Showing papers on "Amplifier published in 2017"
TL;DR: This work shows that the next major interconnect dissipations are in the electronic circuits for receiver amplifiers, timing recovery, and multiplexing, and it can address these through the integration of photodetectors to reduce or eliminate receiver circuit energies, free-space optics to eliminate the need for timing andmultiplexing circuits, and using optics generally to save power by running large synchronous systems.
Abstract: Optics offers unique opportunities for reducing energy in information processing and communications while simultaneously resolving the problem of interconnect bandwidth density inside machines. Such energy dissipation overall is now at environmentally significant levels; the source of that dissipation is progressively shifting from logic operations to interconnect energies. Without the prospect of substantial reduction in energy per bit communicated, we cannot continue the exponential growth of our use of information. The physics of optics and optoelectronics fundamentally addresses both interconnect energy and bandwidth density, and optics may be the only scalable solution to such problems. Here we summarize the corresponding background, status, opportunities, and research directions for optoelectronic technology and novel optics, including subfemtojoule devices in waveguide and novel two-dimensional (2-D) array optical systems. We compare different approaches to low-energy optoelectronic output devices and their scaling, including lasers, modulators and LEDs, optical confinement approaches (such as resonators) to enhance effects, and the benefits of different material choices, including 2-D materials and other quantum-confined structures. With such optoelectronic energy reductions, and the elimination of line charging dissipation by the use optical connections, the next major interconnect dissipations are in the electronic circuits for receiver amplifiers, timing recovery, and multiplexing. We show we can address these through the integration of photodetectors to reduce or eliminate receiver circuit energies, free-space optics to eliminate the need for timing and multiplexing circuits (while also solving bandwidth density problems), and using optics generally to save power by running large synchronous systems. One target concept is interconnects from ∼1 cm to ∼10 m that have the same energy (∼10 fJ/bit) and simplicity as local electrical wires on chip.
485 citations
TL;DR: This paper presents the first reported 28-GHz phased-array IC for 5G communications, implemented in 130-nm SiGe BiCMOS, which includes 32 TRX elements and features concurrent independent beams in two polarizations in either TX or RX operation.
Abstract: This paper presents the first reported 28-GHz phased-array IC for 5G communications. Implemented in 130-nm SiGe BiCMOS, the IC includes 32 TRX elements and features concurrent independent beams in two polarizations in either TX or RX operation. Circuit techniques to enable precise beam steering, orthogonal phase and amplitude control at each front end, and independent tapering and beam steering at the array level are presented. A TX/RX switch design is introduced which minimizes TX path loss resulting in 13.5 dBm/16 dBm Op1dB/Psat per front end with >20% peak power added efficiency of the power amplifier (including switch and off-mode LNA) while maintaining a 6 dB noise figure in the low noise amplifier (including switch and off-mode PA). Comprehensive on-wafer measurement results for the IC across multiple samples and temperature variation are presented. A package with four ICs and 64 dual-polarized antennas provides eight 16-element or two 64-element concurrent beams with 1.4°/step beam steering (<0.6° rms error) across a ±50° steering range without requiring calibration. A maximum saturated effective isotropic radiated power of 54 dBm is measured in the broadside direction for each polarization. Tapering control without requiring calibration achieves up to 20-dB sidelobe rejection without affecting the main lobe direction.
426 citations
TL;DR: The proposed rectenna is general and simple in structure without the need for a matching network, suitable for high-efficiency wireless power transfer or energy harvesting applications and of great significance for many applications.
Abstract: Impedance matching networks for nonlinear devices such as amplifiers and rectifiers are normally very challenging to design, particularly for broadband and multiband devices. A novel design concept for a broadband high-efficiency rectenna without using matching networks is presented in this paper for the first time. An off-center-fed dipole antenna with relatively high input impedance over a wide frequency band is proposed. The antenna impedance can be tuned to the desired value and directly provides a complex conjugate match to the impedance of a rectifier. The received RF power by the antenna can be delivered to the rectifier efficiently without using impedance matching networks; thus, the proposed rectenna is of a simple structure, low cost, and compact size. In addition, the rectenna can work well under different operating conditions and using different types of rectifying diodes. A rectenna has been designed and made based on this concept. The measured results show that the rectenna is of high power conversion efficiency (more than 60%) in two wide bands, which are 0.9–1.1 and 1.8–2.5 GHz, for mobile, Wi-Fi, and ISM bands. Moreover, by using different diodes, the rectenna can maintain its wide bandwidth and high efficiency over a wide range of input power levels (from 0 to 23 dBm) and load values (from 200 to 2000 Ω). It is, therefore, suitable for high-efficiency wireless power transfer or energy harvesting applications. The proposed rectenna is general and simple in structure without the need for a matching network hence is of great significance for many applications.
