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Author

Ronald E. Stegens

Bio: Ronald E. Stegens is an academic researcher from COMSAT. The author has contributed to research in topics: Coplanar waveguide & Low-pass filter. The author has an hindex of 7, co-authored 7 publications receiving 394 citations.

Papers
More filters
Patent
Ronald E. Stegens1
13 May 1974
TL;DR: In this article, a low noise, multistage microwave transistor amplifier constructed using microwave integrated circuit techniques is disclosed, which is the basic building block for broadband, high-gain cascades.
Abstract: A low noise, multistage microwave transistor amplifier constructed using microwave integrated circuit techniques is disclosed. The illustrated embodiment is a two-stage transistor amplifier which is the basic building block for broadband, high-gain cascades. This amplifier features an interstage network consisting of a very short transmission line which minimizes the size and frequency dependence of the amplifier. This is achieved in the satellite communications band of 3.7 to 4.2 GHz by constructing the amplifier on a suitably low dielectric constant substrate rather than the usual high dielectric constant substrates used in microwave amplifier applications.

295 citations

Patent
Ronald E. Stegens1
27 Dec 1979
TL;DR: In this paper, a versatile test structure for coplanar waveguide (CPW) microwave integrated circuits is provided with a support structure or carrier which accommodates any length of CPW circuit.
Abstract: A versatile test structure for coplanar waveguide (CPW) microwave integrated circuits is provided with a support structure or carrier which accommodates any length of CPW circuit. The carrier is provided with a shock mounting means for a CPW substrate which protects the substrate against physical damage, as well as damage caused by widely varying thermal coefficients of expansion. The carrier is provided at each end thereof with a sliding connector to inject or remove microwave energy from the CPW substrate via a coaxial connector. The sliding connector and the carrier together comprise a mounting structure for the substrate which may be further provided with a sliding energy sampler or a right-angle CPW transition which may be used to sample energy levels within the substrate, or test individual portions of a CPW circuit.

47 citations

Patent
Ronald E. Stegens1
27 Dec 1979
TL;DR: In this article, the frequency response of a Microstrip Interdigital Filter (MIDF) is improved by providing a specially dimensioned top cover separated from the ground plane along one or both of its edges by a dielectric layer.
Abstract: The Frequency response of a Microstrip Interdigital Filter (MIDF) is improved by providing a specially dimensioned top cover separated from the MIDF ground plane along one or both of its edges by a dielectric layer comprised of thin dielectric sheets. While the upper frequency skirt is mainly determined by the MIDF itself, the bandwidth may be reduced and the slope of the lower frequency skirt may be enhanced by providing the cover in accordance with the invention. The thickness of the dielectric layer can be chosen to further improve the slope of the low frequency skirt by effectively moving the filter zero closer to the desired low frequency cut-off of the filter. The particular choice of the dielectric thickness will not substantially affect the filter bandwidth.

17 citations

Patent
Ronald E. Stegens1
27 Dec 1979
TL;DR: In this paper, a non-magnetized ferrite material is provided as the propagating medium for a microwave transmission line such as a microstrip or stripline transmission line.
Abstract: A non-magnetized ferrite material is provided as the propagating medium for a microwave transmission line such as a microstrip or stripline transmission line. The transmission system is adapted to provide a "high pass" filter characteristic by selecting the saturation magnetization of the ferrite as a function of the desired cut-off frequency such that frequencies below the cut-off are absorbed by the ferrite material thereby producing a low reflection coefficient, while frequencies above the cut-off are transmitted with very little attenuation. One of the conductors of the transmission system can further have microwave circuit elements located thereon which provide a second "filter" characteristic, such as a reactive filter or a tunnel diode. The filter characteristics produced by the ferrite material and the circuit elements combine to produce a desired system filter characteristic.

11 citations

Patent
22 Nov 1982
TL;DR: In this paper, a coplanar waveguide quadrature hybrid is proposed to produce even E-field symmetry about the center line of transmission during both even and odd-mode excitation.
Abstract: A coplanar waveguide quadrature hybrid is herein disclosed which produces even E-field symmetry about the center line of transmission during both even-and odd-mode excitation. In a first embodiment of the present invention, a first coupling element of a generally elongated shape is bifurcated and is interconnected at its ends to form a first rectangular coupling element. A second rectangular coupling element is disposed within the first rectangular coupling element. In a second embodiment of the present invention, one of the short sides of a first rectangular coupling element is broken and is cross-coupled to a third rectangular coupling element similar to the second rectangular coupling element, the third rectangular coupling element being disposed within a fourth rectangular coupling element similar to the first coupling element. The fourth rectangular coupling element is then directly connected to the second rectangular element to form a composite coupling element. During odd-mode excitation, the resulting CPW structures do not create an E-field between the ground planes and thus eliminate the spurious "slot-line" mode of operation of prior art CPW devices.

