Fields, Waves and Transmission Lines

Benson, F.A.; Benson, T.M.

doi:10.1007/978-94-011-2382-2

Cited by 44 publications

(58 citation statements)

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“…In Table 4 we have also included the estimated H 2 densities and column densities for VLA 1623 and IRAS 20353, assuming kinetic temperatures of 17 K (Wootten et al 1994) and 10 K (Benson 1991) for these outflows, respectively. For VLA 1623, since HN 13 C is not detected in C1, the component that could be associated with the precursor/shock, we cannot compare the excitation conditions between the two molecules.…”

Section: Vla 1623 and Iras 20353mentioning

confidence: 99%

The search for the magnetic precursor of C-type shocks in young molecular outflows

Roberts¹,

Jiménez-Serra²,

Martı́n-Pintado³

2012

A&A

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The detection of very narrow SiO emission and the higher degree of excitation of the ion fluid compared to the neutral one towards the protostar L1448-mm have been interpreted as signatures of the magnetic precursor of C-shocks. Since this is the only source where these features have been observed together, we carried out a survey to map the J = 2 → 1 and 8 → 7 lines of SiO, and the J = 1 → 0 and 4 → 3 lines of H 13 CO + (as the representative ion) and HN 13 C (as the representative neutral species) towards four class 0/I low-mass protostars known to have young outflows (L1448-IRS3, NGC 1333-IRAS 4A/B and SSV 13, VLA 1623 and IRAS 20353). As previously reported, towards L1448-IRS3 and NGC 1333 strong, narrow SiO 2 → 1 is detected, and we also find a velocity component towards each outflow which shows high a H 13 CO + 4 → 3/1 → 0 integrated intensity ratio compared to that of HN 13 C. Towards VLA 1623, we find very weak, narrow SiO, and a component that is visible in H 13 CO + but not at all in HN 13 C. For IRAS 20353, we find neither narrow SiO nor high H 13 CO + 4 → 3/1 → 0 flux ratios. Previous work explained the higher degree of excitation of H 13 CO + by the selective excitation of ions by electrons, whose abundance is expected to increase at the precursor stage. Here, however, by considering a range of kinetic temperatures for the gas, we find that it is possible to fit the observations with a single temperature and density, without an increased electron abundance, despite the large differences in 4 → 3/1 → 0 ratio between the two molecules. The high H 13 CO + 4 → 3/1 → 0 flux ratios may simply be due to protostellar heating. However, the hypothesis that narrow SiO is formed at the precursor stage of shocks remains plausible, since other explanations require either the presence of shocks with larger dynamical timescales, or predict the narrow SiO to have a larger spatial extent than it appears to have towards the sources L1448-IRS3 and VLA 1623. Larger scale maps of the narrow SiO emission are needed to confirm that it is confined to the regions around protostars (as would be expected in the precursor scenario), and mapping of different ion and neutral species is necessary to confirm whether there are indeed precursor regions surrounding young outflows where the ion and neutral species behave as separate fluids.

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Section: Vla 1623 and Iras 20353mentioning

confidence: 99%

The search for the magnetic precursor of C-type shocks in young molecular outflows

Roberts¹,

Jiménez-Serra²,

Martı́n-Pintado³

2012

A&A

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“…Transmission lines of lengths 1 l and 2 l are, in this case, made of air but in general can represent any material parameters. The admittance matrix of each layer in the three-layer stack can be expressed as [18], [25]  are the electrical lengths of the two layers of air,…”

Section: Curved Cfc Model In the Tlmmentioning

confidence: 99%

Modeling Curved Carbon Fiber Composite (CFC) Structures in the Transmission-Line Modeling (TLM) Method

Meng

Sewell

Phang

et al. 2015

IEEE Trans. Electromagn. Compat.

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“…Geometry of Coplanar Waveguide feed line [15] CPW Feeding became popular because of their manufacturing advantages, simple configuration, repeatability, low cost and some characteristics such as low radiation loss, low dispersion and ability of integration with active solid-state devices besides wider bandwidth, and better impedance matching. They also allow easy mounting and integration with other microwave integrated circuits and RF frequency devices [16]. This proposed antenna is analyzed by using CST (Computer Simulation Technology) EM Solver Simulation Software.…”

Section: Introductionmentioning

confidence: 99%

CPW-fed Wideband Antenna with U-shaped Ground Plane

Maheshwari¹,

Jain²,

Agarwal³

2014

IJWMT

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This paper proposes the design of CPW-fed wideband antenna with U-shaped ground plane. The proposed antenna is a simple printed antenna, which is fed by a 50Ω CPW line. The Antenna has a compact size of 13mm×25mm. To obtain wide bandwidth, a slot is cut in ground plane and radiating patch is modified. The proposed antenna yields the operating frequency range from 7.3GHz to 15.1GHz, which offers the bandwidth of 7.79GHz. Simulation has been performed by using CST Microwave Studio Software. This frequency range satisfies the system requirements for Narrowband PCS Services, Satellite, Cellular Phone, Domestic Public Land Mobile Communication and International Public Broadcasting applications.

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Fields, Waves and Transmission Lines

Cited by 44 publications

References 0 publications

The search for the magnetic precursor of C-type shocks in young molecular outflows

The search for the magnetic precursor of C-type shocks in young molecular outflows

Modeling Curved Carbon Fiber Composite (CFC) Structures in the Transmission-Line Modeling (TLM) Method

CPW-fed Wideband Antenna with U-shaped Ground Plane

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