190 citations
TL;DR: A laser system based on thin-disk technology and chirped pulse amplification, providing output pulse energies of 200 mJ at a 5 kHz repetition rate, and an excellent output beam characterized by M2=1.1.
Abstract: We report on a laser system based on thin-disk technology and chirped pulse amplification, providing output pulse energies of 200 mJ at a 5 kHz repetition rate. The amplifier contains a ring-type cavity and two thin Yb:YAG disks, each pumped by diode laser systems providing up to 3.5 kW power at a 969 nm wavelength. The average output power of more than 1 kW is delivered in an excellent output beam characterized by M2=1.1. The output pulses are compressed to 1.1 ps at full power with a pair of dielectric gratings.
178 citations
02 May 2017
TL;DR: The state of the art in THz-capable InP HBT devices and integrated circuit (IC) technologies are reviewed and challenges in extending transistor bandwidth and in circuit design at THz frequencies are addressed.
Abstract: Highly scaled indium phosphide (InP) heterojunction bipolar transistor (HBT) technologies have been demonstrated with maximum frequencies of oscillation ( $f_{\max}$ ) of >1 THz and circuit operation has been extended into the lower end of the terahertz (THz) frequency band. InP HBTs offer high radio-frequency (RF) output power density, millivolt (mV) threshold uniformity, and high levels of integration. Integration with multilevel thin-film wiring permits the realization of compact and complex THz monolithic integrated circuits (TMICs). Circuit results reported from InP HBT technologies include: 200-mW power amplifiers at 210 GHz, 670-GHz amplifiers and fundamental oscillators, and fully integrated 600-GHz transmitter circuits. We review the state of the art in THz-capable InP HBT devices and integrated circuit (IC) technologies. Challenges in extending transistor bandwidth and in circuit design at THz frequencies will also be addressed.
170 citations
20 Sep 2017
TL;DR: In this article, a 21W mid-IR optical parametric chirped pulse amplifier (OPCPA) was proposed to generate 131μJ and 97μJ (sub-9-cycle) pulses at a 160-kHz repetition rate and at a center wavelength of 3.25μm.
Abstract: In attosecond and strong-field physics, the acquisition of data in an acceptable time demands the combination of high peak power with high average power. We report a 21 W mid-IR optical parametric chirped pulse amplifier (OPCPA) that generates 131 μJ and 97 fs (sub-9-cycle) pulses at a 160 kHz repetition rate and at a center wavelength of 3.25 μm. Pulse-to-pulse stability of the carrier envelope phase (CEP)-stable output is excellent with a 0.33% rms over 288 million pulses (30 min) and compression close to a single optical cycle was achieved through soliton self-compression inside a gas-filled mid-IR antiresonant-guiding photonic crystal fiber. Without any additional compression device, stable generation of 14.5 fs (1.35-optical-cycle) pulses was achieved at an average power of 9.6 W. The resulting peak power of 3.9 GW in combination with the near-single-cycle duration and intrinsic CEP stability makes our OPCPA a key-enabling technology for the next generation of extreme photonics, strong-field attosecond research, and coherent x-ray science.
163 citations
TL;DR: In this article, the recent advances of single-frequency fiber oscillators and amplifiers are briefly reviewed in the broad wavelength region of 1-3 μm. And the solution to achieving higher power/energy is also discussed, accompanied by the start-of-the-art results achieved to date.
Abstract: Single-frequency fiber lasers have drawn intense attention for their extensive applications from high-resolution spectroscopy and gravitational wave detection to materials processing due to the outstanding properties of low noise, narrow linewidth, and the resulting long coherence length. In this paper, the recent advances of single-frequency fiber oscillators and amplifiers are briefly reviewed in the broad wavelength region of 1–3 μm. Performance improvements in laser noise and linewidth are addressed with the newly developed physical mechanisms. The solution to achieving higher power/energy is also discussed, accompanied by the start-of-the-art results achieved to date.
155 citations
TL;DR: In this article, a dipole circuit element with third-order nonlinearity was proposed for a non-degenerate amplifier based on the proposed thirdorder non-linearity, which implements three-wave mixing.
