摘要:

AbstractAn analysis using a generalized transmission‐line model (GTLM)for a probe‐fed cylindrical‐rectangular microstrip antenna is presented. The equivalent circuit elements for the microstrip antenna modeled as a transmission line loaded with wall admittances are derived, and the expression for the input impedance is given. Numerical results of the input impedance are calculated and presented as a function of the cylinder radius and the substrate thickness. Excellent agreement of the GTLM solutions with the experimental results is observed. © 1994 John Wiley&Son

ISSN:0895-2477    

DOI:10.1002/mop.4650071602

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

年代:1994

数据来源: WILEY

摘要:

AbstractA new miniaturized 180—degree ring hybrid was developed. Its circumference is only one wavelength, as compared to the one and a half wavelengths of the conventional ring hybrid. Simple formulas for its scattering (S) parameters along with design information were derived. The obtained S parameters and measured performance of the ring at X band (8–12 GHz) confirm the 180—degree hybrid feature. A microstrip singly balanced diode mixer using the new ring was also developed at X band band with less than 6.5 dB of conversion loss and more than 25 dB of LO‐rf isolation. © 1994 John Wiley&S

ISSN:0895-2477    

DOI:10.1002/mop.4650071603

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

年代:1994

数据来源: WILEY

摘要:

AbstractThe numerical absorbing boundary condition (NABC) approach is applied to the problem of deriving the local boundary conditions that can be employed in conjunction with the edge‐based formulation of the finite‐element method (FEM) to s olue electromagnetic scattering and radiation problem. The key step in this approach is to derive linear relationships that link the values of the field along the boundary edges to those at the neighboring ones. These linear relationships are satisfied, to within a certain tolerance, by all of the outgoing wave components. They can thus be used in lieu of the FEM equations employing the usual absorbing boundary conditions for the boundary edges. The NABC approach not only provides a simple way to derive an accurate boundary condition for mesh truncation, but also presemes the banded structure of the FEM matrices. © 2994 John Wiley&Sons,

ISSN:0895-2477    

DOI:10.1002/mop.4650071604

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

年代:1994

数据来源: WILEY

摘要:

AbstractWe describe a new model that yields the transverse component of the conduction current as well as the radiation pattern of the cross‐polar component of a multilayered radiating structure. The structure is com‐posed of a microstrip patch antenna with an arbitrary shape, associated with a director having the same shape and the same axes of symmetry. Losses, dispersion, strip thickness and roughness, and edge diffraction are taken into account. Calculated results agree very well with experimental results previously obtained for a circular shape. © 1994 John Wiley&Sons,

ISSN:0895-2477    

DOI:10.1002/mop.4650071605

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

年代:1994

数据来源: WILEY

摘要:

AbstractThe performance of a paraboloid reflector with an active patch antenna feed has been analyzed. The effects of frequency pulling at the active antenna feed, induced by the parabolic reflector antenna, are measured and predicted. Measured far‐field pattern results for the combined reflector active antenna configuration are also presented. © 1994 John Wiley&Sons, I

ISSN:0895-2477    

DOI:10.1002/mop.4650071606

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

年代:1994

数据来源: WILEY

摘要:

AbstractMicrowave semiconductor diodes are characterized on a picosecond time scale by means of an optoelectronic technique, in which the diode is biased with a variable‐duration high‐voltage pulse, while its output current is integrated with a box‐car integrator. Measured data on three different devices illustrate the technique. © 1994 John Wiley&Son

ISSN:0895-2477    

DOI:10.1002/mop.4650071607

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

年代:1994

数据来源: WILEY

摘要:

AbstractThe guiding structures in photonic and integrated optical circuits have complex geometries and refractive‐index profiles so that numerical methods must be used to analyze them. When it is necessary to evaluate parameters such as group delay or dispersion coefficient, which involve first and second derivatives of the numerically calculated propagation constants of the modes, the required accuracy is not easy to obtain. Suitable functions may be used to fit, in a least‐squares sense, the numerical solutions and to easily obtain derivatives from a direct analytical calculation. © 1994 John Wiley&Sons,

ISSN:0895-2477    

DOI:10.1002/mop.4650071608

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

年代:1994

数据来源: WILEY

摘要:

AbstractThe interplay of spatial and temporal periodicities in a cholesteric liquid crystal is responsible for the three zones into which axial propagation may be classified. Each of the three zones is marked by specific attenuation and handedness characteristics. © 1994 John Wiley&Sons, Inc

ISSN:0895-2477    

DOI:10.1002/mop.4650071609

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

年代:1994

数据来源: WILEY

摘要:

AbstractThe far‐field behavior of a chirostrip dipole antenna on chiroferrite substrates is shown using the generalized spectral domain—exponential matrix technique, and such substrates are made from a nonreciprocal chiral medium and ferrite material. Numerical results show that both beam scanning and pattern reshaping can be achieved by adjusting the constitutive parameters of chiroferrite, and the dispersion effects of substrates are considered in detail. © 1994 John Wiley&Sons,

ISSN:0895-2477    

DOI:10.1002/mop.4650071610

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

年代:1994

数据来源: WILEY

摘要:

AbstractThe resonant frequencies of an eccentric annular microstrip antenna are computed for different modes using the cavity model. The effect of the eccentricity on the resonant frequencies is investigated. The computed resonant frequencies are verified experimentally. The measured resonant frequencies are considered to be located at the minimum locations of the return loss. The magnetic field distribution is also computed and plotted for some patches. © 1994 John Wiley&Sons, Inc

ISSN:0895-2477    

DOI:10.1002/mop.4650071611

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

年代:1994

数据来源: WILEY