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1.
The full set of eigenmodes existing in a ferrite‐slab‐loaded rectangular waveguide is first obtained and then used to compute the scattering matrix of a junction between an air‐filled rectangular waveguide and an H‐plane ferrite‐slab‐loaded rectangular waveguide by using the mode‐matching method. Numerical results for the scattering parameters of the H‐plane waveguide discontinuity are compared to experimental data and those obtained by Ansoft's HFSS. Good agreement is observed. To demonstrate the usefulness of this structure, a computer‐optimized 90° nonreciprocal phase shifter is designed using an H‐plane ferrite‐slab‐loaded waveguide. With only one‐step impedance matching sections at both ends of the ferrite slab, a compact design is achieved to have 2° phase error and less than ?30 dB return loss over about 5% bandwidth. © 2003 Wiley Periodicals, Inc. Int J RF and Microwave CAE 13: 259–268, 2003. 相似文献
2.
A dual‐mode dual‐band rectangular waveguide filtering antenna with fourth‐order Chebyshev response is presented. First, design equations and processes of filtering networks are presented. Then, filtering antenna is constructed through cross‐shaped slot for radiation instead of the output port of filtering networks. A pair of degenerated modes are exploited in waveguide resonator design to miniaturize the whole size and form two passbands. In addition, the bandwidth can be adjusted flexibly in proper range. A prototype at C‐band is fabricated and measured, showing two operation channels of 5 to 5.05 GHz and 5.1 to 5.15 GHz with high rejection between two bands. Good agreement is achieved between the simulations and measurements, showing excellent performance in terms of filtering, out‐of‐band rejection, and gain in bands. 相似文献
3.
Dual‐band filters simplify the system architecture considerably by replacing doubly multiplexed filters. This is especially important in base stations for wireless communications, where high‐selective filtering functions are required, with very stringent requirements in size and insertion losses. For this goal, compact dual‐band filters realized in air‐filled metallic ridge waveguides are proposed. The dual‐band approach shown in this article allows fulfilling the stringent insertion loss specifications of very selective filtering functions. The ridge waveguide resonators are placed in a canonical folded top‐bottom structure layout. Coupling sections that provide cross‐couplings are realized by irises opened in the intermediate wall. Given the high‐order of the dual‐band filter required for actual wireless applications, an efficient modeling by the mode‐matching method is used. A complete challenging filter prototype with 16 poles and 10 transmission zeros with specifications of typical wireless transceivers is built and tested for verification. © 2016 Wiley Periodicals, Inc. Int J RF and Microwave CAE 26:703–712, 2016. 相似文献
4.
This article presents a synthesis method for lumped dual‐band filters by directly adopting traditional Pi‐shaped and Г‐shaped capacitive networks as dual‐mode admittance inverters (J inverters). By following classic coupled‐resonator filter theory, the equivalent circuits (parallel LCs) of the dual‐mode resonators between the J inverters are derived separately at the two passbands. Each dual‐mode resonator is first approximately constructed with a series combination of the two parallel lumped circuit (LC) resonators, and then the element values are iteratively updated for better accuracy. A design example is given and good agreement is achieved between the simulated and measured results, demonstrating the feasibility of the synthesis method. The passband bandwidths are fully controllable. © 2014 Wiley Periodicals, Inc. Int J RF and Microwave CAE 25:75–80, 2015. 相似文献
5.
Sungtek Kahng 《国际射频与微波计算机辅助工程杂志》2003,13(4):285-292
In this article, a new method is suggested to improve the frequency responses of dual‐mode waveguide filters employing cross‐shaped slots. According to this method, regarding one cross‐shaped slot between two cavities, the horizontal (vertical) mode in one cavity influences the vertical (horizontal) mode in the other cavity to a much lesser extent. It enhances the overall performances. A 4th‐order dual‐mode filter is used as an example and it validates the method. © 2003 Wiley Periodicals, Inc. Int J RF and Microwave CAE 13: 285–292, 2003. 相似文献
6.
