This paper introduces damping amplifier friction vibration absorbers(DAFVAs),compound damping amplifier friction vibration absorbers(CDAFVAs),nested damping amplifier friction vibration absorbers(NDAFVAs),and levered ...This paper introduces damping amplifier friction vibration absorbers(DAFVAs),compound damping amplifier friction vibration absorbers(CDAFVAs),nested damping amplifier friction vibration absorbers(NDAFVAs),and levered damping amplifier friction vibration absorbers(LDAFVAs)for controlling the structural vibrations and addressing the limitations of conventional tuned mass dampers(TMDs)and frictiontuned mass dampers(FTMDs).The closed-form analytical solution for the optimized design parameters is obtained using the H_(2)and H_(∞)optimization approaches.The efficiency of the recently established closed-form equations for the optimal design parameters is confirmed by the analytical examination.The closed form formulas for the dynamic responses of the main structure and the vibration absorbers are derived using the transfer matrix formulations.The foundation is provided by the harmonic and random-white noise excitations.Moreover,the effectiveness of the innovative dampers has been validated through numerical analysis.The optimal DAFVAs,CDAFVAs,NDAFVAs,and LDAFVAs exhibit at least 30%lower vibration reduction capacity compared with the optimal TMD.To demonstrate the effectiveness of the damping amplification mechanism,the novel absorbers are compared with a conventional FTMD.The results show that the optimized novel absorbers achieve at least 91%greater vibration reduction than the FTMD.These results show how the suggested designs might strengthen the structure's resilience to dynamic loads.展开更多
In this paper,we have mainly studied the amplification effect of thulium-doped fiber amplifier(TDFA)at 2µm,and compared different amplification effects of the one-stage TDFA,two-stage TDFA and three-stage TDFA at...In this paper,we have mainly studied the amplification effect of thulium-doped fiber amplifier(TDFA)at 2µm,and compared different amplification effects of the one-stage TDFA,two-stage TDFA and three-stage TDFA at proper conditions.The simulation results show that within the effective threshold,with the increase of the pump power,the amplification effect of the optical amplifier improves,but the signal-to-noise ratio(SNR)of the output signal decreases,in order to balance the gain benefit and noise coefficient of TDFA,we can use a multi-stage amplification structure.Three-stage backward-pumped series 2.06µm TDFA,whose slope efficiency can achieve 11%at certain condition.At 5.2 W pump power,the output signal gain of 2µm TDFA exceeds 20 dB,and the output SNR is higher than 32 dB.In addition,the effect of the optimum length of thulium-doped fiber on the amplification performance of 2µm TDFA is also analyzed in this paper.These simulation results are important for the experiment and design of 2µm TDFA.展开更多
Most modern microprocessors have one or two levels of on-chip caches to make things run faster,but this is not always the case.Most of the time,these caches are made of static random access memory cells.They take up a...Most modern microprocessors have one or two levels of on-chip caches to make things run faster,but this is not always the case.Most of the time,these caches are made of static random access memory cells.They take up a lot of space on the chip and use a lot of electricity.A lot of the time,low power is more important than several aspects.This is true for phones and tablets.Cache memory design for single bit architecture consists of six transistors static random access memory cell,a circuit of write driver,and sense amplifiers(such as voltage differential sense amplifier,current differential sense amplifier,charge transfer differential sense amplifier,voltage latch sense amplifier,and current latch sense amplifier,all of which are compared on different resistance values in terms of a number of transistors,delay in sensing and consumption of power.The conclusion arises that single bit six transistor static random access memory cell voltage differential sense amplifier architecture consumes 11.34μW of power which shows that power is reduced up to 83%,77.75%reduction in the case of the current differential sense amplifier,39.62%in case of charge transfer differential sense amplifier and 50%in case of voltage latch sense amplifier when compared to existing latch sense amplifier architecture.Furthermore,power reduction techniques are applied over different blocks of cache memory architecture to optimize energy.The single-bit six transistors static random access memory cell with forced tack technique and voltage differential sense amplifier with dual sleep technique consumes 8.078μW of power,i.e.,reduce 28%more power that makes single bit six transistor static random access memory cell with forced tack technique and voltage differential sense amplifier with dual sleep technique more energy efficient.展开更多
This paper presents a brief overview of several promising design technologies for high efficiency silicon-based radio frequency （RF） power amplifiers （PAs） as well as the use of these technologies in mobile broadb...This paper presents a brief overview of several promising design technologies for high efficiency silicon-based radio frequency （RF） power amplifiers （PAs） as well as the use of these technologies in mobile broadband wireless communications. Four important aspects of PA design are addressed in this paper. First, we look at class-E PA design equations and provide an example of a class-E PA that achieves efficiency of 65-70% at 2.4 GHz. Then, we discuss state-of-the-art envelope tracking （ET） design for monolithic wideband RF mobile transmitter applications. A brief overview of Doherty PA design for the next-generation wireless handset applications is then given. Towards the end of the paper, we discuss an inherently broadband and highly efficient class-J PA design targeting future multi-band multi-standard wireless communication protocols.展开更多
