A NOVEL PHASE CONTROL TECHNIQUE FOR INJECTION LOCKED OSCILLATORS

A novel technique to obtain injection locked oscillators phase tuning beyond 180° is demonstrated. The idea is to cascade injection locked oscillators together for phase change accumulation. A two stage injection locked oscillators can theoretically provide a maximum of 360?phase change within the locking range. This is particularly useful for phased array antenna applications.

Theoretical investigation of frequency characteristics of free oscillation and injection-locked magnetrons

The frequency characteristics of free oscillation magnetron（FOM） and injection-locked magnetron（ILM） are theoretically investigated.By using the equal power voltage obtained from the experiment data,expressions of the frequency and radio frequency（RF） voltage of FOM and ILM,as well as the locking bandwidth,on the anode voltage and magnetic field are derived.With the increase of the anode voltage and the decrease of the magnetic field,the power and its growth rate increase,while the frequency increases and its growth rate decreases.The theoretical frequency and power of FOM agree with the particle-in-cell（PIC） simulation results.Besides,the theoretical trends of the power and frequency with the anode voltage and magnetic field are consistent with the experimental results,which verifies the accuracy of the theory.The theory provides a novel calculation method of frequency characteristics.It can approximately analyze the power and frequency of both FOM and ILM,which promotes the industrial applications of magnetron and microwave energy.

Self-mode-locking optoelectronic oscillator with ultrashort time delay

The optoelectronic oscillator(OEO)is a typical time-delay system with rich nonlinear dynamical characteristics.Most of the previous research on OEOs has been focused on analyzing the properties of OEOs with a long time delay,which makes it difficult to realize mode locking without additional phaselocking mechanisms.We have achieved,for the first time to our knowledge,a self-mode-locking OEO and generated stable microwave frequency combs by analyzing the characteristics of OEOs with an ultrashort time scale.In the experiment,the self-mode-locking OEOs with fundamental mode,second-order harmonic,and sixth-order harmonic were realized by adjusting the system parameters,all of which produced uniform square wave signals with tunable duty cycles,steep rising and falling edges,and periods of less than 20 ns.The self-fundamental-mode-locking OEOs with different time delays were also implemented and experimentally realized.Furthermore,the experiment revealed the self-hybrid mode-locking OEO,which is the coexistence and synchronization of the three measured self-locking modes in one OEO cavity,demonstrating the complex nonlinear dynamical behaviors of the OEO system and enabling the generation of periodic nonuniform hybrid square wave signals.The realization of the self-mode-locking OEO and the generation of flexible and stable square wave signals at ultrashort time scales enrich the study of OEO nonlinear dynamics in the realm of complex microwave waveform generation,offering promising applications in areas such as atomic clocks,radars,communications,and optoelectronic neural networks.

Modeling and experimental studies of a side band power re-injection locked magnetron

A side band power re-injection locked （SBPRIL） magnetron is presented in this paper. A tuning stub is placed between the external injection locked （EIL） magnetron and the circulator. Side band power of the EIL magnetron is reflected back to the magnetron. The reflected side band power is reused and pulled back to the central frequency. A phase-locking model is developed from circuit theory to explain the process of reuse of side band power in SBPRIL magnetron. Theoretical analysis proves that the side band power is pulled back to the central frequency of the SBPRIL magnetron, then the amplitude of the RF voltage increases and the phase noise performance is improved. Particle-in-cell （PIC） simulation of a 10-vane continuous wave （CW） magnetron model is presented. Computer simulation predicts that the frequency spectrum＇s peak of the SBPRIL magnetron has an increase of 3.25 dB compared with the free running magnetron. The phase noise performance at the side band offset reduces 12.05 dB for the SBPRIL magnetron. Besides, the SBPRIL magnetron experiment is presented. Experimental results show that the spectrum peak rises by 14.29% for SBPRIL magnetron compared with the free running magnetron. The phase noise reduces more than 25 dB at 45-kHz offset compared with the free running magnetron.

