一种简易微波VCO的设计*

描述了一种高性能简易微波VCO器件的设计和实验。该器件基于负阻原理设计,利用微波FET和变容二极管等分立元件制作,具有高性价比的特点。设计过程中利用ADS软件进行电路的匹配和优化,通过合适的外电路设计对变容二极管VCO的调频线性度进行改善,同时,降低了VCO的相位噪声。实际电路的测试结果表明,当该VCO的中心频率为4.3GHz时,其调谐范围大于200MHz,输出功率大于5.2dBm,相位噪声优于-112dBc/Hz@1MHz和-83dBc/Hz@100kHz。     

Ka波段GaAs耿氏单片压控振荡器

介绍一个以GaAs Gunn器件为振荡元件的Ka波段微波单片压控振荡器(MMIC VCO)。它以工艺相容的Schottky二极管为调谐元件,采取微带耦合的电路形式。该MMIC VCO制作在5mm×3mm的GaAs芯片上,其中包含了一个Gunn管、一个变容管、匹配网络以及两个直流偏置。单片测试结果:在34.6GHz下得到了3.03mW的输出功率,最大电调带宽90MHz。这是国内Ka波段MMIC VCO的首次报道,其性能接近国外1987年的实验室研制水平;同时也是国内首片毫米波段的MMIC。采用了TOUCHSTONE软件包,进行了毫米波段电路的CAD优化尝试,取得了较为满意的结果。     

一种具有粗细调谐能力的FET VCO

<正>用微波场效应晶体管和砷化镓超突变结变容二极管组成的电压控制振荡器(简称FET VCO),具有调谐速度快,线性好,电路效率高,而且供电简单.使用南京电子器件研究所研制的场效应晶体管(WC59)和砷化镓电调变容二极管(WB62)制成的具有粗细调谐能力的FET VCO,粗调频率在C波段电调带宽600MHz,电调灵敏度的最大最小变化比小于     

8～12GHz FET压控振荡器

<正> 用微波场效应管和砷化镓超突变结变容管组成的电压控制振荡器(简称FET VCO),具有调谐频带宽,调谐速度快,线性较好,电路效率高,加电简单等特点。采用南京电子器件研究所的FET和超突变结变容管制成的宽带FET VCO,其电调频率范围已达4GHz,在X波段覆盖频率为8～12GHz。 整个电路采用集总参数和分布参数相结合的混合结构形式。所用FET和变容管都是封装     

新型复合沟道Al0.3Ga0.7N/Al0.05Ga0.95N/GaN HEMT低相位噪声微波单片集成压控振荡器

设计并研制了一种新型复合沟道Al0.3Ga0.7N/Al0.05Ga0.95N/GaN HEMT(CC-HEMT)微波单片集成压控振荡器(VCO),且测试了电路的性能.CC-HEMT的栅长为1μm,栅宽为100μm.叉指金属-半导体-金属(MSM)变容二极管被设计用于调谐VCO频率.为提高螺旋电感的Q值,聚酰亚胺介质被插入在电感金属层与外延在蓝宝石上GaN层之间.当CC-HEMT的直流偏置为Vgs=-3V,Vds=6V,变容二极管的调谐电压从5.5V到8.5V时,VCO的频率变化从7.04GHz到7.29GHz,平均输出功率为10dBm,平均功率附加效率为10.4%.当加在变容二极管上电压为6.7V时,测得的相位噪声为-86.25dBc/Hz(在频偏100KHz时)和-108dB/Hz(在频偏1MHz时),这个结果也是整个调谐范围的平均值.据我们所知,这个相位噪声测试结果是文献报道中基于GaN HEMT单片VCO的最好结果.     

如何在老化调整后减小TCXO误差

温度偿补晶体振荡器(TCXO)需要定期调整以修正老化漂移。对于内部补偿的振荡器,它是一种在工作温度范围内通过变容管调谐的振荡器,其老化调整是借助于改变振荡环路中电抗元件完成的。但是在老化调整后,继而使原有的频率对变容二极管偏压变化的灵敏度发生改变,因此,变容二极管相当于总负载电抗的差别部分。这种经过老化调整而改变的灵敏度干扰了原来的频率——温度特性,并且引起某一调谐偏离误差。为了充分发挥数字谐偏离误并满足某些新军用规程如SINGARS制定的调谐偏离误差规范要求,需要有一种方法来减小TCXO的调补偿的优点差。实现老化调整的另一种方法,是改变变容二极管的直流偏压。假如振荡器的频率与电压曲线完全是线性的,则电路对变容二极管偏压的灵敏度(PPm′v)就能保持恒定,在频率——温度特性曲线中不会引入附加的误差。对于串联与并联谐振两种振荡器的电压线性度要求,是与使用一个并联谐振晶体的TCXO的误差分析一道讨论的。本文给出了电容和变容二极管调谐的两种振荡器的比较数据。比较数据及误差分析两者表明:变容二极管调谐对于减小TCXO中调谐偏离误差是一种可行的技术。     

