一个紧凑型超宽带微带带通滤波器

设计制作了一种紧凑型超宽带微带带通滤波器。该滤波器采用两对由1/4波长型SIR谐振器和1/4波长终端短路谐振器构成的枝节线对与微带低通滤波器相联而成。在ADS软件上对该滤波器进行仿真验证,然后制作实物。结果表明,该滤波器相对带宽达到112%,阻带带宽超过4 GHz,通带范围内插入损耗小于1 d B,回波损耗大于10 d B,阻带范围回波损耗大于20 d B;滤波器尺寸为14.22 mm×9.65 mm。     

交叉耦合微带带通滤波器

针对无线通信系统小型化的要求,设计了一种带有交叉耦合的带通滤波器,该滤波器采用带过孔的终端短路式耦合线为谐振单元,同时加入了交叉耦合线改善滤波特性;整个结构紧凑,具有插入损耗低、选择性高、带外抑制度佳等特点,实测结果与仿真吻合较好,中心频率为4.2 GHz,3 d B带宽为400 MHz,驻波比小于1.5,体积仅为8 mm×6 mm×0.7 mm。     

T形贴片双模微带带通滤波器

基于传统的T形贴片双模微带带通滤波器,提出了一种新型的加入缝隙耦合的T形双模微带带通滤波器。在T形贴片谐振器的两侧以缝隙耦合的方式插入馈线,并对其进行了优化。优化后的滤波器能在通带两侧都产生衰减极点,提高了阻带的抑制能力,对其进行了仿真。仿真结果表明,该滤波器通带的中心频率为5.0 GHz,与实测结果基本一致,滤波器尺寸为34 mm×24 mm,保证了滤波器的小型化。     

Miniature microstrip bandpass filter with large stopbands

A careful analysis of a classical filter configuration with large stopbands is made. An understanding of the structure behaviour is gained that allows design on safe grounds. A 1.3 GHz microstrip prototype using parallel-coupled-lines inverters is presented. Design equations for this type of inverter are also given.     

Ultra-wideband bandpass filter on aperture-backed microstrip line

A novel ultra-wideband (UWB) bandpass filter is proposed on an aperture-backed microstrip line. With an aperture on the ground, a non-uniform resonator is constructed with the first three resonant modes occurring within the UWB band while the parallel coupling between resonator and feeders is largely enhanced. The designed filter exhibits good UWB passband behaviour with insertion loss <1.0 dB and group delay variation <0.25 ns.     

Compact microstrip stepped impedance wideband bandpass filter

A novel wideband bandpass filter with a very compact size is presented in this article. Using a side-coupled stepped impedance resonator, wideband characteristics with adjustable centre frequency and 3-dB fractional bandwidth can be obtained easily. Finally, a filter sample is designed and fabricated to provide an experimental verification on the proposed topology. Good insertion/return losses, flat group delay, wide bandwidth as well as ultra compact size are achieved as demonstrated in both simulation and experiment, which makes this filter a very promising candidate for applications in future wideband communication system.     

Differential-mode ultra-wideband bandpass filter on microstrip line

A differential-mode ultra-wideband (UWB) bandpass filter on a microstrip line is proposed and implemented with good common-mode suppression. A sixth-stage branch-line differential-mode bandpass filter is designed with the specified UWB passband. By introducing two pairs of open-circuited stubs in the symmetrical plane, the differential-mode frequency response remains unchanged but its common-mode counterpart is reshaped to achieve the stopband in the overall UWB. A filter is then fabricated for experimental verification of the proposed technique.     

新型的方形贴片双模微带带通滤波器

提出了一种新型的方形贴片双模微带带通滤波器。该滤波器结构有一个切角,并且在贴片中心处开了一个两臂等长的十字槽,采用正交直接馈电方式,并在每条馈线上引入了一节与谐振腔有一定耦合的开路短截线。该结构在上下阻带都产生衰减极点,馈线上引入的微带线有效地抑制了寄生通带,提高了阻带抑制特性。仿真结果表明,该滤波器在中心频率2.9 GHz处,回波损耗优于–30.9 dB,通带内最小插入损耗为–0.1 dB,与实测结果基本一致。     

新型微带带通滤波器设计

提出一种新型微带带通滤波器设计，它是由带有J-变频器的零阶谐振ZOR（zeroth-order resonant）系统构成。零阶谐振系统以互补分裂谐振环和一系列沟道组成的左手材料LHM（Left—HandedMaterial）为基本单元，在传统设计的基础上进行改进．得到适合具有严格设计要求的滤波器设计使用模型，并给出此零阶谐振系统的共振频率和导纳斜率参数的确定方法。实验表明，该微带带通滤波器的模拟量与测量之间存在最佳关系，并具有高选择性能、对称的响应曲线以及良好的通带带宽控制性能。     

Compact dual-band microstrip bandpass filter without external feeds

A compact dual-band microstrip bandpass filter is proposed and designed to operate at 2.4 and 5.2GHz without needing any external impedance-matching block. The modified half-wavelength stepped-impedance resonator with sinuous configuration is constructed to simultaneously excite the dual resonances at these two specified frequencies with miniaturized overall size. The parallel-coupled microstrip line is properly characterized to minimize the return losses within both dual passbands. The optimized results exhibit the good dual-band filtering performances with return losses higher than 20dB as well being confirmed by experimentation with a fabricated filter circuit.     