Chaos synchronization in injection-locked semiconductor lasers with optical feedback

Based on the rate equations, we have investigated three types of chaos synchronizations in injection-locked semiconductor lasers with optical feedback. Numerical simulation shows that the synchronization can be realized by the symmetric or asymmetric laser systems. Also, the influence of parameter mismatches on chaos synchronization is investigated, and the results imply that these two lasers can achieve good synchronization, with smaller tolerance of parameter mismatch existing.

High-Power Simultaneous Wireless Information and Power Transfer: Injection-Locked Magnetron Technology

Applications using simultaneous wireless information and power transfer(SWIPT)have increased significantly.Wireless communication technologies can be combined with the Internet of Things to develop many innovative applications using SWIPT,which is mainly based on wireless energy harvesting from electromagnetic waves used in communications.Wireless power transfer that uses magnetrons has been developed for communication technologies.Injection-locked magnetrons that can be used to facilitate high-power SWIPT for several devices are reviewed in this paper.This new technology is expected to pave the way for promoting the application of SWIPT in a wide range of fields.

Analysis of the injection-locked magnetron with a mismatched circulator

Based on the scatter matrix of the four-port lossless mismatched circulator, the phase differential equation of the injection-locked magnetron is derived by comparing different effects of the mismatched and perfect circulator on the injection ratio. Besides, the locking range of the injection-locked magnetron with the mismatched circulator is deduced by functional operation. In addition, the phase differential equation and the locked bandwidth of the injection-locked system with a mismatched circulator are compared with those of the small injection-ratio case with a perfect circulator. The in- fluence of the circulator reflection coefficient on the injection-locked magnetron is also analyzed by numerical calculation. Theoretical analysis shows that the decrement of the locked bandwidth is less than 1% and decrement of the stable phase difference is less than 1.2% when the reflection coefficient is less than 0.1.

INJECTION-LOCKED DIVIDER

An injection-Locked divider(ILD)can provide good synchronization at lower inputsignal to noise ratio,which is its advantage over other types of divider.The general expressionof phase equation and equivalent model are presented for the ILD with an input additive noise.In the absence of noise the performance of the phase-modulated signal through the ILD andsynchronous ranges of the ILD are given.The effects of the additive noise on the ILD arediscuued.The injection-locked amplifier(ILA)is only a particular case in which n=1,thereforethe given results arc applicable to the ILA.

Fiber optical parametric oscillator based on photonic crystal fiber pumped with all-normal-dispersion mode-locked Yb:fiber laser

We demonstrate a cost effective, linearly tunable fiber optical parametric oscillator based on a home-made photonic crystal fiber pumped with a mode-locked ytterbium-doped fiber laser, providing linely tuning ranges from 1018 nm to 1038 nm for the idler wavelength and from 1097 nm to 1117 nm for the signal wavelength by tuning the pump wavelength and the cavity length. In order to obtain the desired fiber with a zero dispersion wavelength around 1060 rim, eight sam- ples of photonic crystal fibers with gradually changed structural parameters are fabricated for the reason that it is difficult to accurately customize the structural dimensions during fabrication. We verify the usability of the fabricated fiber experimen- tally via optical parametric generation and conclude a successful procedure of design, fabirication, and verification. A seed source of home-made all-normal-dispersion mode-locked ytterbium-doped fiber laser with 38.57 ps pulsewidth around the 1064 nm wavelength is used to pump the fiber optical parametric oscillator. The wide picosecond pulse pump laser enables a larger walk-off tolerance between the pump light and the oscillating light as well as a longer photonic crystal fiber of 20 m superior to the femtosecond pulse lasers, resulting in a larger parametric amplification and a lower threshold pump power of 15.8 dBm of the fiber optical parametric oscillator.

A 30GHz Wideband CMOS Injection-Locked Frequency Divider for 60GHz Transceiver

In this paper, a 30 GHz wide locking-range (26.2 GHz-35.7 GHz) direct injection-locked frequency divider (ILFD), which operating in the millimeter-wave (MMW) band, is presented. The locking range of the ILFD is extended by using differential injection topology. Besides, varactors are used in RLC resonant tank for extending the frequency tuning range. The post simulation results show that a wide locking-range of 9.5 GHz (30.7%) is achieved. When the VCO output frequency varies from 26.85 GHz to 34.42 GHz, the proposed ILFD can achieve divide-by-two correctly. Designed in 0.13 μm CMOS technology, the ILFD occupies a core area of 0.76 mm2 while drawing 7 mA of current from 2.5 V power supply.