电调谐滤波器的研究与设计

介绍了可调谐滤波器的电路结构,解释了设计中采用电感耦合并联谐振电路的具体原因。给出了变容二极管的等效电路,并对由变容二极管构成的滤波器的最大频率可调范围进行了分析。设计制作了一个VHF频段的电调谐滤波器,并使用安捷伦公司的微波电路仿真软件ADS进行仿真,测试表明,此滤波器的频率可调范围为100～260 MHz,插入损耗小于3.8 dB,驻波系数小于1.65。同时在频率的可调范围内对滤波器的插入损耗和矩形系数的变化进行了分析,实验结果和理论分析吻合较好。     

基于新颖调谐谐振器的低相噪VCO设计

介绍了一种采用新颖谐振器的低相位噪声窄带压控振荡器(VCO)的设计方法。该谐振器采用源与负载横向交叉耦合结构,形成一个传输零点,提高了谐振器的Q值。该谐振器通过弱耦合与变容二极管连接,从而实现电压控制滤波器通带中心频率调谐。利用该谐振器设计了一个窄带VCO,并在先进设计系统(ADS)软件里仿真验证。该VCO中心频率6.15 GHz,在调谐电压从0到15 V的范围内调谐带宽60 MHz,相位噪声在整个调谐范围内优于-132 dBc/Hz@1MHz,输出功率为8.4 dBm,功率平坦度±0.1 dBm。     

一种新型MOS变容管在射频压控振荡器中的应用

基于0.5μm工艺，设计了一个工作频率在1.8GHz，相位噪声在偏移量为500kHz时小于-100dBc/Hz的压控振荡器（VCO）。并将一个普通的压控MOS变容管改进为只工作在反型区的压控MOS变容管。将这两种MOS电容分别应用到该VCO电路中。结果表明，采用反型模式压控MOS变容管的VCO电路具有更大的调谐范围，调谐曲线由之前的反复变化变为单调变化，并且对电路的相位噪声也起到了抑制作用。     

一种中心和带宽可调VHFL 频段耦合滤波器设计

针对典型电调谐耦合滤波器的两种结构：电感耦合和电容耦合,对滤波器的带宽影响因素进行了理论分析,通 过改变电容耦合单元使得中心频率变化时带宽保持不变。选择了NXP 的BB131 作为谐振变容管,选择NXP 的BB132 作为 耦合变容管,设计了VHFL 频段中心频率及带宽均可调的双调谐耦合滤波器,利用ADS 软件进行了仿真。仿真结果表明此 滤波器在56.9~165.8MHz 的可调范围里,保持接近常数的带宽,矩形系数（30dB/3dB）小于7,具有很好的选择性。实际 电路的测试结果验证了设计的有效性。     

High-performance millimetre-wave suspended stripline Gunn VCO

A novel millimetre-wave integrated circuit Gunn voltagecontrolled oscillator (VCO) has been developed with high output power using suspended stripline. An output power of 100 to 150mW has been achieved at frequencies between 33 and 42 GHz. A varactor diode was mounted in alignment and in close proximity to the Gunn diode to achieve an electronic tuning range of 300 MHz     

U-band shield suspended-stripline Gunn DRO and VCO

A millimeter-wave IC dielectric resonator oscillator (DRO) is proposed. Equations that give the resonant frequency of the dielectric resonator DR in suspended stripline (SSL) are derived. A U-band voltage-controlled oscillator (VCO) with varactor tuning also has been developed. The Gunn diode and varactor used in both of the oscillators are commercially available packaged devices. Restrictions on the performance of the oscillators imposed by packaged and mounted networks and the self-characteristics of the solid-state devices have been analyzed. An electronic tuning range greater than 1000 MHz with an output power exceeding 15 dBm across the bandwidth in the 53-GHz region has been realized for the SSL VCO. An SSL DRO with an output power of more than 17 dBm and a mechanical tuning range of 1.5 GHz in the 54-GHz region has been achieved     

A Gunn-Diode Active Leaky-Wave Frequency Scanning Antenna

A frequency tunable active leaky-wave scanning antenna using Gunn-diode voltage control oscillator (VCO) as source is developed. The frequency tuning controlled by changing either the varactor diode dc bias or the Gunn diode dc bias is demonstrated. The measured scanning angle of active antenna is close to 15 degree as the Gunn VCO frequency tuned from 12.58GHz to 12.98GHz. To excite the first higher order mode of the microstrip leaky-wave antenna is fed asymmetrically. The dominant mode excitation has been successfully suppressed by adding a sequence of covered wire in the middle line of the microstrip leaky wave antenna. This is a prototype of frequency scanning antenna using two terminal device, which can be easily scaled up to millimeter wave frequency region.     

