One of the most important requirements that RF and microwave power amplifiers designed for radiocommunication systems must meet is an optimum power added efficiency (PAE) or an optimal combination of PAE and linearity. A harmonic active load–pull system which allows the control of the first three harmonic frequencies of the signal coming out of the transistor under test is a very useful tool to...

A Class F power amplifier (PA) at 2.5GHz has been designed and fabricated. Test results show 15.7 dB gain with 75.75% power added efficiency (PAE ), at an input level of 25 dBm. The design procedure is presented, with various issues illustrated and addressed. A new method is proposed to obtain the optimum load and source impedances without iterations, which would usually be necessary.

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...

A 36-element monolithic grid amplifier has been fabricated. The active elements are pairs of heterojunction-bipolar-transistors. Measurements show a peak gain of 5dB at 40GHz with a 3-dB bandwidth of 1.8 GHz(4.5%). Here we also report comparisons of p a t t e r n s and tuning curves between the measurements and theory. The grid includes base stabilizing capacitors which result in a highly stabl...

The design of frequency-tunable amplifiers is investigated and the tradeoff between linearity, efficiency and tunability is revealed. Several tunable amplifiers using various varactor diode topologies as tunable devices are designed by using loadpull techniques and their performances are compared. The amplifier using anti-series distortion-free varactor stack topology achieves 38% power added e...

The paper first introduces phased array configurations for radar and astronomy applications. In radar various trends can be observed, on the one hand driven by cost issues and on the other hand by increasing performance demands. The trends discussed, are the increasing bandwidth, the improvement of the Power Added Efficiency of transmit/receive modules, the phase shifter technology, alternative...

A class E power amplifier including coupling coils is proposed for application in a wireless power transfer system using magnetic coupling. The proposed amplifier is directly connected to the coils with no discrete components for harmonic filtering and dc feeding, which could cause efficiency degradation of the amplifier. The system with the differential amplifier shows 6.95 W of transmitted po...