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Load pull with active tuning has been reported for many years, but not widely implemented, even though it does offer some advantages. Load pull with passive tuning, however, is widely used. Combining active tuning with passive tuning creates a hybrid tuning system that offers some of the advantages of both approaches. This paper discusses a hybrid tuning system created by adding active tuning to an...
A continuum of closed-form solutions for voltage waveforms resulting from a complex load at the fundamental and reactive terminations at certain harmonic frequencies is analytically derived for Inverse Class-F power amplifiers based on a finite number of harmonics. The continuum of solutions shows constant RF output power and efficiency for a range of fundamental reactances and appropriately chosen...
This paper presents the experimental analysis of the injection of harmonic signals at the gate of a RF power transistor. The harmonic injection leads to an optimized shape of the waveforms at the inner transistor resulting in an improvement of the efficiency performance. A triplexer, allowing injecting the second as well as the third harmonic into the transistor is designed for these experiments,...
This paper presents a low-power Class-D stage featuring a new harmonic reduction technique, which cancels the 3rd harmonic and reduces the 5th harmonic. The technique creates a voltage level of VDD/2 from a single supply voltage to shape the drain voltage, uses only digital circuits and eliminates the short-circuit current present in inverter-based Class-D stages. From a single Class-D stage operating...
In recent years, there has been a great effort to increase the efficiency of Radio Frequency Power Amplifiers. This can be achieved by using techniques such as Envelope Tracking and Envelope Elimination and Restoration. These techniques require DC/DC converters capable of changing its output voltage very fast, in order to reproduce the envelope of the signal being amplified by the Radio Frequency...
In this work a design flow for class C radiofrequency (RF) power amplifiers (PA) with on-chip output networks in nanometric technologies is presented. This is a new parasitic-aware method intended to reduce time-consuming iterations which are normally required in fully-integrated designs. Unlike other methods it is based on actual transistors DC characteristics and inductors data both extracted by...
Coherent mixed-signal techniques are applied in high-performance N-way Doherty and outphasing amplifier configurations, as well as, in advanced Large-signal RF device characterization systems. These new techniques provide optimum input signal control of the individual branch amplifiers, yielding improved efficiency in power back-off operation and higher bandwidths. When using coherent-mixed signal...
A novel reflection-absorptive harmonic-rejection filter (RA-HRF) is presented for harmonic-terminated high-efficiency RF power amplifier (PA). It basically consists of a pair of reactive band-rejection filter and a dual-band Wilkinson power divider where its isolation resistor absorbs the reflected signals from the band-rejection filters. The reflection-absorptive property can solve a parasitic anti-resonance...
Orthogonal frequency division multiplexing (OFDM) systems are significantly sensitive to the nonlinear distortion caused by RF power amplifiers. Generally, nonlinear distortion of OFDM signals, which generates a huge number of inter-modulation products (IMPs), is treated as a macro phenomenon. In this paper, low order IMPs are classified into various categories by their composition and the characteristics...
A high PA and an antenna switch were implemented in a single die with low noise amplifier to study feasibility of integration of all the RF front end components in a standard bulk CMOS process. Low voltage operation which is the biggest obstacle to implement a high power amplifier and a high power switch in the CMOS technology were resolved to by employing power combining technique using transformer...
In this paper, we propose the new linearization scheme for nonlinear RF power amplifier, generating the third and fifth intermodulation distortion signals it uses the identical structure of intermodulation signal generator. The proposed predistorter generates and controls predistorted third and high order IM signals independently. Using predistorted signals, intermodulation distortion signals of power...
Transmission lines and their lumped approximating networks have long been incorporated into radio-frequency power amplifiers to improve efficiency and shape circuit waveforms, and are beginning to perform a similar roles in high-frequency switched-mode power electronics. Though lumped line-simulating networks are often preferred to their distributed exemplars for reasons of design flexibility and...
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