In the era of rapidly expanding wireless technologies,the push for larger spectrum efficiency and better signal integrity has intensified the need for high-efficient and low noise amplifiers(LNAs).A two-stage LNA base...In the era of rapidly expanding wireless technologies,the push for larger spectrum efficiency and better signal integrity has intensified the need for high-efficient and low noise amplifiers(LNAs).A two-stage LNA based on the GaAs/InGaAs pseudomorphic high electron mobility transistor(pHEMT)with a relatively large gate length of 2μm is designed for high-performance 2.4-GHz wireless communication.The I-V characteristic and two-port high-frequency S-parameter of the transistor are measured by on-wafer probing techniques.The results indicate that a discrete transistor with a gate size of 2μm×50μm can provide a maximum transconductance of 16 mS,corresponding to a maximum current-gain cut-off frequency of 7 GHz and maximum oscillation frequency of 8 GHz at the 1-V drain-source voltage.With the impedance matching networks based transmission line technique,an extended integrated layout structure is designed and simulated by using the momentum simulation tool embedded in Advanced Design System,to alleviate the trade-off between noise figure(NF)and gain of the circuit.The findings show that the transistor based on the GaAs/InGaAs technology is capable of delivering high performance with power consumption low to 16 mW,where the maximum simulated gain of 21.5 dB and minimum NF of 2.4 dB are achieved.In terms of linearity,the proposed LNA provides terrific output 1-dB compression of-3 dBm and output third-order intercept point values of 10 dBm.The bandwidth of 0.12 GHz and figure-of-merit of 12 are obtained,which are comparable to that of existing LNAs based on pHEMT.Such a device may benefit to accelerate the development of more robust and power-efficient front-end modules in modern wireless systems,especially for advancing performance-driven applications.展开更多
Dual-output power amplifiers(PAs)have shown great potential in the area of radar,satellite and wireless communication systems.However,the flexibility of the power allocation in a dual-output PA without sacrificing eff...Dual-output power amplifiers(PAs)have shown great potential in the area of radar,satellite and wireless communication systems.However,the flexibility of the power allocation in a dual-output PA without sacrificing efficiency and circuit complexity still needs further investigation.This paper presents a digitally dual-input dual-output(DIDO)PA with reconfigurable modes for power allocation application.The proposed DIDO PA is consist of two identical sub-amplifiers and a 90◦coupler,showing a simple circuit topology.The input amplitudes of the two sub-amplifiers and their phase difference is dynamically controlled leveraging on the dual-input technique,leading to reconfigurable operation modes from power allocation to Doherty.In the power allocation mode,flexible power allocation between two output ports can be obtained by the DIDO PA without sacrificing drain efficiency(DE).On the other hand,flexible power transferring and enhanced back-off DE can be simultaneously achieved by the DIDO PA when it is in the Doherty mode.As a proof of concept,a DIDO PA operating at 2.4 GHz is fabricated and measured in this paper.In the power allocation mode,the DIDO PA achieves a DE of more than 71.8%with a total output power of larger than 44 dBm.Moreover,when the DIDO PA operates in the Doherty mode,it could deliver a maximum output power of more than 44 dBm with a saturation DE of more than 73.9%and a 6 dB back-off DE of more than 61.2%.展开更多
The noise feature of a single-mode class-A laser amplifier is investigated by solving the Maxwell–Bloch equations of motion in the presence of the fluctuation force of cavity Langevin.The aim is to calculate the simu...The noise feature of a single-mode class-A laser amplifier is investigated by solving the Maxwell–Bloch equations of motion in the presence of the fluctuation force of cavity Langevin.The aim is to calculate the simultaneous fluctuations that are superimposed on the amplitude and phase of the cavity electric field, as well as the atomic population inversion. The correlation function of these fluctuations yields the amplitude, phase, and spontaneous emission noise fluxes, respectively. The amplitude and spontaneous emission noise fluxes exhibit the Lorentzian profiles in both the below-threshold state and the injection-locking region of the above-threshold state. While noise is typically viewed negatively in science and engineering, this research highlights its positive role as a valuable tool for measuring the optical properties of a laser amplifier. For instance, the degree of first-order temporal coherence(DFOTC) is derived by taking the Fourier transform of the amplitude noise flux. The damping rate of DFOTC is associated with the coherence time of the light emitted by the laser amplifier. Furthermore, the uncertainty relation between noise bandwidth and coherence time is confirmed. Finally, it is demonstrated that the input pumping noise flux, together with the output amplitude and spontaneous emission noise fluxes, satisfy the principle of flux conservation.展开更多
In a few-mode erbium-doped fiber(FM-EDF),which is a key section in a space-division multiplexing(SDM)communication system,linearly polarized(LP)and orbital angular momentum(OAM)modes,as twomode bases with different ph...In a few-mode erbium-doped fiber(FM-EDF),which is a key section in a space-division multiplexing(SDM)communication system,linearly polarized(LP)and orbital angular momentum(OAM)modes,as twomode bases with different phase profiles,can be transformed into each other.In principle,the LP and OAM modes have a different mode spatial intensity distribution and a gain difference for FM-EDF amplifiers.How to analyze and characterize the differential mode-bases gain(DMBG)is important,but still an issue.We build,for the first time to our knowledge,a local analysis model composed of discrete elements of the FM-EDF cross section in areas of mode spatial intensity distribution azimuthal variation.Using the model of the two mode bases,analysis of local particle number distribution and detailed description of the local gain difference are realized,and the overall gain difference between the two mode bases is obtained.By building an amplifier system based on mode phase profile controlling,the gain of two mode bases is characterized experimentally.The measured DMBG is∼0.8 dB in the second-order mode,which is consistent with the simulation result.This result provides a potential way to reduce the mode gain difference in the FM-EDF,which is important in improving the performance of the SDM communication system.展开更多
