一种简单的高温超导连续通带双工器设计

在双抛LaAlO3衬底上外延生长的钇系高温超导薄膜YBCO的基片上,设计并制作一个四级高温超导连续通带双工器（工作频率3.0～3.5GHz和3.5～4.0GHz）,与常规金属材料的双工器相比,体积减少3/4,插损减少2dB。在液氮温区77K时,测试结果为：通带内插损小于0.8dB,通带间带外抑制大于30dB通带中心频率。为近一步研制高温超导多工器提供了很好的借鉴,对将来高温超导信道化接收机系统的研究和设计具有重要的意义。     

A Narrow Band Dual Mode HTS Patch Filter With High Power Capability

A novel structure is presented to optimize the design of narrow band dual mode patch filters. Using this method, a narrow band dual mode high power HTS filter with center frequency 2.015 GHz, fractional bandwidth less than 0.35%, return loss greater than 20 dB, near band-edge rejection close to ${-}45$ dB, and insertion loss less than 0.2 dB has been designed and fabricated. The filter can work at a power of 11.7 W without obvious deterioration of its transmission response.      

一种连续通带宽带双工器的研制

设计并制作了工作在2.2～2.8GHz的带状线结构3dB定向耦合器和2只通带分别为2.2～2.5GHz及2.5～2.8GHz的8阶微带发夹线结构带通滤波器,利用该耦合器和带通滤波器设计制作连续通带宽带双工器,并通过ADS进行仿真。由仿真结果可知,在2.2～2.8GHz双工器全频带内输入端口的反射系数S11均优于-17.00dB,通带2.2～2.5GHz带内插损S21最优为-2.09dB,通带2.5～2.8GHz带内插损S31为-2.53dB,其中两通带的交接点2.5GHz处插损约-6.5dB。实测结果与仿真结果基本吻合。     

多口三环CSRR微带低通滤波器的研究与设计

提出一种新型的多口三环CSRR结构,利用CSRR谐振器的单极点低通特性和环与微带线之间的耦合,构成低通滤波器.分析该结构的等效电路模式,指出谐振频率的计算公式.使用HFSS适当优化参数,可以得到性能良好的低通滤波器.其-3 dB截止频率8.76 GHz,通带内插入损耗小于0.3306 dB,通带内回波损耗小于-13.810 2 dB,衰减15 dB以上阻带带宽达到10.31 GHz.为了改善通带内的回波损耗,在微带线两侧加载并联开路枝节.其-3 dB截止频率8.385 GHz,通带内插入损耗小于0.174 7 dB,通带内回波损耗小于-19.707 7 dB,衰减15 dB以上阻带带宽达到10.7 GHz.     

基于磁性光子晶体的高性能微波带通滤波器

提出了一种基于磁性光子晶体的高性能微波带通滤波器。仿真计算和实验测量结果表明,该滤波器矩形系数好,插入损耗小,带外抑制高且带内平坦。研制的中心频率为10.75 GHz的通带滤波器,带宽达1.3GHz,通带内插入损耗小于5dB,带外抑制50dB以上。改变磁性圆柱的半径或磁性光子晶体的晶格常数可设计出工作在不同频段,具有不同带宽的微波滤波器。     

Novel micromachined lumped band pass filter for 5.2 GHz WLAN applications

This paper describes the design, manufacturing and experiments of a lumped element band pass filter in a new topology. The design starts from a second order capacitive coupled resonator topology. An additional series inductor is inserted in the filter classical topology, for shifting two transmission zeros on the real frequency axes in the filter's band stop, to improve the high frequency response. Design equations for the new band stop resonance frequency are presented together with the analysis of the correspondence between the band pass and band stop attenuation vs. the quality factor of the shunt and series inductors used. The filter is supported on a 6.4 μm thin dielectric membrane, and is manufactured using silicon micromachining, in CPW technology. Measurements illustrated a minimum 2.75 dB insertion loss at 5.5 GHz in the band pass, and more than 40 dB attenuation, at 8 GHz.     