Abstract: Parametric conversion and amplification based on three-wave mixing are powerful primitives for efficient quantum operations. For superconducting qubits, such operations can be realized with a quadrupole Josephson junction element, the Josephson Ring Modulator, which behaves as a loss-less three-wave mixer. However, combining multiple quadrupole elements is a difficult task so it would be advantageous to have a three-wave dipole element that could be tessellated for increased power handling and/or information throughput. Here, we present a dipole circuit element with third-order nonlinearity, which implements three-wave mixing. Experimental results for a non-degenerate amplifier based on the proposed third-order nonlinearity are reported.
141 citations
TL;DR: In this article, the authors report on hot test measurements of a wide-bandwidth, 220-GHz sheet beam traveling wave tube amplifier developed under the Defense advanced research projects agency (DARPA) HiFIVE program.
Abstract: We report on hot test measurements of a wide-bandwidth, 220-GHz sheet beam traveling wave tube amplifier developed under the Defense advanced research projects agency (DARPA) HiFIVE program. Nano-computer numerical control (CNC) milling techniques were employed for the precision fabrication of double vane, half-period staggered interaction structures achieving submicrometer tolerances and nanoscale surface roughness. A multilayer diffusion bonding technique was implemented to complete the structure demonstrating wide bandwidth (>50 GHz) with an insertion loss of about −5 dB achieved during transmission measurements of the circuit. The sheet beam electron gun utilized nanocomposite scandate tungsten cathodes that provided over 438-A/cm2 current density in the 12.5:1 ratio sheet beam. An InP HBT-based monolithic microwave integrated circuit preamplifier was employed for TWT gain measurements in the stable amplifier operation region. In the wide-bandwidth operation mode (for gun voltage of 20.9 kV), a gain of over 24 dB was measured over the frequency range of 207–221 GHz. In the high-gain operation mode (for gun voltage of 21.8 kV), over 30 dB of gain was measured over the frequency range of 197–202 GHz. High-power tests were conducted employing an extended interaction klystron.
141 citations
TL;DR: This finding can considerably improve the state-of-the-art interferometry, enable sub-shot-noise phase sensitivity in spectral ranges with inefficient detection, and allow extension to quantum imaging.
Abstract: In an unseeded SU(1,1) interferometer composed of two cascaded degenerate parametric amplifiers, with direct detection at the output, we demonstrate a phase sensitivity overcoming the shot noise limit by 2.3 dB. The interferometer is strongly unbalanced, with the parametric gain of the second amplifier exceeding the gain of the first one by a factor of 2, which makes the scheme extremely tolerant to detection losses. We show that by increasing the gain of the second amplifier, the phase supersensitivity of the interferometer can be preserved even with detection losses as high as 80%. This finding can considerably improve the state-of-the-art interferometry, enable sub-shot-noise phase sensitivity in spectral ranges with inefficient detection, and allow extension to quantum imaging.
138 citations
20 Apr 2017
TL;DR: In this article, the authors report efficient and stable operation of the first multi-joule diode pumped solid state laser delivering 1 kW average power in 105 J, 10 ns pulses at 10 Hz.
Abstract: We report efficient and stable operation of the first multi-joule diode pumped solid state laser delivering 1 kW average power in 105 J, 10 ns pulses at 10 Hz, confirming the power scalability of multi-slab cryogenic gas-cooled amplifier technology.
TL;DR: In this paper, a reconfigurable non-reciprocal device with alternative functions of either a circulator or a directional amplifier via the optomechanically induced coherent photon-phonon conversion or gain is presented.
Abstract: Non-reciprocal devices, which allow the non-reciprocal signal routing, serve as the fundamental elements in photonic and microwave circuits and are crucial in both classical and quantum information processing. The radiation-pressure-induced coupling between light and mechanical motion in traveling wave resonators has been exploited to break the Lorentz reciprocity, realizing non-reciprocal devices without magnetic materials. Here, we experimentally demonstrate a reconfigurable nonreciprocal device with alternative functions of either a circulator or a directional amplifier via the optomechanically induced coherent photon-phonon conversion or gain. The demonstrated device exhibits considerable flexibility and offers exciting opportunities for combining reconfigurability, non-reciprocity and active properties in single photonic structures, which can also be generalized to microwave as well as acoustic circuits.
01 Feb 2017
TL;DR: To achieve 5G Gb/s data-rates with complex modulations, envelope tracking PAs require high-speed/high-precision supply modulators, and outphasing PAs need high- speed baseband computation, both of which pose substantial challenges in practice.
