Showing papers on "Amplifier published in 2019"

Printed subthreshold organic transistors operating at high gain and ultralow power.

Abstract: Overcoming the trade-offs among power consumption, fabrication cost, and signal amplification has been a long-standing issue for wearable electronics. We report a high-gain, fully inkjet-printed Schottky barrier organic thin-film transistor amplifier circuit. The transistor signal amplification efficiency is 38.2 siemens per ampere, which is near the theoretical thermionic limit, with an ultralow power consumption of 60 decibels and noise voltage of <0.3 microvolt per hertz1/2 at 100 hertz.

Generation of three-cycle multi-millijoule laser pulses at 318 W average power

Abstract: The generation of three-cycle multi-millijoule pulses at 318 W power is reported by compressing pulses of a Yb-fiber chirped pulse amplifier in a 6 m long stretched flexible hollow fiber. This technique brings high-power lasers to the few-cycle regime.

An ultraflexible organic differential amplifier for recording electrocardiograms

Abstract: Differential amplifiers based on organic thin-film transistors (OTFTs) are attractive for monitoring human vital signs because of their signal amplification and noise elimination capabilities. However, substantial variations in OTFTs lead to the degradation of signal processing performance in circuits and restrict the development of organic differential amplifiers capable of recording weak physiological potentials. Here, we report a 2-μm-thick ultraflexible organic differential amplifier capable of processing physiological signals with high signal integrity and sensitivity. Our approach uses a circuit design and compensation technique that suppress the mismatch among OTFTs to less than a few percent. This leads to a common-mode noise attenuation factor below −12 dB, even during bending to ~50 μm. Using our flexible amplifier, we monitor electrocardiogram signals, where the power of 60 Hz electrical harmonic noise was reduced ~60 times during amplification, yielding electrocardiogram signals with a signal-to-noise ratio of 34 dB. An ultraflexible organic differential amplifier, which is only 2 μm thick and can conform to a person’s skin, can be used to record electrocardiograms with a signal-to-noise ratio of 34 dB.

Average Power Model of Optical Raman Amplifiers Based on Frequency Spacing and Amplifier Section Stage Optimization

Abstract: The study presents the average power model of optical Raman fiber amplifiers based on frequency spacing and amplifier section stage optimization technique. The amplifier section stage is taken from 25 to 75 km and frequency spacing is taken from 0.2 up to 1 nm. Input/output Raman signal variations are measured versus operating wavelength range and bit time period variations. The suitable input signal power for the optical transmitter is chosen to be −10 dBm and return to zero modulation code is applied with an available data rate of 10 Gb/s. Sixty-four channels are multiplexed to benefit a multi-number of users with suitable power levels.

Femtosecond Mamyshev oscillator with 10-MW-level peak power

Abstract: Ultrafast fiber lasers exhibit high broadband gain per pass, superior thermo-optical properties, and excellent beam quality, making them very suitable for practical use. For simplicity and efficiency, advanced mode-locked oscillator designs which can compete with the amplifier systems are always favorable. Here, we demonstrate a high-peak-power Mamyshev oscillator based on single-polarization, large-mode-area photonic crystal fibers. Using properly arranged filters, the fiber oscillator directly emits pulses with 9 W average power at 8 MHz repetition rate, corresponding to a single-pulse energy exceeding 1 μJ. The pulses are dechirped to 41 fs outside the cavity, leading to a record oscillator peak power as high as 13 MW. With such unprecedented performance, the proposed single-stage oscillator should be very attractive for various applications.