A V-band planar narrow bandpass filter using a new type integrated waveguide transition

A surface mountable planar narrow bandpass filter is proposed and demonstrated at V-band. The filter is constructed using an integrated waveguide in an alumina substrate employing a novel microstrip line to waveguide transition. The insertion loss per one transition is less than 0.1 dB over 43 to 73 GHz. A fabricated three-pole Chebyshev filter exhibits an insertion loss of 3 dB with a 3.3% bandwidth at a center frequency of 62 GHz and the return loss is better than 15 dB in the passband.     

Ultra-wideband bandpass filter using hybrid quasi-lumped elements and defected ground structure

A compact planar microstrip ultra-wideband (UWB) bandpass filter is presented. The proposed UWB filter is realised by cascading a highpass filter (HPF) and a lowpass filter (LPF). Additional U-slot defected ground structure is adopted to improve the attenuation performance in the stop band. The HPF consists of inter-digital capacitors and a short-circuited stub. The LPF achieved by a hybrid microstrip and four backside slots on the ground plane is equivalent to a typical 9-pole stepped-impedance LPF. Combining these two structures, a new UWB bandpass filter is fabricated and measured. Measured results show that the proposed bandpass filter has a wide bandwidth from 3.1 to 11 GHz, and insertion loss is less than 1.2 dB over the most central passband. It also achieves a wide stop band with 20 dB attenuation up to 20 GHz.     

110 GHz带通太赫兹滤波器设计

对滤波器的高精确度理论设计及小误差的工艺实现进行探讨与设计加工。总结了国内外的多种设计经验,讨论了多种类型的滤波器设计方案,选取适当的滤波器结构形式,设计加工了110 GHz的感性窗耦合波导滤波器,其中感性窗耦合结构采用传统机械加工技术实现,与法兰盘结构一并集成。基于高频结构仿真(HFSS)软件进行仿真,结果表明：设计并制作的110 GHz带通滤波器,其中心频率为110 GHz,相对带宽为5%,插入损耗小于1 dB,带内回波损耗大于 20 dB,距中心频率2倍带宽处,带外抑制大于40 dB。     

双波段高抑制的LTCC微型双工器设计

该文设计了基于低温共烧陶瓷(LTCC)技术的双波段高抑制、低损耗的双工器。该双工器由低通滤波器和带通滤波器组成,且在低、高频段的阻带抑制方面运用了传输零点理论,在实现双工器低损耗的同时,也实现了在多波段的高抑制,提升了双工器的性能。该双工器在低频段(0.68~0.95 GHz)及高频段(1.43~2.40 GHz)时插损均小于1.2 dB,但在1.43~2.40 GHz时双工器抑制大于20 dB,0.68~0.95 GHz时双工器抑制大于15 dB。在4.9~5.9 GHz时双工器抑制大于13 dB,具有良好的市场应用前景。     

S 波段高性能微型滤波器的研究

应用LTCC多层耦合带状线谐振器和交叉耦合传输零点原理,在改进的三维梳状带通滤波器结构中引入交叉耦合,增强非相邻谐振级间的交叉耦合;在2、4谐振级间引入Z字形导体层,通过调节Z字形控制传输零点位置;同时适当调节加载电容大小,有效减小了滤波器体积,实现了高次谐波抑制、边带陡峭和通带内线性相位.采用低温共烧陶瓷(LTCC)技术设计制作了中心频率为3GHz,通带为200MHz的微型带通滤波器.实验和仿真结果表明,该滤波器的中心频率插入损耗小于2.6dB,阻带抑制高于40dB,边带陡峭,尺寸仅为4.8mm×4.2mm× 1.5mm.成品率高达85％.     