We present a gain adaptive tuning method for fiber Raman amplifier(FRA) using two-stage neural networks(NNs) and double weights updates. After training the connection weights of two-stage NNs separately in training ph...We present a gain adaptive tuning method for fiber Raman amplifier(FRA) using two-stage neural networks(NNs) and double weights updates. After training the connection weights of two-stage NNs separately in training phase, the connection weights of the unified NN are updated again in verification phase according to error between the predicted and target gains to eliminate the inherent error of the NNs. The simulation results show that the mean of root mean square error(RMSE) and maximum error of gains are 0.131 d B and 0.281 d B, respectively. It shows that the method can realize adaptive adjustment function of FRA gain with high accuracy.展开更多
Miniaturized erbium-doped waveguide amplifiers attracted great interests in recent decades due to their high gain-efficiency and function-scalability in the telecom C-band.In this work,an erbium-doped thin film lithiu...Miniaturized erbium-doped waveguide amplifiers attracted great interests in recent decades due to their high gain-efficiency and function-scalability in the telecom C-band.In this work,an erbium-doped thin film lithium niobate waveguide amplifier achieving>10 dB off-chip(fiber-to-fiber)net gain and>20 mW fiber-output amplified power is demonstrated,thanks to the low-propagation-loss waveguides and robust waveguide edge-couplers prepared by the photolithography assisted chemomechanical etching technique.Systematic investigation on the fabricated waveguide amplifiers reveals remarkable optical gain around the peak wavelength of 1532 nm as well as the low fiber-coupling loss of-1.2 dB/facet.A fiber Bragg-grating based waveguide laser is further demonstrated using the fabricated waveguide amplifier as the external gain chip,which generates>2 mW off-chip power continuous-wave lasing around the gain peak at 1532 nm.The unambiguous demonstration of fiber-to-fiber net gain of the erbium-doped thinfilm lithium niobate(TFLN)waveguide amplifier as well as its external gain chip application will benefit diverse fields demanding scalable gain elements with highspeed tunability.展开更多
A cavity magnonic oscillator uses the coupling of a planar transmission line oscillator(cavity) and spin excitations(magnons) in a ferrimagnetic material to achieve superior frequency stability and reduced phase noise...A cavity magnonic oscillator uses the coupling of a planar transmission line oscillator(cavity) and spin excitations(magnons) in a ferrimagnetic material to achieve superior frequency stability and reduced phase noise. Like many low phase noise oscillators, a cavity magnonic oscillator faces the challenge that its narrow resonance profile is not well suited for injection locking amplification. This work presents an improved design for such an oscillator configured as an injection locking amplifier(ILA) with an extended lock range. The proposed design features a two-stage architecture, consisting of a pre-amplification oscillator and a cavity magnonic oscillator, separated by an isolator to prevent backward locking.By optimizing the circuit parameters of each stage, the proposed design achieved an order of magnitude increase in lock range, when compared to its predecessors, all while preserving the phase noise quality of the input, making it well-suited for narrowband, sensitive signal amplification. Furthermore, this work provides a method for using oscillators with high spectral purity as injection locking amplifiers.展开更多
A theoretical analysis of noise in a high-power cascaded fiber amplifier is presented. Unlike the noise theory in low power communication, the noise of a high power system is redefined as the leaked output energy betw...A theoretical analysis of noise in a high-power cascaded fiber amplifier is presented. Unlike the noise theory in low power communication, the noise of a high power system is redefined as the leaked output energy between pulses with coherent beat noise uncounted. This definition is more appropriate for high power usage in which the pulse energy receives more attention than the pulse shape integrity. Then the low power pre-amplifying stages are considered as linear amplification and analyzed by linear theory. In the high-power amplification stages, the inversion is assumed to recover linearly in the time interval between pulses. The time shape of the output pulse is different from that of the input signal because of different gains at the front and back ends of the pulse. Then, a criterion is provided to distinguish the nonlinear and linear amplifications based on the signal-to-noise ratio （SNR） analysis. Then, an experiment that shows that the output SNR actually drops off in nonlinear amplification is performed. The change in the noise factor can be well evaluated by pulse shape distortion.展开更多
The single event transient effects of the operational amplifier LM124J and the optocoupler HCPL 5231 are investigated by a pulsed laser test facility. The relation of transient pulse shape to pulsed laser equivalent L...The single event transient effects of the operational amplifier LM124J and the optocoupler HCPL 5231 are investigated by a pulsed laser test facility. The relation of transient pulse shape to pulsed laser equivalent LET is tested,the sensitive areas of the SET effects are identified in voltage follower application mode of LM124J, and the mechanism is initially analyzed. The transient amplitude and duration of HCPL5231 at various equivalent LET are examined,and the SET cross-section is measured. The results of our test and heavy ion experimental data coincide closely,indicating that a pulsed laser test facility is a valid tool for single event effect evaluation.展开更多
