摘要:

AbstractA technique to estimate the frequency dependence of electromagnetic scattering centers is proposed. The technique employs a superresolution algorithm to estimate poles corresponding to the various scattering centers contributing to the total backscattered field. A relationship between the amplitudes of the estimated poles and the frequency dependence of the scatterers is derived. The technique is applied to estimate the frequency dependence of simulated and measured backscattered field data. © 1995 John Wiley&Sons, Inc

ISSN:0895-2477    

DOI:10.1002/mop.4650100202

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1995

数据来源: WILEY

摘要:

AbstractA 400–550‐GHz fixed tuned quasioptical Nb/AlOx/Nb SIS heterodyne receiver has been built, and its performance has been evaluated. The receiver, operated at 3.5 K, showed noise temperatures ≤ 300‐K DSB within the tuning range of the available LO source (440–520 GHz). The SIS junction capacitance was tuned out by a novel twin‐junction circuit, which offered 130‐GHz fixed tuned bandwidth at 480 GHz. Large‐area SIS junctions (3.5 μm2, ωRnC ≈︁ 7.5 at 500 GHz), patterned by optical lithography, were used. © 199

ISSN:0895-2477    

DOI:10.1002/mop.4650100203

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1995

数据来源: WILEY

摘要:

AbstractIn this article a new pattern‐forming synthesis for an arbitrary conformal‐array antenna is shown. Using this method, various antenna patterns of hemielliptical array for varying the ratio of vertical and horizontal length and number of elements are calculated. As a result, it is confirmed that the side‐lobe level is almost suppressed within the desirable level by using the optimum number of elements. © 1995 John Wiley&Son

ISSN:0895-2477    

DOI:10.1002/mop.4650100204

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1995

数据来源: WILEY

摘要:

AbstractWe present a superresolution procedure that applies ESPRIT in both the time and frequency domains to obtain a parametrized representation of electromagnetic scattering mechanisms due to structural dispersion. This procedure is applied to the backscattered data from an open‐ended circular waveguide. The dispersive waveguide modes are identified with very good accuracy. © 1995 John Wiley&Sons, I

ISSN:0895-2477    

DOI:10.1002/mop.4650100205

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1995

数据来源: WILEY

摘要:

AbstractA novel architecture is presented for beam formers in multiple‐beam active phased arrays operating over one or more octaves in frequency. The photonics‐based beam former is suitable for large‐scale arrays with multiple simultaneous and independent antenna beams, and substantially reduces the number of required interconnects between antennas and beam ports, when compared to conventional beam‐forming architectures. We show that a significant reduction of 96.5% in the required number of delay lines for a 512‐beam array is possible, through the use of a new wavelength division multiplexing (WDM) delay unit in the novel architecture. © 1995 John Wiley

ISSN:0895-2477    

DOI:10.1002/mop.4650100206

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1995

数据来源: WILEY

摘要:

AbstractAn optoelectronic switch with very high isolation and bandwidth from dc to microwave frequency range is demonstrated both theoretically and experimentally. The switch consists of a p‐i‐n photodiode and a GaAs MESFET in a common gate configuration as a transmission gate. An analytical expression is derived to calculate the isolation level of the switch. Measured isolation levels of 70 dB at 300 KHz and 55 dB up to 1.0 GHz were obtained for the proposed optoelectronic switch. © 1995 John Wiley&Sons,

ISSN:0895-2477    

DOI:10.1002/mop.4650100207

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1995

数据来源: WILEY

摘要:

AbstractA modified analysis of conical horns ispresented that takes into account the true phase relationships between the feeding waveguide, the conical horn section, and the aperture phase variation. It is demonstrated that, especially for low‐gain applications, an accurate account of the aperture phase error results in higher gains than those obtained by widely used design methods‐or that a slightly shorter horn is obtained for identical gain specifcations. Comparisons with measured data reveal the advantage of this relatively simple analysis compared with techniques involving the conical waveguide mode spectrum. © 1995 John Wiley&Sons,

ISSN:0895-2477    

DOI:10.1002/mop.4650100208

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1995

数据来源: WILEY

摘要:

AbstractA very efficient iterative algorithm is presented for the analysis of planar scatterers at the very fine detail regime. The mechanisms causing slow convergence in other techniques have been identified and corrected. The resultant algorithm converges very fast for problems with fine details sampled faster than 0.001°, where other methods fail. © 1995 John Wiley&Sons, In

ISSN:0895-2477    

DOI:10.1002/mop.4650100209

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1995

数据来源: WILEY

摘要:

AbstractWhen the semiconductor substrate under the microstrip transmission lines is properly doped, a substantial phase shift of the propagating wave by an applied DC bias voltage is demonstrated. The device is inexpensive to fabricate and easy to implement, especially in monolithic structures. © 1995 John Wilet&Sons, Inc

ISSN:0895-2477    

DOI:10.1002/mop.4650100210

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1995

数据来源: WILEY

摘要:

AbstractIn this article an analytical investigation has been made of a slab waveguide with a small circular deformation across the direction of wave propagation. The resulting guide can be considered as a waveguide having a large annular cross section. Using the approximation of vanishing refractive index difference between the guiding and the nonguiding regions, fractional powers have been estimated that flow individually through these regions. © 1995 John Wiley&Sons, Inc

ISSN:0895-2477    

DOI:10.1002/mop.4650100211

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1995

数据来源: WILEY