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Author

Daniel J. Hoppe

Other affiliations: Jet Propulsion Laboratory
Bio: Daniel J. Hoppe is an academic researcher from California Institute of Technology. The author has contributed to research in topics: Antenna (radio) & NASA Deep Space Network. The author has an hindex of 16, co-authored 77 publications receiving 1046 citations. Previous affiliations of Daniel J. Hoppe include Jet Propulsion Laboratory.


Papers
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Journal ArticleDOI
TL;DR: In this article, a TE/TM modal solution for a longitudinally corrugated rectangular waveguide is developed, which can be used to achieve the hard boundary condition resulting in the quasi-TEM wave in a hard waveguide for discrete values of corrugation depth.
Abstract: A TE/TM modal solution for a longitudinally corrugated rectangular waveguide is developed. These longitudinal corrugations can be used to excite a quasi-TEM wave and form a hard waveguide by correctly choosing the impedance at the guide wall. The correctly chosen impedance is referred to as the hard boundary condition. The modal solution developed here solves the problem of longitudinal corrugations filled with a dielectric material by first finding and solving the characteristic equation for a complete TE/TM modal set. It is shown that this TE/TM mode solution can be used to achieve the hard boundary condition resulting in the quasi-TEM wave in a hard waveguide for discrete values of corrugation depth. Beyond each of these depths, a mode becomes a surface wave. The theoretical mode set is amenable to the solution of problems using the mode-matching method. A combination of the mode-matching method and the TE/TM modal solution will allow the solution of larger problems.

11 citations

Patent
07 Jul 2016
TL;DR: In this paper, a reflectarray antenna comprises panels connected by rotating hinges, which are stowed folded around a satellite body and deploy by actuating the spring loaded hinges to extend and form a reflect array for operation in the K/Ka or X-band.
Abstract: A reflectarray antenna comprises panels connected by rotating hinges. The panels are stowed folded around a satellite body and deploy by actuating the spring loaded hinges to extend and form a reflectarray for operation in the K/Ka or X-band. The feed deploys from the satellite body to allow formation of a high gain reflectarray antenna that occupies limited space in small satellite operations.

10 citations

Journal ArticleDOI
TL;DR: In this paper, the scattered fields from axisymmetric problems containing anisotropic media are found by a hybrid finite element method, in particular a symmetric formulation for bodies of revolution that incorporates a finite element formulation for axially magnetized ferrite materials.
Abstract: The scattered fields from axisymmetric problems containing anisotropic media are found by a hybrid finite element method. In particular a symmetric formulation for bodies of revolution that incorporates a finite element formulation for axially magnetized ferrite materials is presented. The method is applied to a ferrite cylinder with quartz matching layers. A Gaussian beam input is used to predict the Faraday rotation through the ferrite cylinder and display it visually. >

10 citations

Proceedings ArticleDOI
06 Mar 2010
TL;DR: In this paper, the authors evaluated the performance of two design concepts operating under realistic daytime conditions, with particular emphasis on spatial and temporal acquisition algorithms and receiver optimization to achieve the best possible communication performance at high data rates.
Abstract: There is considerable interest in determining whether suitably modified versions of existing 34-meter antennas at NASA's Goldstone Communications Complex, originally designed for X-band (nominally 8 GHz) and Ka-band (32 GHz) operation, could also be used to receive near-infrared optical signals1. The robust backup structure of these antennas, together with extremely large collecting apertures and milli-degree pointing capabilities suggest that dual RF/Optical communications may indeed be possible, at optical data-rates approaching 1 gigabit per second (GBPS) from typical Mars distances2. Several design concepts have emerged as possible candidates, requiring modifications ranging from polishing and coating of the existing aluminum panels of the main reflector, to significant redesign involving replacement of the panels with optical reflectors. Optical receiver parameters such as collecting area, field-of-view (FOV), and immunity to reflected sunlight differ markedly for each design concept, hence will likely lead to different levels of performance in terms of data-throughput at a given BER, and in terms of the ability to point close to the sun. The communications performance of two candidate design concepts operating under realistic daytime conditions is evaluated, with particular emphasis on spatial and temporal acquisition algorithms and receiver optimization to achieve the best possible communication performance at high data rates.

10 citations

01 May 2004
TL;DR: The design and development of the low cost 6-meter breadboard antenna is described to be used as part of the interferometer to prove the performance and cost of a very large DSN array.
Abstract: Development of very large arrays of small antennas has been proposed as a way to increase the downlink capability of the NASA deep space network (DSN) by two or three orders of magnitude thereby enabling greatly increased science data from currently configured missions or enabling new mission concepts. The current concept is for an array of 400/spl times/12-m antennas at each of the three longitudes. The DSN array utilizes radio astronomy sources for phase calibration and has wide bandwidth correlation processing for this purpose. A program is currently underway to develop the technology and prove the performance and cost of a very large DSN array. The program includes a 3-element interferometer to be completed by late 2004. This paper describes the design and development of the low cost 6-meter breadboard antenna to be used as part of the interferometer.

