BST-Varactor Tunable Dual-Mode Filter Using Variable ${Z}_{C}$ Transmission Line

Ferroelectric materials like barium-strontium-titanate (BST) have become attractive for microwave tunable circuit applications. This letter presents an investigation of BST-varactor tunable dual-mode filter using variable characteristic impedance or Z_C transmission line. The interdigital BST varactors are fabricated and modeled, which are then deployed to realize a bandpass filter with tunable bandwidth capability. The use of tunable impedance line provides additional flexibilities in the design of microwave tunable circuits. A tunable bandpass filter of this type with a center frequency of 1.8 GHz and a bandwidth tuning ratio of 1.15:1 is demonstrated experimentally.     

Octave-tunable miniature RF resonators

The development and testing of a miniaturized, high-Q, broadly tunable resonator is described. An exemplary device, with a center frequency that is continuously tunable from 1.2 to 2.6GHz, was tested in detail. Experimental results demonstrated a resonator Q of up to 380, and typical insertion loss of -1.9dB for a 25MHz 3-dB bandwidth. These resonators have been used to stabilize a broadly-tunable oscillator with phase noise of -132dBc/Hz at 100-kHz offset, with a center frequency tunable from 1.2-2.6GHz, and a tuning speed of 1GHz/ms.     

微波小型化固态介质谐振器振荡器的发展

介绍了近年来微波小型化固态介质谐振器振荡器（ＤＲＯ）研究方面的新成就。重点介绍了介质材料、ＤＲＯ的频率调谐特性、相位噪声性能的优化、ＤＲＯ的拓展设计以及焊封和可靠性。     

A 0.13-μ m CMOS Phase Shifter Using Tunable Positive/Negative Refractive Index Transmission Lines

This letter presents a tunable positive/negative refractive index transmission line (TL) phase shifter utilizing active circuits. It comprises a microstrip TL loaded with series varactors and a shunt monolithic microwave integrated circuit (MMIC) to synthesize a tunable inductor. This implementation increases the phase tuning range and maintains the input and output matching of the phase shifter across the entire phase tuning range, while eliminating the need for bulky passive inductors. The phase shifter is capable of providing both positive and negative phase shifts. The MMIC tunable inductors are fabricated in a 0.13-mum CMOS process and operate from a 1.5-V supply. The phase shifter achieves a phase of -40deg to +34deg at 2.5GHz from a single stage with less than -19dB return loss, and better than 1.1-dB insertion loss at 2.5 GHz. The phase shifter has a 1-GHz bandwidth over which the return loss remains better than 12.1dB     

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。     

Analysis and Design of Planar Tunable Inner-Coupling Step Impedance Resonator

A full planar tunable band pass resonator is introduced,which is constructed by using novel symmetric step impedance resonator(SIR) and hyperabrupt varactors for wide bandwidth tuning and size reduction.The equivalent circuit model of the proposed resonator is set up.Theoretical analysis based on transmission line as well as odd and even-mode method is completed.The attractiveness of the approach presented lies in its simplicity.Based on the detailed analysis,a 6 GHz to 10 GHz varactor tuned resonator is designed,fabricated,and measured.It shows wideband tuning ability of 37%.The experimental results of the resonator have a good agreement with the analysis results.     

Electronically tunable ring resonator microstrip and suspended-substrate filters

Electronically tunable ring resonator microstrip and suspended substrate microwave filters with high tuning speed are presented. The filters are realised using two coupled ring resonators with GaAs varactors as the tuning elements. Computer optimised circuits are used at the input and the output to obtain better than 10 dB return loss across the tuning band. Tuning ranges of 1.075-2.25 GHz for the microstrip filter and 1.35-2.075 GHz for the narrower suspended substrate filter are predicted by computer simulation.<>     

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     

Broadband electronically tunable planar active radiating elementsand spatial power combiners using notch antennas

A Gunn device has been integrated with two types of active planar notch antennas. The first types uses a coplanar waveguide (CPW) resonator an a stepped-notched antenna with bias tuning to achieve a bandwidth of 275 MHz centered at 9.33 GHz with a power output of 14.2±1.5 dBm. The second type uses a CPW resonator with a varactor for frequency tuning to achieve a bandwidth of over 1.3 GHz centered at 9.6 GHz with a power output of 14.5±0.8 dBm. This is equivalent to over 14% electronic tuning bandwidth. Both configurations exhibit a very clean and stable output signal. A theoretical circuit model was developed to facilitate the design. The model agrees well with experimental results. Injection-locking experiments on the second configuration show a locking gain of 30 dB with a locking bandwidth of 30 MHz at 10.2 GHz. Power combining experiments of two-varactor-tuned CPW active notch antenna elements in a broadside configuration have achieved well over 70% combining efficiency throughout the wide tuning range. The circuits have advantages of small size, low cost, and excellent performance     

