Band Amplifier Research Articles

Research Effect of Four-Quadrant Detector Detection Spot in Atmospheric Turbulence

Movement frequency of atmospheric turbulence is varied between a few Hz to hundreds Hz. when laser is transmitted in atmospheric some characteristic will be changed by turbulence modulation. The energy distribution form and shape of spot will be varied with movement frequency of turbulence. When spot is detected by four-quadrant detector output of detector will be effect. In order to test effect of turbulence to detector and ensure output signal can be amplified and processing effectively a kind of spot detection circuit was designed in turbulent environment. Two bands amplification was used in system. The noise suppression was completed in first band and variable gain amplifier was used in second to meet require of light intensity. Testing system was set up which can research characteristic of quadrant detector in turbulence. Experiment of spot detection in field was done. Distance from transmitting to receiving is 800m and 12.5km. Conclusions have been obtained by experimental when Distance is 800m subdivision can be up to 7 in photosensitive surface. At the same time we can see that impact of turbulence on laser transmission is a combination result with modulation of high and low frequency. And ability to spot detection has been invalid in 12.5 kilometers distances because of photosensitive surface occupied by noise from impact of turbulence, which show subdivision of quadrant detector has been broken in long distance.

Normal-Metal Hot-Electron Nanobolometer With Johnson Noise Thermometry Readout

The sensitivity of a THz hot-electron nanobolometer (nano-HEB) made from a normal metal is analyzed. Johnson Noise Thermometry (JNT) is employed as a readout technique. In contrast to its superconducting Transition-Edge Sensor (TES) counterpart, the normal-metal nano-HEB can operate at any cryogenic temperature depending on the required radiation background limited Noise Equivalent Power (NEP). It does not require bias lines; 100s of nano-HEBs can be read by a single low-noise <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex Notation="TeX">$X$</tex> </formula> -band amplifier via a filter bank channelizer. The modeling predicts that even with the sensitivity penalty due to the amplifier noise, an <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex Notation="TeX">${\rm NEP}{\sim} 10^{-20}{\hbox{--}}10^{-19}{\hbox{W/Hz}}^{1/2}$</tex> </formula> can be expected at 50–100 mK in 10–20 nm thin titanium (Ti) normal metal HEBs with niobium (Nb) contacts. This NEP is fairly constant over a range of readout frequencies <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex Notation="TeX">$\sim$</tex></formula> 10 GHz. Although materials with weaker electron-phonon coupling (bismuth, graphene) do not improve the minimum achievable NEP, they can be considered if a larger than 10 GHz readout bandwidth is required.

Qualification of 50 V GaN on SiC technology for RF power amplifiers

This paper describes the qualification of the 50V, 0.5μm GaN on SiC process that has been released at the III–V fab of UMS in Ulm in cooperation with IAF and NXP Semiconductors. The qualification at NXP is split into two parts: Part 1: investigation of die related wear-out failure mechanisms using a power device with 7.2mm gate width and Part 2: final process release using the first product of NXP, a 50W wide band amplifier. The aim of the first part is to determine the acceleration factors for the major electric failure mechanism. These will be then used to define the qualification program of the wide band amplifier which will also include all package related tests. In this paper we will show how the tests are defined using the mission profile of the product. In addition, we will show the results. They are compared to results published in literature and are shown to be very promising.

Luminescence properties and energy transfer mechanism of Er3+/Tm3+ co-doped tellurite glasses

