Ultra-Wideband (UWB) Bandpass Filter With Embedded Band Notch Structures

A compact ultra-wideband (UWB) bandpass filter (BPF) with narrow notched (rejection) band in the UWB passband realized on a microstrip line is implemented and presented in this letter for use in wireless communication applications within the unlicensed UWB range set by the Federal Communications Commission (FCC). The filter consists of five short-circuited stubs separated by nonredundant connecting lines in order to exhibit a high selectivity filtering characteristic. The narrow notched (rejection) band was introduced by using a new technique which involves embedding open stubs in the first and last connecting lines in order to reject any undesired existing radio signal which may interfere with the determined UWB passband. The bandwidth of the notched filter can be controlled by adjusting the width of the stubs or the gaps or both. The length of the stubs can be tuned to select a specific frequency for the notched band. The embedded stubs can be used to excite single or double band-reject response. Two UWB BPFs with narrow notched band having a fractional bandwidth (FBW) of about 4.6% and 6.5% were realized theoretically and verified by full-wave EM simulation and the experiment. Excellent agreement between the predicted and measured results was obtained and is demonstrated     

Dual-Mode Dual-Band Bandpass Filter Using Stacked-Loop Structure

In this letter, a dual-mode dual-band bandpass filter using stacked-loop structure is proposed, which allows two transmission paths to radio frequency (RF) signals. Each of them using dual-mode resonators results in respective passband. This can provide convenience to easily change one passband frequency, while another keeps almost the same. Several attenuation poles in the stopband are realized to improve the selectivity of the proposed bandpass filter. The theoretical and measured results are presented and show good agreement.     

A Coplanar Stripline Ultra-Wideband Bandpass Filter With Notch Band

In this letter, a design of a compact coplanar stripline ultra-wideband bandpass filter with a narrow rejection band is reported. The filter characteristic is obtained by using stepped impedance open-circuited series stubs. It is shown that the rejection band can be placed at a desired frequency by tuning the width of the high impedance section of the series stub. Full-wave simulated and experimental results of a filter prototype are presented.      

Multilayer Dual-Band Filter Using a Reflector Cavity and Dual-Mode Resonators

A dual-band filter has been designed using a multilayer approach. The structure includes a reflector cavity and dual-mode resonators. The walls of the reflector cavity have been designed using metalized vias enabling the integration characteristics of standard planar microwave circuits. The principle includes the passband division of a fourth-order fully canonical form into two narrowband second-order passbands. The designed topology exhibits a dual-band response with center frequencies of 5.2 and 5.7GHz and in-between isolation of 30 dB created by two in-band transmission zeros. The enclosing cavity reduces radiation loss and increases the unloaded of the resonant modes. The hybrid design provides insertion losses better than 1.7 dB and narrow fractional bandwidths of 2.5%.     

A 2.45/5.2 GHz Image Rejection Mixer With New Dual-Band Active Notch Filter

A 2.45/5.2 GHz dual-band Gilbert downconversion mixer with image rejection function is presented, which is implemented using the 0.18 $mu$m CMOS technology. The proposed differential dual-band image rejection circuitry is employed for the 2.45/5.2 GHz WLAN application to effectively diminish the dc power consumption and complexity of circuit design compared to the traditional Hartley or Weaver architectures. Moreover, the cross-connected pair consisted of NMOS and PMOS transistors in the proposed notch filter will further ameliorate the image rejection capability. The IC prototype achieves conversion gain of $10.5/11$ dB, IIP3 of ${-}4.9/-5.2$ dBm for ${rm RF}= 2.45/5.2$ GHz and ${rm IF}=500$ MHz while the image rejection ratio is better than 36/45 dB in the whole operation bandwidth.      

A Novel Dual-Mode Dual-Band Bandpass Filter Based on a Single Ring Resonator

A dual-mode dual-band bandpass filter with two transmission poles in both passbands using a single ring resonator is proposed. Two excited ports are placed at the 135$^{circ}$ -separated positions along the ring resonator and coupled with the ring via parallel-coupled lines, leading to synchronous excitation of two transmission poles in dual passbands. After the principle of this initial filter is described, an improved ring resonator with periodic loading of open-circuited stubs is constructed and studied to achieve compact size and adjustable spacing between the two passbands. Finally, a dual-band ring resonator filter with center frequencies at 2.4 and 5.8 GHz is designed and fabricated. Measured results verify the design principle.      