Power Amplifiers for mm-Wave 5G Applications: Technology Comparisons and CMOS-SOI Demonstration Circuits

Abstract: A review is presented of key power amplifier (PA) performance requirements for millimeter-wave 5G systems, along with a comparison of the potential of different semiconductor technologies for meeting those requirements. Output power, efficiency, and linearity considerations are highlighted, and related to semiconductor material characteristics. Prototype 5G PAs based on silicon technologies are then reviewed, with primary emphasis on CMOS-SOI. Stacked FET PAs based on nMOS and pMOS for 28-GHz operation are presented, along with outphasing and Doherty amplifiers. Peak power-added efficiency (PAE) up to 46% is demonstrated for a two-stack pMOS amplifier with saturation power (Psat) above 19 dBm. PAE at 6 dB backoff above 27% is shown for an nMOS Doherty PA with 22-dBm Psat. Operation with 64QAM OFDM modulation signals at 800-MHz bandwidth is reported, with up to 13-dBm output power and more than 17% PAE, without the use of digital predistortion. Future challenges for PA development are discussed.

Full-Angle Digital Predistortion of 5G Millimeter-Wave Massive MIMO Transmitters

Abstract: In this paper, a full-angle digital predistortion (DPD) technique is proposed to linearize fifth-generation (5G) millimeter-wave (mmWave) massive multiple-input-multiple-output (mMIMO) transmitters with low implementation complexity. It is achieved by compensating the differences of power amplifiers (PAs) in different transmitter chains first and then adopting a common digital block to linearize the whole subarray. Based on this operation, all the transmitter chains can be efficiently linearized simultaneously, providing the merits of full-angle linearization including the main beam and sidelobes. To validate the proposed idea, an mmWave full-digital beam-forming transmitter has been developed, which is operated at the center frequency of 24.75–28.5 GHz to meet the 5G candidate frequency bands. Experimental results show that the proposed method can effectively linearize the mmWave mMIMO transmitter in all directions, which provides a promising linearization solution for 5G mMIMO beam-forming systems.

Space-Energy Digital-Coding Metasurface Based on an Active Amplifier

Abstract: Power amplifiers display some interesting physical phenomena, such as nonreciprocity, but their characteristics have not been fully explored. In this study of the detailed relationship between supply power and amplification, the authors combine a coding metasurface with active amplifiers to realize arbitrary editing of the spatial distribution of a propagating wave's energy. With this metasurface, the energy in space of linearly polarized microwaves can be amplified or reduced at will by controlling the voltage.

The Engagement of Hybrid Dispersion Compensation Schemes Performance Signature for Ultra Wide Bandwidth and Ultra Long Haul Optical Transmission Systems

Abstract: This paper presents the performance signature of the engagement of hybrid symmetrical hybrid compensation techniques for ultra wide bandwidth and ultra long haul optical transmission systems. These schemes that are namely optigrating, ideal dispersion compensation fiber Bragg Grating (IDCFBG), and dispersion compensation fiber (DCF). The combination of mixing these techniques together which is called hybrid symmetrical dispersion compensation techniques in that case. The employment of these mixing schemes is in symmetrical configuration with the presence of Erbium doped fiber amplifiers in order to upgrade optical fiber system capacity to reach transmission distance up to 432 km and transmission data rate up to 320 Gb/s. Maximum signal quality factor, minimum bit error rate (BER), output optical signal to noise ratio, electrical received power after APD photodetector, noise figure, and gain are the major interesting performance parameters for measuring the system operation efficiency. It is observed that the optimum case for maximum quality factor and minimum BER is achieved with 15 m EDFA amplifier length and 150 mW EDFA pump power.

A Review of Electric Impedance Matching Techniques for Piezoelectric Sensors, Actuators and Transducers

Abstract: Any electric transmission lines involving the transfer of power or electric signal requires the matching of electric parameters with the driver, source, cable, or the receiver electronics. Proceeding with the design of electric impedance matching circuit for piezoelectric sensors, actuators, and transducers require careful consideration of the frequencies of operation, transmitter or receiver impedance, power supply or driver impedance and the impedance of the receiver electronics. This paper reviews the techniques available for matching the electric impedance of piezoelectric sensors, actuators, and transducers with their accessories like amplifiers, cables, power supply, receiver electronics and power storage. The techniques related to the design of power supply, preamplifier, cable, matching circuits for electric impedance matching with sensors, actuators, and transducers have been presented. The paper begins with the common tools, models, and material properties used for the design of electric impedance matching. Common analytical and numerical methods used to develop electric impedance matching networks have been reviewed. The role and importance of electrical impedance matching on the overall performance of the transducer system have been emphasized throughout. The paper reviews the common methods and new methods reported for electrical impedance matching for specific applications. The paper concludes with special applications and future perspectives considering the recent advancements in materials and electronics.

