基于高次谐波体声波谐振器的微波振荡器设计

基于高次谐波体声波谐振器(HBAR)的高品质因数(Q)值和多模谐振特性,设计了Colpitts和Pierce两种形式的微波振荡器。采用HBAR与LC元件组成谐振回路的方法,与放大电路构成反馈环路直接基频输出微波频段信号。Colpitts振荡器输出信号频率为980 MHz,信号输出功率为-4.92dBm,信号相位噪声达-119.64dBc/Hz@10kHz;Pierce振荡电路输出信号频率达到2.962GHz,信号输出功率为-9.77dBm,信号相位噪声达-112.30dBc/Hz@10kHz。     

Ultra low phase noise sapphire-SiGe HBT oscillator

A state of the art C-band oscillator is presented. It is based on a high Q WGM sapphire resonator combined with a low residual phase noise SiGe HBT amplifier. A two oscillator experiment performed on this system has revealed a phase noise level of -133 dBc/Hz at 1 kHz offset from the 4.85 GHz carrier, which is the best published phase noise result for a single loop, free running microwave oscillator     

V-band harmonic injection-locked frequency divider using cross-coupled FETs

A V-band 1/2 frequency divider is developed using harmonic injection-locked oscillator. The cross-coupled field effect transistors (FETs) and low quality-factor microstrip resonator are employed as a wide-band oscillator to extend the locking bandwidth. The second harmonic of free-running oscillation signal is injected to the gates of cross-coupled FETs for high-sensitivity superharmonic injection locking. The fabricated microwave monolithic integrated circuit frequency divider using 0.15-/spl mu/m GaAs pHEMT process showed a maximum locking range of 7.4 GHz (from 65.1 to 72.5 GHz) under a low power dissipation of 100 mW. The maximum single-ended output power was as high as -3 dBm.     

An Ultra-Low Noise Microwave Synthesizer

A silicon bipolar transistor together with a barium titanate dielectric resonator were used to design a low noise microwave synthesizer. The oscillator was phase locked to a low-frequency (LF) reference with microwave frequency selection provided by a high-speed digital programmable divider within the phase-locked loop. The resulting FM noise Delta f/sub rms/ was 0.0003 Hz in a 1-Hz band greater than 1000 Hz from the 1-GHz carrier.     

Difference frequency technique to achieve frequency-temperaturecompensation in whispering-gallery sapphire resonator-oscillator

A new difference frequency technique to obtain frequency-temperature compensation using high quality anisotropic dielectric resonators is presented (patent pending). Compensation was demonstrated near room temperature by frequency locking two microwave oscillators to orthogonally polarised whispering-gallery modes in the same sapphire resonator     

A Highly Stabilized Low-Noise GaAs FET Integrated Oscillator with a Dielectric Resonator in the C Band

A GaAs FET integrated oscillator stabilized with a BaO--TiO/sub 2/ system ceramic dielectric resonator provides a high-frequency-stabilized low-noise compact microwave power source. The newly developed ceramic has an expansion coefficient and dielectric constant temperature coefficient that offset each other and result in a small resonant frequency temperature coefficient. A stabilized oscillator output of 100 mW with a 17-percent efficiency and a frequency temperature coefficient as low as 2.3 ppm//spl deg/C are obtained at 6 GHz. FM noise level is reduced more the 30 dB by the stabilization. The dynamic properties of the oscillator and resonator are precisely measured to determine equivalent circuit representations. A large-signal design theory based on these equivalent circuit representations is presented to realize the optimal coupling condition between the oscillator and stabilizing resonator. The stabilized oscillator performance is sufficient for application to microwave communications systems.     

Combination dielectric resonator, power combiner, and antenna

A rectangular dielectric resonator housed in a cutoff parallel-plate waveguide is used both as a radiating element and microwave power combiner. The resonator is excited by using tuned electrically short monopole antennas to induce a longitudinal electric operating mode. The resonator is then used in conjunction with free-running oscillators in order to provide, via mutual injection locking, stable in-phase power combining. Furthermore, the resonator is arranged such that one of its faces radiates a portion of the power-combined signal. Since the resonator is housed in a cutoff waveguide, the cross-polarization radiation from the antenna is suppressed. It was found that, for a single element, a gain in the azimuthal plane of 5 dB could be achieved and, for a two-element array, a gain of 7 dB was obtained with better than -25-dB cross polarization for each case. The oscillator power-combining efficiency for a single-element antenna (two oscillators) was 91%, and the spatial power-combining efficiency for a two-element antenna array, (four oscillators) was found to be 90%. In addition, it is shown that the presence of the dielectric inserts in conjunction with coupled oscillator dynamics provides moderate overall oscillator phase noise improvement     