Abstract: Millimeter-wave fifth-generation (5G) systems will extensively leverage massive multiple-input multiple-output (MIMO) architectures to improve their link performance. These array systems will employ many power amplifiers (PAs) operating at moderate output power (P out ), e.g., 16 PAs each with +7dBm P out [1]. The PA energy efficiency is of paramount importance in MIMO systems for improved battery life and thermal management. Due to spectrum-efficient modulations with high peak-to-average power ratios, both PA peak efficiency and power back-off (PBO) efficiency are critical. To achieve 5G Gb/s data-rates with complex modulations, envelope tracking PAs require high-speed/high-precision supply modulators, and outphasing PAs need high-speed baseband computation, both of which pose substantial challenges in practice. Although Doherty PAs support high data-rates, existing silicon mm-wave Doherty PAs exhibit very limited PBO efficiency enhancement, mainly due to inefficient Doherty power combiners and imperfect main/auxiliary PA cooperation [2,3].
TL;DR: A 12-bit 10-GS/s interleaved (IL) pipeline analog-to-digital converter (ADC) is described in this paper, which achieves a signal to noise and distortion ratio (SNDR) and a spurious free dynamic range (SFDR) of 66 dB with a 4-GHz input signal.
Abstract: A 12-bit 10-GS/s interleaved (IL) pipeline analog-to-digital converter (ADC) is described in this paper. The ADC achieves a signal to noise and distortion ratio (SNDR) of 55 dB and a spurious free dynamic range (SFDR) of 66 dB with a 4-GHz input signal, is fabricated in the 28-nm CMOS technology, and dissipates 2.9 W. Eight pipeline sub-ADCs are interleaved to achieve 10-GS/s sample rate, and mismatches between sub-ADCs are calibrated in the background. The pipeline sub-ADCs employ a variety of techniques to lower power, like avoiding a dedicated sample-and-hold amplifier (SHA-less), residue scaling, flash background calibration, dithering and inter-stage gain error background calibration. A push–pull input buffer optimized for high-frequency linearity drives the interleaved sub-ADCs to enable >7-GHz bandwidth. A fast turn-ON bootstrapped switch enables 100-ps sampling. The ADC also includes the ability to randomize the sub-ADC selection pattern to further reduce residual interleaving spurs.
TL;DR: In this article, the authors proposed a high-efficiency current-mode and voltage-mode (VM) Class-E power amplifiers for MHz wireless power transfer (WPT) systems and the design methodology for them is presented.
Abstract: The high-efficiency current-mode (CM) and voltage-mode (VM) Class-E power amplifiers (PAs) for MHz wireless power transfer (WPT) systems are first proposed in this paper and the design methodology for them is presented. The CM/VM Class-E PA is able to deliver the increasing/decreasing power with the increasing load and the efficiency maintains high even when the load varies in a wide range. The high efficiency and certain operation mode are realized by introducing an impedance transformation network with fixed components. The efficiency, output power, circuit tolerance, and robustness are all taken into consideration in the design procedure, which makes the CM and the VM Class-E PAs especially practical and efficient to real WPT systems. 6.78-MHz WPT systems with the CM and the VM Class-E PAs are fabricated and compared to that with the classical Class-E PA. The measurement results show that the output power is proportional to the load for the CM Class-E PA and is inversely proportional to the load for the VM Class-E PA. The efficiency for them maintains high, over 83%, when the load of PA varies from 10 to 100 $\Omega$ , while the efficiency of the classical Class-E is about 60% in the worst case. The experiment results validate the feasibility of the proposed design methodology and show that the CM and the VM Class-E PAs present superior performance in WPT systems compared to the traditional Class-E PA.
TL;DR: In this paper, a scalable microwave SQUID multiplexing of TES microcalorimeters has been demonstrated with small numbers of detectors, in which 128 TES detectors are read out on a single pair of coaxial cables.
Abstract: The number of elements in most cryogenic sensor arrays is limited by the technology available to multiplex signals from the arrays into a smaller number of wires and readout amplifiers. The largest demonstrated arrays of transition-edge sensor (TES) microcalorimeters contain roughly 250 detectors and use time-division multiplexing with Superconducting Quantum Interference Devices (SQUIDs). The bandwidth limits of this technology constrain the number of sensors per amplifier chain, a quantity known as the multiplexing factor, to several 10s. With microwave SQUID multiplexing, we can expand the readout bandwidth and enable much larger multiplexing factors. While microwave SQUID multiplexing of TES microcalorimeters has been previously demonstrated with small numbers of detectors, we now present a fully scalable demonstration in which 128 TES detectors are read out on a single pair of coaxial cables.