Bi-doped fiber amplifiers and lasers [Invited]

Abstract: Bismuth (Bi) doped fibers have shown promising potential for lasers and amplifiers in the 1150-1500 nm and 1600-1800nm wavelength region. Bi-doped aluminosilicate, phosphosilicate and germanosilicate fibers provide luminescence around 1150 nm, 1300 nm and 1450 nm, respectively. Recent results have demonstrated the possibility to extend the Bi luminescence window beyond 1600 nm using Bi-doped high (≥ 50 mol %) germanosilicate fibers. These spectral regions can serve a wide range of applications in medicine, astronomy, defense and to extend the optical fiber communication. However, Bi-doped fiber lasers and amplifiers are still far from their optimum performance owing to the unclear nature of the near-infrared emitting Bi active centers. In this paper, we review the current state of the art of Bi-doped silica fiber lasers (CW and pulsed) and amplifiers in different wavelength bands. Also, we present our work on the development of Bi-doped aluminosilicate and phosphosilicate fiber lasers and amplifiers in the 1180 nm and 1330 nm bands. These lasers and amplifiers find applications in generating visible light sources and to access the second telecommunication window. The fibers used here were fabricated by modified chemical vapor deposition-solution doping technique and characterized for their unsaturable loss. Moreover, we present the influence of pump wavelengths on the gain, noise figure and laser efficiency of these Bi-doped fiber amplifiers and lasers. We also discuss Bi-doped fibers for pulsed laser application and demonstrate a mode-locked Bi-doped fiber laser operating at 1340 nm.

A 5G 28-GHz Common-Leg T/R Front-End in 45-nm CMOS SOI With 3.7-dB NF and −30-dBc EVM With 64-QAM/500-MBaud Modulation

Abstract: This paper presents a 28-GHz common-leg phased-array front-end in 45-nm CMOS silicon on insulator with transmit and receive capabilities. The design alternates cascode amplifiers with passive switched- $LC$ phase-shifter cells to result in 5-bit phase control with an rms phase and gain error <4° and <0.8 dB, respectively, at 24–30 GHz, over 32 phase states. The front-end has 2- and 3-bit variable gain amplifiers with 7.5-dB total gain control, without affecting the system noise figure (NF). Two low-loss high-linearity single-pole double-throw switches are used to switch between transmit and receive modes. In the receive (Rx) mode, the measured gain, NF, input 1-dB compression point (P1dB), and input third-order intercept point are 16 dB, 3.7 dB, −15 dBm, and −7 dBm, respectively, with 54-mW dc power consumption. In the transmit (Tx) mode, measurements show 16.5-dB gain, an output P1dB of 8 dBm, and an output IP3 of 16 dBm with 100-mW dc power consumption. The error-vector magnitude and adjacent-channel-power-ratio measurements demonstrate quadrature phase-shift keying, 16-quadrature amplitude modulation (QAM), 64-QAM, and 16-QAM orthogonal frequency-division multiplexing modulations with several symbol-rates reaching up to 8 Gb/s data-rate for both the Rx and Tx modes at 2- and 5-dB back-off. The application areas are in fifth-generation phased arrays requiring high-linearity receivers and using external front-end modules for added transmit power.