K波段推-推介质振荡器设计

为了满足现代通信系统对于高频率与高稳定性信号源的需求,提出一种K波段介质振荡器。该振荡器通过推-推结构将两路子振荡器合二为一,使其能够在一个电路中同时实现振荡器和倍频器。在介质谐振器的两条耦合微带线上增加变容二极管模块,通过改变变容二极管的偏置电压调整谐振器中传输信号的相位。变容二极管模块的加入能够有效降低有源器件不一致性对电路的影响,减少两个子振荡器在基频处对输出信号的干扰,同时让振荡器获得200 MHz左右的输出信号频率可调范围。测试结果表明:在输出频率为20.96 GHz时,输出功率约为-4.59 dBm,在10 kHz时达到-66.50 dBc/Hz的相位噪声,在100 kHz时达到-94.31 dBc/Hz的相位噪声,基波抑制度达到-25.42 dBc。     

基于CST与ADS的介质谐振振荡器的设计

分析了介质谐振振荡器的起振和稳频的原理,研究了一种低相位噪声的介质谐振振荡器的设计方法。以X波段为例,利用CST Microwave Studio 2010软件仿真了微带线与介质谐振器耦合的模型,将仿真得到的结果导入S2P文件中。再利用Agilent ADS 2011软件仿真介质谐振振荡器的完整电路,采用S参数仿真和谐波仿真分析等方法设计介质谐振振荡器,结合理论分析,调整和修改实验电路的参数值,使模型达到最好的优化结果。最后通过测试验证仿真结果。采用NEC公司的2SC5508芯片作为放大器,得出微波振荡器的输出频率为10.6 GHz,输出功率为5.19 dBm和较低的相位噪声,其在偏离中心频率10 kHz处小于-121 dBc/Hz。     

Quasi-planar K-band push-push low phase noise oscillator stabilized by cavity resonator

The results of developing a K-band (24 GHz) push-push low phase noise transistor oscillator have been presented. This oscillator is stabilized by a rectangular resonant metallic cavity. The power level of output signal is ?9.5 dBm, the fundamental harmonic suppression is 21 dB. Single sideband (SSB) phase noise spectral density of ?98 dBc/Hz at 10 kHz and ?128 dBc/Hz at 100 kHz offset from the carrier frequency is at the level of dielectric resonator oscillators (DRO) scaled to the same frequency. The oscillator features a compact size, low cost quazi-planar design and it is built using commercially available off the shelf parts.     

低相噪锁相介质振荡器研究

针对高的相位噪声指标要求,对取样锁相介质振荡器进行了研究.通过相位噪声分析,明晰了采用介质振荡器与取样锁相技术降低相位噪声的机理,并分别对介质振荡器与锁相环路进行了设计.设计中,应用HFSS与ADS对介质振荡器进行了联合仿真,体现了计算机辅助设计的优势.最终研制出17 GHz锁相介质振荡器,测试结果为:输出功率13.1 dBm;杂波抑制>70 dB;谐波抑制>25 dB; 相位噪声为-105 dBc/Hz@1 kHz,-106 dBc/Hz@10 kHz,-111 dBc/Hz@100 kHz,-129 dBc/Hz@1 MHz.     

Injection Locking of Klystron Oscillators

If certain criteria are met, a microwave oscillator may be synchronized by the injection of a controlling signal into the oscillator cavity. Synchronization is dependent upon oscillator circuit parameters, the ratio of injected power to oscillator power, and frequency difference between the free-running oscillator and the injection signal. Locking has been observed with injection signals 70 db below the oscillator output and 30-db ratios have been demonstrated to be easily realizable. Injection locking may be considered a form of amplification that permits taking advantage of the fact that microwave oscillators are smafler, lighter, less expensive and more efficient than amplifier devices. The low-frequency theory of Adler is shown to describe accurately the locking phenomena in reflex klystron oscillators and the transient response is extended to determine limitations on the amplification of modulated signals. Experimental verification of the theory is shown for 180/spl deg/ phase modulation of the locking signal at rates up to 100 kc for a VA-201 klystron. Design relations and curves are presented and applications and improvements are discussed.     