TL;DR: A complementary noise-canceling CMOS low-noise amplifier (LNA) with enhanced linearity is proposed, while an active shunt feedback input stage offers input matching, while extended input matching bandwidth is acquired by a
Abstract: A complementary noise-canceling CMOS low-noise amplifier (LNA) with enhanced linearity is proposed. An active shunt feedback input stage offers input matching, while extended input matching bandwidth is acquired by a $\pi$ -type matching network. The intrinsic noise cancellation mechanism maintains acceptable noise figure (NF) with reduced power consumption due to the current reuse principle. Multiple complementary nMOS and pMOS configurations commonly restrain nonlinear components in individual stage of the LNA. Complementary multigated transistor architecture is further employed to nullify the third-order distortion of noise-canceling stage and compensate the second-order nonlinearity of that. High third-order input intercept point (IIP3) is thus obtained, while the second-order input intercept point (IIP2) is guaranteed by differential operation. Implemented in a 0.18- $\mu \text{m}$ CMOS process, the experimental results show that the proposed LNA provides a maximum gain of 17.5 dB and an input 1-dB compression point (IP1 dB) of −3 dBm. An NF of 2.9–3.5 dB and an IIP3 of 10.6–14.3 dBm are obtained from 0.1 to 2 GHz, respectively. The circuit core only draws 9.7 mA from a 2.2 V supply.
11 May 2017-Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment
TL;DR: In this paper, the authors describe a dark matter axion detector designed, constructed, and operated both as an innovation platform for new cavity and amplifier technologies and as a data pathfinder in the 5 − 25 GHz range ( ∼ 20 − 100 μ eV ).
Abstract: We describe a dark matter axion detector designed, constructed, and operated both as an innovation platform for new cavity and amplifier technologies and as a data pathfinder in the 5–25 GHz range ( ∼ 20 – 100 μ eV ) . The platform is small but flexible to facilitate the development of new microwave cavity and amplifier concepts in an operational environment. The experiment has recently completed its first data production; it is the first microwave cavity axion search to deploy a Josephson parametric amplifier and a dilution refrigerator to achieve near-quantum limited performance.
TL;DR: An integrated on-chip matching network serves to both PA and low-noise transconductance amplifier, thus allowing a 1-pin direct antenna connection with no external band-selection filters.
Abstract: We present an ultra-low-power Bluetooth low-energy (BLE) transceiver (TRX) for the Internet of Things (IoT) optimized for digital 28-nm CMOS. A transmitter (TX) employs an all-digital phase-locked loop (ADPLL) with a switched current-source digitally controlled oscillator (DCO) featuring low frequency pushing, and class-E/F2 digital power amplifier (PA), featuring high efficiency. Low 1/ $f$ DCO noise allows the ADPLL to shut down after acquiring lock. The receiver operates in discrete time at high sampling rate (~10 Gsamples/s) with intermediate frequency placed beyond 1/ $f$ noise corner of MOS devices. New multistage multirate charge-sharing bandpass filters are adapted to achieve high out-of-band linearity, low noise, and low power consumption. An integrated on-chip matching network serves to both PA and low-noise transconductance amplifier, thus allowing a 1-pin direct antenna connection with no external band-selection filters. The TRX consumes 2.75 mW on the RX side and 3.7 mW on the TX side when delivering 0 dBm in BLE.
TL;DR: A pixel pitch-matched readout chip for 3-D photoacoustic (PA) imaging, featuring a dedicated signal conditioning and delta-sigma modulation integrated within a pixel area of 250, that obviates the need for area-consuming Nyquist ADCs and enables an efficient in-pixel A/D conversion.
Abstract: This paper presents a pixel pitch-matched readout chip for 3-D photoacoustic (PA) imaging, featuring a dedicated signal conditioning and delta-sigma modulation integrated within a pixel area of 250 $\mu \text{m}$ by 250 $\mu \text{m}$ . The proof-of-concept receiver was implemented in an STMicroelectronics’s 28-nm Fully Depleted Silicon On Insulator technology, and interfaces to a $4 \times 4$ subarray of capacitive micromachined ultrasound transducers (CMUTs). The front-end signal conditioning in each pixel employs a coarse/fine gain tuning architecture to fulfill the 90-dB dynamic range requirement of the application. The employed delta-sigma beamforming architecture obviates the need for area-consuming Nyquist ADCs and thereby enables an efficient in-pixel A/D conversion. The per-pixel switched-capacitor $\Delta \Sigma $ modulator leverages slewing-dominated and area-optimized inverter-based amplifiers. It occupies only 1/4th of the pixel, and its area compares favorably with state-of-the-art designs that offer the same SNR and bandwidth. The modulator’s measured peak signal-to-noise-and-distortion ratio is 59.9 dB for a 10-MHz input bandwidth, and it consumes 6.65 mW from a 1-V supply. The overall subarray beamforming approach improves the area per channel by 7.4 times and the single-channel SNR by 8 dB compared to prior art with similar delay resolution and power dissipation. The functionality of the designed chip was evaluated within a PA imaging experiment, employing a flip-chip bonded 2-D CMUT array.