CMOS Direct-Injection Divide-by-3 Injection-Locked Frequency Dividers

This paper proposes CMOS LC-tank divide-by-3 injection locked frequency dividers(ILFDs)fabricated in 0.18μn and 90nm CMOS process and describes the circuit design,operation principle and measurement results of the ILFDs.The ILFDs use two injection series-MOSFETs across the LC resonator and a differential injection signal is applied to the gates of injection MOSFETs.The direct-injection divide-by-3 ILFDs are potential for radio-frequency application and can have wide locking range.

Numerical study of converting beat-note signals of dual-frequency lasers to optical frequency combs by optical injection locking of semiconductor lasers

The optical injection locking of semiconductor lasers to dual-frequency lasers is studied by numerical simulations.The beat-note signals can be effectively transformed to optical frequency combs due to the effective four wave-mixing in the active semiconductor gain medium. The low-noise Gaussian-like pulse can be obtained by locking the relaxation oscillation and compensating the gain asymmetry. The simulations suggest that pulse trains of width below 30 ps and repetition rate in GHz frequency can be generated simply by the optical injection locking of semiconductor lasers. Since the optical injection locking can broaden the spectrum and amplify the optical power simultaneously, it can be a good initial stage for generating optical frequency combs from dual-frequency lasers by multi-stage of spectral broadening in nonlinear waveguides.

An injection-locking diode laser at 671 nm with a wide tuning range up to 6 GHz

We present a compact injection-locking diode laser module to generate 671 nm laser light with a high output power up to 150 m W.The module adopts a master-slave injection-locking scheme,and the injection-locking state is monitored using the transmission spectrum from a Fabry-Perot interferometer.Beat frequency spectrum measurement shows that the injection-locked slave laser has no other frequency components within the 150-MHz detection bandwidth.It is found that without additional electronic feedback,the slave laser can follow the master laser over a wide range of 6 GHz.All the elements of the module are commercially available,which favors fast construction of a complete 671-nm laser system for the preparation of cold^(6)Li atoms with only one research-grade diode laser as the seeding source.

A Low Phase Noise Ring-VCO Based PLL Using Injection Locking for ZigBee Applications

A low power low phase noise frequency synthesizer with subharmonic injection locking is proposed for ZigBee applications. The PLL is based on a ring VCO to decrease area and production cost. In order to improve phase noise performance, a high frequency injection signal of which frequency varies with channel number is used. The circuit is designed in TSMC 0.18 μm CMOS technology and simulated in ADS (Advanced Design System). The phase noise at 3.5 and 10 MHz offsets is -116 and -118 dBc/Hz, respectively, and total circuit consumes 2.2 mA current.

PHASE-LOCKING OF HIGH POWER GYROTRON OSCILLATOR

The phase-locking process is studied for high-power gyrotron oscillator driven by an external signal. The phase-locking nonlinear differential equations are derived, and the condition of phase-locking is shown and analyzed. The phase-locking signal can be introduced after gyrotron oscillates into saturation or before it. Two different ways of inputting signal make markable influence on the phase-locking process, this phenomenon is discussed. In this paper, the numerical calculations and analysis are given for gyrotron TE13 mode.

Dual-Delay-Path Ring Oscillator with Self-Biased Delay Cells for Clock Generation

This work summarizes the structure and operating features of a high-performance 3-stage dual-delay-path (DDP) voltage-controlled ring oscillator (VCRO) with self-biased delay cells for Phase-Locked Loop (PLL) structurebased clock generation and digital system driving. For a voltage supply VDD = 1.8 V, the resulting set of performance parameters include power consumption PDC = 4.68 mW and phase noise PN@1MHz = -107.8 dBc/Hz. From the trade-off involving PDC and PN, a system level high performance is obtained considering a reference figure-of-merit ( FoM = -224 dBc/Hz ). Implemented at schematic level by applying CMOS-based technology (UMC L180), the proposed VCRO was designed at Cadence environment and optimized at MunEDA WiCkeD tool.