Varactor-tuned combline bandpass filter using step-impedance microstrip lines

In this paper, a varactor-tuned combline bandpass filter using step-impedance microstrip lines is considered so that the absolute passband bandwidth can be maintained nearly constant within the tuning range. The difference between the odd- and even-mode characteristics of the coupled microstrip line makes it difficult to design a tunable bandpass filter with minimum degradation in passband performance. By using step-impedance microstrip lines, couplings between resonators can be controlled so that the constant bandwidth requirement could be satisfied with reasonable design parameter values. Lumped inductors are used for input and output coupling networks. Design equations are derived, and experimental results are compared with theoretical ones based on these equations.     

新型微带带通滤波器设计

提出一种新型微带带通滤波器设计,它是由带有J-变频器的零阶谐振ZOR(zeroth-order resonant)系统构成.零阶谐振系统以互补分裂谐振环和一系列沟道组成的左手材料LHM(Left-Handed Material)为基本单元,在传统设计的基础上进行改进,得到适合具有严格设计要求的滤波器设计使用模型,并给出此零阶谐振系统的共振频率和导纳斜率参数的确定方法.实验表明,该微带带通滤波器的模拟量与测量之间存在最佳关系,并具有高选择性能、对称的响应曲线以及良好的通带带宽控制性能.     

Compact microstrip bandpass filter with sharp transition bands

The design of a two-pole compact microstrip bandpass filter is presented. The filter consists of only one miniaturized center-stubbed half-wavelength resonator and tapped-line input/output ports, and exhibits transmission zeros at both sides of the passband. Therefore, it is very compact, and provides sharp transition bands. The measurement results of filters designed at 4.4GHz are given to validate the theory.     

Compact microstrip bandpass filter with two transmission zeros

A novel compact microstrip bandpass filter is proposed using a half-wavelength (/spl lambda//2) microstrip line resonator and an end-coupling resonator. The filter has two transmission zeros at both low and high rejection bands, as well as low insertion loss and compact design by giving two paths to the input signals. A demonstration filter has been designed and tested. Theoretical and experimental results are presented.     

Improved and compact 0.7 GHz tune-all bandpass filter

A compact tune-all bandpass filter is presented. This electronically tuned filter is based on series-coupled slow-wave resonators. It allows wide simultaneous and continuous tunings of centre frequency (+/-15% around 0.7 GHz) and bandwidth (from 50 to 100 MHz) with insertion loss IL<5.4 dB and return loss RL>11 dB. This two-pole bandpass filter exhibits also a very small surface of only 7.3times10^-3 lambda₀ ² and a -20 dB stop-band that extends up to 10 GHz     

Design of a compact microstrip tunable dual-band bandpass filter

A novel microstrip tunable dual-band bandpass filter with high attenuation level in the upper stopband region is presented. The proposed structure comprises of T-shaped resonators and the coupled microstrip feeding lines. To reach a compact size, the feeding lines are bended. By altering the physical lengths, the characteristics of BPF can easily tune. So, the operational frequencies of the filter can be adjusted and has been fixed to 2.1 GHz and 2.63 GHz, which are applicative for 3G and 4G systems. The insertion-losses of the first and second pass-bands are only 0.68 dB and 1.08 dB, respectively. The undesired harmonics in the upper stopband, with an excellent attenuation level of −38 dB, are rejected up to 6.65 GHz. The results exhibit high return loss of 19.3 dB and 30.7 dB in the first and second pass-bands. The proposed circuit has been fabricated and tested that the obtained results are well close to the simulations results. The total size of the designed circuit is only 16.4 × 13.4 mm².     

Miniaturised microstrip bandpass filter using stepped impedance ring resonators

A novel microwave bandpass filter using microstrip stepped impedance ring resonators is reported. The new filter has the advantages of compact size together with sharp rejection of outbands. A two-pole microstrip bandpass filter of this type has been implemented and examined, theoretically and experimentally.     

A novel microstrip dual-mode bandpass filter with harmonic suppression

A novel dual-mode microstrip bandpass filter (BPF) with harmonic suppression is presented in this letter. The filter is composed of a perturbed square-ring resonator and two end-open L-shaped microstrip lines for the input and output of the resonator. The harmonic suppression of the BPF may be realized by choosing a proper length for the L-shaped microstrip line. The BPF has been investigated numerically and experimentally. Measured results show that the stop-band of the filter is increased up to near the third-order harmonic of the square-ring resonator due to harmonic suppression, and the rejection level is kept below -27dB.     

平行耦合微带线带通滤波器的研究与设计

由于其优越的性能,微带线形式的各种滤波器已成为广泛使用的射频器件.本文重点研究平行耦合微带线带通滤波器的原理和设计方法,并且对其不足之处,提出了全等宽平行耦舍微带线带通滤波器的设计思路.最后,结合具体应用实例,通过仿真计算,对两种形式的滤波器进行比较.结果表明全等宽平行耦合微带线带通滤波器适用带宽较宽,且结构简洁,大大降低了设计及仿真调试的复杂度.     

多次谐波抑制的微波滤波器

提出一种新型的具有多次谐波抑制功能的发夹型微波带通滤波器,主要工作在2GHz频率。对该滤波器通过仿真优化,并进行实际设计测量。在该结构滤波器中,采用阶跃阻抗结构的发夹谐振器来达到缩小尺寸、多次谐波的目的。该滤波器相比于传统的微带线发夹型滤波器具有尺寸小,频率选择性好,阻带宽的特点。