Er3+ single doped and Er3+/Tm3+ co-doped tellurite glasses with composition of TeO2–ZnO–Na2O were prepared by the melt-quenching method, and the absorption and fluorescence spectra were measured. The intensity parameters Ωt (t=2, 4, 6), spontaneous radiative transition rates A, fluorescence branching ratios β and radiative lifetimes τrad of Tm3+ ions were calculated from the measured absorption spectra based on the Judd–Ofelt theory, and the luminescence properties of samples with different doped concentration of Er3+–Tm3+ ions were investigated from the measured fluorescence emission spectra under the 800nm LD excitation. It was shown that the 1.53μm fluorescence emission intensity of Er3+ ions decreases with the increasing of Tm3+ ion doped concentration, while the 1.85μm fluorescence emission intensity of Tm3+ ions increases accordingly. The energy transfer mechanisms between Er3+ and Tm3+ ions were investigated to explain the fluorescence varying behavior, and it indicates that phonon-assisted non-resonant energy transfers from Er3+ to Tm3+ ions play a very important role in the 1.85μm fluorescence emission of Tm3+ ions. The energy transfer coefficient and phonon contribution for the existed energy transfer process between Er3+ and Tm3+ ions were calculated and analyzed. Meanwhile, the 1.85μm band stimulated absorption, emission cross-sections and gain coefficient of Tm3+:3F4→3H6 transitions were also obtained and analyzed. The research shows that Er3+/Tm3+ co-doped TeO2–ZnO–Na2O glass is a promising host material applied for 1.85μm band solid lasers and amplifiers.

Design and Performance of a 600-W $C$-Band Amplifier Using Spatially Combined GaAs FETs for Satellite Communications

This paper describes the design and performance of a C-band amplifier with over 600 W of saturated output power. This amplifier is intended for use in commercial broadcast satellite uplink base stations. The amplifier uses spatial power combining to combine the output powers of sixteen internally matched 45-W GaAs FETs. The amplifier also comprises pre-amplification and driver amplification stages, a level control variable attenuator, and a predistortion linearizer. The unit also includes a power supply as well as a user monitor and control interface. We will present various measures of this amplifier's linearity performance, demonstrating its suitability for use in broadcast applications. Finally, we will present results from power combining two of these amplifiers, resulting in a solid-state amplifier with 1.4 kW of saturated C-band output power.

$W$-Band Amplifiers With 6-dB Noise Figure and Milliwatt-Level 170–200-GHz Doublers in 45-nm CMOS

This paper presents low-noise -band amplifiers and milliwatt-level 170-200-GHz output doublers in 45-nm semiconductor-on-insulator (SOI) CMOS technology. The transistors are modeled using R/C extraction and full electromagnetic modeling. The measured of a 30 1- transistor is 200-210 GHz at a bias current of 0.3-0.5 . A three-stage -band amplifier shows a record noise figure of 6.0 dB and a saturated output power of 7.5-8.0 dBm with a power-added efficiency of 9%, all at 95 GHz. The -band balanced doubler results in an output power of 1 mW at 180 GHz. A -band amplifier/ -band doubler chip is also demonstrated, with a peak output power of 0.5-1 mW at 170-195 GHz and a conversion gain from to . This paper shows that 45-nm SOI CMOS, built for digital and mixed-signal applications, results in state-of-the-art performance at - and -band.

메타물질 전송선로를 이용한 이중대역 평형증폭기

This paper describes a design of dual band balanced amplifier using a lefted handed meta-material transmission line structure for high frequency application. Meta-material transmission lines have been known to have dual band frequency responses. A dual band branch line hybrid coupler is designed using the meta-material transmission lines, and measured at first. Two identical dual band amplifiers are also designed, built and tested using the same meta-material transmission structure. The proposed dual band balanced amplifier is composed of those dual band branch line hybrid coupler and amplifiers. In order to suggest an design example, a prototype of dual band balanced amplifier is built and measured at the dual frequencies, 1800㎒(f₁) and 2300㎒(f₂). The simulation and measurement show that the fabricated balanced amplifier operates well at the desired dual frequencies bands with the gain of 11.12㏈ and 17.67㏈ at f₁ and f₂, respectively, with a good agreement with the simulation results.

