Dual Fed Distributed Amplifier With Controlled Termination Adjustment

Abstract

Abstract-A new circuit and technique to extend the bandwidth of the Dual Fed Distributed Amplifier (DFDA) while preserving the improvement on efficiency performance in comparison to conventional distributed amplifiers (DAs) is presented. The theoretical analysis is described in detail, and a test vehicle is realized to demonstrate the effectiveness of the proposed method. Output power of ∼ 29 dBm, gain of 10 dB, covering a bandwidth from 100 to 800 MHz, with a PAE of 20-45% is experimentally demonstrated. The results are compared with measured results of the conventional DA, demonstrating a significant improvement in bandwidth and efficiency.

Optimised high‐efficiency Class E radio frequency power amplifier for wide bandwidth and high harmonics suppression

“…The results showed the proposed topology provides higher harmonic suppression while preserving high efficiency performance over the entire bandwidth of interest. Pole-zero identification method is based on transfer function approach, where the function of the linearised frequency of steady-state response is obtained to extract the stability information [22]. As explained in [22], the large-signal frequency response in any node of the linearised circuit can be easily computed by introducing a small signal current generator in that particular node and measuring the resonance impedance observed by the current source as the frequency of the current source is swept.…”

“…To find best compromise between stability and circuit performance, it is essential to combine the large-signal stability analysis with judicious stabilisation strategy [22]. The gain expansion of deep class AB bias is required in order to achieve high efficiency performance, but typically causes oscillation issues [22]. After careful consideration, an optimum solution is the feedback stabilisation circuits of 100 Ω and 0.1 uF, referring to Fig.…”

“…Pole‐zero identification method is based on transfer function approach, where the function of the linearised frequency of steady‐state response is obtained to extract the stability information [22]. As explained in [22], the large‐signal frequency response in any node of the linearised circuit can be easily computed by introducing a small signal current generator in that particular node and measuring the resonance impedance observed by the current source as the frequency of the current source is swept. Generally, power amplifiers are prone to spurious oscillations because of the presence of multiple non–linear elements and feedback loops.…”

“…In fact, under certain conditions, the amplifier can exhibit parametric oscillations, that is, spurious response of autonomous nature that are a function of the input power and input frequency. Small‐signal stability techniques are unable to detect parametric oscillation, but with pole‐zero technique [22], stability detection is guaranteed and appropriate stabilisation circuit can be implemented in design stage.…”

A design technique to improve harmonic suppression in high efficiency wideband Class E RF power amplifier

“…Few works related to impedance transformation have been demonstrated, e.g. using parallel-coupled line [16] and nonsynchronous noncommensurate technique [17]. However, the proposed topology shown in Fig.…”