Varactor-tuned integrated Gunn oscillators

Electronic tuning of Gunn diodes in hybrid integrated circuits has been studied. Microstrip transmission lines were used to form resonant circuits into which a Gunn diode and a varactor diode were mounted to provide the microwave power and frequency tuning, respectively. Basically, two types of circuits have been investigated. The first is a half-wavelength open-circuited microstrip `cavity' with this transmission line and the varactor diode attached between the end of the cavity and an RF ground. The second is a lumped LC circuit in which the inductance of a short high-impedance microstrip line is resonated with the lumped capacitance of the varactor diode. The latter circuit provides a tuning range of over 10 percent at 7.5 GHz. The power output varies within 2 dB in the tuning range.     

Novel varactor-tuned millimetre-wave Gunn oscillator

A novel design of varactor-tuned millimetre-wave second-harmonic Gunn oscillator is reported in which a varactor is mounted in a secondary cavity resonant at the fundamental frequency of the Gunn diode. This has the advantage that the varactor does not significantly load the Gunn diode at the output second-harmonic frequency, and enables the oscillator to produce the maximum possible output power from the diode while still offering varactor tuning and high Q.     

Nonlinear Frequency-Modulation Distortion Analysis for VCO Based on Harmonic Balance Method

The analysis methods for the steady-state responses of the voltage tuning negative resistance oscillator (voltage-controlling oscillator, VCO) by the microwave nonlinear autonomous circuit harmonic balance method in millimeter-wave bands are studied in the paper. Firstly, the quasi-periodic characteristic of the steady-state response of the VCO modulated by a periodic signal is proved. Then, on the bases of the harmonic balance analysis and the inter-modulation balance analysis, a novel method for obtaining the steady-state tuning performance and the nonlinear frequency-modulation distortion characteristic of the VCO is presented. The total analysis process is aimed to a kind of NRD-guide Gunn diode VCO. The large-signal lumped equivalent circuit model of the millimeter-wave P⁺N-junction varactor is also given for explaining the algorithm and the principle of the NRD-guide VCO.     

Varactor-tuned gunn diode voltage controlled oscillator antenna array

A simple varactor tuned X-band Gunn diode VCO antenna array which is strongly coupled has been demonstrated. These arrays have the advantages of simple biasing circuit, no resistors required to eliminate multimode problem and suitable for monolithic integration circuit. Preliminary results show a maximum tuning range of 47MHz for 1×1 array and 170MHz for 2×2 array. In order to solve power combining heating problem, we move the backside metal forward and it becomes a microstrip form. The measured frequency and radiation patterns of these grid arrays agree very well with theoretical calculations.     

The effect of operating parameters and oscillator characteristics upon the phase angle between a locked X-band Gunn oscillator and its locking signal

Experiments have been carried out to measure the phase angle between a locked negative-resistance (Gunn) oscillator and its locking oscillator. Phase angle has been measured as a function of ambient temperature, oscillator bias voltage, locking power, and the voltage applied to a varactor tuning diode coupled into the locked oscillator. Results indicate that given a knowledge of the oscillator characteristics and the operating conditions, it is possible to predict, with reasonable accuracy, the phase of the locked oscillator. The relative merits of various methods of phase control are discussed and it is concluded that the best method is to use a varactor diode coupled into the negative-resistance oscillator.     

Varactor Diodeless Harmonic VCOs for GHz-Range Applications

Most radio frequency voltage-controlled harmonic oscillators are tunedby changing the capacitance of a pn-junction diode. The inadequate capacitancetuning range of the pn-junction diode severely limits the achievable frequencytuning range of the oscillator. Two methods for extending the tuning range of monolithic LC-oscillators are discussed in this paper. The first approach is touse actively synthesized capacitor based on the Miller effect instead of a pn-junction varactor diode for the VCO tuning. An analytical model is developed forstudying the capacitance tuning range and the corresponding Q-value. Inthe second approach we are using a balanced variable impedance converter for theVCO tuning. In this approach tuning is based on current steering using the Gilbertcell. Altogether nine experimental circuits have been fabricated with a 0.8 mBiCMOS process. All circuits oscillate around 2 GHz and tuning ranges exceeding30% have been measured.     

Selection and modeling of integrated RF varactors on a 0.35-/spl mu/m BiCMOS technology

Integrated varactors are becoming a common feature for many RF designs and in particular RF voltage controlled oscillators (VCOs). Optimization of the quality of both the inductor and the varactor from the VCO core is essential. This work details the characterization and optimization of a number of varactor types available on a typical submicron BiCMOS process. Engineering of the bottom plate of the varactor was used to optimize the quality factor of the varactor. No additional mask layers or processing steps were required to achieve this. Integrated isolated diode varactors with quality factors of 30 at 2 GHz have been demonstrated with tuning capacitance ranges of 2.5. Integrated MOS capacitor varactors with quality factors of 50 at 2 GHz have been demonstrated with tuning capacitance range of 5. A spice model for one of the varactor types is further developed in this paper. Accurate prediction of varactor performance over voltage bias and frequency was achieved.