Design of a Wide Stopband Microstrip Bandpass Filter With Asymmetric Resonators

In this letter, a novel microstrip bandpass filter (BPF) with asymmetric resonators is presented. With the asymmetric structure and capacitively loaded coupling, a wide bandwidth with sufficient rejection level can be achieved easily. A full-wave electromagnetic simulator IE3D is used, and the prototype of the BPF is fabricated and measured. Comparisons of simulated results and experimental data are shown; moreover, good match validates the proposed filter.     

Design of a Wide Stopband Microstrip Bandpass Filter With Interdigital Resonators

In this letter, a novel microstrip bandpass filter (BPF) with interdigital resonators is presented. With the interdigital resonators and shorted asymmetrical coupled-lines, a wide bandwidth with sufficient rejection level can be achieved easily. A full-wave electromagnetic simulator IE3D is used, and the prototype of the BPF is fabricated and measured. Comparisons of simulated results and experimental data are shown; moreover, good match validates the proposed filter.      

Microstrip Lowpass Filter with Very Sharp Transition Band and Wide Stopband

A novel lowpass filter with a very sharp transition band and wide stopband is proposed. The proposed filter is based on T‐shaped patches which are etched in symmetrical structures and folded open stub. To obtain a wide stopband, we have used stub loaded semi‐circle stepped‐impedance structures. By designing the resonator with high inductance and capacitance, a very sharp transition band is achieved. The proposed filter has a 3‐dB cutoff frequency at 2.37 GHz and a 40‐dB rejection at 2.44 GHz. The stopband with an attenuation level better than –13.2 dB is up from 2.4 GHz to 16 GHz, and consequently we have reached the high and wide rejection in stopband with compact size. Good agreements between the simulated and the measured results are presented.     

Compact Electronically Switchable Parallel-Coupled Microstrip Bandpass Filter With Wide Stopband

In this letter, a compact electronically switchable parallel-coupled microstrip bandpass filter (BPF) based on quarter- wavelength resonators and p-i-n diode switch is proposed. The proposed filter occupies only half the circuit size of the conventional parallel-coupled filter. In addition, the type and length of each coupled-line section is suitably chosen such that the inherent transmission zeros associated with the coupled-lines can be used to reject the spurious passbands effectively. By adding only one p-i-n diode along with a simple bias control circuitry, the proposed filter becomes electronically switchable with no current consumption when the filter is turned off. Specifically, a switchable fourth-order microstrip BPF with a center frequency f₀ of 2 GHz, passband insertion loss less than 3 dB, and wide stopband up to 7.7 f₀ in the ON state is demonstrated. The isolation of the filter is better than 30 dB from dc up to 7.7 f₀ in the OFF state.     

A Microstrip Bandpass Filter With Ultra-Wide Stopband

This paper develops a novel microstrip bandpass filter with ultra-wide stopband. With the assistance of open stubs and interdigital capacitors, a very wide stopband with a sufficient rejection level can be achieved easily. Detailed design and synthesis procedures are provided. Moreover, the electromagnetic simulator IE3D is used, and the prototype of the bandpass filter is fabricated and measured. Good agreement between measured and theoretically predicted results demonstrates feasibility of the proposed filter.     

一种高滚降宽阻带低通微带滤波器

普通的阶梯阻抗低通滤波器滚降系数一般低于80 dB/GHz,阻带抑制小于20 dB,使其应用受到较大限制;文中首先从理论上分析并设计了具有宽阻带优势的阶梯阻抗滤波器,然后引入扇形短截线结构提高滚降系数,设计了一款通带为0~6 GHz 的高滚降宽阻带的微带低通滤波器。利用ADS 和HFSS分别对滤波器进行了建模、仿真和优化;最后采用RO4003 板材加工并对实物进行了测试。测试结果显示,所设计的滤波器3 dB 截止频率为6.02 GHz,滚降系数为123 dB/ GHz,阻带6.24~20 GHz,阻带抑制大于30 dB。     

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.     

Compact Wideband Bandpass Filters With Wide Upper Stopband

In this letter, a T-shaped microstrip feeding arrangement is proposed to design wideband bandpass filter (BPF) using shorted slot-line resonators. This feed line produces frequency selective external coupling which is utilized to suppress unwanted harmonics. Up to sixth order harmonics are suppressed. Other advantages are low passband group delay variation, ease of fabrication, low insertion loss (IL), and compact size. A fabricated BPF of fractional bandwidth 56.3% at midband frequency 2.3 GHz has a maximum IL of 1.2 dB in its passband and 30-dB upper stopband extends over 11.53 GHz     

Design of the Compact Parallel Coupled Wideband Bandpass Filter With Very High Selectivity and Wide Stopband

In this letter, a compact and high performance parallel coupled line wideband bandpass filter (PCL-WBF) with open stubs is designed and implemented on the commercial substrate, RT/Duroid 5880. The PCL-WBF is composed of a one-stage coupled line and two open stubs connected near the input/output ports. The design procedure and limit are discussed in detail. The designed filter was fabricated and measured, showing good characteristics of wide stopband and very high passband selectivity. Measured results also have a good agreement with the simulated results.     

Compact Ultra-Wideband Bandpass Filter With Improved Upper Stopband

In this letter, a design of a compact bandpass filter with wide upper stopband is presented for the ultra-wideband communication systems. The filter structure is composed of a modified square slot-line resonator with parallel microstrip feed lines. Improved upper stopband is obtained by exploiting the frequency dispersive coupling behavior between the feed lines and the resonator. Measurements show that the 20.9 dB upper stopband extends at least up to 20 GHz. Filter occupying area is 0.26lambdag times 0.28g, lambdag being the microstrip line guided wavelength at 6.85 GHz.     