To reduce the number of digital predistortion coefficients, a step memory polynomial （SMP）predistorter is presented. The number of predistortion coefficients is decreased by adjusting the maximum nonlinear order for...To reduce the number of digital predistortion coefficients, a step memory polynomial （SMP）predistorter is presented. The number of predistortion coefficients is decreased by adjusting the maximum nonlinear order for different memory orders in the traditional memory polynomial （MP）predistorter. The proposed SNIP predistorter is identified by an offline learning structure on which the coefficients can be extracted directly from the sampled input and output of a PA. Simulation results show that the SMP predistorter is not tied to a particular PA model and is, therefore, robust. The effectiveness of the SMP predistorter is demonstrated by simulations and experiments on an MP model, a parallel Wiener model, a Wiener-Hammerstein model, a sparsedelay memory polynomial model and a real PA which is fabricated based on the Freescale LDMOSFET MRF21030. Compared with the traditional MP predistorter, the SMP predistorter can reduce the number of coefficients by 60%.展开更多
We propose a novel all-optical sampling method using nonlinear polarization rotation in a semiconductor optical amplifier. A rate-equation model capable of describing the all-optical sampling mechanism is presented in...We propose a novel all-optical sampling method using nonlinear polarization rotation in a semiconductor optical amplifier. A rate-equation model capable of describing the all-optical sampling mechanism is presented in this paper. Based on this model, we investigate the optimized operating parameters of the proposed system by simulating the output intensity of the probe light as functions of the input polarization angle, the phase induced by the polarization controller, and the ori- entation of the polarization beam splitter. The simulated results show that we can obtain a good linear slope and a large linear dynamic range,which is suitable for all-optical sampling. The operating power of the pump light can be less than lmW. The presented all-optical sampling method can potentially operate at a sampling rate up to hundreds GS/s and needs low optical power.展开更多
A 12 Gbit/s limiting amplifier for fiber-optic transmission system is realized in a 2μm GaAs HBT technology. The whole circuit consists of an input buffer, three similar amplifier cells, an output buffer for driving ...A 12 Gbit/s limiting amplifier for fiber-optic transmission system is realized in a 2μm GaAs HBT technology. The whole circuit consists of an input buffer, three similar amplifier cells, an output buffer for driving 50 ft transmission lines and a pair of feedback networks for offset cancellation. At a positive supply voltage of 2 V and a negative supply voltage of - 2V, the power dissipation is about 280 mW. The small-signal gain is higher than 46 dB and the input dynamic range is about 40 dB with a constant single-ended output voltage swing of 400 mV. Satisfactory eye-diagrams are obtained at the bit rate of 12 Gbit/s limited by the test set-up. The chip area is 1.15 mm ×0.7 mm.展开更多
The impedance characteristics of distributed amplifiers are analyzed based on T-type matching networks, and a distributed power amplifier consisting of three gain cells is proposed. Non-uniform T-type matching network...The impedance characteristics of distributed amplifiers are analyzed based on T-type matching networks, and a distributed power amplifier consisting of three gain cells is proposed. Non-uniform T-type matching networks are adopted to make the impedance of artificial transmission lines connected to the gate and drain change stage by stage gradually, which provides good impedance matching and improves the output power and efficiency. The measurement results show that the amplifier gives an average forward gain of 6 dB from 3 to 16. 5 GHz. In the desired band, the input return loss is typically less than - 9. 5 dB, and the output return loss is better than -8.5 dB. The output power at 1-dB gain compression point is from 3.6 to 10. 6 dBm in the band of 2 to 16 GHz while the power added efficiency （PAE） is from 2% to 12. 5% . The power consumption of the amplifier is 81 mW with a supply of 1.8 V, and the chip area is 0.91 mm × 0.45 mm.展开更多
Good performance SiGe power amplifiers applicable to wireless communications are demonstrated.The output power can reach more than 30dBm in class B mode.And in class AB mode,the output power at 1dB compression point (...Good performance SiGe power amplifiers applicable to wireless communications are demonstrated.The output power can reach more than 30dBm in class B mode.And in class AB mode,the output power at 1dB compression point ( P 1dB ) is 24dBm,the output third order intercept (TOI) power is 39dBm under V cc of 4V.The highest power added efficiency (PAE) and PAE at 1dB compression point are 34% and 25%,respectively.The adjacent channel power rejection for CDMA signal is more than 42dBc,which complies with IS95 specification.展开更多
A power amplifier MIC with power combining based on AlGaN/GaN HEMTs was fabricated and measured. The amplifier consists of four 10 × 120μm transistors. A Wilkinson splitters and combining were used to divide and...A power amplifier MIC with power combining based on AlGaN/GaN HEMTs was fabricated and measured. The amplifier consists of four 10 × 120μm transistors. A Wilkinson splitters and combining were used to divide and combine the power. By biasing the amplifier at VDS = 40V, IDS = 0.9A, a maximum CW output power of 41.4dBm with a maximum power added efficiency （PAE） of 32.54% and a power combine efficiency of 69% was achieved at 5.4GHz.展开更多