20 May 2017
TL;DR: In this article, the authors report a record low propagation loss of 3±1 dB/m across the entire telecommunications C-band for a CMOS-compatible Ta2O5-core/SiO2-clad planar waveguide.
Abstract: An increasing number of systems and applications depend on photonics for transmission and signal processing. This includes data centers, communications systems, environmental sensing, radar, lidar, and microwave signal generation. Such systems increasingly rely on monolithic integration of traditionally bulk optical components onto the chip scale to significantly reduce power and cost while simultaneously maintaining the requisite performance specifications at high production volumes. A critical aspect to meeting these challenges is the loss of the waveguide on the integrated optic platform, along with the capability of designing a wide range of passive and active optical elements while providing compatibility with low-cost, highly manufacturable processes, such as those found in CMOS. In this article, we report the demonstration of a record low propagation loss of 3±1 dB/m across the entire telecommunications C-band for a CMOS-compatible Ta2O5-core/SiO2-clad planar waveguide. The waveguide design, fabrication process, and optical frequency domain reflectometry characterization of the waveguide propagation loss and group index are described in detail. The losses and dispersion properties of this platform enable the integration of a wide variety of linear and nonlinear optical components on-chip, as well as integration with active rare-earth components for lasers and amplifiers and additionally silicon photonic integrated devices. This opens up new integration possibilities within the data communications, microwave photonics, high bandwidth electrical RF systems, sensing, and optical signal processing applications and research communities.
TL;DR: In this article, a transformer gate-drain feedback technique was used to peak the gain at high frequency while the wideband input matching was obtained by employing a new transformer-based input matching network to produce two resonant points separately located at low and high frequencies.
Abstract: This letter presents a compact wideband low-noise amplifier (LNA) with utilizing the transformers for gain and input matching bandwidth extensions based on the source degeneration topology. The wideband gain response is achieved by using a transformer gate–drain feedback technique to peak the gain at high frequency while the wideband input matching is obtained by employing a new transformer-based input matching network to produce two resonant points separately located at low and high frequencies within the operating band. Implemented in 65-nm CMOS process, the proposed LNA shows a measured peak gain of 10.2 dB with its 3-dB bandwidth ranging from 15.8 to 30.3 GHz and minimum noise figure of 3.3 dB. Taking advantage of the superior compactness from the transformer-based techniques, the LNA occupies very compact chip area of only 0.18 mm2, exhibiting as one of the most compact wideband LNAs.
TL;DR: It is concluded that decreasing the empirical parameter of a general class-B/J voltage equation with increasing frequency leads to a clockwise trajectory on the Smith chart of the second harmonic at the package plane.
Abstract: This brief explores the design space for realizable solution of a broadband class-B/J continuous mode of power amplifier (PA). The PA is initially designed at the current-source reference plane with the correct voltage and current waveforms. The intrinsic impedances are then projected to the package reference plane using the model-based nonlinear-embedding technique. An insight is provided into engineering the extrinsic harmonic impedance to rotate clockwise on the Smith chart to be able to match it using a Foster circuit. It is concluded that decreasing the empirical parameter $ {\alpha }$ of a general class-B/J voltage equation with increasing frequency leads to a clockwise trajectory on the Smith chart of the second harmonic at the package plane. In order to validate the advantage of this analysis, the PA is implemented using a 15 W gallium nitride high electron mobility transistor in the frequency range of 1.3 to 2.4 GHz and drain efficiency between 63% and 72% in measurement was achieved over the entire bandwidth.
TL;DR: A transformer-based broadband low-noise amplifier for millimeter-wave application that has four common-source stages and a maximum gain of 17.7 GHz at 67 GHz and a 3-dB gain bandwidth of 35.6 GHz is proposed.