8 citations


Cited by
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Patent
16 Jul 2002
TL;DR: In this paper, the fabrication and growth of sub-microelectronic circuitry is described, and the arrangement of such articles to fabricate electronic, optoelectronic, or spintronic devices and components.
Abstract: The present invention relates generally to sub-microelectronic circuitry, and more particularly to nanometer-scale articles, including nanoscale wires which can be selectively doped at various locations and at various levels. In some cases, the articles may be single crystals. The nanoscale wires can be doped, for example, differentially along their length, or radially, and either in terms of identity of dopant, concentration of dopant, or both. This may be used to provide both n-type and p-type conductivity in a single item, or in different items in close proximity to each other, such as in a crossbar array. The fabrication and growth of such articles is described, and the arrangement of such articles to fabricate electronic, optoelectronic, or spintronic devices and components. For example, semiconductor materials can be doped to form n-type and p-type semiconductor regions for making a variety of devices such as field effect transistors, bipolar transistors, complementary inverters, tunnel diodes, light emitting diodes, sensors, and the like.

598 citations

Journal ArticleDOI
TL;DR: In this paper, a review of the literature related to the vibratory behavior of carbon nanotubes and their composites is presented, along with key conclusions and recommendations from these studies.

502 citations

Patent
04 Oct 2006
TL;DR: A bulk-doped semiconductor is a semiconductor that is at least one of the following: a single crystal, an elongated and bulk-depletioned semiconductor with a largest cross-sectional dimension less than 500 nanometers as discussed by the authors.
Abstract: A bulk-doped semiconductor that is at least one of the following: a single crystal, an elongated and bulk-doped semiconductor that, at any point along its longitudinal axis, has a largest cross-sectional dimension less than 500 nanometers, and a free-standing and bulk-doped semiconductor with at least one portion having a smallest width of less than 500 nanometers. Such a semiconductor may comprise an interior core comprising a first semiconductor; and an exterior shell comprising a different material than the first semiconductor. Such a semiconductor may be elongated and may have, at any point along a longitudinal section of such a semiconductor, a ratio of the length of the section to a longest width is greater than 4:1, or greater than 10:1, or greater than 100:1, or even greater than 1000:1. At least one portion of such a semiconductor may a smallest width of less than 200 nanometers, or less than 150 nanometers, or less than 100 nanometers, or less than 80 nanometers, or less than 70 nanometers, or less than 60 nanometers, or less than 40 nanometers, or less than 20 nanometers, or less than 10 nanometers, or even less than 5 nanometers. Such a semiconductor may be a single crystal and may be free-standing. Such a semiconductor may be either lightly n-doped, heavily n-doped, lightly p-doped or heavily p-doped. Such a semiconductor may be doped during growth. Such a semiconductor may be part of a device, which may include any of a variety of devices and combinations thereof, and a variety of assembling techniques may be used to fabricate devices from such a semiconductor. Two or more of such a semiconductors, including an array of such semiconductors, may be combined to form devices, for example, to form a crossed p-n junction of a device. Such devices at certain sizes may exhibit quantum confinement and other quantum phenomena, and the wavelength of light emitted from one or more of such semiconductors may be controlled by selecting a width of such semiconductors. Such semiconductors and device made therefrom may be used for a variety of applications.

460 citations

Journal ArticleDOI
TL;DR: In this paper, the authors proposed a wideband ultra wideband (UWB) communication protocol with a low EIRP level (−41.3dBm/MHz) for unlicensed operation between 3.1 and 10.6 GHz.
Abstract: Before the emergence of ultra-wideband (UWB) radios, widely used wireless communications were based on sinusoidal carriers, and impulse technologies were employed only in specific applications (e.g. radar). In 2002, the Federal Communication Commission (FCC) allowed unlicensed operation between 3.1–10.6 GHz for UWB communication, using a wideband signal format with a low EIRP level (−41.3dBm/MHz). UWB communication systems then emerged as an alternative to narrowband systems and significant effort in this area has been invested at the regulatory, commercial, and research levels.

452 citations

Book
01 Oct 2002
TL;DR: In this article, a method of moments (MoM) was proposed for electromagnetic modeling of composite metallic and dielectric structures using entire-domain basis functions defined over bilinear surfaces, resulting in a remarkably small number of unknowns.
Abstract: Starting from the equivalence theorem any composite metallic and dielectric structure can be analyzed by using SIE (surface integral equations). Such integral equations are usually solved by MoM (method of moments). Most of the existing MoM methods for solving SIE are developed for BORs (bodies of revolution). There are only few such methods that can handle structures of arbitrary shape. These methods use sub-domain basis functions defined over triangles, requiring a very large number of unknowns even for the simplest problems. This paper presents a new MoM method for electromagnetic modeling of composite metallic and dielectric structures. The method uses entire-domain basis functions defined over bilinear surfaces, resulting in a remarkably small number of unknowns.

439 citations