In this article, a folded circular waveguide dual‐mode filter without tuning screws is designed for the fifth‐generation (5G) mobile communication system. The folded filter is composed of two stacked circular cavities operated at 3.5 GHz. Each cavity has two resonant modes, which can generate and control two transmission zeroes at specific frequencies. Through a coupling iris, the two single‐cavity filters are connected together, and can control four poles, which helps to expand the 3dB fractional bandwidth to 11.4%. The measured insertion losses are around 0.5 dB in the passband (from 3.4–3.6 GHz). The experiment results show an excellent agreement with the simulation results. Such folded filters have the advantages of very low insertion loss, compact size, high frequency selectivity, and low cost. 相似文献
7.
Qiang Chen Hou Zhang Lu‐chun Yang Hai‐peng Li Tao Zhong Xue‐liang Min Shi‐li Tan 《国际射频与微波计算机辅助工程杂志》2017,27(1)
A novel dual‐band, dual‐circularly polarized antenna is proposed and fabricated. The proposed antenna consists of an asymmetric U‐shaped slot and an inverted L‐shaped slot which are designed to excite two orthogonal E vectors with equal amplitude and 90° phase difference (PD), in addition, fed by a coplanar waveguide (CPW) Furthermore, a left‐hand circular polarization in the direction of z > 0 and a right‐hand circular polarization instead of the opposite direction both at the lower and upper bands are exhibited by the radiations of the antenna. Good agreement is achieved between the measurement and simulation, which indicates that a 10‐dB bandwidth of 38.75% from 2.56 to 3.8 GHz and 21.8% from 10.01 to 12.53 GHz, while a 3‐dB axial‐ratio bandwidth (ARBW) of 13.4% from 2.77 to 3.2 GHz and 9.23% from 10.25 to 11.25 GHz at two operation bands, respectively, are covered in the designed antenna. To explain the mechanism of dual‐band dual‐circular polarization, the analysis of magnetic fields distributions and a parametric study of the design are given. Meanwhile, compared to other recent works, a single layer structure, wider axial ratio and impedance bandwidths and a more compact size are the key features of the proposed antenna. 相似文献
8.
A novel dual‐mode optimized patch capacitor loaded T‐type resonator is proposed for the design of a dual‐band filter (DBF). The resonator has its lowest even‐ and odd‐mode at the two expected passband frequencies and the first spurious mode far away from the passbands. For tuning of the two sets of coupling strengths for both passbands, open/shorted secondary coupling structures are introduced as a fine‐tuning coupling structure to increase/decrease the primary coupling strength. A four‐pole DBF with passbands centered at 2450 and 3500 MHz, respectively, is proposed and fabricated using the HTS material. The measured results of the filter indicate superior performance and good fitting with the simulation results. The return losses of both passbands and the insertion losses obtained by measurements are greater than 14 dB and less than 0.3 dB, respectively. The stopband rejection exceeds 50 dB up to 8.0 GHz. 相似文献
9.
Jin Xu 《国际射频与微波计算机辅助工程杂志》2015,25(7):601-609
In this article, the shorted stub loaded stepped‐impedance resonator (SSLSIR) with the individually tunable first even resonant mode and first odd resonant mode is applied to design dual‐, tri‐, and quad‐band bandpass filters (BPFs). The SSLSIR dual‐band BPF with asymmetrical coupling is realized using the first even resonant modes and the first odd resonant modes of a set of SSLSIRs. Then, the high‐impedance feeding lines of SSLSIR dual‐band BPF is modified to produce a new passband, and thus a new tri‐band BPF is realized. The proposed quad‐band BPF consists of two sets of SSLSIRs with symmetrical coupling. Each of the designed circuits occupies a very compact size and has a good in‐band out‐of‐band performance. Good agreements are observed between the simulated and measured results. © 2015 Wiley Periodicals, Inc. Int J RF and Microwave CAE 25:601–609, 2015. 相似文献
10.
In this article, a novel concept of 3D integrated V‐band diplexer, which permits the realization of compact size using a dual‐mode cavity and four single‐mode cavities, has been realized in low‐temperature cofired ceramic technologies. The dual‐mode cavity resonator acting as one resonator for both Rx and Tx filters is developed to generate two resonant modes (TE102 and TE103) at the center frequency of Rx (56.5–58.5 GHz) and Tx (64–66 GHz) channels, separately. Meanwhile, this dual‐mode cavity becomes the interconnect between Rx/Tx channels and help to realize good isolation without using conventional T‐junction. In the measurement, each filter designed for Rx and Tx channels exhibits excellent performance. Channel‐to‐channel isolations better than 35 dB across the Rx band and better than 32.5 dB across the Tx band are also obtained. © 2014 Wiley Periodicals, Inc. Int J RF and Microwave CAE 25:141–145, 2015. 相似文献
11.
