Non Linear Equivalent Circuit For Broadband GaAs MESFET Power Amplifier Design

Author(s):  
R. Soares ◽  
M. Goudelis ◽  
B. Loriou ◽  
E. de Los ◽  
R. Devo
2021 ◽  
Vol 11 (19) ◽  
pp. 9120
Author(s):  
Jihoon Kim

A new gallium nitride (GaN) high electron mobile transistor (HEMT) small-signal model is proposed considering source via effects. In general, GaN HEMTs adopt a source via structure to reduce device degradation due to self-heating. In this paper, the modified drain-source capacitance (Cds) circuit considering the source via structure is proposed. GaN HEMTs fabricated using a commercial 0.15 μm GaN HEMT process are measured with a 67 GHz vector network analyzer (VNA). The fabricated device is an individual source via (ISV) type. As a result, it is difficult to predict the measured S12 in the conventional small-signal model equivalent circuit. This causes errors in maximum stable gain/maximum available gain (MSG/MAG) and stability factor (K), which are important for circuit design. This paper proposes a small-signal equivalent circuit that adds the drain-source inductance to the drain-source capacitance considering the source via structure. The proposed equivalent circuit better reproduces the measured S12 without compromising the accuracy of other S-parameters up to 67 GHz and improves the accuracy of MSG/MAG and K. It is expected that the proposed model can be utilized in a large-signal model for 5G millimeter-wave GaN HEMT power amplifier design in the future.


2018 ◽  
Vol 12 (1) ◽  
pp. 34-40
Author(s):  
Said Elkhaldi ◽  
Naima Amar Touhami ◽  
Mohamed Aghoutane ◽  
Taj-eddin Elhamadi

Introduction:This paper focuses on improving the power amplifier linearity for wireless communications. The use of a single branch of a power amplifier can produce high distortion with low efficiency.Method:In this paper, the Linear Amplification with Nonlinear Components (LINC) technique is used to improve the linearity and efficiency of the power amplifier. The LINC technique is based on converting the envelope modulation signal into two constant envelope phase-modulated baseband signals. After amplification and combining the resulting signals, the required linear output signal is obtained. To validate the proposed approach, LINC technique is used for linearizing an amplifier based on a GaAs MESFET (described by an artificial neural network Model).Conclusion:Good results have been achieved, and an improvement of about 40.80 dBc and 47.50 dBc respectively is obtained for the Δlower C/I and Δupper C/I at 5.25 GHz.


Author(s):  
Sandeep R. Sainkar ◽  
Alice N. Cheeran ◽  
Gajendrakumar Shinde ◽  
Promod K. Sharma ◽  
Harish V. Dixit

Electronics ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 263
Author(s):  
Roberto Quaglia

In high-frequency power-amplifier design, it is common practice to approach the design of reactive matching networks using linear simulators and targeting a reflection loss limit (referenced to the target impedance). It is well known that this is only a first-pass design technique, since output power or efficiency contours do not correspond to mismatch circles. This paper presents a method to improve the accuracy of this approach in the case of matching network design for power amplifiers based on gallium nitride (GaN) technology. Equivalent mismatch circles, which lay within the power or efficiency contours targeted by the design, are analytically obtained thanks to geometrical considerations. A summary table providing the parameters to use for typical contours is provided. The technique is demonstrated on two examples of power-amplifier design on the 6–12 GHz band using the non-linear large-signal model of a GaN High Electron Mobility Transistor (HEMT).


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