Very-compact Waveguide Bandpass Filter based on Dual-Mode TM Cavities for Satellite Applications in Ku-band

Pelliccia, Luca; Tomassoni, Cristiano; Cacciamani, Fabrizio; Vallerotonda, Paolo; Sorrentino, R.; Galdeano, Jaione; Ernst, Christoph

doi:10.23919/eumc.2018.8541740

Cited by 14 publications

(9 citation statements)

References 10 publications

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“…One of the most resourceful methods of accomplishing this has been through the adoption of nonresonating nodes (NRN) and nonresonating modes (NRM) in order to connect resonators more flexibly or allocate new bypass couplings throughout the structure; several advanced examples can be reviewed in [5], [6], [7], [8], [9], [10], [11], [12], where new classes of highlycompact filter components that utilize transverse magnetic (TM) mode cavities are demonstrated. The use of TM-mode filters with nonresonating modes has driven much innovation and research into modular building-block designs and have allowed for many new filter structures to be demonstrated, for example [13], [14], [15], [16], [17], [18], [19].…”

Section: Introductionmentioning

confidence: 99%

Improved TM Dual-Mode Filters With Reduced Fabrication Complexity

2023

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This work presents an alternate and improved approach for the design of dual-mode filters that utilize transverse magnetic (TM) and nonresonating modes. The method that is proposed in this work allows for an improvement of the typical TM dual-mode filter design through the reformation of the coupling irises that connect the TM dual-mode cavity to the source/load waveguide ports, where the new interconnection means takes the form of resonate slot-irises. In this manner, a fourth-order quasi-elliptic response can be achieved within a very limited physical geometry and able to cover more than double the usable fractional bandwidth than previously reported. Furthermore, the selectivity and insertion loss of the filter response is significantly improved when compared to the typical single-cavity TM dual-mode filter response that uses coupling irises, while on the comparison of equal-order structures, a reduction in fabrication complexity and improved insertion loss is achieved. A characterization of the dimensional variations and effects of altering one of the source/load port positions in the proposed filter design is investigated in order to demonstrate notable effects on the rejection characteristics and positions of transmission zeros. A presentation on the design theory is given and formulations of various filter responses are examined. The fabrication of an experimental prototype with approximately 7.3% fractional bandwidth (FBW), centered at 90 GHz is conducted using high-precision computer numerical control (CNC) milling in order to demonstrate that the unique simplicity and overall compaction of this method can be easily applied at millimetre-wave frequencies without the need of tuning means. The results which are presented demonstrate highly accurate measurements throughout the W-band range, while an additional Q-factor analysis is provided in order to compare the improved filter scheme with other known design methodologies.

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Section: Introductionmentioning

confidence: 99%

Improved TM Dual-Mode Filters With Reduced Fabrication Complexity

2023

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“…Of course, the filter performance can be improved by using postprocessing techniques such as brazing, silverplating, etc. Some of such techniques have already been successfully applied to this kind of filters [38], [39]. However, this is beyond the scope of the paper that consists in demonstrating that the theory of the spurious self-suppression works, and it is applicable to real filters.…”

Section: Measurement Of the Proposed Sixth-order Tm Cavity Filtermentioning

confidence: 99%

Spurious Self-Suppression Method: Application to TM Cavity Filters

Rehman

Tomassoni

2023

IEEE Trans. Microwave Theory Techn.

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This article presents a new approach for improving spurious free bands in filters. The main idea is to control the coupling coefficients of the spurious resonances, in order to force them to cancel each other. This approach is completely different from the classical one where all couplings are minimized in order to excite spurious resonances as less as possible. In fact, in this approach, all spurious couplings are maximized except the central coupling that is instead minimized. This method is first explained in terms of equivalent circuits. Then, in order to show its applicability to real microwave filters, it is applied to the TM cavity filters and used to remove both spurious resonances due to higher order cavity modes and to TE 10 mode of coupling irises. Design examples of fourth-and sixth-order TM cavity filters are presented. With respect to the classical TM cavity filter, where the first spurious appears around 11.4 GHz, the TM filters designed by exploiting the self-suppression method present spurious free bands up to 20.2 GHz (20 GHz for sixth-order filter), improving the filter response up to 2.2 times the center frequency of 9.2 GHz. Another advantage is that, in contrast to the classical spurious suppression method that does not allow responses with TZs in TM filters, the self-suppression method allows for a number of TZs equal to N-2 (N being the filter order) and it also allows a certain control of their position.

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“…Waveguide filters have high power, low insertion loss, and high Q-value characteristics, which are especially suitable for narrow-band applications. The cascaded structure of standard waveguide resonators [1][2][3][4] or coupling between modes in a multimode cavity [5][6][7][8][9] are commonly used to achieve narrowband characteristics in waveguide filters. Nevertheless, the high power requirement is hardly considered in the above structures.…”

Section: Introductionmentioning

confidence: 99%

A narrow‐band overmoded rectangular waveguide filter for high‐power microwaves (HPMs)

Zheng

et al. 2023

Micro & Optical Tech Letters

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An overmoded rectangular waveguide filter with the advantages of narrowband and high power is presented in this paper. The transmission efficiency of each mode in the filter is analyzed based on mode-matching techniques and optimized by combining it with the calculation method. Due to the overmoded waveguide and direct coupling topology, the designed structure has characteristics of narrowband and high power. The overall size of the proposed filter is only 17.45 × 36.20 × 126.67 mm 3 (0.54λ 0 × 1.12λ 0 × 3.93λ 0 , λ 0 is the wavelength of the center frequency in free space). The test results match well with the simulated ones and they both show that the transmission efficiency of TE 10 mode is higher than 99.77%. Meanwhile, the proposed filter achieves 1% fractional bandwidth and 134.5 kW power capacity, which reveals that the filter has both narrow-band and high-power characteristics. The designed filter would be an attractive candidate for HPM systems.

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Very-compact Waveguide Bandpass Filter based on Dual-Mode TM Cavities for Satellite Applications in Ku-band

Cited by 14 publications

References 10 publications

Improved TM Dual-Mode Filters With Reduced Fabrication Complexity

Improved TM Dual-Mode Filters With Reduced Fabrication Complexity

Spurious Self-Suppression Method: Application to TM Cavity Filters

A narrow‐band overmoded rectangular waveguide filter for high‐power microwaves (HPMs)

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