Tunable Dielectric Resonator Bandpass Filter With Embedded MEMS Tuning Elements

This paper presents a novel approach for constructing a tunable dielectric resonator bandpass filter by using the microelectromechanical system (MEMS) technology. The tunability is achieved by unique MEMS tuning elements to perturb the electrical and magnetic fields surrounding the dielectric resonators. The use of such elements as a tuning mechanism results in a wide tuning range at a relatively low tuning voltage and fast tuning speed. A three-pole tunable dielectric resonator bandpass filter is designed, fabricated, and tested. The experimental filter has a center frequency of 15.6 GHz, a 1% relative bandwidth, and an unloaded Q of 1300. A tuning range of 400 MHz is obtained by using MEMS tuning elements with 2 mmtimes2 mm tuning disks. The measured results demonstrate the feasibility of the proposed concept     

A novel microstrip square-loop dual-mode bandpass filter with simultaneous size reduction and spurious response suppression

In this paper, a new capacitively stepped-impedance resonator(CSIR) is proposed to develop the microstrip square-loop dual-mode bandpass filter. Using this new design, simultaneous size reduction and spurious response suppression for the dual-mode bandpass filter can be achieved. An analytical formulation of this novel resonator is given in order to elucidate the spurious frequencies relocation design. Together with this formulation, a generalized dual-mode bandpass filter model is developed so as to ease the analysis of transmission zero and insertion loss. A prototype filter is designed at 900MHz with 1.5% fractional bandwidth. Significant spurious suppressions up to 33 and 35 dB are measured at 1.8 and at 2.7 GHz, respectively. A circuitry size reduction of 54% is achieved when compared with that of the conventional structure. Moreover, the CSIR allows frequency tuning and, thus, a varactor-tuned filter is designed and a measured tunable center frequency between 1.5-1.62GHz is demonstrated. Utilizing the proposed structure, not only size reduction,as well as spurious response suppression, but also center frequency tuning can be achieved.     

Distributed MEMS analog phase shifter with enhanced tuning

The design, fabrication, and measurement of a tunable microwave phase shifter is described. The phase shifter combines two techniques: a distributed capacitance transmission line phase shifter, and a large tuning range radio frequency (RF) microelectromechanical system (MEMS) capacitor. The resulting device is a large bandwidth, continuously tunable, low-loss phase shifter, with state-of-the-art performance. Measurements indicate analog tuning of 170/spl deg/ phase shift per dB loss is possible at 40 GHz, with a 538/spl deg/ phase shift per centimeter. The structure is realized with high-Q MEMS varactors, capable of tuning C/sub max//C/sub min/= 3.4. To our knowledge, this presents the lowest loss analog millimeter wave phase shifter performance to date.     

基于双光源的可调谐微波光子滤波器

提出了一种基于双光源与双相移光纤光栅(DPS- FBG)的可调谐微波光子滤波器。双光源经过相 位调制后,利用DPS-FBG的反射模式中的两超窄陷波分别对两相位调制光信号的边带进行抑 制,实现相 位调制至强度调制的转换。通过调节两光源的中心波长可以实现单通带与双通带之间的切换 ,实现单通带 的中心频率可调以及3dB带宽可调,实现双通带频率同时可调或者单独可调。建立了理论模 型并进行了数 值分析,最后通过实验进行了验证。实现了滤波器通带的3dB带宽由180MHz增加为319MHz,中心频率从1GHz到7GHz可调。     

Magnetostatic surface wave straight-edge resonators

The performance of the magnetostatic surface wave straight-edge resonator (MSSW-SER) is presented. The resonator uses a rectangular YIG film to propagate MSSWs where the straight edge serves as a reflector. Problems arising from coupling to width mode resonances and their effect on the main resonance are investigated. Through a careful choice of YIG and transducer parameters, the interference effects of the width mode resonances with the main resonance are minimized. As a result, highQ tunable microwave resonators with a tuning range from 2–20 GHz, insertion loss less than 10 dB, and spurious rejection better than 10 dB could be designed and fabricated. This MSSW resonator could be used to construct a tunable low-phase-noise feedback oscillator. However, the tuning range of this MSW feedback oscillator is limited by the phase change of the external amplifier circuit.     