一种X 波段串联反馈介质振荡器的设计

在毫米波通信系统中,振荡器是最基本的微波频率源。本文介绍了一种串联反馈型介质振荡器的设计方法, 基于负阻理论和谐波平衡法,利用HFSS 和ADS 设计了10.5Ghz 的低相位噪声串联反馈型介质振荡器。HFSS 用来精 确仿真介质谐振器与微带线的耦合;ADS 用来对振荡器非线性仿真,优化相位噪声和输出功率。在设计过程中,采 用低噪声PHEMT 晶体管ATF-34143 作为振荡器的有源器件,高Q 值、高介电常数的介质谐振器作为稳频元件,确 定振荡器的谐振频率。     

Large Signal Design of GaAs FET Oscillators Using Input Dielectric Resonators

A dielectric resonator may be placed at the input of an active two-port device (FET or microwave transistor) yielding a stable frequency source. For this input configuration, a large signal design is presented. The method is simple, and power output prevision is also reached. The practical results obtained with an X-band medium-power oscillator are presented.     

Design of a negative conductance dielectric resonator oscillator for X-band applications

An X-band tunable microwave low-phase noise planar oscillator employing a novel-fed dielectric resonator (DR) with a single transistor has been investigated and realized. A ZrSnTi oxide composite ceramic-based DR with dielectric permittivity of 95 enclosed in a metallic cavity with an unloaded Q factor of 5,000 at 10 GHz is proposed. The resonant frequency affinity with respect to geometric parameters is established by using the compensation technique based on dual negative conductance feedback, the outputs of which are combined via a Wilkinson power divider (WPD). The feedback parallel-coupled DR oscillator is incorporated into a laminate microwave board using the photolithographic technique. The oscillator includes a pseudomorphic low noise amplifier based on a high-electron-mobility transistor. Hence, the proposed oscillator with mechanic tuning is measured, and the results show that DR resonates at TE _01δ mode with frequency of 10 GHz. The measured phase noise of the oscillator is –81.03 dBc/Hz at a 100 kHz offset.     

Computer study of the phase-locking characteristics of the LSA-mode transferred-electron-effect diode oscillator

The phase-locking characteristics of an LSA-mode transferred-electron-effect diode oscillator in a microwave circuit are studied by time domain computer simulations. The fundamental generated power and the fundamental efficiency are plotted as functions of the locking signal power at fundamental frequency, and also as functions of the locking signal power at twice the fundamental frequency.     

PHASE AND FREQUENCY LOCKING OF MICROWAVE AND MILLIMETER WAVE POWER COMBINING

The phase and frequency locking of microwave, millimeter wave power combining were analysed and summarized in an all-round way. The master/slave phase locking of cavity oscillators, the peer phase locking of mutually coupled oscillators, and the peer phase locking of ring-connected multiple oscillators were investigated. The results of numerical calculations, and the relations of phase to phase locking model and oscillator parameters were given. And the cavity and space power combining aspects for microwave and millimeter wave were presented.     

Frequency instability measurement system of cryogenic maser oscillator

The frequency stability measurement of a new kind of secondary frequency standard, the whispering gallery mode maser oscillator, is reported. Based on a very simple design the beatnote comparison with a state-of-the-art cryogenic sapphire resonator oscillator gave a preliminary result of 10^-14 frequency instability at 1 s integration time. The measurement is limited by the microwave synthesis chain used to evaluate the maser stability.     

X波段介质谐振器振荡器和缓冲放大器的研究

微波振荡器代表所有基本微波通信系统的能源来源。研究设计8．95GHz的低噪声砷化镓场效应管并联反馈介质谐振器振荡器,为了放大输出功率和提高负载牵引,在介质谐振器振荡器后一级加缓冲放大器,最终的输出功率是＋13．33dBm。测试证明输出信号的相位噪声偏离中心频率100kHz可达-116．49dBc／Hz,偏离中心频率10kHz可达-91．74dBc／Hz。     

A Highly Stabilized GaAs FET Oscillator Using a Dielectric Resonator Feedback Circuit in 9-14 GHz

A new type of highly stabilized GaAs FET oscillator using a dielectric resonator and a stabilization resistor in the feedback circuit has been developed. The oscillator fabricated with a microwave integrated circuit has a high external quality factor Q/sub ex/ for more than1000 with no hysteresis phenomena. The microwave characteristics of the GaAs FET oscillator has revealed 1) high efficiency of 20 percent with 70-mW output power at 11.85 GHz, 2) a wide tuning range more than1000 MHz, 3) a wide oscillation frequency from 9 to 14 GHz with same MIC pattern by using five dielectric resonators of different sizes, 4) a high-frequency stability as low as /spl plusmn/ 150kHz in the tempature range from -20 to + 60/spl deg/ C, and 5) low FM noise of 0.07 Hz/ /spl radic/Hz at off-carrier frequency of 100kHz.