This article presents a dual‐plane structure high selectivity tri‐band bandpass filter (BPF) which consists of a pair of T‐shaped microstrip feed lines with capacitive source‐load coupling as well as spur lines embedded, and three resonators, i.e., a dual‐mode stub‐loaded stepped impedance resonator and two nested dual‐mode defected ground structure resonators. Using the intrinsic characteristics of the resonators and feed lines, nine transmission zeros near the passband edges and in the stopband can be generated to achieve high selectivity. An experimental tri‐band BPF located at 2.4/5.7 GHz [wireless local area networks (WLAN) application] and 3.5 GHz [worldwide interoperability for microwave access (WiMAX) application] has been simulated and fabricated. Good agreement between the simulated and measured results validates the design approach. © 2012 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2013. 相似文献
12.
In this article, a novel E‐plane substrate inserted waveguide bandpass filter with high selectivity and compact size is proposed in Ka‐band. By integrating an extra resonator between two metal septa, the E‐plane waveguide filter is achieved with two transmission zeros at both sides of the passband which contribute to the high‐skirt selectivity. One sample is fabricated, whose total length is just 5 mm, namely, less than 0.5 and the minimum insertion loss is only about 0.3 dB. Good agreements between simulated and measured results are obtained. © 2013 Wiley Periodicals, Inc. Int J RF and Microwave CAE 24:451–456, 2014. 相似文献
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14.
An analysis method based on the coupled‐integral‐equations technique (CIET) and the mode‐matching technique (MMT) is presented for the design of a variety of direct‐coupled waveguide filters suitable for applications in the lower gigahertz frequency range. The method is verified by comparison with data obtained through other numerical techniques and measurements. With reference to standard waveguide filters, the issues of filter miniaturization and stopband extension toward higher frequency bands are investigated. For given frequency specifications in the 2‐GHz frequency range, examples of rectangular coaxial waveguide filters, ridge waveguide filters, ridge waveguide filters including coupling irises and T‐septum waveguide filters are presented. It is demonstrated that the rectangular/square coaxial waveguide filter achieves the highest degree of miniaturization, but that ridge and, especially, T‐septum waveguide filter technology is advantageous with respect to stopband performance toward higher frequencies. In particular, a T‐septum filter centered at 2.155 GHz is shown to block the entire frequency range up to 7.5 GHz. © 2002 Wiley Periodicals, Inc. Int J RF and Microwave CAE 12: 217–225, 2002. 相似文献
15.
A novel super compact filter based on half‐mode substrate‐integrated waveguide (HMSIW) technology loaded by the modified complementary split‐ring resonator (MCSRR) is proposed. The working principle of the proposed filter is based on the evanescent‐mode propagation technique. According to this technique, by loading the complementary split‐ring resonator (CSRR) on the metal surface of the substrate‐integrated waveguide (SIW) structure, an additional passband below the SIW cutoff frequency can be obtained. In order to miniaturize the physical size of the conventional CSRR, a new method is introduced. In the proposed MCSRR unit‐cell, the meander slots are carved inside all of the interior space of the ring. Accordingly, the length of the slot is increased which leads to an increase in the inductor and capacitor of the proposed structure without occupying the extra space. Therefore, the electrical size of the proposed MCSRR unit‐cell is reduced. Consequently, the resonance frequency of the proposed MCSRR unit‐cell is decreased compared to the conventional CSRR with the same sizes. Namely, the lower resonance frequencies can be achieved by using this technique without increasing the size of the unit‐cell. In order to confirm the miniaturization technique, two HMSIW filters loaded by the proposed MCSRR unit‐cell are designed, fabricated, and experimental verifications are provided. The results show that a miniaturization about 67% is achieved. 相似文献
16.
