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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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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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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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Mortazavi, S.M. (author), Shen, Y. (author), Mul, D.P.N. (author), de Vreede, L.C.N. (author), Spirito, M. (author), Babaie, M. (author)This article presents an efficient digital polar transmitter (DPTX) at mm-wave frequencies that exploit a novel N -way series Doherty combiner (SDC) to enhance its drain and system efficiency at deep power back-off (PBO). The proposed N -way SDC is scalable and can be implemented elegantly using N transformers and N-1 shunt capacitors. As a...journal article 2022
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Zhang, L. (author), Shen, Y. (author), de Vreede, L.C.N. (author), Babaie, M. (author)This letter presents a millimeter-wave (mm-wave) vector-modulated phase shifter (VMPS) for phased-array applications. To improve the phase-shift accuracy without drastically increasing design complexity, the proposed VMPS structure employs variable-gain amplifiers (VGAs) that offer 2× better resolution at their low-gain...journal article 2022
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Beikmirza, M.R. (author), Shen, Y. (author), de Vreede, L.C.N. (author), Alavi, S.M. (author)To support wideband complex modulated signals and comply with the stringent requirements of modern communication standards in an energy-efficient manner, recently, digital transmitters (DTXs) have been explored to fully benefit from the high-speed switching and integration capabilities of nanoscale CMOS technologies [1]–[5]. These DTXs are...conference paper 2022
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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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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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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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Shen, Y. (author)This thesis focuses on digital-intensive up-converters for sub-6GHz wireless communication. Nowadays, wireless cellular communication is entering its 5th generation (5G), driven by the demand for faster mobile access and higher data throughput. 5G utilizes larger modulation bandwidths, higher-order modulations, and (many) more transmitters and...doctoral thesis 2021
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Beikmirza, M.R. (author), Shen, Y. (author), de Vreede, L.C.N. (author), Alavi, S.M. (author)We present a wideband, 12-bit four-way Doherty Cartesian digital transmitter (DTX) featuring an innovative 50%-LO signed I/Q interleaved up-conversion technique that enables close to perfect orthogonal I/Q summation. The DTX incorporates a compact four-way lumped-element Doherty power combining network to enhance its average efficiency at...journal article 2021
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Hashemi, M. (author), Zhou, Lei (author), Shen, Y. (author), de Vreede, L.C.N. (author)This article presents the first application of a digital-intensive intrinsically linear digitally controlled class-E technique in a Doherty configuration. By careful nonlinear segmentation and multiphase RF-clocking along with overdrive-voltage control and automatic duty-cycle correction, it is shown that even the nonlinearities related to...journal article 2019
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Shen, Y. (author), Lindenbergh, R.C. (author), Wang, Jinguo (author), Ferreira, Vagner G. (author)Bricks are the vital component of most masonry structures. Their maintenance is critical to the protection of masonry buildings. Terrestrial Light Detection and Ranging (TLidar) systems provide massive point cloud data in an accurate and fast way. TLidar enables us to sample and store the state of a brick surface in a practical way. This...journal article 2018
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Shen, Y. (author), Wang, Jinguo (author), Lindenbergh, R.C. (author), Hofland, Bas (author), Ferreira, Vagner G. (author)The use of a terrestrial laser scanner is examined to measure the changes of rock slopes subject to a wave attack test. Real scenarios are simulated in a water flume facility using a wave attack experiment representing a storm of 3000 waves. The stability of two rock slopes of different steepness was evaluated under the set conditions. For...journal article 2018
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Shen, Y. (author), Lindenbergh, R.C. (author), Hofland, Bas (author), Kramer, R. (author)For better understanding how coastal structures with gentle slopes behave during high energy events, a wave attack experiment representing a storm of 3000 waves was performed in a flume facility. Two setups with different steepness of slope were compared under the same conditions. In order to quantify changes in the rock slopes after the wave...conference paper 2017
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Shen, Y. (author), Lindenbergh, R.C. (author), Wang, J. (author)A method is introduced for detecting changes from point clouds that avoids registration. For many applications, changes are detected between two scans of the same scene obtained at different times. Traditionally, these scans are aligned to a common coordinate system having the disadvantage that this registration step introduces additional...journal article 2017
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Sirmacek, B. (author), Shen, Y. (author), Lindenbergh, R.C. (author), Zlatanova, S. (author), Diakite, A.A. (author)We present a comparison of point cloud generation and quality of data acquired by Zebedee (Zeb1) and Leica C10 devices which are used in the same building interior. Both sensor devices come with different practical and technical advantages. As it could be expected, these advantages come with some drawbacks. Therefore, depending on the...journal article 2016
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Wang, J. (author), Lindenbergh, R.C. (author), Shen, Y. (author), Menenti, M. (author)Laser scanning samples the surface geometry of objects efficiently and records versatile information as point clouds. However, often more scans are required to fully cover a scene. Therefore, a registration step is required that transforms the different scans into a common coordinate system. The registration of point clouds is usually conducted...journal article 2016
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