectors in terms of output back-off (OBO) in the transmit power...

Orthogonal frequency division multiplexing (OFDM) is regarded widely as the key underlying air interface technology for wireless systems such as WiMAX, 3GPP long-term evolution (LTE), and 3GPP2 ultra-mobile broadband (UMB). Due to the inherent nature of these technologies, OFDM signals have high peak-to-average power ratio (PAR) that adversely affects the efficiency of power amplifiers (PAs) us...