Cavity-backed Archimedean spiral antenna with strip absorber

Nakano, Hisamatsu; Sasaki, Sokichi; Ōyanagi, H.; Yamauchi, Junji

doi:10.1049/iet-map:20080022

Cited by 67 publications

(33 citation statements)

References 4 publications

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“…The lower bound of bandwidth predicted by the band theory can therefore be approximated using r out . For the upper bound of operating frequency, there is historically no prediction of it, but it can be approximated using r in if there is no tapered feed region in the spiral center [28]. In the region between the upper and lower frequency bounds, a band of nearly constant impedance can be seen.…”

Section: Archimedean Spiral Antennamentioning

confidence: 99%

Travelling Wave Mechanism and Novel Analysis of the Planar Archimedean Spiral Antenna in Free Space

Chen¹,

Huff²

2014

PIER

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Abstract-While Archimedean spiral antennas were invented a half-century ago, only selfcomplementary impedance can be evaluated directly from the Babinet's principle. This paper examines the effects of metal width and arm spacing on printed spiral's input impedance. A model is proposed based on examination by decomposition of planar spiral. A closed-form expression for the input impedance of Archimedean spiral antenna is obtained by evaluating the proposed model with conformal mapping techniques. Full-wave numerical simulations, Babinet's principle, and a fabricated antenna demonstrate the accuracy of the proposed model. The expression in this work can be used to find the impedance of a variety of spiral complementary structures analytically. The examination and discussion on the effects of other parameters and features in addition to the spiral itself are also provided through numerical simulation.

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Section: Archimedean Spiral Antennamentioning

confidence: 99%

Travelling Wave Mechanism and Novel Analysis of the Planar Archimedean Spiral Antenna in Free Space

Chen¹,

Huff²

2014

PIER

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“…A planar spiral antenna, characterized by an Archimedean function and isolated in free space, has wideband characteristics with respect to the input impedance, radiation pattern, and gain, when the strip arm width and the spacing between neighboring arms, , are chosen to be the same: [13]. Using the spiral constant…”

Section: Feed Line Spacingmentioning

confidence: 99%

“…The absorber used in this paper is non-conducting TDK EM absorber (model ISFA), where the relative permittivity and dielectric loss are frequency-dependent; varies from to 1.78 and varies from 0.75 to 0.41 within the design frequency range of (3 GHz) to (9 GHz). Note that the radiation characteristics of the BALSs with and without this TDK absorber have already been discussed in [13].…”

Section: Introductionmentioning

confidence: 99%

Unbalanced-Mode Spiral Antenna Backed by an Extremely Shallow Cavity

Nakano

Igarashi

Ōyanagi

et al. 2009

IEEE Trans. Antennas Propagat.

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Abstract-This paper describes a two-arm Archimedean spiral antenna backed by a conducting cavity, where only one arm is directly excited, with the other arm being parasitically excited; in other words, the spiral arms are excited in an unbalanced mode. A balun circuit required for a conventional two-arm spiral is not used for this unbalanced-mode spiral. The design of the unbalanced-mode spiral is performed over a frequency range of Ld = 3 GHz to Hd = 9 GHz (1:3 bandwidth), where the antenna height is selected to be extremely small (7 mm = 0 07 wavelength at Ld ) to realize a low-profile antenna. For reference, a corresponding spiral antenna excited in balanced mode is also analyzed. It is found that the unbalanced-mode spiral shows an acceptably small VSWR over the design frequency range of Ld to Hd . The radiation is circularly polarized around the antenna axis normal to the spiral plane. The gain shows behavior similar to that of the balanced-mode spiral. Results for other antenna heights (5 mm, 10.5 mm, and 14 mm) are also presented and briefly discussed. It can be said that the unbalanced-mode spiral is a circularly polarized wideband antenna with a simple feed system.

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“…There are many methods to transform the bi-directional radiation of an ASA to be uni-directional radiation, such as backing the antenna by a cavity [2][3][4], using high impedance surface (HIS) and electromagnetic band-gap (EBG) as reflector [5][6][7] or loading a PEC reflector behind the antenna [8,9].…”

Section: Introductionmentioning

confidence: 99%

Archimedean Spiral Antenna With Two Opposite Uni-Directional Circularly Polarized Radiation Bands Designed by Resonance Based Reflectors

Xie¹,

Peng²,

Wen³

et al. 2017

PIER Letters

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Abstract-Two opposite uni-directional radiation bands with good circular polarization (CP) characteristics are achieved in an Archimedean Spiral Antenna (ASA). A sandwich configuration is formed by utilizing two resonance based reflectors (RBRs) at the bottom and top sides of the ASA. Owing to the resonance characteristic, the RBRs do not act as reflectors at the other operational band, then, opposite uni-directional radiations are obtained, and the two uni-directional bands can be tuned independently. The proposed ASA with two uni-directional bands (ASA-TUB) has a wide impedance bandwidth about 4.4 : 1 (1.8-8 GHz), while its front-fire band (FFB) ranges from 1.8 GHz to 2.2 GHz (20.0%), and its back-fire band (BFB) is 4.4-7.1 GHz (46.9%) for front-to-back ratio (FBR) larger than 5 dB. The maximal FBRs for the FFB and BFB are 11.3 dB and 20 dB, respectively. Moreover, good CP performances are also obtained for the FFB and BFB. Besides, the whole profile of the proposed antenna is only 0.16λ at the lowest operational frequency. The proposed antenna has the properties of dual opposite uni-directional radiation bands, low profile, good FBR and CP.

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Cavity-backed Archimedean spiral antenna with strip absorber

Cited by 67 publications

References 4 publications

Travelling Wave Mechanism and Novel Analysis of the Planar Archimedean Spiral Antenna in Free Space

Travelling Wave Mechanism and Novel Analysis of the Planar Archimedean Spiral Antenna in Free Space

Unbalanced-Mode Spiral Antenna Backed by an Extremely Shallow Cavity

Archimedean Spiral Antenna With Two Opposite Uni-Directional Circularly Polarized Radiation Bands Designed by Resonance Based Reflectors

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