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Kumaran, A.K. (author), Pashaeifar, M. (author), Alexanderson, Mats (author), de Vreede, L.C.N. (author), Alavi, S.M. (author)<br/>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, enhances broadband power back-off (PBO) efficiency, and reduces...journal article 2024
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Kumaran, A.K. (author), Pashaeifar, M. (author), Nemati, Hossein Mashad (author), de Vreede, L.C.N. (author), Alavi, S.M. (author)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 mm2delivers a peak power/gain of more than 20 dBm/16 dB and a drain...conference paper 2023
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Singh, G.D. (author), Nemati, Hossein Mashad (author), Alavi, S.M. (author), de Vreede, L.C.N. (author)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 PA even when exposed to 2:1 VSWR mismatch conditions. When...conference paper 2023
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Beikmirza, M.R. (author), de Vreede, L.C.N. (author), Alavi, S.M. (author)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 this technique, a four-way Doherty DTX is linearized....conference paper 2023
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Singh, G.D. (author), Nemati, Hossein Mashad (author), Alavi, S.M. (author), de Vreede, L.C.N. (author)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 load variation, a low-loss tunable resonator (TR) is used to...journal article 2023
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Shen, Y. (author), Hoogelander, M. (author), Bootsman, R.J. (author), Alavi, S.M. (author), de Vreede, L.C.N. (author)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 operate standalone or as a driver for a common-gate (CG)/common-base ...journal article 2023
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Beikmirza, M.R. (author), Shen, Y. (author), de Vreede, L.C.N. (author), Alavi, S.M. (author)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 clocks with different duty cycle in the interleaving/non...journal article 2023
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Gao, Z. (author), He, J. (author), Fritz, Martin (author), Shen, Y. (author), Zong, Z. (author), Spalink, Gerd (author), Alavi, S.M. (author), Staszewski, R.B. (author), Babaie, M. (author)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 inputs - the period of a digitally controlled oscillator (DCO)...journal article 2023
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Bootsman, R.J. (author), Mul, D.P.N. (author), Shen, Y. (author), Hashemi, M. (author), Heeres, Rob M. (author), van Rijs, Fred (author), Alavi, S.M. (author), de Vreede, L.C.N. (author)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 far has been limited to low RF output powers. This article...journal article 2022
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Singh, G.D. (author), Mul, D.P.N. (author), Nemati, Hossein Mashad (author), Alavi, S.M. (author), de Vreede, L.C.N. (author)This paper presents a low-loss load-insensitive Doherty power amplifier (DPA) technique. The proposed DPA is insensitive to ohmic load variation by adjusting its supply voltages and input drive of the main and peaking stages in a mirrored approach. Moreover, a low-loss tunable matching network (TMN) is employed to cancel out any reactive part of...conference paper 2022
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Gao, Z. (author), He, J. (author), Fritz, Martin (author), Gong, J. (author), Shen, Y. (author), Zong, Z. (author), Chen, Peng (author), Staszewski, R.B. (author), Alavi, S.M. (author), Babaie, M. (author)In a fractional-N PLL, it is beneficial to minimize the input range of its phase detector (PD) as it promotes better linearity and higher PD gain for suppressing noise contributions of the following loop components. This can be done by canceling the predicted instantaneous time offset between the frequency reference (FREF) and the variable...conference paper 2022
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Song, Minyoung (author), Huang, Yu (author), Shen, Yiyu (author), Shi, Chengyao (author), Breeschoten, Arjan (author), Konijnenburg, Mario (author), Visser, Huib (author), Romme, J.P.A. (author), Dutta, Barundeb (author), Alavi, S.M. (author)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-electrode arrays (MEAs) in vivo across the brain, each with 1000's of...conference paper 2022
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Gao, Z. (author), Fritz, Martin (author), He, J. (author), Spalink, Gerd (author), Staszewski, R.B. (author), Alavi, S.M. (author), Babaie, M. (author)We present a broadband digital PLL (DPLL)-based phase modulator supporting wide frequency modulation (FM) bandwidth (BW). It compensates for the EVM degradation due to the non-uniform period of the retimed updating clock and shortens the nonlinearity calibration time of the digitally controlled oscillator (DCO) with a phase-domain digital pre...conference paper 2022
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Pashaeifar, M. (author), de Vreede, L.C.N. (author), Alavi, S.M. (author)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 impedances to improve TX-to-antenna insertion loss and TX-to-RX...conference paper 2022
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Kumaran, A.K. (author), Nemati, Hossein Mashad (author), de Vreede, L.C.N. (author), Alavi, S.M. (author)This paper presents a design procedure for compact lumped-element 3-/4-/5-way Doherty power combiners suitable for mm-wave 5G transmitters. Among them, the 3-way Doherty power combiner is favored due to its low complexity, compact layout, and average drain efficiency at 12 dB power back-off (PBO) when implemented using lossy lumped elements....conference paper 2022
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Beikmirza, M.R. (author), Shen, Y. (author), de Vreede, L.C.N. (author), Alavi, S.M. (author)A 40nm CMOS wideband digital Cartesian push-pull inverted Doherty operating in class-E is presented. Wideband Doherty operation is achieved over a 1.9-to-3GHz frequency band, using an off-chip power combining network. The fully digital transmitter (DTX) provides 25.3dBm peak power with a drain/DTX line-up efficiency (DE/SE) of 58.7%/44.9%,...conference paper 2022
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Bootsman, R.J. (author), Shen, Y. (author), Mul, D.P.N. (author), Rousstia, Mohadig (author), Heeres, Rob (author), van Rijs, Fred (author), Gajadharsing, John (author), Alavi, S.M. (author), de Vreede, L.C.N. (author)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 RF speed. An inverted Doherty power combiner is proposed that...conference paper 2022
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Pashaeifar, M. (author), de Vreede, L.C.N. (author), Alavi, S.M. (author)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 signs, and thus, they can cancel each other at specific bias...journal article 2022
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Pashaeifar, M. (author), de Vreede, L.C.N. (author), Alavi, S.M. (author)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 (PBO) efficiency enhancement. The amplitude-to-amplitude (AM-AM)...journal article 2022
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Shen, Y. (author), Bootsman, R.J. (author), Alavi, S.M. (author), de Vreede, L.C.N. (author)This article presents a wideband 2× 12 -bit direct-digital RF modulator (DDRM) operating in a 0.5-to-3-GHz band for 5G transmitters. The proposed digital Cartesian modulator features an advanced IQ-mapping technique to boost RF power by 3 dB and suppress the I/Q image. To verify the proposed concept, a 40-nm CMOS prototype is implemented...journal article 2022
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