Very Compact Spiral Resonator Implementation of Narrow-band Superconducting Quasi-Elliptic Filters

Huang, F.; Xiong, Xuming

doi:10.1109/euma.2003.340842

Cited by 8 publications

(12 citation statements)

References 12 publications

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“…Otherwise, wide-band single-layer filters would be possible. For mm, magnetic coupling dominates, which is consistent with previous research [15], where the spirals are on the same metal layer so no overlap is permitted.…”

Section: Coupling Between Double Spiralssupporting

confidence: 87%

“…2. The filter was designed using standard data from [19] together with graphs of , examples of which are given above, together with an iteration procedure [15]. The input and output coupling technique is described in [4].…”

Section: Fourth-order Filtermentioning

confidence: 99%

“…Practical aspects have been explored by other researchers [14] using a lower order spiral LTCC filter. Manuscript The design procedure is based on an iterative cycle [15] where an initial design is simulated, the resonant frequencies and the actual coupling coefficients obtained are found by curve fitting and compared with their desired values, and then the microstrip lengths and spacings are corrected. The iterations converge rather slowly because of certain approximations.…”

Section: Introductionmentioning

confidence: 99%

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Quasi-dual-mode microstrip spiral filters using first and second harmonic resonances

Huang¹

2006

IEEE Trans. Microwave Theory Techn.

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The range of bandwidths that can be implemented using spiral microstrip resonators has been extended using a structure with two patterned metal layers plus a ground plane, which also enhances compactness. Each microstrip section can be regarded as a dual-mode half-wave resonator employing the fundamental and second harmonic or as two coupled quarter-wave resonators. A fourth-order and an eighth-order filter are presented, both with 50% fractional bandwidth and 600-MHz center frequency, using basic printed-circuit-board fabrication. The eighth-order filter has an active area of approximately 45 mm 18 mm, and a linewidth of 0.5 mm. The topology, suitably scaled for higher frequency, may be suited for low-temperature co-fired ceramic filters.

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Section: Coupling Between Double Spiralssupporting

confidence: 87%

Section: Fourth-order Filtermentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Quasi-dual-mode microstrip spiral filters using first and second harmonic resonances

Huang¹

2006

IEEE Trans. Microwave Theory Techn.

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“…Superconducting and copper spirals have previously been used in bandpass filters with no notches [14]- [17] and with only one type of spiral in each filter. This study also employs a paired quarter-wave spiral (or dual-mode quarter-wavelength/half-wavelength spiral pair) presented in [17].…”

Section: Introductionmentioning

confidence: 99%

Dual-Band Superconducting Spiral Filters Including Narrow Bandstop Notches

Huang

2009

IEEE Trans. Microwave Theory Techn.

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Dual-band filters designed as bandpass filters containing bandstop notches are described. The design formulation is simplified by considering the resonators in pairs. Two microstrip superconducting spiral filters are presented with 400-MHz center frequency, 15%-16% overall bandwidth, and notches of 1% and 0.1%, respectively. Internal dimensions of the enclosures are only 32 mm 30 mm 6 mm. Suitable spiral shapes and orientations enable the required wide range of coupling coefficients to be implemented, and also reduce unwanted coupling without using partitions. The remaining low level of unwanted coupling is cancelled using capacitive bridges. A qualitative understanding of spurious interactions between spirals is obtained via electromagnetic simulations.

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“…The miniaturisation can be achieved by folding, meandering and/or capacitive-loading the microstrip straight resonators [1]. HTS spiral resonators usually exhibit a much smaller size and have a higher unloaded quality factor than the conventional hairpin resonators [2]. Cross-couplings between nonadjacent resonators can be applied in the same manner to achieve a multiband bandpass filter [3].…”

mentioning

confidence: 99%

Dual-band HTS filter using modified dual-spiral resonators

Abu‐Hudrouss¹,

Jayyousi²,

Lancaster³

2010

Electron. Lett.

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A symmetric dual-band filter with a centre frequency of 887 MHz is presented. The filter uses a modified structure of dual spiral resonators with interdigital capacitive load. At the same resonant frequency, the resonator can occupy an area of less than 2.75% of the area of the square loop resonator. Moreover, the resonator has a very low sensitivity to substrate thickness. The resonator structure also allows two types of couplings and, hence, allows application of cross-couplings with different signs to the direct couplings.Introduction: Planar resonators are the building blocks of planar bandpass and bandstop filters. The low surface resistance of high-temperature superconductors (HTS) allows the investigation of new miniaturised structures consisting of planar resonators. The miniaturisation can be achieved by folding, meandering and/or capacitive-loading the microstrip straight resonators [1]. HTS spiral resonators usually exhibit a much smaller size and have a higher unloaded quality factor than the conventional hairpin resonators [2]. Cross-couplings between nonadjacent resonators can be applied in the same manner to achieve a multiband bandpass filter [3]. To this end, transmission zeros are located within the passband of a bandpass filter, thus dividing it into smaller passbands [4].In [5], Zhou et al. introduced a highly miniaturised dual-spiral resonator with capacitive load. A method of achieving negative cross-couplings was introduced later by the same authors by connecting the coupled pair of resonators with a crossing microstrip line [6]. In this circuit the resonators need to be well spaced from each other to make electric coupling dominant. This restricts the application of this type of cross-coupling to certain topologies. This Letter introduces a modification of the resonator structure, which allows an alternative to the negative coupling.

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Very Compact Spiral Resonator Implementation of Narrow-band Superconducting Quasi-Elliptic Filters

Abstract: ABSTRACT:

Cited by 8 publications

References 12 publications

Quasi-dual-mode microstrip spiral filters using first and second harmonic resonances

Quasi-dual-mode microstrip spiral filters using first and second harmonic resonances

Dual-Band Superconducting Spiral Filters Including Narrow Bandstop Notches

Dual-band HTS filter using modified dual-spiral resonators

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