A 4-12GHz wideband power amplifier,using a balanced configuration with a strip line Lange coupler, is designed and fabricated. This power amplifier shows a maximum continuous wave output power of 29.5dBm at 8GHz cente...A 4-12GHz wideband power amplifier,using a balanced configuration with a strip line Lange coupler, is designed and fabricated. This power amplifier shows a maximum continuous wave output power of 29.5dBm at 8GHz center frequency with an associated gain of 8.5dB and a gain flatness of ＋ /- 0.6dB in the 4-12GHz frequency range.展开更多
基金the postdoctoral research grant received from the University of Glasgow for the partial financial support for this research work。
文摘This paper introduces damping amplifier friction vibration absorbers(DAFVAs),compound damping amplifier friction vibration absorbers(CDAFVAs),nested damping amplifier friction vibration absorbers(NDAFVAs),and levered damping amplifier friction vibration absorbers(LDAFVAs)for controlling the structural vibrations and addressing the limitations of conventional tuned mass dampers(TMDs)and frictiontuned mass dampers(FTMDs).The closed-form analytical solution for the optimized design parameters is obtained using the H_(2)and H_(∞)optimization approaches.The efficiency of the recently established closed-form equations for the optimal design parameters is confirmed by the analytical examination.The closed form formulas for the dynamic responses of the main structure and the vibration absorbers are derived using the transfer matrix formulations.The foundation is provided by the harmonic and random-white noise excitations.Moreover,the effectiveness of the innovative dampers has been validated through numerical analysis.The optimal DAFVAs,CDAFVAs,NDAFVAs,and LDAFVAs exhibit at least 30%lower vibration reduction capacity compared with the optimal TMD.To demonstrate the effectiveness of the damping amplification mechanism,the novel absorbers are compared with a conventional FTMD.The results show that the optimized novel absorbers achieve at least 91%greater vibration reduction than the FTMD.These results show how the suggested designs might strengthen the structure's resilience to dynamic loads.
基金supported by the Natural Science Foundation of Guangdong Province(Nos.2023A1515010093)the Shenzhen Fundamental Research Program(Nos.JCYJ20220809170611004,20231121110828001 and 20231121113641002)the Taipei University of Technology-Shenzhen University Joint Research Program(No.2024001).
文摘In this paper,we have mainly studied the amplification effect of thulium-doped fiber amplifier(TDFA)at 2µm,and compared different amplification effects of the one-stage TDFA,two-stage TDFA and three-stage TDFA at proper conditions.The simulation results show that within the effective threshold,with the increase of the pump power,the amplification effect of the optical amplifier improves,but the signal-to-noise ratio(SNR)of the output signal decreases,in order to balance the gain benefit and noise coefficient of TDFA,we can use a multi-stage amplification structure.Three-stage backward-pumped series 2.06µm TDFA,whose slope efficiency can achieve 11%at certain condition.At 5.2 W pump power,the output signal gain of 2µm TDFA exceeds 20 dB,and the output SNR is higher than 32 dB.In addition,the effect of the optimum length of thulium-doped fiber on the amplification performance of 2µm TDFA is also analyzed in this paper.These simulation results are important for the experiment and design of 2µm TDFA.
基金Research General Direction funded this research at Universidad Santiago de Cali,Grant Number 01-2021 and APC was funded by 01-2021.
文摘Most modern microprocessors have one or two levels of on-chip caches to make things run faster,but this is not always the case.Most of the time,these caches are made of static random access memory cells.They take up a lot of space on the chip and use a lot of electricity.A lot of the time,low power is more important than several aspects.This is true for phones and tablets.Cache memory design for single bit architecture consists of six transistors static random access memory cell,a circuit of write driver,and sense amplifiers(such as voltage differential sense amplifier,current differential sense amplifier,charge transfer differential sense amplifier,voltage latch sense amplifier,and current latch sense amplifier,all of which are compared on different resistance values in terms of a number of transistors,delay in sensing and consumption of power.The conclusion arises that single bit six transistor static random access memory cell voltage differential sense amplifier architecture consumes 11.34μW of power which shows that power is reduced up to 83%,77.75%reduction in the case of the current differential sense amplifier,39.62%in case of charge transfer differential sense amplifier and 50%in case of voltage latch sense amplifier when compared to existing latch sense amplifier architecture.Furthermore,power reduction techniques are applied over different blocks of cache memory architecture to optimize energy.The single-bit six transistors static random access memory cell with forced tack technique and voltage differential sense amplifier with dual sleep technique consumes 8.078μW of power,i.e.,reduce 28%more power that makes single bit six transistor static random access memory cell with forced tack technique and voltage differential sense amplifier with dual sleep technique more energy efficient.
文摘This paper presents a brief overview of several promising design technologies for high efficiency silicon-based radio frequency （RF） power amplifiers （PAs） as well as the use of these technologies in mobile broadband wireless communications. Four important aspects of PA design are addressed in this paper. First, we look at class-E PA design equations and provide an example of a class-E PA that achieves efficiency of 65-70% at 2.4 GHz. Then, we discuss state-of-the-art envelope tracking （ET） design for monolithic wideband RF mobile transmitter applications. A brief overview of Doherty PA design for the next-generation wireless handset applications is then given. Towards the end of the paper, we discuss an inherently broadband and highly efficient class-J PA design targeting future multi-band multi-standard wireless communication protocols.