直接馈电的小型化微带双模带通滤波器

采用直接接触馈电的方法设计制作了一款微带结构的双模带通滤波器.该滤波器采用了分布式电容加载的双模环形谐振器,馈电时不需额外的耦合结构或阻抗变换器,在实现较大耦合量的同时,可保持谐振器的小型化.所制作的单级和两级的滤波器样品分别获得了0.6dB(在22.0%的相对带宽下)和1.1dB的最小插入损耗(在16.7%的相对带宽下)、40.0dB的带外抑制并在通带的两侧各有两个传输零点的较好测试结果,测试值与仿真值相当吻合.测试结果还表明,在得到相对较小的插入损耗的同时,也得到了优于-15.0dB的带内匹配.     

Dual-Band Capacitive Loaded Frequency Selective Surfaces With Close Band Spacing

In this letter, a novel miniaturized dual-band capacitive loaded frequency selective surface (FSS) is presented, in which each periodic cell consist of two neighboring capacitive loaded ring slot resonator with the same dimension. To eliminate the undesired coupling between unit cells, the unit cell is placed in a Faraday cage structure created by arrays of metallic substrate vias. An S-band dual-band FSS with such structures is designed and fabricated, both simulated and measured results show that the proposed FSS provides high transmission with close band spacing at 2.5 and 3.5 GHz, and there is no other resonance frequency up to 15 GHz. Furthermore, the FSS dimension is miniaturized to $0.082lambda$ ($lambda$ refer to the resonant wavelength of 2.5 GHz). Also, it is not sensitive to the angle of oblique incidence wave. The design and discussion about dual-band FSS loading with lumped elements is presented for the first time.      

60-GHz Band Dual-Mode Microstrip Ring Resonator Bandpass Filter Using Micromachining Technology

A new compact millimeter-wave dual-mode ring resonator bandpass filter is proposed. This filter has a 15% bandwidth at 58 GHz with 3.4 dB insertion loss. Input/output lines and ring resonator are directly connected to obtain tight coupling, and an open-end stub is inserted for dual-mode operation. This filter is fabricated on a GaAs wafer by using MEMS technology and can be applied for the millimeter- wave SoC.     

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%.     

Novel Dual-Mode Dual-Band Filters Using Coplanar-Waveguide-Fed Ring Resonators

This paper presents a novel approach for designing dual-mode dual-band bandpass filters with independently controlled center frequencies and bandwidths. Two microstrip perturbed ring resonators are employed to obtain dual-mode dual-band responses. Novel feeding structures are introduced to simultaneously feed the ring resonators and conveniently control the coupling strength between resonators and feeding lines, resulting in a wide tunable range of external quality factors. Two kinds of filter configurations with compact size are proposed. Both of them provide sufficient degrees of freedom to satisfy various requirements of external qualify factors and coupling coefficients at both passbands. Therefore, the center frequencies and fractional bandwidths of both passbands can be independently tuned to desired specifications within a wide range. To verify the proposed method, four filters are implemented. The measured results exhibit dual-mode dual-band bandpass responses with high selectivity.     

Miniaturized Dual-Mode Ring Resonator Bandpass Filter With Microstrip-to-CPW Broadside-Coupled Structure

A microstrip-to-coplanar waveguide broadside-coupled section is used to replace a 34-section of the conventional dual-mode 1-ring resonator filter for circuit area miniaturization. It is believed that it is a new idea to incorporate the broadside-coupled section into a ring resonator filter for size reduction. For design purpose, some important characteristics of the broadside-coupled lines are investigated. In experiments, two realized circuits show only 19.4% of the area of a uniform ring. Measured responses show good agreement with simulation.     

Dual-Band Filter Design With Flexible Passband Frequency and Bandwidth Selections

In this paper, improved dual-band filter design is studied. The dual-band resonators are composed of shunt open- and short-circuited stubs. In order to fulfil the requirements of dual-band inverters, a structure of stepped-impedance asymmetric coupled lines is proposed and its equivalent circuit is also derived. The dual-band filter is then designed based on this equivalent circuit. This type of filter can achieve relatively large practical passband center frequency ratios (in theory infinite), and it has more freedom of bandwidth ratio. The circuit size is also reduced. Detailed design procedure is presented and, finally, a filter example is given to validate the theoretical study     

Design and Analysis of UWB Filter with Single Notch Band

Wireless Personal Communications - In this article, design and electrical analysis of UWB filter with a notch band is presented. Initially basic UWB filter is designed by using parallel coupled...     

