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Your search keyword '"Beyer, J. B."' showing total 16 results
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16 results on '"Beyer, J. B."'

1. S parameter measurements on single superconducting thin-film three-terminal devices made of high-Tc and low-Tc materials.

Author

Martens, J. S., Hohenwarter, G. K. G., Beyer, J. B., Nordman, J. E., and Ginley, D. S.

Subjects
SUPERCONDUCTORS, YTTRIUM, BARIUM, COPPER oxide, NIOBIUM
Abstract

Presents a study which investigated three-terminal single-layer thin-film superconducting devices made of yttrium barium copper oxide and niobium. Information on the structure and direct current behavior of the device; Details of the test setup and radio frequency data; Conclusions.

Published
1989
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2. Distributed amplifier using Josephson vortex flow transistors.

Author

McGinnis, D. P., Beyer, J. B., and Nordman, J. E.

Subjects
*JOSEPHSON junctions, *TRANSISTORS, *ELECTRIC impedance
Abstract

Proposes a wide-band traveling wave amplifier using vortex flow transistors (VFT), a Josephson junction used as a current controlled voltage source. Description of a VFT; Means to be used in order to overcome the problem of low impedance and low power levels; Maximum average power possible in the load.

Published
1986
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4. A radio altimeter antenna for a planetary probe

Author

Beyer, J. B, Afanasjevs, J, and Levanon, N

Subjects
Spacecraft Instrumentation
Abstract

The design of a 400 MHz directional radio altimeter antenna for use in a freely falling probe in a planetary atmosphere is described. It is required that the antenna be physically large to exploit the dependence of the return power on the square of the wavelength. The antenna must be deployable so that it can be stowed behind the heat shield during the phase of atmospheric penetration. The electrical requirement, imposed by the power available and the system noise, is that the gain in the direction of the probe be at least 3 dB over a dipole. The altimeter application imposes the requirement of linear polarization. Dipole elements are impractical because of the proximity of the heat shield, hence monopole elements using the heat shield as an integral part (the ground plane) of the antenna are used. A parasitic element is placed behind the driven element to increase both the front-to-back ratio and the directive gain. The antenna which has been selected has a gain of 4 dB over a dipole, a front-to-back ratio of 8 dB, and a -6 dB beam angle of 34 degrees. Experiments for evaluating the effects of element spacing, length, and tilt angle with respect to the probe axis were conducted on a 1/25 scale model of the antenna at 10 GHz, and impedance measurements were performed on a full scale antenna at 400 MHz.

Published
1976

7. BAND-PASS DISTRIBUTED AMPLIFIERS.

Author

Prasad, S. N. and Beyer, J. B.

Subjects
*DISTRIBUTED amplifiers, *VACUUM-tube amplifiers, *BROADBAND amplifiers, *ELECTRONIC amplifiers, *VACUUM tubes
Abstract

A novel hand-pass distributed amplifier design concept is presented. The amplifier can be realized in monolithic form using GaAs FETs. The amplifier has excellent widehand gain and phase response characteristics. It shows promise for applications in the millimeter wave region. In this paper the results of analytical modelling as well as computer simulations are discussed. [ABSTRACT FROM AUTHOR]

Published
1989
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9. Microwave surface resistance of YBa2Cu3O6.9 superconducting films.

Author

Martens, J. S., Beyer, J. B., and Ginley, D. S.

Subjects
*MICROWAVES, *SUPERCONDUCTORS, *THICK films, *YTTRIUM alloys
Abstract

The microwave surface resistance of an YBa2Cu3O6.9 superconducting thick film was measured over the range 7.0–16.7 GHz at 77 K. This was done by placing a sample in a TE01n wavemeter cavity and observing the change in selectivity of the cavity. The material’s surface resistance is of the same order of magnitude as that of silver at 77 K from 8 to 12 GHz and improves about another order at 4.2 K. The power-law behavior of surface resistance with frequency is probably close to quadratic. This is similar to the behavior of low critical temperature superconductors. [ABSTRACT FROM AUTHOR]

Published
1988
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10. A BROADBAND MICROWAVE LINEAR PHASE MODULATOR MADE OF HIGH Tc SUPERCONDUCTORS.

Author

Martens, J. S., Beyer, J. B., Nordman, J. E., and Ginley, D. S.

Subjects
*SUPERCONDUCTORS, *ELECTRONIC modulators, *BROADBAND amplifiers, *ELECTRONIC modulation, *ELECTRONICS
Abstract

A superconducting linear phase modulator using a single film device made of Tl-Ca-Ba-Cu-O for operation at 77 K is presented The modulator has been analyzed from 300 MHz to about 6 GHz with good linearity for peak phase deviations up to 100 rad. Modulation has been observed for carriers up to 35 GHz. [ABSTRACT FROM AUTHOR]

Published
1990
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11. Model predicts large-signal modfet performance

Author

O'Callaghan Castellà, Juan Manuel|||0000-0002-2740-0202, Beyer, J. B., Universitat Politècnica de Catalunya. Departament de Teoria del Senyal i Comunicacions, and Universitat Politècnica de Catalunya. RF&MW - Grup de Recerca de sistemes, dispositius i materials de RF i microones

Subjects
Modulation-doped field-effect transistors, small-signal measurements, large-signal models, semiconductor device models, Enginyeria de la telecomunicació::Radiocomunicació i exploració electromagnètica::Circuits de microones, radiofreqüència i ones mil·limètriques [Àrees temàtiques de la UPC], microwave applications, equivalent circuits, nonlinear equivalent circuit, solid-state microwave devices, high electron mobility transistors, Microwave devices, HEMT, MODFET performance
Abstract

Modulation doped FETs (MODFETs) provide low-noise performance in many medium- and high-power microwave applications. Unfortunately, there are few large-signal models available for MODFETs, and determining the parameters of these models at high power levels is often difficult. A good large-signal model can be obtained from small-signal measurements that require relatively common microwave instrumentation. The authors explain how small-signal measurements of various bias points yield a useful nonlinear equivalent circuit.

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