Frequency-Agile Class-J Power Amplifier With Clockwise Fundamental- and Second-Harmonic Loads

Abstract A novel, broadband, nonlinear behavioral model, based on support vector regression (SVR) is presented in this paper. The proposed model, distinct from existing SVR-based models, incorporates frequency information into its formalism, allowing the model to perform accurate prediction across a wide frequency band. The basic theory of the proposed model, along with model implementation and the model extraction procedure for radio frequency transistor devices is provided. The model is verified through comparisons with the simulation of an equivalent circuit model, as well as experimental measurements of a 10 W Gallium Nitride (GaN) transistor. It is seen that the efficiency prediction throughout the Smith chart, for varying fundamental and second harmonic loads, across a wideband frequency range, show excellent fidelity to the measured results. Device dc self-biasing is also modelled to allow prediction of power amplifier (PA) efficiency, which is shown to be highly accurate when compared with corresponding measured data. Finally, a class-J PA is constructed and measured across the frequency with a large-signal input tone. The resulting measured and modelled values of key PA performance figures are shown to be in excellent agreement, indicating the model is suitable for broadband PA design.

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X-Band High-Efficiency Continuous Class B Power Amplifier GaN MMIC Assisted by Input Second-Harmonic Tuning

Electronics ◽

10.3390/electronics8111312 ◽

2019 ◽

Vol 8 (11) ◽

pp. 1312 ◽

Cited By ~ 1

Author(s):

Chen Jin ◽

Yuan Gao ◽

Wei Chen ◽

Jianhua Huang ◽

Zhiyu Wang ◽

...

Keyword(s):

Power Amplifier ◽

Integrated Circuit ◽

High Efficiency ◽

Second Harmonic ◽

Power Added Efficiency ◽

Optimum Load ◽

Measurement Results ◽

Class B ◽

Point To Point ◽

Output Capacitance

This paper presents a high-efficiency continuous class B power amplifier MMIC (Monolithic Microwave Integrated Circuit) from 8 GHz to 10.5 GHz, fabricated with 0.25 μm GaN-on-SiC technology. The Pedro load-line method was performed to calculate the optimum load of the GaN field-effect transistor (FET) for efficiency enhancement. Optimized by an output second-harmonic tuned network, fundamental to second-harmonic impedance, mapping was established point-to-point within a broad frequency band, which approached the classic continuous class B mode with an expanded high-efficiency bandwidth. Moreover, the contribution to the output capacitance of the FET was introduced into the output second-harmonic tuned network, which simplified the structure of the output matching network. Assisted by the second-harmonic source-pull technique, the input second-harmonic tuned network was optimized to improve the efficiency of the power amplifier over the operation band. The measurement results showed 51–59% PAE (Power Added Efficiency) and 19.8–21.2 dB power gain with a saturated power of 40.8–42.2 dBm from 8 GHz to 10.5 GHz. The size of the chip was 3.2 × 2.4 mm2.

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A Class-J Power Amplifier Implementation for Ultrasound Device Applications

Sensors ◽

10.3390/s20082273 ◽

2020 ◽

Vol 20 (8) ◽

pp. 2273 ◽

Cited By ~ 5

Author(s):

Kiheum You ◽

Seung-Hwan Kim ◽

Hojong Choi

Keyword(s):

Power Amplifier ◽

High Efficiency ◽

Second Harmonic ◽

Signal Spectrum ◽

Electronic Components ◽

Echo Signal ◽

Ultrasonic Device ◽

Device Applications ◽

Ultrasonic Devices ◽

High Output

In ultrasonic systems, power amplifiers are one of the most important electronic components used to supply output voltages to ultrasonic devices. If ultrasonic devices have low sensitivity and limited maximum allowable voltages, it can be quite challenging to detect the echo signal in the ultrasonic system itself. Therefore, the class-J power amplifier, which can generate high output power with high efficiency, is proposed for such ultrasonic device applications. The class-J power amplifier developed has a power efficiency of 63.91% and a gain of 28.16 dB at 25 MHz and 13.52 dBm input. The pulse-echo measurement method was used to verify the performance of the electronic components used in the ultrasonic system. The echo signal appearing with the discharged high voltage signal was measured. The amplitude of the first echo signal in the measured echo signal spectrum was 4.4 V and the total-harmonic-distortion (THD), including the fundamental signal and the second harmonic, was 22.35%. The amplitude of the second echo signal was 1.08 V, and the THD, including the fundamental signal and the second harmonic, was 12.45%. These results confirm that a class-J power amplifier can supply a very high output echo signal to an ultrasonic device.

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Realization of a 30-W highly efficient and linear reconfigurable dual-band power amplifier using the continuous mode approach

International Journal of Microwave and Wireless Technologies ◽

10.1017/s1759078713000937 ◽

2013 ◽

Vol 6 (2) ◽

pp. 115-128 ◽

Cited By ~ 4

Author(s):

Vincenzo Carrubba ◽

Stephan Maroldt ◽

Markus Mußer ◽

Herbert Walcher ◽

Friedbert Van Raay ◽

...

Keyword(s):

Power Amplifier ◽

Continuous Wave ◽

Second Harmonic ◽

Power Level ◽

Dual Band ◽

Power Efficient ◽

Frequency Bands ◽

Class Ab ◽

Output Performance ◽

Band Power

This paper presents the design methodology and the realization of a highly linear and power-efficient reconfigurable dual-band amplifier based on the continuous/Class-ABJ approach. The Class-ABJ theory allows presenting different reactive solutions on both fundamental and second harmonic terminations compared with the standard Class-AB mode. Despite the various terminations, a constant optimum output performance in terms of power, gain, and efficiency can still be achieved. The output impedances are then translated into frequency thus allowing the realization of broadbandpower amplifiers(PAs) at high-power level of 30 W. In this work, the Class-ABJ broadband approach will be used for the realization of a reconfigurable dual-band power amplifier operating in the two frequency bands 2.1–2.2 and 2.5–2.6 GHz. Continuous wave (CW) measurements on the realized PA show power and efficiency greater than 17 W and 55% in the two frequency bands with peak values up to 30 W and 63.7%. Indeed, it is shown that such novel modes can be predistorted and therefore the linearity requirement can also be met.

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