High gain S-band semiconductors optical amplifier with double-pass configuration

In this paper we propose and demonstrate a double-pass configuration of a compact high gain short wavelength (S-) band amplifier based on a semiconductor optical amplifier (SOA) operating from 1480 to 1520 nm. The proposed system provides gain value of 31.07 dB at a signal power level of −40 dBm taken at 1500 nm. The measure gain profile of the double-pass configuration over different power levels and at different signal wavelengths outperforms that of the single-pass configuration. The noise figure of both configurations averages out to 10 dB. This system provides a good alternative as a high-gain and compact amplifier in the S-band region.

A Wideband Receiver for Multi-Gbit/s Communications in 65 nm CMOS

High-rate communications technology leveraging the unlicensed spectrum around 60 GHz is almost ready for deployment with several demonstrations of successful wireless links. One key aspect of the transceiver is the ability to handle analog fractional bandwidths in the order of 20%, challenging for both the linear processing chain and the frequency reference generator. In classical LC loaded stages bandwidth trades with gain making them unsuitable for wide band amplifiers at millimeter-waves where the available device gain is relatively low. In this work, we exploit inter-stage coupling realizing higher order filters where wider bandwidth is achieved at the expense of in-band gain ripple only. The receiver adopts a sliding IF architecture employing an integer-N type-II synthesizer, with a three state phase frequency detector charge pump combination, a switched tuned LC VCO followed by a low power wide range divider chain. By judicious choice of charge pump current and filter components integrated phase noise, critical for signal constellation integrity at high rate, is kept low. This paper inspects the inter-stage coupling technique, providing design formulas, and discusses the design of each receiver block. Experiments performed on 65 nm prototypes provide: 6.5 dB maximum noise figure over >;13 GHz bandwidth, -22.5 dBc integrated phase noise while consuming 84 mW.

A 500 Mb/s Differential Input Non-coherent BPSK Receiver for UWB-IR Communication

A differential input non-coherent BPSK receiver for the UWB-IR communication, based on threshold detection, has been presented in this paper. The chip can recover BPSK modulated Gaussian monocycle pulses (GMP), along with its first derivative, at a data rate of 500 Mb/s. No clock reception is required, as the receiver recovers data based on the relative phase of the two simultaneously received inputs. While retrieving the data, it consumes a power of 63 mW from a supply voltage of 1.8 V. A shunt-peaked narrow band amplifier, matched to the input antenna, is used to amplify the received GMP. Wireless data have been successfully recovered using a pair of horn antennas at a distance of 6 cm. The chip, developed in a 180 nm CMOS technology, occupies a die area of 3.4 mm 2 . The receiver is suitable for the non-coherent (self-synchronized) UWB-IR communication.

A wideband active feedback LNA with a modified 3D inductor

A modified miniature 3D inductor to implement a fully-integrated feedback wide band amplifier in a standard SiGe low cost 0.35 μm process is presented. According to the measurement results, the proposed technique achieves a 40% area reduction with minor performance degradation over the same circuit implemented with conventional inductors. The circuit provides a gain from 14 dB to 7 dB in the band between 3.1 GHz to 10.6 GHz. In the same band the noise figure (NF) varies from 2.9 dB to 4 dB. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52: 1561–1567, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.25283

A Design of Dual Band Amplifier Using Left Handed Transmission Lines

This paper describes a design of dual band amplifier using left handed (LHJ) transmission line, which is a part of composite right/left handed (CRLH) transmission line. It is well known that CRLH transmission lines show dual band frequency response. At first, two single-band amplifiers for frequency f1 and f2 are designed, and their matching networks at both amplifiers are synthesized into the dual band matching network by adopting CRLH structure. As an example for proving the validity of the proposed design, a dual band amplifier operating at 1800MHz and 2300MHz is designed, fabricated and measured. The simulation and measurement show that the proposed amplifier operates well at the desired dual bands with the gain of 13.65dB and 19dB at 1850MHz and 2360MHz, respectively, and a good matching performances. In addition, a quite good agreement between the simulation and measurement is observed.