基金supported by Engineering and Physical Sciences Research Council(EPSRC)under Grant No.EP/P006973/1.
文摘In the era of rapidly expanding wireless technologies,the push for larger spectrum efficiency and better signal integrity has intensified the need for high-efficient and low noise amplifiers(LNAs).A two-stage LNA based on the GaAs/InGaAs pseudomorphic high electron mobility transistor(pHEMT)with a relatively large gate length of 2μm is designed for high-performance 2.4-GHz wireless communication.The I-V characteristic and two-port high-frequency S-parameter of the transistor are measured by on-wafer probing techniques.The results indicate that a discrete transistor with a gate size of 2μm×50μm can provide a maximum transconductance of 16 mS,corresponding to a maximum current-gain cut-off frequency of 7 GHz and maximum oscillation frequency of 8 GHz at the 1-V drain-source voltage.With the impedance matching networks based transmission line technique,an extended integrated layout structure is designed and simulated by using the momentum simulation tool embedded in Advanced Design System,to alleviate the trade-off between noise figure(NF)and gain of the circuit.The findings show that the transistor based on the GaAs/InGaAs technology is capable of delivering high performance with power consumption low to 16 mW,where the maximum simulated gain of 21.5 dB and minimum NF of 2.4 dB are achieved.In terms of linearity,the proposed LNA provides terrific output 1-dB compression of-3 dBm and output third-order intercept point values of 10 dBm.The bandwidth of 0.12 GHz and figure-of-merit of 12 are obtained,which are comparable to that of existing LNAs based on pHEMT.Such a device may benefit to accelerate the development of more robust and power-efficient front-end modules in modern wireless systems,especially for advancing performance-driven applications.
基金supported in part by the National Natural Science Foundation of China(No.62201100).
文摘Dual-output power amplifiers(PAs)have shown great potential in the area of radar,satellite and wireless communication systems.However,the flexibility of the power allocation in a dual-output PA without sacrificing efficiency and circuit complexity still needs further investigation.This paper presents a digitally dual-input dual-output(DIDO)PA with reconfigurable modes for power allocation application.The proposed DIDO PA is consist of two identical sub-amplifiers and a 90◦coupler,showing a simple circuit topology.The input amplitudes of the two sub-amplifiers and their phase difference is dynamically controlled leveraging on the dual-input technique,leading to reconfigurable operation modes from power allocation to Doherty.In the power allocation mode,flexible power allocation between two output ports can be obtained by the DIDO PA without sacrificing drain efficiency(DE).On the other hand,flexible power transferring and enhanced back-off DE can be simultaneously achieved by the DIDO PA when it is in the Doherty mode.As a proof of concept,a DIDO PA operating at 2.4 GHz is fabricated and measured in this paper.In the power allocation mode,the DIDO PA achieves a DE of more than 71.8%with a total output power of larger than 44 dBm.Moreover,when the DIDO PA operates in the Doherty mode,it could deliver a maximum output power of more than 44 dBm with a saturation DE of more than 73.9%and a 6 dB back-off DE of more than 61.2%.
文摘The noise feature of a single-mode class-A laser amplifier is investigated by solving the Maxwell–Bloch equations of motion in the presence of the fluctuation force of cavity Langevin.The aim is to calculate the simultaneous fluctuations that are superimposed on the amplitude and phase of the cavity electric field, as well as the atomic population inversion. The correlation function of these fluctuations yields the amplitude, phase, and spontaneous emission noise fluxes, respectively. The amplitude and spontaneous emission noise fluxes exhibit the Lorentzian profiles in both the below-threshold state and the injection-locking region of the above-threshold state. While noise is typically viewed negatively in science and engineering, this research highlights its positive role as a valuable tool for measuring the optical properties of a laser amplifier. For instance, the degree of first-order temporal coherence(DFOTC) is derived by taking the Fourier transform of the amplitude noise flux. The damping rate of DFOTC is associated with the coherence time of the light emitted by the laser amplifier. Furthermore, the uncertainty relation between noise bandwidth and coherence time is confirmed. Finally, it is demonstrated that the input pumping noise flux, together with the output amplitude and spontaneous emission noise fluxes, satisfy the principle of flux conservation.
基金supported by the National Key Research and Development Program of China(Grant No.2019YFA0706300)the National Natural Science Foundation of China(Grant Nos.U22B2010,62035018,and U2001601)+1 种基金the Program of Marine Economy Development Special Fund(Six Marine Industries)under the Department of Natural Resources of Guangdong Province(Grant No.GDNRC[2024]16)the project supported by the Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai)(Grant No.SML2023SP231).
文摘In a few-mode erbium-doped fiber(FM-EDF),which is a key section in a space-division multiplexing(SDM)communication system,linearly polarized(LP)and orbital angular momentum(OAM)modes,as twomode bases with different phase profiles,can be transformed into each other.In principle,the LP and OAM modes have a different mode spatial intensity distribution and a gain difference for FM-EDF amplifiers.How to analyze and characterize the differential mode-bases gain(DMBG)is important,but still an issue.We build,for the first time to our knowledge,a local analysis model composed of discrete elements of the FM-EDF cross section in areas of mode spatial intensity distribution azimuthal variation.Using the model of the two mode bases,analysis of local particle number distribution and detailed description of the local gain difference are realized,and the overall gain difference between the two mode bases is obtained.By building an amplifier system based on mode phase profile controlling,the gain of two mode bases is characterized experimentally.The measured DMBG is∼0.8 dB in the second-order mode,which is consistent with the simulation result.This result provides a potential way to reduce the mode gain difference in the FM-EDF,which is important in improving the performance of the SDM communication system.