Phased Array Shaped-Beam Satellite Antenna With Boosted-Beam Control

Abstract: This communication presents a beamforming shaped-beam satellite (SBS) antenna based on a phased array technique and a boosted-beam control. The presented SBS antenna is specifically designed to cover the whole regions of Korea including the southern and northern areas. The proposed SBS antenna consists of waveguide feed network, beamforming circuits, waveguide circular polarizers, 19 radiation elements, and a boosted-beam control panel with active component calibration for temperature variation. To maximize the flexible performance, boosted-beam mode is supported to meet the required high-power signal regardless of bad weather conditions. The adjustable effective isotropic radiated power (EIRP) range was around 6 dB and there are a total of 19 beamforming units each configured by drive amplifier, phase shifter, and attenuator. Also, one extra beamforming unit synchronized with the other 19 elements is integrated for active component calibration. Each beamforming element can control relative phase shift up to 360° with 5° step and relative amplitude variation up to 10 dB with 1 dB step as well. Also, each radiation element is configured by waveguide horn and the return losses were better than 25 dB at 21 GHz.

Improved Three-Stage Doherty Amplifier Design With Impedance Compensation in Load Combiner for Broadband Applications

Abstract: This paper presents a broadband three-stage Doherty power amplifier (DPA) using impedance compensation for bandwidth extension. Different from the conventional design, an impedance-compensating load combiner is proposed to broaden the bandwidth of the three-stage DPA by employing the output impedances of the peaking amplifiers. Considering the load impedance of the peaking branch as an independent design variable, the Doherty load modulations are analyzed in theory, pointing out the optimized solution for the load combiner. To achieve the impedance compensation, the peaking output matching networks are deliberately designed with the dual-impedance matching topology. Experimental results show that a three-stage DPA is realized from 1.6 to 2.6 GHz (48% fractional bandwidth) with a measured efficiency of 50%–53% at 9.5-dB back-off and a saturated output power around 45.5 dBm. When stimulated by the 20- and 40-MHz modulated signals at an average output power of around 36.5 dBm, the proposed DPA can achieve the adjacent channel leakage ratio of −50 dBc over the whole frequency band after linearization, with an average efficiency of higher than 50%.

Octave Bandwidth Doherty Power Amplifier Using Multiple Resonance Circuit for the Peaking Amplifier

Abstract: This paper presents a broadband Doherty power amplifier (DPA) design with an octave bandwidth based on a new load network consisting of a quasi-lumped impedance transformer for the carrier amplifier, a multiple resonance circuit for the peaking amplifier, and a broadband post-matching network. The quasi-lumped impedance transformer and the multiple resonance circuit were designed based on accurate equivalent circuits for internal components inside the packaged transistor. Based on power bandwidth analysis, optimum susceptance provided by the multiple resonance circuit at the peaking amplifier, was obtained. The proposed broadband DPA was designed using 45 W gallium–nitride high electron mobility transistor for both carrier and peaking amplifiers. For continuous-wave signals in frequency range of 0.9 to 1.8 GHz, the implemented broadband DPA exhibited a drain efficiency of 54.2% to 73.4% at peak output power of 49.7 to 51.4 dBm and a drain efficiency of 41.7% to 58.0% at output back-off of 6 dB. For the down-link long-term evolution signal with a channel bandwidth of 10 MHz and a peak-to-average power ratio of 6.5 dB, a drain efficiency of 41.3% to 57.4% and an adjacent channel leakage power ratio of −22.5 to −30.2 dBc at an average output power of 43.2 to 449 dBm were achieved at an octave bandwidth.

Kerr-Free Three-Wave Mixing in Superconducting Quantum Circuits

Abstract: Quantum-limited Josephson parametric amplifiers are crucial components in readout chains for circuit quantum electrodynamics. The power handling of state-of-the-art parametric amplifiers is limited by signal-induced Stark shifts. The authors use an innovative circuit element with a Stark-shift-free sweet spot in parameter space to boost the power handling of such an amplifier by an order of magnitude, which is quite promising for the implementation of bilinear Hamiltonians with high dynamic range in quantum information processing.

