Frequency-dependent power amplifier modeling and correction for distortion in wideband radar transmissions

Dunn, Zachary; Yeary, Mark; Fulton, Caleb

doi:10.1109/mwscas.2014.6908352

Cited by 9 publications

(4 citation statements)

References 6 publications

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“…When the baseband is up-converted to a high frequency, RF linearity is distorted and may cause spectrum and phase noise. Several studies have been performed using RF linearity analysis of high-power amplifiers in SAR and telemetry systems [21,[23][24][25]. The use of the multiplier may amplify the various errors generated at intermediate frequencies, but the proposed method in this study can directly a high-performance wide bandwidth waveform.…”

Section: Hardware Outputmentioning

confidence: 99%

Wideband Waveform Generation Using MDDS and Phase Compensation for X-Band SAR

Kim

2020

Remote Sensing

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This study investigated wideband waveform generation using a field programmable gate array (FPGA) for X-band high-resolution synthetic aperture radar (SAR). Due to the range resolution determined by the bandwidth, we focused on wide bandwidth generation while preserving spectrum quality. The proposed method can generate wide bandwidth using a relatively low system clock. The new approach was designed in Simulink and implemented by very-high-speed-integrated-circuits hardware description language (VHDL). We also proposed a hardware structure in accordance with the proposed method. Signal connections of FPGA and digital analog converter (DAC) are described in the design of the proposed hardware structure. The developed X-band waveform generator using the proposed method output the desired pulse waveform. For the reduction of phase error and improvement of spectrum quality at the X-band, phase error compensation and pre-distortion were applied to the waveform generator. The results of the simulation and the hardware output demonstrate that the variation and standard deviation of the phase error were improved within the frequency spectrum. Accordingly, the proposed method and the developed waveform generator have the potential to produce a high-resolution image of the area of interest.

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Section: Hardware Outputmentioning

confidence: 99%

Wideband Waveform Generation Using MDDS and Phase Compensation for X-Band SAR

Kim

2020

Remote Sensing

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“…The nonlinear behavior of the amplifier introduces distortion in the output pulse. Dunn et al used the digital pre-distortion technique to minimize the distortion of amplified signals that appear to be linearly amplified [20][21][22][23]. With the linear assumption on the amplifier in the WPPAR system, this paper focuses on the frequency response of the antenna systems.…”

Section: Theoretical Formulation Of Biasmentioning

confidence: 99%

“…However, the frequency-dependent power amplifier (PA) and antenna system distort the output waveform in the WPPAR [18,19]. To circumvent the problem from PA, some digital pre-distortion schemes have been explored in [20][21][22][23]. Another challenge is from the transmitting/receiving antenna.…”

Section: Introductionmentioning

confidence: 99%

Bias Correction to Antenna Frequency Response for Wideband Polarimetric Phased Array Radar

Wang

Pang

et al. 2019

Electronics

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The frequency response of wideband polarimetric phased array radar antenna biases polarization measurement. A bias correction method named the iterative frequency division (IFD) algorithm is proposed in this paper to eliminate the effect of frequency response of the antenna system. The method is built on a new measurement bias model in which the effects of frequency response on the backscattering covariance matrix are analyzed. To demonstrate the effectiveness of the proposed method, a wideband microstrip patch array element is designed. Simulation results show that the biases of differential reflectivity ( Z D R ) and linear depolarization ratio ( L D R ) can be decreased to less than 0.1 dB and − 40 dB even for wide beam direction. The proposed method maintains a favorable polarization measurement accuracy for wideband polarimetric phased array radar.

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“…Both QAM and OFDM are particularly sensitive to transmittance changes generated mainly by output stages of base station transmitter power amplifiers [8][9][10][11][12][13]. Currently, such amplifiers must be linearized to meet wireless transmission standards defined e.g., by following parameters: in-band error vector magnitude (EVM), adjacent channel power ratio (ACPR), or the shape of spectrum mask [14][15][16]. There are many techniques for the amplifier linearity improvement such as e.g., analog feedforward, digital pre-distortion [6], dynamic biasing [7], envelope tracking [10], or Chireix's outphasing method [17].…”

Section: Introductionmentioning

confidence: 99%

A GaN HEMT Amplifier Design for Phased Array Radars and 5G New Radios

2020

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Power amplifiers applied in modern active electronically scanned array (AESA) radars and 5G radios should have similar features, especially in terms of phase distortion, which dramatically affects the spectral regrowth and, moreover, they are difficult to be compensated by predistortion algorithms. This paper presents a GaN-based power amplifier design with a reduced level of transmittance distortions, varying in time, without significantly worsening other key features such as output power, efficiency and gain. The test amplifier with GaN-on-Si high electron mobility transistors (HEMT) NPT2018 from MACOM provides more than 17 W of output power at the 62% PAE over a 1.0 GHz to 1.1 GHz frequency range. By applying a proposed design approach, it was possible to decrease phase changes on test pulses from 0.5° to 0.2° and amplitude variation from 0.8 dB to 0.2 dB during the pulse width of 40 µs and 40% duty cycle.

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Frequency-dependent power amplifier modeling and correction for distortion in wideband radar transmissions

Cited by 9 publications

References 6 publications

Wideband Waveform Generation Using MDDS and Phase Compensation for X-Band SAR

Wideband Waveform Generation Using MDDS and Phase Compensation for X-Band SAR

Bias Correction to Antenna Frequency Response for Wideband Polarimetric Phased Array Radar

A GaN HEMT Amplifier Design for Phased Array Radars and 5G New Radios

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