基金supported by the Natural Science Research Project of Colleges and Universities in Anhui Province (No.KJ2021A0479)the Science Research Program of Anhui University of Finance and Economics (No.ACKYC22082)。
文摘We present a gain adaptive tuning method for fiber Raman amplifier(FRA) using two-stage neural networks(NNs) and double weights updates. After training the connection weights of two-stage NNs separately in training phase, the connection weights of the unified NN are updated again in verification phase according to error between the predicted and target gains to eliminate the inherent error of the NNs. The simulation results show that the mean of root mean square error(RMSE) and maximum error of gains are 0.131 d B and 0.281 d B, respectively. It shows that the method can realize adaptive adjustment function of FRA gain with high accuracy.
基金financial supports from National Key R&D Program of China(Grant No.2022YFA1205100,2022YFA1404600)National Natural Science Foundation of China(Grant Nos.12192251,12334014,12474325,12134001,12304418,12474378,12274133,12174107,12174113,12274130)+2 种基金the Innovation Program for Quantum Science and Technology(Grant No.2021ZD0301403)Shanghai Municipal Science and Technology Major Project(Grant No.2019SHZDZX01)Fundamental Research Funds for the Central Universities,the Engineering Research Center for Nanophotonics&Advanced Instrument,Ministry of Education,East China Normal University(No.2023nmc005).
文摘Miniaturized erbium-doped waveguide amplifiers attracted great interests in recent decades due to their high gain-efficiency and function-scalability in the telecom C-band.In this work,an erbium-doped thin film lithium niobate waveguide amplifier achieving>10 dB off-chip(fiber-to-fiber)net gain and>20 mW fiber-output amplified power is demonstrated,thanks to the low-propagation-loss waveguides and robust waveguide edge-couplers prepared by the photolithography assisted chemomechanical etching technique.Systematic investigation on the fabricated waveguide amplifiers reveals remarkable optical gain around the peak wavelength of 1532 nm as well as the low fiber-coupling loss of-1.2 dB/facet.A fiber Bragg-grating based waveguide laser is further demonstrated using the fabricated waveguide amplifier as the external gain chip,which generates>2 mW off-chip power continuous-wave lasing around the gain peak at 1532 nm.The unambiguous demonstration of fiber-to-fiber net gain of the erbium-doped thinfilm lithium niobate(TFLN)waveguide amplifier as well as its external gain chip application will benefit diverse fields demanding scalable gain elements with highspeed tunability.
基金funded by NSERC Discovery Grants, NSERC Discovery Accelerator Supplements, Innovation Proof-of-Concept Grant of Research Manitoba, and Faculty of Science Research Innovation and Commercialization Grant of University of Manitoba (C.-M.H.)。
文摘A cavity magnonic oscillator uses the coupling of a planar transmission line oscillator(cavity) and spin excitations(magnons) in a ferrimagnetic material to achieve superior frequency stability and reduced phase noise. Like many low phase noise oscillators, a cavity magnonic oscillator faces the challenge that its narrow resonance profile is not well suited for injection locking amplification. This work presents an improved design for such an oscillator configured as an injection locking amplifier(ILA) with an extended lock range. The proposed design features a two-stage architecture, consisting of a pre-amplification oscillator and a cavity magnonic oscillator, separated by an isolator to prevent backward locking.By optimizing the circuit parameters of each stage, the proposed design achieved an order of magnitude increase in lock range, when compared to its predecessors, all while preserving the phase noise quality of the input, making it well-suited for narrowband, sensitive signal amplification. Furthermore, this work provides a method for using oscillators with high spectral purity as injection locking amplifiers.
基金Project supported by the National High Technology Research and Development Program of China(Grant No.2011AA8042032)the National Natural Science Foundation of China(Grant Nos.61077034 and 61301190)
文摘A theoretical analysis of noise in a high-power cascaded fiber amplifier is presented. Unlike the noise theory in low power communication, the noise of a high power system is redefined as the leaked output energy between pulses with coherent beat noise uncounted. This definition is more appropriate for high power usage in which the pulse energy receives more attention than the pulse shape integrity. Then the low power pre-amplifying stages are considered as linear amplification and analyzed by linear theory. In the high-power amplification stages, the inversion is assumed to recover linearly in the time interval between pulses. The time shape of the output pulse is different from that of the input signal because of different gains at the front and back ends of the pulse. Then, a criterion is provided to distinguish the nonlinear and linear amplifications based on the signal-to-noise ratio （SNR） analysis. Then, an experiment that shows that the output SNR actually drops off in nonlinear amplification is performed. The change in the noise factor can be well evaluated by pulse shape distortion.