A photonic crystal Josephson traveling wave parametric amplifier

Abstract: An amplifier combining noise performances as close as possible to the quantum limit with large bandwidth and high saturation power is highly desirable for many solid state quantum technologies such as high fidelity qubit readout or high sensitivity electron spin resonance for example. Here we introduce a new Traveling Wave Parametric Amplifier based on Superconducting QUantum Interference Devices. It displays a 3 GHz bandwidth, a -102 dBm 1-dB compression point and added noise near the quantum limit. Compared to previous state-of-the-art, it is an order of magnitude more compact, its characteristic impedance is in-situ tunable and its fabrication process requires only two lithography steps. The key is the engineering of a gap in the dispersion relation of the transmission line. This is obtained using a periodic modulation of the SQUID size, similarly to what is done with photonic crystals. Moreover, we provide a new theoretical treatment to describe the non-trivial interplay between non-linearity and such periodicity. Our approach provides a path to co-integration with other quantum devices such as qubits given the low footprint and easy fabrication of our amplifier.

A 0.044-mm 2 0.5-to-7-GHz Resistor-Plus-Source-Follower-Feedback Noise-Cancelling LNA Achieving a Flat NF of 3.3±0.45 dB

Abstract: A wideband noise-cancelling low-noise amplifier (LNA) combining resistor feedback and source-follower feedback (SFF) is proposed. The SFF facilitates upsizing of the feedback resistor to improve the gain and noise figure (NF), without compromising the input-impedance matching. Another benefit is that the noise contributions of both the feedback resistor and noise-cancelling transistors are significantly reduced. Fabricated in 65-nm CMOS, the LNA exhibits a voltage gain of 16.8 dB, and a flat NF of 3.3 ± 0.45 dB over a −3-dB bandwidth of 0.5 to 7 GHz. The power consumption is 11.3 mW at 1.2 V, and the die area is 0.044 mm2.

Low-Voltage OTA–C Filter With an Area- and Power-Efficient OTA for Biosignal Sensor Applications

Abstract: This paper presents a systematic method for decreasing the amount of transconductors used by an operational transconductance amplifier–capacitor (OTA–C) filter to decrease the power consumption and the active area. An OTA with a local-feedback linearized technique and a transconductance booster is proposed based on the presented method. The proposed OTA combines current division with source degeneration to enhance linearity and implement low transconductance. This topology enables the proposed OTA to drive multiple integration capacitors without an additional output stage. The OTA-based circuit realizes low power consumption by operating under a weak inversion at a supply voltage of 1 V. Thus, a fifth-order ladder-type low-pass Butterworth OTA–C filter is implemented for the acquisition of electrocardiograph signals. The proposed method is validated using a prototype fabricated through a 1P6M 0.18-μm CMOS process. Results show that in ECG signal acquisition, the proposed filter has a signal bandwidth located within 250 Hz, a dynamic range of 61.2 dB, and a power consumption of 41 nW to achieve a figure-of-merit of 5.4 × 10−13. The active area of the filter is 0.24 mm2.

3.7 kW monolithic narrow linewidth single mode fiber laser through simultaneously suppressing nonlinear effects and mode instability

Abstract: In this paper, we report a 3.7 kW all fiber narrow linewidth single mode fiber laser. The full width at half-maximum is about 0.30 nm, and the beam quality is Mx2=1.358, My2=1.202 at maximum output power. The laser is achieved by simultaneously suppressing nonlinear effects and mode instability (MI). Different seeds are injected into the main amplifier to study stimulated Raman scattering (SRS) effect. The results show that the phase modulated single frequency seed is benefit to suppress the SRS effect. For the phase modulated single frequency seed, inserting a filter in preamplifier will suppress amplified spontaneous emission (ASE) and decrease the backward power. By optimizing the coiling of active fiber, the MI effect is suppressed.