A Compact HTS Duplexer for Communication Application

A compact L-band high temperature superconducting (HTS) microstrip input duplexer for satellite communication application has been developed. The duplexer has two output channels with center frequencies at 1200 and 1250 MHz, respectively. It was fabricated on a single piece of 2-in double-sided YBCO thin film on $hbox{LaAlO}_{3}$ substrate with a dimension of 26 $times$ 42 mm. The duplexer consists of a T-junction and two bandpass filters, i.e., a ten-pole filter and an eight-pole filter for the two transmission channels, respectively. Both of the two HTS bandpass filters were specially designed to suppress the second-harmonic spurious passband. Moreover, an HTS bandstop filter is added to the duplexer to improve the out-of-band rejection at a special frequency band. As a result of the preceding special designs, in addition to a very low insertion loss (0.2 dB), considerably sharp band edge (21 dB/MHz), and good voltage standing wave ratio (better than 1.4:1), much deeper out-of-band rejection (more than 75 dB) can be realized in a much wider frequency range, i.e., up to 3 GHz, which is almost three times above the center frequency of the passbands. Although all the elements of the duplexer are integrated within a single-piece YBCO film and the layout is compact, excellent isolation (higher than 80 dB) between the two channels has still been achieved.      

A 12–18-GHz Three-Pole RF MEMS Tunable Filter

This paper presents a state-of-the-art RF microelectromechanical systems (MEMS) wide-band tunable filter designed for the 12–18-GHz frequency range. The coplanar-waveguide filter, fabricated on a glass substrate using loaded resonators with RF MEMS capacitive switches, results in a tuning range of 40% with very fine resolution, and return loss better than 10 dB for the whole tuning range. The relative bandwidth of the filter is$hbox5.7pm hbox0.4hbox%$over the tuning range and the size of the filter is 8 mm$, times ,4$mm. The insertion loss is 5.5 and 8.2 dB at 17.8 and 12.2 GHz, respectively, for a 2-$hboxkOmega/hboxsq$bias line. The loss improves to 4.5 and 6.8 dB at 17.8 and 12.2 GHz, respectively, if the bias line resistance is increased to 20$hboxkOmega/hboxsq$. The measured$ IIP_3$level is$≫$37 dBm for$Delta f ≫ 200$kHz. To our knowledge, this is the widest band planar tunable filter to date.     

Temperature Dependence of Microwave Properties of HTS Multipole Lowpass Filters Consisting of Microstrip Open-Stub Lines

Using high quality high-T_c superconducting (HTS) YBCO thin films, we designed and fabricated 3-pole, 5-pole, and 7-pole lowpass filters consisting of microstrip transmission lines and open-stub lines. We measured the microwave response of the filters in the temperature range of T=85 K to 27 K. At T = 30 K, the observed inband insertion loss was 0.14 dB and 0.02 dB for the 5-pole and 7-pole filters, respectively. The cut-off frequency was 4.7 GHz for the 5-pole filter and 7.9 GHz for the 7-pole filter. To the authors’ knowledge, the measured inband insertion losses are the best values reported so far for the open-stub line type HTS multipole lowpass filters. The skirt property of the 5-pole filter showed a large improvement over that of the 3-pole filter as predicted from the simulation. We found that, to obtain a stable performance, the HTS multipole lowpass filters should be operated at the temperatures between 60% and 70% of T_c.     

基于齿状缺陷地的宽阻带交叉耦合SIW滤波器

提出了一种齿状缺陷地低通传输线结构,该低通传输线由多级齿状缺陷地构成,通过调节齿状缺陷地枝节长度,可以有效调节低通和阻带频率范围。利用该齿状缺陷地结构,级联交叉耦合扇形基片集成波导(SIW)滤波器,该文设计了一款高带外抑制的宽阻带滤波器,与传统SIW带通滤波器相比,其矩形系数K_{40 dB}=2,阻带范围大于2倍的中心频率,具有较好的通带和阻带选择特性。测试结果表明,滤波器的中心频率为10.35 GHz,3 dB和40 dB带宽分别为507 MHz和1.05 GHz,插入损耗优于1.47 dB,与仿真结果基本一致。     