Multilayer Dual-Mode Dual-Bandpass Filter

A dual-mode dual-bandpass filter for the U-NII bands is proposed and demonstrated. Its effective size reduction is achieved by using a multilayer configuration. The first and the third layers incorporate microstrip dual-mode bandpass filters with operating center-frequencies of f₁ =5.2 GHz and f₂ =5.8 GHz, respectively. The second layer is used as a common ground plane for both filters, which also serves as a decoupling interface. Capacitive coupling transition is used to connect both filters to I/O coplanar waveguide (CPW) ports. Single and dual-band passband filter prototypes are designed, fabricated, and measured in this work, thus validating the design principle. Designed topologies of single passband filters with center frequencies of 5.2 and 5.8 GHz exhibit an out-of-band rejection better than 40 dB with a 3 dB bandwidth of 5.8% and 6%, respectively. The proposed multilayer dual-passband response with center frequencies of 5.2 and 5.8 GHz provide band-to-band isolation better than 30 dB. Measured insertion losses are lower than 2.76 dB, with 3 dB bandwidth lower than 5%.     

Dual-Band Microstrip Bandpass Filter Using Stepped-Impedance Resonators With New Coupling Schemes

A microstrip bandpass filter using stepped-impedance resonators is designed in low-temperature co-fired ceramic technology for dual-band applications at 2.4 and 5.2 GHz. New coupling schemes are proposed to replace the normal counterparts. It is found that the new coupling scheme for the interstages can enhance the layout compactness of the bandpass filter; while the new coupling scheme at the input and output can improve the performance of the bandpass filter. To validate the design and analysis, a prototype of the bandpass filter was fabricated and measured. It is shown that the measured and simulated performances are in good agreement. The prototype of the bandpass filter achieved insertion loss of 1.25 and 1.87 dB,$ S_11$of$-$29 and$-$40 dB, and bandwidth of 21% and 12.7% at 2.4 and 5.2 GHz, respectively. The bandpass filter is further studied for a single-package solution of dual-band radio transceivers. The bandpass filter is, therefore, integrated into a ceramic ball grid array package. The integration is analyzed with an emphasis on the connection of the bandpass filter to the antenna and to the transceiver die.     

Design of Miniature Planar Dual-Band Filter Using Dual-Feeding Structures and Embedded Resonators

A new dual-band planar filter has been proposed. It is shown that the two transmission bands can be excited and designed using proposed resonators which combine different sizes of open-loop resonators. The main resonators control the low-band resonant frequency and the sub resonators control the high-band resonant frequency. With dual-feeding structures added, the performances of the filter such as frequency selectivity and insertion loss are much improved. The embedded resonators structure can further miniaturize the dimensions of the overall structure. The proposed dual-band filter will find applications in wireless communication circuits     

Dual-Mode Reconfigurable Filter With Asymmetrical Transmission Zeros and Center Frequency Control

A reconfigurable bandpass filter with asymmetrical responses is demonstrated using a dual-mode microstrip resonator. The proposed topology introduces several fixed and switchable perturbations to control the center frequency and the location of the transmission zeros of the filter. The tuning mechanism consists of capacitively loading the edges of a modified square patch resonator, in order to manipulate the current distribution of the degenerate modes. This operation results in asymmetrical responses with a center frequency tuning ratio of 10% at$X$band, and angular transmission zero displacement of$Deltaomega_z=$3.5rad/s or greater in both a lower and higher side of the passband.     

Generalized Adaptive Notch Filter With a Self-Optimization Capability

The paper presents a self-optimizing version of a generalized adaptive notch filter (GANF). Generalized adaptive notch filters are used for identification/tracking of quasi-periodically varying dynamic systems and can be considered an extension, to the system case, of classical adaptive notch filters. The tracking properties of a GANF algorithm depend on two adaptation gains, which should be chosen so as to match the degree of nonstationarity of the identified system. First, an analytical study of a tracking performance of a GANF algorithm is presented. Then, based on the obtained theoretical results, a self-optimizing GANF algorithm is proposed, capable of automatic tuning of its adaptation gains.     

S波段低插损FBAR陷波器的研制

该文介绍了一种单端口、端口阻抗50Ω的S波段薄膜体声波谐振器(FBAR)陷波器,其采用了梯形拓扑结构与外围匹配电路相结合的方式.对FBAR陷波器芯片的设计过程、工艺实现进行了说明.测试制备的FBAR陷波器,其陷波频段为2399～2412 MHz,陷波抑制达35 dBc;通带频率分别为1800～2300 MHz和2500...