文摘The single event transient effects of the operational amplifier LM124J and the optocoupler HCPL 5231 are investigated by a pulsed laser test facility. The relation of transient pulse shape to pulsed laser equivalent LET is tested,the sensitive areas of the SET effects are identified in voltage follower application mode of LM124J, and the mechanism is initially analyzed. The transient amplitude and duration of HCPL5231 at various equivalent LET are examined,and the SET cross-section is measured. The results of our test and heavy ion experimental data coincide closely,indicating that a pulsed laser test facility is a valid tool for single event effect evaluation.
基金The National High Technology Research and Development Program of China (863 Program) (No.2008AA01Z211)the Project of Industry-Academia-Research Demonstration Base of Education Ministry of Guangdong Province (No.2007B090200012)
文摘To reduce the number of digital predistortion coefficients, a step memory polynomial （SMP）predistorter is presented. The number of predistortion coefficients is decreased by adjusting the maximum nonlinear order for different memory orders in the traditional memory polynomial （MP）predistorter. The proposed SNIP predistorter is identified by an offline learning structure on which the coefficients can be extracted directly from the sampled input and output of a PA. Simulation results show that the SMP predistorter is not tied to a particular PA model and is, therefore, robust. The effectiveness of the SMP predistorter is demonstrated by simulations and experiments on an MP model, a parallel Wiener model, a Wiener-Hammerstein model, a sparsedelay memory polynomial model and a real PA which is fabricated based on the Freescale LDMOSFET MRF21030. Compared with the traditional MP predistorter, the SMP predistorter can reduce the number of coefficients by 60%.
文摘We propose a novel all-optical sampling method using nonlinear polarization rotation in a semiconductor optical amplifier. A rate-equation model capable of describing the all-optical sampling mechanism is presented in this paper. Based on this model, we investigate the optimized operating parameters of the proposed system by simulating the output intensity of the probe light as functions of the input polarization angle, the phase induced by the polarization controller, and the ori- entation of the polarization beam splitter. The simulated results show that we can obtain a good linear slope and a large linear dynamic range,which is suitable for all-optical sampling. The operating power of the pump light can be less than lmW. The presented all-optical sampling method can potentially operate at a sampling rate up to hundreds GS/s and needs low optical power.
文摘A 12 Gbit/s limiting amplifier for fiber-optic transmission system is realized in a 2μm GaAs HBT technology. The whole circuit consists of an input buffer, three similar amplifier cells, an output buffer for driving 50 ft transmission lines and a pair of feedback networks for offset cancellation. At a positive supply voltage of 2 V and a negative supply voltage of - 2V, the power dissipation is about 280 mW. The small-signal gain is higher than 46 dB and the input dynamic range is about 40 dB with a constant single-ended output voltage swing of 400 mV. Satisfactory eye-diagrams are obtained at the bit rate of 12 Gbit/s limited by the test set-up. The chip area is 1.15 mm ×0.7 mm.
基金The National Natural Science Foundation of China(No.61106021)the Postdoctoral Science Foundation of China(No.2015M582541)+1 种基金the Natural Science Foundation of Higher Education Institutions of Jiangsu Province(No.15KJB510020)the Research Fund of Nanjing University of Posts and Telecommunications(No.NY215140,No.NY215167)
文摘The impedance characteristics of distributed amplifiers are analyzed based on T-type matching networks, and a distributed power amplifier consisting of three gain cells is proposed. Non-uniform T-type matching networks are adopted to make the impedance of artificial transmission lines connected to the gate and drain change stage by stage gradually, which provides good impedance matching and improves the output power and efficiency. The measurement results show that the amplifier gives an average forward gain of 6 dB from 3 to 16. 5 GHz. In the desired band, the input return loss is typically less than - 9. 5 dB, and the output return loss is better than -8.5 dB. The output power at 1-dB gain compression point is from 3.6 to 10. 6 dBm in the band of 2 to 16 GHz while the power added efficiency （PAE） is from 2% to 12. 5% . The power consumption of the amplifier is 81 mW with a supply of 1.8 V, and the chip area is 0.91 mm × 0.45 mm.
文摘Good performance SiGe power amplifiers applicable to wireless communications are demonstrated.The output power can reach more than 30dBm in class B mode.And in class AB mode,the output power at 1dB compression point ( P 1dB ) is 24dBm,the output third order intercept (TOI) power is 39dBm under V cc of 4V.The highest power added efficiency (PAE) and PAE at 1dB compression point are 34% and 25%,respectively.The adjacent channel power rejection for CDMA signal is more than 42dBc,which complies with IS95 specification.
文摘A power amplifier MIC with power combining based on AlGaN/GaN HEMTs was fabricated and measured. The amplifier consists of four 10 × 120μm transistors. A Wilkinson splitters and combining were used to divide and combine the power. By biasing the amplifier at VDS = 40V, IDS = 0.9A, a maximum CW output power of 41.4dBm with a maximum power added efficiency （PAE） of 32.54% and a power combine efficiency of 69% was achieved at 5.4GHz.
文摘A 4-12GHz wideband power amplifier,using a balanced configuration with a strip line Lange coupler, is designed and fabricated. This power amplifier shows a maximum continuous wave output power of 29.5dBm at 8GHz center frequency with an associated gain of 8.5dB and a gain flatness of ＋ /- 0.6dB in the 4-12GHz frequency range.