Abstract: This paper proposes a transformer-based broadband low-noise amplifier (LNA) for millimeter-wave application. The proposed LNA has four common-source stages. Three transformers are used to connect the drains of the former transistors and the sources of the following transistors to boost the transconductances of the following transistors. Thus, the gain of the circuit is effectively increased. In addition, the noise figure (NF) is decreased because the noise contributions of the following stages are further suppressed by the application of the transformers. To enhance the gain bandwidth, the gate inductor in each inter-stage matching network is independently adjusted to separate the main poles of the four stages. The LNA is demonstrated using a commercial 65-nm CMOS process. According to the measurement results, a maximum gain of 17.7 GHz at 67 GHz and a 3-dB gain bandwidth of 35.6 GHz are achieved. The measured NF is 5.4–7.4 dB at 54–67 GHz. The tested input 1-dB gain compression point (IP $_{1\,\text {dB}}$ ) ranges from −15.4 to −11.7 dBm in the entire 3-dB gain bandwidth. With 1-V power supply, the LNA consumes 19-mA dc current. The chip size is only 0.37 mm2 with all pads.
TL;DR: A phase-compensation technique through which the active matching and load modulation tracks the frequency-dependent optimal loading trajectory of a packaged device is introduced, and the result is a load-modulation power amplifier architecture able to perform an active, modulated match over an octave bandwidth.
Abstract: This paper presents an octave-bandwidth load modulated balanced amplifier (LMBA) that operates directly on a single modulated RF input. The architecture is based on the recently proposed LMBA technique, in which a control signal applied at the output isolation port of a balanced amplifier is used to modulate the apparent load impedance of the two devices comprising the balanced amplifier. In our approach, the injected control signal is used both as an active match and to dynamically load modulate the main devices to provide efficiency enhancement at back-off, thus extending the dynamic range compared to the original LMBA formulation. In this paper, we introduce a phase-compensation technique through which the active matching and load modulation tracks the frequency-dependent optimal loading trajectory of a packaged device. The result is a load-modulation power amplifier architecture able to perform an active, modulated match over an octave bandwidth. The technique is demonstrated over 1.8–3.8 GHz using packaged devices and an off-the-shelf hybrid coupler. The proof-of-concept octave RF-input LMBA has a peak CW output power of 44 dBm, with power added efficiency (PAE) over the 1.8–3.8 GHz operating frequency range of 37%–59% at peak power and 29%–45% at 6-dB output backoff. The RF-input nature of this architecture enables straightforward measurement with modulated signals; a W-CDMA signal at 3.8 GHz with 9-dB (measured) peak to average power ratio is demonstrated with adjacent channel leakage ratio of −30 dBc and average PAE of 18% for a 31-dBm average output power (2-dB backoff).
TL;DR: It is shown that integrated circuits for low-frequency noise and offset rejection as a motivation for the presented digitally-assisted neural amplifier design methodology has been validated in online intracranial EEG monitoring in freely moving rats.
Abstract: We review integrated circuits for low-frequency noise and offset rejection as a motivation for the presented digitally-assisted neural amplifier design methodology. Conventional AC-coupled neural amplifiers inherently reject input DC offset but have key limitations in area, linearity, DC drift, and spectral accuracy. Their chopper stabilization reduces low-frequency intrinsic noise at the cost of degraded area, input impedance and design complexity. DC-coupled implementations with digital high-pass filtering yield improved area, linearity, drift, and spectral accuracy and are inherently suitable for simple chopper stabilization. As a design example, a 56-channel 0.13 [Formula: see text] CMOS intracranial EEG interface is presented. DC offset of up to ±50 mV is rejected by a digital low-pass filter and a 16-bit delta-sigma DAC feeding back into the folding node of a folded-cascode LNA with CMRR of 65 dB. A bank of seven column-parallel fully differential SAR ADCs with ENOB of 6.6 are shared among 56 channels resulting in 0.018 [Formula: see text] effective channel area. Compensation-free direct input chopping yields integrated input-referred noise of 4.2 μVrms over the bandwidth of 1 Hz to 1 kHz. The 8.7 [Formula: see text] chip dissipating 1.07 mW has been validated in vivo in online intracranial EEG monitoring in freely moving rats.
TL;DR: This paper presents a 190-GHz direct conversion transceiver (TRX) chipset with on-chip antennas implemented in a 130-nm SiGe BiCMOS technology for short-distance high-data-rate wireless links that leads to a very low required energy per transferred bit.