Linearity-Enhanced Doherty Power Amplifier Using Output Combining Network With Predefined AM–PM Characteristics

Abstract: In this paper, a new method is proposed to synthesize a linearity-enhanced Doherty power amplifier (DPA) without deteriorating its efficiency. This method determines the combiner network parameters so that a predefined amplitude-to-phase (AM–PM) characteristic is produced while maintaining proper load modulation and consequently good back-off efficiency. The predefined AM–PM characteristic is chosen to be the inverse of the main transistor to enhance the overall DPA linearity. For proof-of-concept validation purposes, a linearity-enhanced DPA circuit prototype is designed to provide linear overall AM–PM characteristics over the frequency band of 4.7–5.3 GHz. Meanwhile, its input matching network is designed to minimize the amplitude-to-amplitude (AM–AM) distortion by properly selecting the source impedances. The measurement results of the DPA prototype under continuous-wave stimuli reveal AM–PM and AM–AM characteristics with maximum phase and gain compression/expansion below ±1° and ±0.25 dB, respectively, when the input power level is swept up to a saturation level of 39 dBm over 4.9–5.3 GHz. Furthermore, when driven with carrier aggregated signals with modulation bandwidths of up to 160 MHz and a peak-to-average power ratio equal to 7.4 dB, the DPA prototype maintains an adjacent channel leakage ratio of better than −40 dBc with a drain efficiency in the excess of 40% and an average output power of 32 dBm, without resorting to any additional linearization schemes. The proposed DPA methodology paves the road for the application of the DPA technique to 5G massive multiple-input and multiple-output transmitters with relaxed linearity requirements as it avoids the extra complexity and power consumption overhead associated with dedicated linearization schemes.

Wide-band parametric amplifier readout and resolution of optical microwave kinetic inductance detectors

Abstract: The energy resolution of a single photon counting microwave kinetic inductance detector can be degraded by noise coming from the primary low temperature amplifier in the detector's readout system. Until recently, quantum limited amplifiers have been incompatible with these detectors due to the dynamic range, power, and bandwidth constraints. However, we show that a kinetic inductance based traveling-wave parametric amplifier can be used for this application and reaches the quantum limit. The total system noise for this readout scheme was equal to ∼2.1 in units of quanta. For incident photons in the 800–1300 nm range, the amplifier increased the average resolving power of the detector from ∼6.7 to 9.3 at which point the resolution becomes limited by noise on the pulse height of the signal. Noise measurements suggest that a resolving power of up to 25 is possible if the redesigned detectors can remove this additional noise source.

A 0.2-V Energy-Harvesting BLE Transmitter With a Micropower Manager Achieving 25% System Efficiency at 0-dBm Output and 5.2-nW Sleep Power in 28-nm CMOS

Abstract: This paper reports an ultralow-voltage (ULV) energy-harvesting bluetooth low-energy (BLE) transmitter (TX). It features: 1) a fully integrated micropower manager ( $\mu $ PM) to customize the internal supply and bias voltages for both active and sleep modes; 2) a gate-to-source-coupling ULV voltage-controlled oscillator (VCO) using a high-ratio (5.6:1) stacking transformer to improve the phase noise and output swing; 3) an ULV class-E/F2 power amplifier (PA) with an inside-transformer LC notch to suppress the HD3, and finally 4) an analog type-I phase-locked loop (PLL) with a reduced duty cycle of its master-slave sampling filter (MSSF) to suppress the jitter and reference spur. The TX prototyped in 28-nm CMOS occupies an active area of 0.53 mm2 and exhibits 25% system efficiency at 0-dBm output at a single 0.2-V supply. Without resorting from any external components, both the output HD2–49.6 dBm) and HD3–47.4 dBm) comply with the BLE standard. The FSK error is 2.84% and the frequency drift in a 425- $\mu \text{s}$ data packet is <5 kHz under open-loop modulation. The use of negative-voltage power gating suppresses the sleep power of the entire TX to 5.2 nW.