A printed dual‐band filtering antenna with decent frequency selectivity at 2.45 and 5.2 GHz for wireless local area network (WLAN) applications is developed. The filtering antenna is compact, which comprises a tapped feed line, two dual‐band stub‐loaded open‐loop resonators, and a dual‐band bended monopole. It can be easily printed on a single layer PCB substrate with low profile and low cost. The entire structure is very simple compared with the previously reported dual‐band filtering antennas that requiring multi‐layer structures. The monopole functions as not only a radiator, but also the last resonator of a dual‐band filter. The developed antenna exhibits good frequency selectivity and out‐of‐band suppression. In addition, the two operation bands can be adjusted relatively individually. The proposed antenna is optimized and fabricated. The experimental results show it has good frequency selectivity at both 2.45 and 5.2 GHz, wide bandwidth 11.8% and 7.8%, and excellent out‐of‐band suppression. 相似文献
17.
Saffrine Kingsly Malathi Kanagasabai Gulam Nabi Alsath Mohammed Sangeetha Subbaraj Yogeshwari Panneer Selvam Rajesh Natarajan 《国际射频与微波计算机辅助工程杂志》2018,28(6)
This article presents the design and testing of a novel frequency reconfigurable microwave filter. The filter structure is composed of an all stop resonator coupled with C‐ and E‐shaped parasitic resonators. PIN diodes are located at suitable positions to achieve multi‐band reconfiguration from 1.2 to 3.2 GHz making the filter suitable for multiple wireless communication systems. The frequency and bandwidth of the filter are governed by the length of the resonators and coupling between the resonators and the transmission line, respectively. A sharp rejection of ?30 dB is observed between the passbands. The proposed filter offers 56% size reduction with flat group delay performance. The prototype filter is fabricated and the simulation results are validated using experimental measurements. The measurement results show good agreement with the simulation results. 相似文献
18.
The paper presents the internal details of a developed full‐wave algorithm for the computer‐aided design of evanescent‐mode bandpass filters formed by single‐ or double‐short ridged waveguide sections. New filter configurations with an enlarged cross section of filter housing and nonconventional notch‐strip‐notch elements providing improved stopband performance are given special considerations. Additional input–output transformers built on rectangular waveguide sections are used in designing broadband filters. Characteristics of one of the designed filters are verified by measured data. © 2001 John Wiley & Sons, Inc. Int J RF and Microwave CAE 11: 354–365, 2001 相似文献
19.
Daniel L. Faircloth Michael E. Baginski Sadasiva M. Rao Stuart M. Wentworth Manohar D. Deshpande 《国际射频与微波计算机辅助工程杂志》2007,17(3):367-375
In this study, we present an improved genetic algorithm (GA) to design user‐specified filters housed in a waveguide of arbitrary cross‐sectional dimensions. An edge‐based finite element method (FEM) is employed as the forward solver for the problem. Additionally, the structures generated via the GA are easily constructed using standard printed circuit board fabrication techniques. Two of the major improvements to the GA are: (1) a technique for enhancing the GA's ability to avoid local minima and (2) a fine‐tuning mechanism which allows the GA to more efficiently seek out a minimum once a low error has been obtained. Using the aforementioned techniques, numerical/experimental results are presented for notch, low pass, high pass, and bandpass filters. © 2007 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2007. 相似文献
20.
In this article, a quadruple‐mode stub‐loaded resonator (QM‐SLR) is introduced and its four modes are excited using a simple approach, which can provide a dual‐band behavior. By changing the length of the loaded stubs, independently tunable transmission characteristics of the proposed quadruple‐mode stub‐loaded resonator were extensively described for filter design. Moreover, microwave varactors were adopted to represent the length variation of the loaded stubs for the dual‐band tunability. The equivalent circuit modeling of the open stub with microwave varactor was given and discussed. Then, adopting the compact quadruple‐mode stub‐loaded resonator with three varactors, an independently controllable dual‐band bandpass filter (BPF) was designed, analyzed, and fabricated. Its separated bandwidths and transmission zeros can be tuned independently by changing the applying voltage of the microwave varactors. A good agreement between simulated and measured results verified the design methodology. The proposed filter possesses compact size, simple structure, and excellent dual‐band performances. © 2016 Wiley Periodicals, Inc. Int J RF and Microwave CAE 26:602–608, 2016. 相似文献