Maryam Sajedin | University of Aveiro (original) (raw)
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Papers by Maryam Sajedin
Enabling 6G Mobile Networks
Electronics
This work develops a novel dynamic load modulation Power Amplifier (PA) circuity that can provide... more This work develops a novel dynamic load modulation Power Amplifier (PA) circuity that can provide an optimum compromise between linearity and efficiency while covering multiple cellular frequency bands. Exploiting monolithic microwave integrated circuits (MMIC) technology, a fully integrated 1W Doherty PA architecture is proposed based on 0.1 μm AlGaAs/InGaAs Depletion-Mode (D-Mode) technology provided by the WIN Semiconductors foundry. The proposed wideband DPA incorporates the harmonic tuning Class-J mode of operation, which aims to engineer the voltage waveform via second harmonic capacitive load termination. Moreover, the applied post-matching technique not only reduces the impedance transformation ratio of the conventional DPA, but also restores its proper load modulation. The simulation results indicate that the monolithic drive load modulation PA at 4 V operation voltage delivers 44% PAE at the maximum output power of 30 dBm at the 1 dB compression point, and 34% power-added ...
The OFDM is generally known as an effective technique for high Bit-rate applications. In OFDM sys... more The OFDM is generally known as an effective technique for high Bit-rate applications. In OFDM systems, the combination of different signals with different phase and amplitude give a large dynamic range that is used to be characterized by a high PAPR. To obtain maximum efficiency Power Amplifier should be driven near the saturation region, but since the OFDM signal has high PAPR, this power amplifier will cross over to the nonlinear region causing serious in band distortion, and operation in nonlinear mode reduces performances of the output signal. To compensate for this distortion, liberalizers are proposes to utilize a digital pre-distortion of baseband signals, which is efficient and illustrates a high performance for linearization of OFDM transmitters. This paper presents an adaptive digital pre-distortion techniques based on Look Up LUT) method which will result in cancellation of nonlinear distortion appearing in power amplifier through Advanced Design System(ADS) software. It is shown that the new simplified structure exhibits fast convergence and LUT pre-distorter can effectively suppress the spectrum regrowth caused by the dynamic nonlinearity of power amplifier. describes the basic algorithm implemented in the LUT design. The incoming complex samples in I and Q, have correction factors applied from the LUT and sent to module. The addresses for the LUT are derived from the input power. The LUT must contain two values for each location the real part and the imaginary part Q. in the module ,samples are unconverted and sent to the PA . In the feedback loop, the output of the PA is downconverted-transformed to polar form-and compared with the delayed version of the input to the predistorter in polar form. This error is then used to update the values currently stored in the LUT. The LUT address is derived from the input power. Hence this algorithm is only able to correct for phase and magnitude error that are purely a function of the current input power. The LUT coefficient is fed into the predistorter, which reads an appropriate correction value (LUT value) from the LUT and uses it to modify the input data .the resultant modified coefficient is referred to as predistorted data.
Enabling 6G Mobile Networks
Electronics
This work develops a novel dynamic load modulation Power Amplifier (PA) circuity that can provide... more This work develops a novel dynamic load modulation Power Amplifier (PA) circuity that can provide an optimum compromise between linearity and efficiency while covering multiple cellular frequency bands. Exploiting monolithic microwave integrated circuits (MMIC) technology, a fully integrated 1W Doherty PA architecture is proposed based on 0.1 μm AlGaAs/InGaAs Depletion-Mode (D-Mode) technology provided by the WIN Semiconductors foundry. The proposed wideband DPA incorporates the harmonic tuning Class-J mode of operation, which aims to engineer the voltage waveform via second harmonic capacitive load termination. Moreover, the applied post-matching technique not only reduces the impedance transformation ratio of the conventional DPA, but also restores its proper load modulation. The simulation results indicate that the monolithic drive load modulation PA at 4 V operation voltage delivers 44% PAE at the maximum output power of 30 dBm at the 1 dB compression point, and 34% power-added ...
The OFDM is generally known as an effective technique for high Bit-rate applications. In OFDM sys... more The OFDM is generally known as an effective technique for high Bit-rate applications. In OFDM systems, the combination of different signals with different phase and amplitude give a large dynamic range that is used to be characterized by a high PAPR. To obtain maximum efficiency Power Amplifier should be driven near the saturation region, but since the OFDM signal has high PAPR, this power amplifier will cross over to the nonlinear region causing serious in band distortion, and operation in nonlinear mode reduces performances of the output signal. To compensate for this distortion, liberalizers are proposes to utilize a digital pre-distortion of baseband signals, which is efficient and illustrates a high performance for linearization of OFDM transmitters. This paper presents an adaptive digital pre-distortion techniques based on Look Up LUT) method which will result in cancellation of nonlinear distortion appearing in power amplifier through Advanced Design System(ADS) software. It is shown that the new simplified structure exhibits fast convergence and LUT pre-distorter can effectively suppress the spectrum regrowth caused by the dynamic nonlinearity of power amplifier. describes the basic algorithm implemented in the LUT design. The incoming complex samples in I and Q, have correction factors applied from the LUT and sent to module. The addresses for the LUT are derived from the input power. The LUT must contain two values for each location the real part and the imaginary part Q. in the module ,samples are unconverted and sent to the PA . In the feedback loop, the output of the PA is downconverted-transformed to polar form-and compared with the delayed version of the input to the predistorter in polar form. This error is then used to update the values currently stored in the LUT. The LUT address is derived from the input power. Hence this algorithm is only able to correct for phase and magnitude error that are purely a function of the current input power. The LUT coefficient is fed into the predistorter, which reads an appropriate correction value (LUT value) from the LUT and uses it to modify the input data .the resultant modified coefficient is referred to as predistorted data.