基于基片集成波导谐振器的压控振荡器设计

设计了一种基于基片集成波导谐振器的X波段压控振荡器。首先分析了串联反馈式振荡器以及基片集成波导谐振器的理论,然后在高频电磁仿真软件ADS中进行仿真和设计,并通过将变容管合理地引入谐振器,实现了电调谐的目的。最终设计完成了一个工作于X波段的基片集成波导压控振荡器。此压控振荡器与传统的介质压控振荡器(DRO)相比,具有稳定性高、平面化以及成本低的优点。由于采用了ADS中的联合仿真功能进行振荡器的设计,仿真结果的准确性得到了提高,减小了实物的调试工作量。测试结果为:工作频率为7 GHz,调谐范围为30 MHz,输出功率≥7 dBm,谐波抑制度≥22 dBc,相位噪声优于-106 dBc/Hz@100 kHz。     

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。     

Ka波段介质谐振器的研究

介质谐振器由于具有体积小、损耗低等优点,得到了越来越广泛的应用.设计了一款Ka波段介质稳频振荡器,振荡器中集成了介质谐振器用于选频.通过采用合适的介质振荡子及适当尺寸的金属屏蔽腔,使介质谐振器谐振在Ku波段,再通过单片进行倍频放大,从而得到Ka波段信号.介绍了介质振荡子的选取及参数计算.并以此为根据作为介质谐振器的设计原则,最后得到的Ka波段信号输出频率(fo)为38.22 GHz,输出功率(Po)为7.38 dBm,相位噪声为-80 dBc/Hz@100 kHz.     

Photonic Microwave Channel Selective Filter Incorporating a Thermooptic Switch Based on Tunable Ring Resonators

A photonic microwave (MW) channel selective filter was demonstrated incorporating a 1times2 switch based on two tunable polymeric resonators with different free-spectral ranges (FSRs). Each resonator plays a role as an ON-OFF switch through the thermooptic effect, consisting of two cascaded rings with an electrode formed on one of them. The optical signal carrying the MW signal is routed to either port of the switch and detected to exhibit the filtered output at the frequency determined by the FSR of the corresponding resonator. When the channel centered at 10 GHz was chosen, the extinction ratio was ~30 dB, the bandwidth 1 GHz, and the electrical power consumption 4.1 mW. And for the other channel located at 20 GHz, we have achieved the extinction ratio of ~30 dB, the bandwidth of 2 GHz, and the required power of 8.0 mW. Finally, the crosstalk between the selected and blocked channels was higher than 24 dB.     

Demonstration of a Fourth-Order Pole-Zero Optical Filter Integrated Using CMOS Processes

We demonstrate a compact fully tunable narrowband fourth-order pole-zero optical filter that is fabricated in a silicon complementary-metal-oxide-semiconductor foundry. The filter is implemented using silicon on oxide channel waveguides and consists of a Mach-Zehnder interferometer with two ring resonator all-pass filters (APFs) on each arm. The filter architecture is based on the sum and difference of the APFs responses. The ring resonators introduce a nonlinear phase response in each arm that allows carving narrow frequency bands out of a broad spectrum. In this paper, we demonstrate a 3-dB filter bandwidth of 1.0 GHz with a stopband rejection of better than 25 dB. The filter free spectral range is 16.5 GHz. Thermooptic phase shifters are used to tune the filter. As silicon has a large thermooptic coefficient compared to silica, the demonstrated filter requires a low tuning power of less than 300 mW. In addition, this filter is compact with dimensions 25 times smaller than the same filter would be if it were made using standard silica on silicon waveguides with a 0.8% step index contrast     

Theoretical and experimental investigation of novel varactor-tunedswitchable microstrip ring resonator circuits

A microstrip ring resonator circuit loaded with two p-i-n diodes has been developed for use as a switchable filter. By replacing one p-i-n diode with a varactor diode, the switchable filter can be made electronically tunable. Isolation exceeding 20 dB with 9% tuning bandwidth was demonstrated. An analysis based on transmission line theory was used to model both circuits. The analysis includes the effects of diode parasitics, coupling gaps, dispersion, and mounting-gap capacitance. The experimental results agree very well with the theoretical calculation