Abstract: This paper presents a 190-GHz direct conversion transceiver (TRX) chipset with on-chip antennas implemented in a 130-nm SiGe BiCMOS technology for short-distance high-data-rate wireless links. The transmitter (TX) consists of an active fundamental upconversion mixer, a local oscillator (LO) driver, and a passive balun for differential to single-ended conversion of the RF signal. The receiver (RX) is composed of a low-noise amplifier, an active fundamental mixer, an LO driver, a variable-gain baseband (BB) amplifier, and a totem-pole output stage. The wireless communication between TX and RX is enabled by on-chip monopole antennas, which are fabricated using standard wire-bonding tools. Measurements of the TRX chipset equipped with these antennas show a 6-dB BB link bandwidth of 20 GHz, corresponding to 40 GHz of the RF link bandwidth. In a data transmission test setup based on a BPSK modulation, data rates of up to 40 Gbit/s over 20 mm and up to 50 Gbit/s over 6 mm are demonstrated. Consuming only 122 mW in the RX and 32 mW in the TX, this leads to a very low required energy per transferred bit of 3.9 and 3.1 pJ for the 40- and 50-Gbit/s link, respectively.
TL;DR: In this paper, a femtosecond polycrystalline ZnS and ZnSe laser and amplifiers were designed to obtain few-optical-cycle pulses with a multi-Watt average power in a very broad range of repetition rates.
Abstract: Transition-metal-doped II-VI semiconductors possess a unique blend of physical, spectroscopic, optical, and technological parameters. These materials enable high power lasers in important middle-infrared range. Furthermore, they combine superb ultra-fast laser capabilities with high nonlinearity and polycrystalline microstructure, which provides random quasi-phase matching. We developed flexible design of femtosecond polycrystalline Cr:ZnS and Cr:ZnSe lasers and amplifiers in the spectral range 2–3 µm. We obtained few-optical-cycle pulses with a multi-Watt average power in a very broad range of repetition rates 0.07–1.2 GHz. We also report on efficient nonlinear frequency conversion directly in the polycrystalline gain elements of ultra-fast lasers and amplifiers including second harmonic generation with sub-Watt power and generation of an octave-spanning middle-infrared supercontinuum.
Book•
09 Oct 2017
TL;DR: In this paper, the major transimpedance amplifier (TIA) topologies and their circuit implementations for optical receivers are analyzed and optimized for direct detection, coherent, burst-mode, and analog-receiver TIA.
Abstract: This book covers the major transimpedance amplifier (TIA) topologies and their circuit implementations for optical receivers. This includes the shunt-feedback TIA, common-base TIA, common-gate TIA, regulated-cascode TIA, distributed-amplifier TIA, nonresistive feedback TIA, current-mode TIA, burst-mode TIA, and analog-receiver TIA. The noise, transimpedance, and other performance parameters of these circuits are analyzed and optimized. Topics of interest include post amplifiers, differential vs. single-ended TIAs, DC input current control, and adaptive transimpedance. The book features real-world examples of TIA circuits for a variety of receivers (direct detection, coherent, burst-mode, etc.) implemented in a broad array of technologies (HBT, BiCMOS, CMOS, etc.).
TL;DR: In this paper, a scalable electrothermal large-signal AlGaN/GaN HEMTs model for both fundamental and multiharmonics is presented based on the modified Angelov model.
Abstract: A scalable electrothermal large-signal AlGaN/GaN HEMTs model for both fundamental and multiharmonics is presented based on the modified Angelov model. To obtain accurate scalability of the electrothermal model, a simple empirical expression is proposed for the geometric and power-dissipation-dependent nonlinear thermal resistance $R_{{\mathrm {th}}}$ . Only one additional parameter with linear scaling rule is needed in the drain-source current ( $I_{{\mathrm {ds}}}$ ) model for a scalable large-signal multiharmonic model. The proposed model has been validated by different AlGaN/GaN HEMTs characterized by on-wafer measurements. It shows that the presented scalable model can well predict the dc $I$ – $V$ , pulsed $I$ – $V$ , scattering (S) parameters, and large-signal performance up to third harmonic. Furthermore, to further validation, a C-band power amplifier is designed. The amplifier is realized using the second-harmonic tuned approach to enhance the efficiency. Measurement results show that the GaN high power amplifier (HPA) microwave monolithic integrated circuit (MMIC) exhibits more than 40% power-added efficiency and 60-W output power ( $P_{{\mathrm {out}}}$ ) with associated gain of 25 dB in 5–6 GHz measured at 28-V drain voltage and pulse signal with 100- $\mu \text{s}$ pulsewidth and 10% duty cycle. The area of the chip is 3.2 mm $\times5.3$ mm (16.96 mm2). These results show that the proposed model will be useful for high-efficiency HPA MMIC design.