A New Loss Compensation Technique for CMOS Distributed Amplifiers

This brief presents a circuit technique to compensate for the metal and substrate loss of the on-chip transmission lines (TLs), and, consequently, to improve the gain flatness and bandwidth of CMOS distributed amplifiers (DAs). An eight-stage DA suitable for 40-Gb/s optical communication is devised and implemented in a 0.13-mum CMOS process. The DA achieves a flat gain of 10 dB from dc to 44 GHz with an input and output matching better than -8 dB. The measured noise figure varies from 2.5 to 7.5 dB with the amplifier's band. The proposed DA dissipates 103 mW from two 1-V and 1.2-V dc supplies.

GaN TRANSISTORS FOR POWER SWITCHING AND MILLIMETER-WAVE APPLICATIONS

We review our state-of-the-art GaN -based device technologies for power switching at low frequencies and for future millimeter-wave communication systems. These two applications are emerging in addition to the power amplifiers at microwave frequencies which have been already commercialized for cellular base stations. Technical issues of the power switching GaN device include lowering the fabrication cost, normally-off operation and further increase of the breakdown voltages extracting full potential of GaN -based materials. We establish flat and crack-free epitaxial growth of GaN on Si which can reduce the chip cost. Our novel device structure called Gate Injection Transistor (GIT) achieves normally-off operation with high enough drain current utilizing conductivity modulation. Here we also present the world highest breakdown voltage of 10400V in AlGaN / GaN HFETs. In this paper, we also present high frequency GaN -based devices for millimeter-wave applications. Short-gate MIS-HFETs using in-situ SiN as gate insulators achieve high fmax up to 203GHz. Successful integration of low-loss microstrip lines with via-holes onto sapphire enables compact 3-stage K -band amplifier MMIC of which the small-signal gain is as high as 22dB at 26GHz. The presented devices are promising for the two future emerging applications demonstrating high enough potential of GaN -based transistors.

A High-Power $Ka$-Band (31–36 GHz) Solid-State Amplifier Based on Low-Loss Corporate Waveguide Combining

A method of using low-loss waveguide septum combiners is developed into a high-power -band (31-36 GHz) amplifier producing 50 W at 33 GHz (Ka-band) using 32 low-power (>2 W) solid-state amplifier modules. By using low-loss waveguide combining and a packaged monolithic microwave integrated circuit with a low-loss microstrip-to-waveguide launcher, the output loss is minimized, allowing for the overall power-combining efficiency to remain high, 80% (average insertion loss of combiner < 0.7 dB and average insertion loss of launcher <0.3 dB) over 31-36 GHz. In the past, lower power-combining efficiencies have limited the number of modules that can be combined at -band, and hence, have limited the power output. The approach demonstrated in this paper, with high power-combining efficiency, allows a very large number (32) of solid-state amplifier modules to be combined to produce high powers. Greater than 50 W was demonstrated with low power modules, but even higher powers 120 W are possible. The current approach is based on corporate combining, using low-loss waveguide septum combiners that provide isolation, maintaining the true graceful degradation of a modular solid-state amplifier system.

Radio frequency analog electronics based on carbon nanotube transistors

The potential to exploit single-walled carbon nanotubes (SWNTs) in advanced electronics represents a continuing, major source of interest in these materials. However, scalable integration of SWNTs into circuits is challenging because of difficulties in controlling the geometries, spatial positions, and electronic properties of individual tubes. We have implemented solutions to some of these challenges to yield radio frequency (RF) SWNT analog electronic devices, such as narrow band amplifiers operating in the VHF frequency band with power gains as high as 14 dB. As a demonstration, we fabricated nanotube transistor radios, in which SWNT devices provide all of the key functions, including resonant antennas, fixed RF amplifiers, RF mixers, and audio amplifiers. These results represent important first steps to practical implementation of SWNTs in high-speed analog circuits. Comparison studies indicate certain performance advantages over silicon and capabilities that complement those in existing compound semiconductor technologies.