Force sensing in hybrid Bose-Einstein-condensate optomechanics based on parametric amplification

Abstract: In this paper, the scheme of a force sensor is proposed which has been composed of a hybrid optomechanical cavity containing an interacting cigar-shaped Bose-Einstein condensate (BEC) where the $s$-wave scattering frequency of the BEC atoms as well as the spring coefficient of the cavity moving end-mirror (the mechanical oscillator) are parametrically modulated. It is shown that, in the red-detuned regime and under the so-called impedance-matching condition, the mechanical response of the system to the input signal is enhanced substantially which leads to the amplification of the weak input signal while the added noise of measurement (backaction noise) can be suppressed and lowered much below the standard quantum limit. Furthermore, because of its large mechanical gain, such a modulated hybrid system is a much better amplifier in comparison to the (modulated) bare optomechanical system which can generate a stronger output signal while keeping the sensitivity nearly the same as that of the (modulated) bare one. The other advantages of the presented nonlinear hybrid system accompanied with the mechanical and atomic modulations in comparison to the bare optomechanical cavities are its controllability as well as the extension of the amplification bandwidth.

A Low-Noise Chopper Amplifier Designed for Multi-Channel Neural Signal Acquisition

Abstract: This paper proposed the design of a low-noise, low total harmonic distortion (THD) chopper amplifier for neural signal acquisition. A dc servo loop (DSL) based on active Gm-C integrator is proposed to reject the electrode-dc-offset (EDO). Architecture of a complementary input very low-transconductance (VLT) operational transconductance amplifier (OTA) was proposed and integrated in the active Gm-C integrator to improve the linearity as well as to reduce the noise, featuring a transconductance ranging from 45 pS to a few nS. The proposed amplifier was fabricated in a TSMC 0.18- $\mu \text{m}$ CMOS process, occupying an area of 0.2 mm 2, featuring a power consumption of $3.24~\mu \text{W}$ /channel under a 1.8-V supply voltage. The THD for a 5-mVpp input is lower than −61 dB. An input-referred thermal noise power spectral density (PSD) of 39 nV/ $\sqrt {\text {Hz}}$ is measured. The measured input-referred noise is $0.65~\mu \text {V}_{\text {rms}}$ in the 0.3–200-Hz frequency band and $2.14~\mu \text{V}_{\text {rms}}$ in the 200-Hz–5-kHz frequency band, respectively, leading to a noise-efficiency factor of 2.37 (0.3–200 Hz) and 1.56 (0.2 k–5 kHz). In addition, the high-pass corner frequency can be precisely configured and linearly adjusted with the external bias current from 0.35 to 54.5 Hz.

A 24-43 GHz LNA with 3.1-3.7 dB Noise Figure and Embedded 3-Pole Elliptic High-Pass Response for 5G Applications in 22 nm FDSOI

Abstract: This paper presents a 20-44 GHz low-noise amplifier in 22 nm FDSOI with low noise figure and low DC power consumption. The LNA is based on a 3-stage cascode amplifier which is co-designed with embedded high-pass filters so as to results in a very sharp rejection at 11 17 dB at 20-43 GHz with a peak of 23 dB at 40 GHz. The LNA achieves a NF of 3.1-3.7 dB (3.4±0.3 dB) at 24-43 GHz, an in-band IIP3 of -13.2 to -19 dBm at 20-40 GHz, all at a power consumption of 20.5 mW. Operation at 12 mW is also shown, with a maximum gain and minimum NF of 18.2 dB and 3.4 dB at 24-43 GHz. To our knowledge, the LNA represents the highest FoM achieved at this frequency range todate and includes an embedded 3-pole filter response.

