scholarly journals Ku-Band 50 W GaN HEMT Power Amplifier Using Asymmetric Power Combining of Transistor Cells

Micromachines ◽  
2018 ◽  
Vol 9 (12) ◽  
pp. 619 ◽  
Author(s):  
Seil Kim ◽  
Min-Pyo Lee ◽  
Sung-June Hong ◽  
Dong-Wook Kim

In this paper, we present a Ku-band 50 W internally-matched power amplifier that asymmetrically combines the power transistor cells of the GaN high electron mobility transistor (HEMT) (CGHV1J070D) from Wolfspeed. The amplifier is designed using a large-signal transistor cell model in the foundry process, and asymmetric power combining, which consists of a slit pattern, oblique wire bonding and an asymmetric T-junction, is applied to obtain the amplitude/phase balance of the combined signals at the transistor cell combining position. Input and output matching circuits are implemented using a thin film process on a titanate substrate and an alumina substrate with the relative dielectric constants of 40 and 9.8, respectively. The pulsed measurement of a 330 μs pulse period and 6% duty cycle shows the maximum saturated output power of 57 to 66 W, drain efficiency of 40.3 to 46.7%, and power gain of 5.3 to 6.0 dB at power saturation from 16.2 to 16.8 GHz.

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).


Electronics ◽  
2020 ◽  
Vol 9 (6) ◽  
pp. 899
Author(s):  
Jihoon Kim

A broadband millimeter-wave (mmWave) power amplifier (PA) was implemented using a modified 2D distributed power combining technique. The proposed power combining was based on a single-ended dual-fed distributed combining (SEDFDC) design technique using zero-phase shifting (ZPS) transmission lines. To improve the input/output power distribution of each power cell within a wide frequency range, N/2-way power dividers/combiners were inserted into the distributed combining structure. Modified ZPS lines also simplified the combining structure and curbed phase variation according to the frequency. These modifications enabled power combining cells to increase without degrading the power bandwidth. The proposed PA was fabricated with a commercial 0.15 μm GaAs pseudo high electron-mobility transistor (pHEMT) monolithic microwave-integrated circuit (MMIC) process. It exhibited 20.3 to 24.2 dBm output power (Pout), 12.9 to 21.8 dB power gain, and 5.2% to 12.7% power-added efficiency (PAE) between 26 and 56 GHz.


Electronics ◽  
2019 ◽  
Vol 8 (1) ◽  
pp. 99 ◽  
Author(s):  
Ruitao Chen ◽  
Ruchun Li ◽  
Shouli Zhou ◽  
Shi Chen ◽  
Jianhua Huang ◽  
...  

This paper presents an X-band 40 W power amplifier with high efficiency based on 0.25 μm GaN HEMT (High Electron Mobility Transistor) on SiC process. An equivalent RC (Resistance Capacitance) model is presented to provide accurate large-signal output impedances of GaN HEMTs with arbitrary dimensions. By introducing the band-pass filter topology, broadband impedance matching networks are achieved based on the RC model, and the power amplifier MMIC (Monolithic Microwave Integrated Circuit) with enhanced bandwidth is realized. The measurement results show that this power amplifier at 28 V operation voltage achieved over 40 W output power, 44.7% power-added efficiency and 22 dB power gain from 8 GHz to 12 GHz. The total chip size is 3.20 mm × 3.45 mm.


2021 ◽  
Vol 11 (19) ◽  
pp. 9017
Author(s):  
Jinho Jeong ◽  
Yeongmin Jang ◽  
Jongyoun Kim ◽  
Sosu Kim ◽  
Wansik Kim

In this paper, a high-power amplifier integrated circuit (IC) in gallium-nitride (GaN) on silicon (Si) technology is presented at a W-band (75–110 GHz). In order to mitigate the losses caused by relatively high loss tangent of Si substrate compared to silicon carbide (SiC), low-impedance microstrip lines (20–30 Ω) are adopted in the impedance matching networks. They allow for the impedance transformation between 50 Ω and very low impedances of the wide-gate transistors used for high power generation. Each stage is matched to produce enough power to drive the next stage. A Lange coupler is employed to combine two three-stage common source amplifiers, providing high output power and good input/output return loss. The designed power amplifier IC was fabricated in the commercially available 60 nm GaN-on-Si high electron mobility transistor (HEMT) foundry. From on-wafer probe measurements, it exhibits the output power higher than 26.5 dBm and power added efficiency (PAE) higher than 8.5% from 88 to 93 GHz with a large-signal gain > 10.5 dB. Peak output power is measured to be 28.9 dBm with a PAE of 13.3% and a gain of 9.9 dB at 90 GHz, which corresponds to the power density of 1.94 W/mm. To the best of the authors’ knowledge, this result belongs to the highest output power and power density among the reported power amplifier ICs in GaN-on-Si HEMT technologies operating at the W-band.


Micromachines ◽  
2020 ◽  
Vol 11 (9) ◽  
pp. 831
Author(s):  
Wenyuan Liu ◽  
Lin Zhu ◽  
Feng Feng ◽  
Wei Zhang ◽  
Qi-Jun Zhang ◽  
...  

This paper presents a nonlinear microwave device modeling technique that is based on time delay neural network (TDNN). The proposed technique can accurately model the nonlinear microwave devices when compared to static neural network modeling method. A new formulation is developed to allow for the proposed TDNN model to be trained with DC, small-signal, and large signal data, which can enhance the generalization of the device model. An algorithm is formulated to train the proposed TDNN model efficiently. This proposed technique is verified by GaAs metal-semiconductor-field-effect transistor (MESFET), and GaAs high-electron mobility transistor (HEMT) examples. These two examples demonstrate that the proposed TDNN is an efficient and valid approach for modeling various types of nonlinear microwave devices.


Electronics ◽  
2020 ◽  
Vol 9 (10) ◽  
pp. 1588
Author(s):  
Sungjae Oh ◽  
Eunjoo Yoo ◽  
Hansik Oh ◽  
Hyungmo Koo ◽  
Jaekyung Shin ◽  
...  

In this paper, a frequency selective degeneration technique using a parallel network with a resistor and capacitor is proposed for a 6–18 GHz GaAs pseudomorphic high electron mobility transistor (pHEMT) broadband power amplifier integrated circuit (PAIC). The proposed degeneration network is applied to the source of the transistor to flatten the frequency response of the transistor in conjunction with feedback and resistor biasing circuits. An almost uniform frequency response was achieved at the wide frequency band through optimizing the values of the capacitor and resistor for the degeneration circuit. Single-section matching networks for small chip sizes were adopted for the two-stage amplifier following the flat frequency characteristics of the degenerated transistor. The proposed broadband PAIC for the 6 to 18 GHz band was fabricated using a 0.15 μm GaAs pHEMT process and had a chip size of 1.03 × 0.87 mm2. The PAIC exhibited gain of 15 dB to 17.2 dB, output power of 20.5 dBm to 22.1 dBm, and linear output power of 11.9 dBm to 13.45 dBm, which satisfies the IMD3 of −30 dBc in the 6–18 GHz band. Flatness for the gain and output power was achieved as ±1.1 dB and ±0.8 dB, respectively.


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