Tellurite-based fibers and their applications to optical communication networks

This paper reviews tellurite-based fibers and their applications to optical communication networks. First, an investigation of tellurite-based glass and the fabrication of conventional step-index fibers and photonic crystal fibers (PCF) are described. By purifying the raw materials and employing a novel PCF fabrication process, low background losses were achieved for an Er3+-doped, an undoped tellurite-based fiber and a tellurite-based PCF. Second, the optical properties of Er3+-doped tellurite-based glass and fiber, and the gain characteristics of erbium doped tellurite fiber amplifiers (EDTFAs) were studied. A seamless, low noise and gain flattened C + L band EDTFA was realized, and an S + C + L band amplifier was constructed by combining an EDTFA and a thulium-doped fluoride fiber amplifier (TDFFA) in parallel. Third, it is confirmed that the Raman scattering characteristic of tellurite-based fiber has such a large gain coefficient and Stokes shift that it is possible achieve a wideband tellurite-based fiber Raman amplifier. To overcome several problems, a distributed/discrete hybrid tellurite- and silica-based fiber Raman amplifier (FRA) was constructed as an S + C + L band WDM repeater with a gain bandwidth of 127-nm. Fourth, Brillouin amplification and the simulated performance of slow light generation in a tellurite-based fiber were investigated. The fiber exhibits the largest time delay per unit power of 19.9 ns/mW. Finally, a carrier-envelope offset (CEO)-locked frequency comb with low fiber coupling pulse energy (230 pJ) was demonstrated by using a tellurite-based PCF. This method has the potential to lock the CEO with a lower pulse energy and thus provide a low-noise and high-accuracy optical frequency comb at telecommunication wavelengths. These tellurite-based fibers with low background loss thus offer attractive functions for applications in the optical communication field.

Accurate characterization of intermodulation noise in multi carrier wide band power amplifiers based on a digital synthesis of pseudo noise gaussian stimuli

This paper presents an accurate technique for the characterization of intermodulation noise in wide band multi carrier power amplifiers. Band limited pseudo noise stimuli which are generated by using a computer controlled arbitrary waveform generator (Awg) connected to anI/q modulator drive the input of the amplifier under test (Aut). The complex envelopes of the pseudo noises are measured using a sampling scope. A vector error correction is applied in order to remove systematic errors due to the imperfections of the measurement channels. Using this technique, the linearity of L and Ka band amplifiers was characterized by the noise power ratio criterion (Npr). This paper focuses also on the particular attention that must be paid to the statistical properties and peak to average ratio (Par) of pseudo noise test signals which significantly impact theNpr measurement accuracy.

A Dedicated TLP Set-Up to Investigate the ESD Robustness of RF Elements and Circuits

This work describes the development of a combined RF-TLP test set-up. It alternates between pulsed high current characterization and scattering parameter measurements up to 10 GHz in order to investigate the influence of the stress pulses on the RF behaviour of the DUT. As an example, the high current behaviour of a broad band amplifier circuit is analyzed.

Improved Fluorescence from Tm‐Ho‐ and Tm‐Ho‐Eu‐Codoped Transparent PbF2 Glass‐Ceramics for S+‐Band Amplifiers

Tm3+‐Ho3+‐ and Tm3+‐Ho3+‐Eu3+‐ion‐codoped oxyfluoride transparent glass‐ceramics containing PbF2 nanocrystals were prepared, and the near‐infrared fluorescence properties of the Tm3+ ions were investigated for their potential use as a 1.4 μm amplifier. For all samples, the lifetime of the Tm3+:3H4 level increased with heat treatment because of the decrease of the phonon energy as PbF2 crystals were formed. Moreover, it was revealed that codoping with Ho3+ or Eu3+ was effective in suppressing the lifetime of the Tm3+:3F4 level by energy transfer to the Ho3+:5I7 or Eu3+:7F6 level. For the codoped samples, the heat treatments decreased the Tm3+:3F4 lifetime and increased the Tm3+:3H4 lifetime. This was attributed to the concentration of rare‐earth ions in the fluoride crystallites. These properties improved the population inversion of the 1.4 μm transition.