摘要:

AbstractThe effect of a dielectric coating on the gain, co‐polar radiation pattern, and cross‐polarization level of a linearly polarized parabolic reflector antenna is investigated for both dry and wet surface conditions using a physical optics analysis of the equivalent surface currents. By choosing the correct thickness, the effect of a dielectric coating can be minimized, and, at the same time, an equivalent metal‐reflector representation shows that the antenna gain is less sensitive to the coating surface acc

ISSN:0895-2477    

DOI:10.1002/mop.4650080102

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

年代:1995

数据来源: WILEY

摘要:

AbstractA novel technique combining two‐dimensional method‐of‐lines (MOL) analysis with a mode‐matching procedure to analyze microstrip step discontinuties is presented. The MOL is used to calculate the propagation constants and field distributions at discrete points for a number of modes on both sides of a discontinuity. These modes are matched using a modified discrete mode‐matching procedure to produce a generalized S‐parameter description of the discontinuity. The method uses memory sparingly. Results for two microstrip steps ar

ISSN:0895-2477    

DOI:10.1002/mop.4650080103

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

年代:1995

数据来源: WILEY

摘要:

AbstractMicrowave transmission‐line theory has been applied to calculate p‐i‐n photodiode systems in which the carrier transit time, the geometric configuration, and the transmission‐line characteristics were considered. The thickness of the intrinsic layer has been optimized to obtain a wide 3‐dB bandwidth and a maximum gain‐bandwidth product. A simulated result of 40‐GHz bandwidth has been obtained for a device with a 20 × 20

ISSN:0895-2477    

DOI:10.1002/mop.4650080104

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

年代:1995

数据来源: WILEY

摘要:

AbstractDielectric‐coated hemispherical dielectric resonator (DR) antennas fed by a microstrip line through a coupling slot are analyzed. The broadside TE111mode is studied, and the reciprocity theorem is applied in this analysis. In this case the dielectric‐coated DR antenna can be viewed as a series load at the slot position as seen by the microstrip line. The impedance of this series load is calculated by using a Green's‐function formulation, and the input impedance of the slot‐coupled DR antenna can then be obtained using transmission‐line theory. Numerical results for the input impedance are calculated and presented, and the antenna bandwidth is discussed. It is observed that the antenna bandwidth of a dielectric‐coated DR antenna can be as high as two times that of a DR antenna withou

ISSN:0895-2477    

DOI:10.1002/mop.4650080105

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

年代:1995

数据来源: WILEY

摘要:

AbstractW‐band dual‐frequency circulators have been develoved. The dual‐frequency circulator resulting from a dual higher‐order mode is used as stated in [3, 4]. The calculated properties of the dual modes, especially the mode‐change frequency point between the dual higher‐order modes, have been verified exp

ISSN:0895-2477    

DOI:10.1002/mop.4650080106

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

年代:1995

数据来源: WILEY

摘要:

AbstractA chirowaveguide with an annular cross section where the chiral region is bounded by dielectric media has been analytically studied for cutoff conditions. The annular guiding region can be looked upon as a bent slab waveguide with a circular curvature. The origin of this curvature may be deliberate or the result of warping due to fabricating defects. The effect of changing chiral admittance on the cutoff conditions is also discussed.

ISSN:0895-2477    

DOI:10.1002/mop.4650080107

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

年代:1995

数据来源: WILEY

摘要:

AbstractIn this article we show that, when the direct coupling between antennas is very weak, the limited support, on which two microstrip patches lie, can be the source of an important parasitic coupling. We consider also the influence of the dimensions and the shape of this support. The theoretical results and the measurements are in a very good agreement in the validity domain of the method.

ISSN:0895-2477    

DOI:10.1002/mop.4650080108

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

年代:1995

数据来源: WILEY

摘要:

AbstractIn this article, under the quasi‐TEM assumption, using the two‐fluid model and the London equations, and through an exact electromagnetic field analysis, we get an analytic solution for the current density inside the superconductors of a superconductive circular two‐wire transmission line. Finally, the analytic solutions for its ac resistance and internal inductance are obt

ISSN:0895-2477    

DOI:10.1002/mop.4650080109

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

年代:1995

数据来源: WILEY

摘要:

AbstractWe propose a practical technique to determine the normalizing input/output impedances by a couple of terminated conditions. The realized quantity of the normalizing input/output impedances could be applicable in the design and implementation of microwave amplifiers.

ISSN:0895-2477    

DOI:10.1002/mop.4650080110

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

年代:1995

数据来源: WILEY

摘要:

AbstractWave scattering from the trees generated by the stochastic Lindenmayer system is studied by Monte Carlo simulations in this article. The scattering coefficients are calculated in three ways: wave approach, tree‐independent scattering, and independent scattering. It shows that the results of tree‐independent scattering agree well with that of wave approach for medium to high frequency. However, independent scattering is not a good approximation except for very high freque

ISSN:0895-2477    

DOI:10.1002/mop.4650080111

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

年代:1995

数据来源: WILEY