High Performance Microstrip Low Pass Filter for Wireless Communications

A microstrip low-pass filter using T-shaped resonators is designed to achieve an ultra-sharp transition band and high suppression level. The performance of the resonators is investigated based on an LC equivalent circuit and a transfer function to compute the equations of the transmission zeros. This filter has an acceptable stopband with high insertion loss (28 dB) by adopting a rectangular suppressor. Also, the width of the transition band is 0.09 GHz (with – 3 and ? 40 dB attenuation levels), that exhibits a very high sharpness (ξ = 411 dB/GHz). The proposed filter with a 3 dB cut-off frequency (f_c) of 1.32 GHz presents a high return loss in the passband (17 dB) and high figure of merit of 57,073. The designed filter is fabricated and measured, demonstrating sufficient agreement between the simulation and experimental results.

     

A planar X-band electromagnetic band-gap (EBG) 3-pole filter

A Duroid-based X-band electromagnetic band gap (EBG) Chebyshev 3-pole bandpass filter that is compatible with standard printed circuit board (PCB) fabrication techniques has been designed, fabricated, and tested. The filter consists of three EBG cavities in a multi-layer design. It provides a 5.95% bandwidth response at the resonant frequency f_res=9.72 GHz with a corresponding insertion loss of 0.9 dB. Isolation is higher than 30 dB below 9 GHz and above 11 GHz     

基于PBG结构的双模带通滤波器设计及理论分析

本文应用传输线理论对PBG结构带通滤波器进行分析,并在此基础上仿真、设计一种新颖的K波段的双模带通滤波器.光子带隙结构具有独特的带阻特性,对高次模具有很好的抑制特性,能够提高微波电路系统的抗干扰能力.由于PBG的慢波特性,使得带通滤波器的结构尺寸大为减小,符合系统小型化的要求.在此基础上,就这种结构应用Ensemble软件进行优化仿真.最后制作出滤波器并进行了测试.仿真结果与实验结果吻合很好,插入损耗为-4.5dB,通带中心频率为25.2GHz,-3dB带宽为1.8GHz,相对带宽7%.     

A compact low-loss reconfigurable monolithic low-pass filter using multiple-contact MEMS switches

A high-performance reconfigurable low-pass filter based on the quasifractal self-similar structures has been developed at millimeter-waves using multiple-contact MEMS switches. Three-cell cascaded low-pass structure was reconfigured to one-cell low-pass counterpart by activating the micromachined switches to achieve 3:1 frequency scaling. Two types of special multiple-contact MEMS switches were developed to reduce the number of switching elements as well as to reduce the insertion loss and, thus, extend the operating frequencies to mm-waves. In addition, bias-decoupling circuits were eliminated, resulting in a small chip size of 1.2 mm /spl times/ 1.5 mm. The measured 3-dB cut-off frequency of the reconfigurable low-pass filter changed from 67 GHz to 28 GHz with minor change in the insertion loss from 0.32 dB to 0.27 dB. This work demonstrates the possibility of high-performance compact-size reconfigurable filters at mm-waves using multiple-contact micromachined switches.     

一种IPD吸收式低通滤波器的设计

为解决反射信号损害系统性能的问题,提出了一种具有高带外抑制和高带外吸收的小型化吸收式低通滤波器。该滤波器通过高通通路和低通通路实现了吸收式低通滤波器;通过抑制增益支路实现了高带外抑制。利用ADS和HFSS仿真软件对滤波器结构进行优化设计,并进行了实物的加工和测试。实测结果表明:该滤波器的3 dB截止频率为4 GHz,其带内最小插入损耗0.88 dB,通带内DC到3.5 GHz的回波损耗大于20 dB,阻带回波损耗大于10 dB,10.5 GHz处的阻带抑制大于45dB,从8 GHz到30 GHz的带外抑制大于33 dB,实测结果与仿真结果有较好的吻合。该滤波器尺寸仅为1220μm×650μm×87.71μm,相比传统PCB、LTCC工艺的滤波器,体积大大缩小,符合现代射频与微波系统小型化的发展趋势。