10 citations


Cited by
More filters
Journal ArticleDOI
TL;DR: In this article, the power line is approximated as a transmission line and the two intrinsic parameters, the characteristic impedance and the propagation constants, are derived based on the lumped-element circuit model.
Abstract: This paper presents a novel approach to model the transfer function of electrical power lines for broadband power line communication. In this approach, the power line is approximated as a transmission line and the two intrinsic parameters, the characteristic impedance and the propagation constants, are derived based on the lumped-element circuit model. Using these intrinsic parameters, the transfer characteristics for a N-branch power distribution network are derived based on the scattering matrix method. Detail derivation of this line model is given in this paper. The model has been verified with practical measurements conducted on actual power networks. It is demonstrated that the model accurately determine the line characteristics under different network configuration and when different household appliances are connected.

329 citations

Journal ArticleDOI
TL;DR: A comprehensive method of designing a broadband Doherty power amplifier is presented, which also takes the output matching networks of both sub-amplifiers into account and the essential limitations of bandwidth extension are discussed.
Abstract: A comprehensive method of designing a broadband Doherty power amplifier is presented in this paper. The essential limitations of bandwidth extension of a Doherty power amplifier are discussed based on the proposed structure of the Doherty power amplifier, which also takes the output matching networks of both sub-amplifiers into account. The broadband matching is realized by applying the simplified real frequency technique with the desired frequency-dependent optimum impedances. GaN transistors were selected to implement the circuit structure.

198 citations

Book
01 Jan 2015
TL;DR: In this paper, a transistor-level, design-intensive overview of high speed and high frequency monolithic integrated circuits for wireless and broadband systems from 2 GHz to 200 GHz is presented.
Abstract: A transistor-level, design-intensive overview of high speed and high frequency monolithic integrated circuits for wireless and broadband systems from 2 GHz to 200 GHz, this comprehensive text covers high-speed, RF, mm-wave and optical fiber circuits using nanoscale CMOS, SiGe BiCMOS and III-V technologies. Step-by-step design methodologies, end-of-chapter problems and practical simulation and design projects are provided, making this an ideal resource for senior undergraduate and graduate courses in circuit design. With an emphasis on device-circuit topology interaction and optimization, it gives circuit designers and students alike an in-depth understanding of device structures and process limitations affecting circuit performance.

173 citations

Journal ArticleDOI
TL;DR: In this paper, a pure-mode vector-network analyzer (PMVNA) is proposed for on-wafer measurements of differential circuits, and the transformation between standard S-parameters and mixed-mode Sparameters is developed.
Abstract: A practical measurement system is introduced for measurement of combined differential and common-mode (mixed-mode) scattering parameters, and its operation is discussed. A pure-mode system measures network parameters of a differential circuit in the fundamental modes of operation, and has improved accuracy over a traditional network analyzer for the measurement of such circuits. The system is suitable for on-wafer measurements of differential circuits. The transformation between standard S-parameters and mixed-mode S-parameters is developed. Example microwave differential structures are measured with the pure-mode vector-network analyzer (PMVNA), and the corrected data is presented. These structures are simulated, and the simulated mixed-mode S-parameters correlate well with the measured data.

146 citations

Journal ArticleDOI
TL;DR: This work presents a framework for the analysis of mutually-coupled antennas in a multiple-input multiple-output system and illustrates the performance gains possible from matching the coupled antenna/receive amplifier subsystem for minimum noise figure as compared to matching for maximum signal power transfer.
Abstract: This work presents a framework for the analysis of mutually-coupled antennas in a multiple-input multiple-output system. The approach uses network theory to formulate the transfer matrix relating the signals input to the transmit antennas to the signals at the output of the receiver front end. This transfer function includes the coupled transmit and receive antennas, the multipath propagation channel, the receiver matching network, and a realistic noise model for the receive amplifiers. Application of the formulation to coupled dipole antennas characterized using full-wave electromagnetic analysis illustrates the performance gains possible from matching the coupled antenna/receive amplifier subsystem for minimum noise figure as compared to matching for maximum signal power transfer.

120 citations