Power-combining based on master-slave injection-locking magnetron

A microwave power-combining system composed of two Panasonic 2M244-M1 magnetrons based on master–slave injection-locking is demonstrated in this paper. The principle of master–slave injection-locking and the locking condition are theoretical analyzed. Experimental results are consistent with the theoretical analysis and the experimental combined efficiency is higher than 96%. Compared with the external-injection-locked system, the power-combining based on the master–slave injection-locking magnetron is superior by taking out the external solid-state driver and the real-time phase control system. Thus, this power-combining system has great potential for obtaining a high efficiency, high stability, low cost, and high power microwave source.

Current Mismatches in Charge Pumps of DLL-Based RF CMOS Oscillators

A research on the spurious tones due to the current mismatch in charge pumps of DLL(Delay Locked Loop) based RF CMOS oscillators is performed.An equation for strength evaluation of the spurious tones is derived.Two tables are provided to make it obvious to understand for the characteristics of spurious tones changing with related parameters.Some suggestions are given for the design of a DLL based RF CMOS oscillators.

MATHEMATICAL AND PHYSICAL MODELING OF INTERFACIALPHENOMENA IN CONTINOUS CASTING MOULD WITH ARGONINJECTION THROUGH SUBMERGED ENTRV NOZZLE

The study on the fluid flow, meniscus oscillation, slag entrapment in continuous casting mould was conducted mathematically and experimentally. The results show that the injection of argon into submerged nozzle enhances the meniscus oscillation, thus increases the probability of slag entrapment, and the critical argon blowing flow rate, which will give rise to slag entrapment, is around 10l/min. The trajectory of bubble is affected by the bubble diameter and the molten steel flow, and the bubble diameter is dominant. The bubble with diameter 1.4mm floats fastest with 0.47m/s terminal velocity.

Biomechanical Comparison of Prototype of a Novel Intramedullary Injectable Bioresorbable Polymer-Bioresorbable Balloon Osteosynthesis and a Volar Locking Plate for Treatment of Distal Radius Fractures

Background: There is a large assortment of modalities for the surgical treatment/management of distal radius fractures (DRFs), where the most widely used is the fixed-angle volar plating (VLP) system, which, sometimes, is referred to as the “surgical modality of choice”. While outcomes with each modality are usually good to excellent, each has its share of shortcomings and complications. Thus, there is scope for improvements to existing modalities and/or introduction of new ones. Study Purpose: We introduce a novel modality, namely, the prototype of an intramedullary injectable bioresorbable polymer-bioresorbable balloon osteosynthesis (IPBO) system, and investigated its plausibility. Experimental Procedures: The biomechanical performance of a construct comprising a synthetic distal radius (fourth-generation Sawbones?) on which a simulated fracture was created (4-mm wide osteotomy positioned 25 mm from the most distal end of the radius) and fixated with a placement of the IPBO system (SIPBO Construct) was compared to that when the fixation was with an approved Ti-6Al-4V alloy VLP system (SVLP Construct), under a clinically-relevant compressive loading protocol. Performance involved determination of quantitative parameters of the construct (initial longitudinal stiffness (ICLS), final longitudinal stiffness (FCLS), and load-to-failure (Pf)) and observation and recording of features of the construct at the fracture point. We also determined the quantitative parameters for the intact synthetic distal radius (control). Results: For each of the quantitative parameters, the range of values for SIPBO Construct was within that for SVLP Construct, suggesting that the IPBO System is a plausible modality. Also, for SIPBO Construct, failure occurred within the polymer zone, whereas, for SVLP Construct, some failure features were fracture of the cortical wall and of the dorsal proximal fragments. Conclusion: The findings suggest that the IPBO system is plausible. As such, it merits further study;for example, determination of the influence of fracture gap fill ratio (defined as the proportion of the fracture gap that is filled by the expanding balloon as the polymer is injected into the balloon) on a large collection of quantitative biomechanical parameters.