Linearization of broadband two-way microstrip Doherty amplifier

Males-Ilic, Natasa; Đorić, Aleksandra; Atanasković, Aleksandar

doi:10.2298/fuee1601127m

Cited by 6 publications

(2 citation statements)

References 15 publications

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“…The microstrip two-way Doherty amplifier for the broadband application in the frequency range of 0.9-1 GHz was designed by the ADS software in [16] in standard configuration with the quarter-wave impedance inverter and transformer in the output combining circuits with the characteristic impedance R 0 = 50 Ω and R t = R 0 /√2, respectively, the 3dB quadrature branch-line coupler at the input to compensate for the phase difference of 90° caused by the 50 Ω quarter-wave impedance inverter at the output and two offset lines.…”

Section: Linearization Of a Broadband Doherty Amplifiermentioning

confidence: 99%

Linearization of the Fifth Generation Power Amplifiers by Injection of the Second Order Digitally Processed Signals

Atanaskovic,

Djoric,

Males Ilic

et al. 2024

RADIOENGINEERING

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This paper conducts a validation of two linearization approaches that utilize baseband nonlinear linearization signals of the 2nd order, through practical experiments on an asymmetrical two-way microstrip Doherty amplifier (ADA), and simulations on a symmetrical twoway Doherty amplifier (DA) as well as the single stage power amplifier (PA) for the post-OFDM 5G modulation formats. In the first approach, linearization signals are led at the input and output of the carrier transistor in the DA, while in the second approach, they are injected at the outputs of both the carrier and peaking amplifiers. The DA was tested in simulation for the FBMC signal of 20 MHz bandwidth, while the experimental measurements were performed for the FBMC signal on the ADA for different useful signal frequency bandwidths, 5 MHz, 7.5 MHz, and 10 MHz. The maximal improvement of DA linearity obtained in simulation is 10 dB for lower power and 5 dB for maximum amplifier output power, while the second approach gives around 2 dB better results for higher power levels. The experimental test for ADA performed for considered signal bandwidths indicates 3 dB to 5 dB linearity improvement for the implemented approaches and more symmetrical results achieved by the second approach. Additionally, the simulation tests for the PA were carried out for the FBMC, UFMC, and FOFDM signals of 100 MHz bandwidth, with the application of the first linearization approach. The minimal achieved linearization improvement is 13 dB for the FOFDM signal and a maximal of 18 dB for the FBMC signal.

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Section: Linearization Of a Broadband Doherty Amplifiermentioning

confidence: 99%

Linearization of the Fifth Generation Power Amplifiers by Injection of the Second Order Digitally Processed Signals

Atanaskovic,

Djoric,

Males Ilic

et al. 2024

RADIOENGINEERING

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“…In the previously deployed linearization technique that uses the fundamental signals' second-order (IM2) and fourth-order nonlinear signals (IM4) at frequencies around the second harmonics, [6][7][8][9][10][11][12], the signals for linearization were generated and prepared for injection at the input and output of the transistor amplifier in the RF analogue signal domain. Linearization effects were validated on the single stage RF power amplifiers throughout the simulation process [6]- [8] and experiments [9], as well as on the Doherty amplifiers [10][11][12].…”

Section: Introductionmentioning

confidence: 99%

RF pa linearization by signals modified in baseband digital domain

2017

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This paper represents the linearization of the RF power amplifier performed by a new approach that combines two different methods exploiting the modified baseband signals. The signals for linearization in both methods are formed and processed in digital domain. The required modified baseband signals for linearization are products of the second order nonlinearity of a nonlinear system fed by the useful baseband signal. In the first method, adequate part of the modified baseband signal is adjusted in amplitude and polarity and injected at the input and output of the amplifier transistor across the series LC resonant circuit. In the second method, the appropriate modified baseband signal set on the appropriate amplitude and phase modulates the fundamental carrier second harmonic, which is then inserted at the input and output of the amplifier transistor. The effects of the combined linearization method are considered on a single stage power amplifier for quadrature amplitude modulated signals characterized with frequency spacing between spectral components up to 60 MHz for different input power levels, as well as for WCDMA digitally modulated signal.

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