Microstrip Coupled-Line Lowpass Filter with Wide Stopband for RF/Wireless Systems

We present the design of a compact microstrip lowpass filter with a wide stopband which is up to ten times the cutoff frequency. The filter is based on a coupled-line configuration and shunt open stubs. The open stubs create additional transmission zeros, which are used to extend the stopband of the filter without any additional components or cascaded units. A prototype lowpass filter with a 3 dB cutoff frequency of 0.428 GHz and a 15 dB stopband extended up to 4.77 GHz is fabricated to validate the theoretical predictions.     

一种双通带微带滤波器的设计

设计了由两个H-谐振器以边缘耦合方式组成的双通带滤波器。在两条平行微带线之间桥接一条微带线,构成一个双频谐振器。随着馈电位置与中间微带线间距的增大,双频谐振器的两个外部品质因数呈相反的趋势变化。随着两个谐振器间距的增大,双频谐振器间对应的两个耦合系数逐渐减小。由此特性,将两个谐振器组合可构成双通带滤波器。     

双波段微带/波导单脉冲天线的工程实现方法

在有限的空间内采用小型化微带天线阵列与波导缝隙天线阵列复合,实现了两个频段的单脉冲天线共口径排布。通过在微带板背后添加金属带线的方法,解决了微带板与金属波导间不完全贴合带来的口面相位不一致的工程问题,兼顾了两个频段的单脉冲性能。经过仿真与实验的双重优化,加工了样机,测试结果表明该微带/波导复合天线能够在X、K 两个特定频段实现与单模相当的单脉冲方向图性能,满足了未来复合制导系统对高性能天线的需求。     

一种超宽阻带微带低通滤波器的设计

基于传统阶跃阻抗滤波器,提出了一种易于实现的超宽阻带微带低通滤波器改进设计方案。低阻抗线部分采用扇形微带结构,在同等阶数下,该结构的滤波器与传统阶跃阻抗滤波器相比,具有更紧凑的电路结构以及更好的阻带特性。在滤波器末端并联开路短截线,使得阻带增加额外传输陷波点来抑制寄生通带。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,通带3 dB 截止频率为2 GHz,通带内0-1.8 GHz 回波损耗大于20 dB,3-20 GHz 频率范围内的阻带抑制能达到25 dB 以上。     

实现高阻带衰减声表面波滤波器的一种新的设计方法

本文提出一种新的声表面波滤波器设计方法，该方法具有传统的本征函数方法和窗口函数方法的全部优点，可以实现非常高的阻带衰减，不需要叠代计算，计算量小。     

一种新型宽阻带管状带通滤波器的设计

为改进原管状带通阻带特性,设计了一种新型结构.基于阻抗匹配,可在端头引入任意多“r型”网络.同时其衰减极点能有效抑制“谐振峰”状寄生,阻带拓宽多达1倍频程(现为1.27fo～17fo).改进后,滤波器具有低插损(小于等于0.77 dB)、轻量化(小于等于64 g)、高寄生抑制(大于等于75 dB)等特点.目前,该滤波器...     

A Wideband Bandpass Filter With Wide Upper Stopband Using Stepped-Impedance Cascadable 180 ° Hybrid Rings

This letter proposes a wideband bandpass filter by cascading two 3-dB stepped-impedance cascadable 180deg hybrid rings with a pair of stepped-impedance lines. Thanks to the stepped-impedance lines, a broad upper stopband is achieved. The stepped-impedance vertically installed planar (VIP) coupler is used to implement the ideal 180deg phase inverter and crossovers. The experimental results show that this 2-GHz center frequency, fourth order filter has a 10-dB return loss bandwidth of 92.5% and upper stopband rejection levels of better than -20 dB up to 6.8 GHz. This proposed filter achieves wide passband and broad stopband performance simultaneously.     

A Simple Ultra-Wideband Suspended Stripline Bandpass Filter With Very Wide Stop-Band

This letter introduces a simple ultra-wideband suspended stripline filter with a pass-band from 3.1 to 10.6 GHz and a very wide stop-band up to more than 25 GHz. The filter is realized by capacitive coupling of a quasi-lumped low-pass filter to the I/O ports. Insertion loss in the pass-band is better than 0.5 dB. The filter has a length of 13.8 mm. Excellent agreement is achieved between measured and simulated results.     

一种小型化宽阻带窄带通滤波器研究

为实现滤波器设计小型化,降低带通滤波器的高次谐波干扰,本文结合传统的1/4波长谐振器结构,采用在谐振器微带线上添加开路线的方法,降低高次谐振频点处的插入损耗,消减谐波影响。相比半波谐振器,1/4波长谐振器能有效地减小滤波器尺寸,此外开路线的添加除具有消减高次谐波作用,同时还能降低基频谐振点,促进设计小型化。通过仿真软件对该方案的验证及网络分析仪的实物测试表明,此方案具有良好效果,能广泛应用于窄带通滤波器小型化及谐波抑制。     

一种新型的窄带远寄生小型化微带滤波器

设计了一种新型的窄带远寄生小型化微带滤波器,其远寄生特性通过在带通滤波器之后级联低通来实现。其中带通部分采用两阶带有调节支节的含源-负载非相邻耦合新型电路结构,文中给出其相应的拓扑与耦合系数矩阵,并分析了调节支节的作用;对于用于抑制远端寄生信号的低通滤波器,给出其集总参数原型等效电路。基于此,进行建模与仿真,设计了一款工作于S波段的微带滤波器,实测结果与仿真值、理论值有很好的吻合度,实现指标为中心频率3.93 GHz下的相对带宽8%,寄生远于12 GHz,体积27 mm×10.16 mm×7.45 mm,可以满足实际工程应用的需要。该电路结构新颖,产品尺寸小,设计方法简洁实用,适于推广应用。