S.M. Alavi
54 records found
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An implementation strategy for high-power, high resolution, fully digital transmitters (DTX) is proposed. It is based on a high-speed CMOS controller featuring a high-density flip-chip interconnect to an LDMOS power MMIC containing large arrays of custom low-VT LDMOS gate segment
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The RF performance of current-scaling digital transmitters (DTX) with polar, unsigned Cartesian, signed Cartesian, and multiphase architectures have been compared regarding power utilization of their output-stage switch banks and drain efficiency. The analysis includes various sw
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A wideband harmonic rejection voltage-domain mixer using resistive scaling is presented with excellent linearity and high IF bandwidth. Thin-oxide devices with constant gate-to-source voltages (VGS) are utilized to maximize the switching linearity. A novel switching core topology
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This article introduces an N-way chain-weaver balanced power amplifier (PA) for millimeter-wave (mm-wave) phased-array transmitters (TXs). Taking advantage of the proposed combining network, an embedded impedance/power sensor is implemented, which can be utilized for output power
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OpenDPD
An Open-Source End-to-End Learning & Benchmarking Framework for Wideband Power Amplifier Modeling and Digital Pre-Distortion
With the rise in communication capacity, deep neural networks (DNN) for digital pre-distortion (DPD) to correct non-linearity in wideband power amplifiers (PAs) have become prominent. Yet, there is a void in open-source and measurement-setup-independent platforms for fast DPD exp
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Digital predistortion (DPD) enhances signal quality in wideband radio frequency (RF) power amplifiers (PAs). As signal bandwidths expand in modern radio systems, DPD's energy consumption increasingly impacts overall system efficiency. Deep neural networks (DNNs) offer promising a
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This article introduces a single-supply balun-first three-way parallel Doherty power amplifier (PA) tailored for millimeter-wave (mm-wave) fifth-generation (5G) applications. It incorporates a bandwidth enhancement technique that widens the operational frequency range, enhan ...
This paper presents an advanced yet simple digital pre-distortion (DPD) technique for digital I/Q transmitters (DTXs). Exploiting the I/Q orthogonality, an effective 2×1-D DPD procedure is proposed to bypass the exhaustive 2-D search of the entire constellation diagram. Utilizing
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This article introduces a low-jitter low-spur fractional-N phase-locked loop (PLL) adopting a new concept of a time-mode arithmetic unit (TAU) for phase error extraction. The TAU is a time-signal processor that calculates the weighted sum of input time offsets. It processes two i
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This paper presents a 40nm CMOS mm-wave 3-way Doherty power amplifier (PA) suitable for 5G mm-wave transmitters. It features a bandwidth-enhanced technique using a compact single-supply balun-first 3-way Doherty combiner. The realized front-end with a core area of 0.77 mm2deliver
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This paper proposes a power amplifier (PA) correction technique to recover from load mismatch. It utilizes a main PA, two auxiliary PAs, and a coupler. By adjusting the input drive levels of the PAs it can recover the output power and to a great extent the efficiency of the main
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This article presents a wideband, energy-efficient digital transmitter (DTX) suitable for multi-mode/multi-band wireless communication applications. It features various operation modes comprising Cartesian (Modes-1/-2) and multi-phase (Modes-3/-4) configurations utilizing LO cloc
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This article presents an inverted Doherty power amplifier (IDPA) made load insensitive up to 2:1 voltage standing wave ratio (VSWR) across its fractional bandwidth with a very compact wideband impedance sensor embedded in its output power-combining network (OPCN). To correct for
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A current-mode direct-digital RF modulator (DDRM)-based transmitter (TX) architecture is proposed in this article for energy-efficient wireless applications. To demonstrate its key principles, a 2×13 bit demonstrator is implemented in a 40-nm CMOS technology. This DDRM can operat
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This work presents an ultra-compact single-antenna FD/FDD transceivers front-end. It comprises a nonreciprocal circulator, RX, and an integrated power amplifier (PA). In the proposed circulator, we devise a ring quarter-wave transmission line topology with adjusted characteristic
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Fully digital transmitters (DTXs) have the potential of replacing analog-intensive transmitter (TX) line-ups in future massive multiple-input and multiple-output (mMIMO) systems since they hold the promise of higher system integration level and energy efficiency. DTX operation so
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This article presents a wideband series-Doherty power amplifier (SDPA) for millimeter-wave (mm-wave) fifth-generation (5G) applications. It features a compact two-step impedance inverting-based series-Doherty power combiner that provides broadband close-to-perfect power back-off
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Intra-cortical extracellular neural sensing is being rapidly and widely applied in several clinical research and brain-computer interfaces (BCIs), as the number of sensing channels continues to double every 6 years. By distributing multiple high-density extracellular micro-electr
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A high-power fully-digital Doherty transmitter (DDTX) is proposed. It features two segmented LDMOS output switch banks implemented in a custom V T -down-shifted LDMOS technology. A 40 nm CMOS controller digitally activates the individual LDMOS gate segments of the output stage at
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This letter presents a novel load-modulation-based 3rd-order intermodulation distortion (IMD3) cancellation technique for class-B CMOS power amplifiers (PAs). In a class-B PA, the IMD3 generated by the 3rd-order transconductance ( $g_{m3}$ ) and the gain compression have opposite
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