High power, single-frequency, monolithic fiber amplifier for the next generation of gravitational wave detectors

Abstract: Low noise, high power single-frequency lasers and amplifiers are key components of interferometric gravitational wave detectors. One way to increase the detector sensitivity is to increase the power injected into the interferometers. We developed a fiber amplifier engineering prototype with a pump power limited output power of 200 W at 1064 nm. No signs of stimulated Brillouin scattering are observed at 200 W. At the maximum output power the polarization extinction ratio is above 19 dB and the fractional power in the fundamental transverse mode (TEM 00) was measured to be 94.8 %. In addition, measurements of the frequency noise, relative power noise, and relative pointing noise were performed and demonstrate excellent low noise properties over the entire output power slope. In the context of single-frequency fiber amplifiers, the measured relative pointing noise below 100 Hz and the higher order mode content is, to the best of our knowledge, at 200 W the lowest ever measured. A long-term test of more than 695 h demonstrated stable operation without beam quality degradation. It is also the longest single-frequency fiber amplifier operation at 200 W ever reported.

Digital Predistortion of Millimeter-Wave RF Beamforming Arrays Using Low Number of Steering Angle-Dependent Coefficient Sets

Abstract: This paper proposes a single-input single-output (SISO) digital predistortion (DPD) model for linearizing millimeter-wave (mm-wave) RF beamforming arrays. It starts with a dual-input power amplifier (PA) model that accounts for steering angle-dependent load modulation effects. This dual-input model is then transformed into a SISO model under the assumption of weak PA nonlinearity and RF beamforming architecture. The underlying coefficients of the SISO array model incorporate the beamforming weights, antenna cross-coupling, channel coefficients, and any possible phase-shifter gain variation with phase shift setting. An over-the-air (OTA) measurement setup is finally developed to validate the capacity of a SISO DPD model to linearize two different arrays-under-test with 4 and 64 elements and radiating mm-wave modulated signals with 320- and 800-MHz bandwidth. Although, in principle, the DPD coefficients should be retrained for each steering angle, experimental results have shown that the same set of coefficients can be used over a wide range of steering angles, and only a few sets of trained DPD coefficients are sufficient to minimize the distortion in a mm-wave RF beamforming array across a 120° steering range.

Low-Power Fast-Transient Capacitor-Less LDO Regulator With High Slew-Rate Class-AB Amplifier

Abstract: This brief presents a low-power fast-transient capacitor-less low-dropout regulator (CL-LDO) for system-on-a-chip applications. A low-quiescent-current class-AB amplifier with embedded slew-rate enhancement (SRE) circuit is proposed to improve both current efficiency and load transient performance. As the SRE circuit is directly controlled by the amplifier, only a minimum hardware overhead is required. The proposed CL-LDO is fabricated in a 0.18- ${\mu }\text{m}$ standard CMOS process. It occupies an active area of 0.031 mm2 and consumes a quiescent current of $10.2~\mu \text{A}$ . It is capable of delivering a maximum load current of 100 mA at 1.0-V output from a 1.2-V power supply. The measured results show that a settling time of $0.22~\mu \text{s}$ is achieved for load steps from 1 mA to 100 mA (and vice versa) with an edge time of $0.1~\mu \text{s}$ .

A Ka-Band Phase-Compensated Variable-Gain CMOS Low-Noise Amplifier

Abstract: A variable-gain low-noise amplifier implemented in a 65-nm CMOS process for a beamforming front-end chip is presented, of which the phase remains constant during gain variations. The phase compensation characteristic is achieved by introducing a shunt PMOS and a parallel resistor at the differential outputs of common-gate (CG) transistors. This allows the gain to be controlled without phase variation by adjustment of the combined gate voltage of the CG transistor and the shunt PMOS at the same time. The proposed device shows a gain of 20.8 dB and a noise figure of 3.71 dB at 31 GHz. It shows a root-mean-square phase error of less than 3° over the gain control range of 10.6 dB at 30–34.5 GHz.