Time-domain optical sampling of switched-mode microwave amplifiers and multipliers

Abstract

Time-domain measurements of the output waveforms of two 8-GHz high-efficiency power amplifiers, a 1-GHz frequency doubler, and a 5-GHz frequency doubler are presented in this paper. A new photoconductive probe has enabled nonintrusive time-domain voltage measurements, which confirm switched-mode class-E and class-F amplifier operation. In order to analyze nonlinear amplifiers designed to deliver a sinusoidal wave to the load, voltages at characteristic points inside the circuit need to be known. In multipliers, waveform measurements track harmonic leakage, expediting the design cycle. The highimpedance probe used here is an optoelectronic sampler, which can sense the charge on an exposed interconnect or the field associated with a buried interconnect. These electric-field data are then converted into voltage.

High-efficiency switched-mode power amplifier using gallium nitride on silicon hemt technology

“…The drain voltage and current waveforms in Figure 5.31 confirm th a t, at least in simulation, th e PA operates in quasi Class E mode. The simulations agree w ith previously reported work noting th a t the desired (ideal) peak voltage and current levels of 71 V and 660 mA are never reached in practice [76]. The true test of a PA 's capability to amplify a desired RF input signal lies in its ability to do so as efficiently as possible w ith a reasonable gain.…”

“…thesis[38,73]. His work has been carried forward over the years[74][75][76], b u t to the best of the au th o r's knowledge, has never been implemented in a GaN-on-Si PA. The GaN-based Class E switched-mode concept is not novel.…”

An efficient x -band 16-element spatial combiner of switched-mode power amplifiers

“…However, due to the relatively low linear gain of the device, and the fact that it will operate deep in compression (more than 3 dB), lower PAE, on the order of 50%-60%, is expected. For an amplifier with similar performance, optical sampling measurements of time-domain voltage waveforms confirmed the approximate class-E mode of operation [22].…”

Highly efficient 5.8‐GHz class E−1 frequency doubler using a transmission‐line‐based notch filter

“…The switching-mode operation of transistors is advantageous in improving the output efficiency due to the nonlinear characteristics, and a frequency multiplier using the class E operation can ideally obtain a drain efficiency of 100% and high PCE due to both zero voltage switching (ZVS) and zero voltage-derivative switching (ZVDS) characteristics. 3 An inverse class E topology, which changes the operating characteristics from ZVS and ZVDS to zero current switching and zero current derivative switching, is known to provide higher output power and PCE in the switching-mode circuit over frequencies of a few GHz, compared to classical class E topology. 4,5 Compared with the voltage-driven class E topology, the current-driven inverse class E topology can operate with a lower switching voltage and relax the breakdown voltage constraint at the switching transistor.…”