Perspectives of Hf Half Loop Antennas for Stealth Combat Ships

In this study, the authors propose a new idea to employ mantle cloaking in order to reduce the mutual coupling between electrically small antennas (ESAs) placed on man‐pack radio systems. They determined and numerically optimised the parameters of the mantle cloak on loop and monopole antennas; these antennas are to provide near vertical incidence skywave (NVIS) and ground wave high frequency (HF) communication in man‐pack radio systems. The authors’ designed cloak can effectively minimise the mutual coupling between the ESAs – in the man‐pack radios – for only a very small impact on the antenna's radiation characteristics. The authors believe that these improvements pave the way toward effectively applying these compact radio structures in emergency HF communication in areas with limited access to conventional communication links.

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“…In this type of antennas, there is a compromise between bandwidth and efficiency of the antenna. This relation specified by (1) [20]…”

Section: Loop Antennamentioning

confidence: 99%

“…By knowing that in practice the ESA efficiency is low, a reduction in the directivity leads to the further reduction in the gain and the communication range. The link budget can be expressed by [20]…”

Section: Loop Antennamentioning

confidence: 99%

Application of the mantle cloak in near vertical incidence skywave/ground wave high frequency communication

Mizuji

Arand

Forooraghi

et al. 2019

IET Microwaves, Antennas & Propagation

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“…To improve access to it, the authors published an overview article on NVIS that refers to 128 NVIS publications, organized per subject [15]. To support work from other groups that optimize High Frequency (HF) antennas for mobile platforms [16,17,18] and fixed installations [19,20]. The authors provided elevation angle measurements and raytracing simulations [21] to extend graphs published by McNamara [22] and Davies [6].…”

Section: Introductionmentioning

confidence: 99%

Design and Validation of Probes and Sensors for the Characterization of Magneto-Ionic Radio Wave Propagation on Near Vertical Incidence Skywave Paths

Witvliet

Alsina-Pagès

Maanen

et al. 2019

Sensors

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This article describes the design and validation of deployable low-power probes and sensors to investigate the influence of the ionosphere and the Earth’s magnetic field on radio wave propagation below the plasma frequency of the ionosphere, known as Near Vertical Incidence Skywave (NVIS) propagation. The propagation of waves that are bent downward by the ionosphere is dominated by a bi-refractive mechanism called ‘magneto-ionic propagation’. The polarization of both downward waves depends on the spatial angle between the Earth’s magnetic field and the direction of propagation of the radio wave. The probes and sensors described in this article are needed to simultaneously investigate signal fading and polarization dynamics on six radio wave propagation paths. The 1-Watt probes realize a 57 dB signal-to-noise ratio. The probe polarization is controlled using direct digital synthesis and the cross-polarization is 25–35 dB. The intermodulation-free dynamic range of the sensor exceeds 100 dB. Measurement speed is 3000 samples/second. This publication covers design, practical realization and deployment issues. Research performed with these devices will be shared in subsequent publications.

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“…By introducing the lumped capacitance and inductance, the antenna in [6] works at 434 MHz ISM (Industrial Scientific Medical) band with the size of 18 mm × 18 mm × 12 mm in the sensor package. By tuning a series of switchable capacitors that are parallel with the antenna [7,8], the ESHLA resonance is shifted from 2 to 12 MHz, with each frequency band of 3.5 kHz. However, the bandwidths of all these antennas are narrow.…”

Section: Introductionmentioning

confidence: 99%

“…The detailed electromagnetic analysis about half-loop antenna [3,4] or the multi-turn half-loop antenna [5] dates back to the 1990s. One typical way to resonate the ESHLA is capacitive loading [6][7][8]. By introducing the lumped capacitance and inductance, the antenna in [6] works at 434 MHz ISM (Industrial Scientific Medical) band with the size of 18 mm × 18 mm × 12 mm in the sensor package.…”

Section: Introductionmentioning

confidence: 99%

Investigation of an Electrically Small Half-Loop Antenna Embedded With a Non-Foster Network Using the Characteristic Mode Theory

Sun¹,

Sun²,

Zhang³

2017

PIER M

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Abstract-An electrically small half-loop antenna (ESHLA) embedded with Foster elements is analyzed using the characteristic mode (CM) theory. The resonant frequency and radiation characteristics of the ESHLA are mainly determined by the resonant mode (Mode 1). The characteristic currents of resonant mode (Mode 1) and non-resonant mode (higher order mode) prove the parallel resonance of the ESHLA. However, owing to the modal significance (MS) of the resonant mode varying fast with frequency, the proposed ESHLA has a narrow bandwidth. Analysis shows the MS of the resonant mode and the higher order mode are changed by tuning the Foster element, leading to a negative admittance variation slope in accordance with the non-Foster behavior. By replacing the Foster capacitor with the nonFoster network, both the characteristic currents and the MS are changed over a wide bandwidth. As a consequence, the introduced non-Foster network turns Mode 1 from the narrowband resonant mode into a continuous resonant mode with its radiation pattern kept invariant over a wide bandwidth. The proposed ESHLA with its non-Foster network is fabricated and measured. The measured 6-dB return loss bandwidth is about 12.7% (11.45-13 MHz), with its reflection coefficient curve being an envelope of those of Foster elements embedded ESHLA.

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Perspectives of Hf Half Loop Antennas for Stealth Combat Ships

Cited by 17 publications

References 7 publications

Application of the mantle cloak in near vertical incidence skywave/ground wave high frequency communication

Application of the mantle cloak in near vertical incidence skywave/ground wave high frequency communication

Design and Validation of Probes and Sensors for the Characterization of Magneto-Ionic Radio Wave Propagation on Near Vertical Incidence Skywave Paths

Investigation of an Electrically Small Half-Loop Antenna Embedded With a Non-Foster Network Using the Characteristic Mode Theory

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