摘要:

The usual enhancement devices are constructed to give a maximum monostatic echo area. This is achieved by setting up a uniform phase distribution in the effective aperture of the device independent of the angle of incidence. Bistatic echo-area enhancement may be achieved by altering this phase distribution. Gable phase distribution is considered for the rectangular aperture and is applied to the case of the triple-bounce corner reflector. Both linear radial and quadratic radial phase distributions are treated for circular apertures and applied to the Luneberg reflector and those spherical devices described by Kay.It is shown that the echo pattern may be approximated as an exponentially decaying function of the bistatic angle θ, i.e. ε−γθ. In each case the parameter γ is related to some physical parameter of the device by a design process. The validity of this design process has been verified for a triangular triple-bounce corner reflector and a Luneberg reflector.

DOI:10.1049/pi-c.1962.0001

出版商:IEE    

年代:1962

数据来源: IET

摘要:

The paper suggests a way of explaining the mechanism of force production in slotted structures which leads into a method of determining the precise location of these forces.The case of the rounded corner slot is also studied, and by the application of numerical techniques the fluxes at the boundary are integrated to study the force distribution in depth.

DOI:10.1049/pi-c.1962.0002

出版商:IEE    

年代:1962

数据来源: IET

摘要:

The most usual form of launcher of an axial surface wave is a horn which acts as a mode transducer between a coaxial line and a surface waveguide.A full mathematical treatment of the horn presents considerable difficulty and therefore, as a step towards obtaining a solution for such a mode transducer, a launcher in the form of an annular slot in a conducting plate has been investigated. An exact mathematical solution has been obtained for the electromagnetic field at a large distance from the slot. Expressions for the surface-wave field and the radiated field were obtained and used to calculate the power carried by the two waves. The efficiency of launching of a surface wave was evaluated and the results were confirmed by experimental methods.

DOI:10.1049/pi-c.1962.0003

出版商:IEE    

年代:1962

数据来源: IET

摘要:

A difficulty with present mathematical antenna models is the fact that there is no theoretical justification for equating the computed input impedances with those measured experimentally. It is shown that a rigorous definition of antenna impedance can be based only on a computation of the complex power in the electromagnetic field from energy integrals. To account for this power it is essential to consider the transmission-line feed to the antenna, and an antenna model is derived on this basis. This model is then compared with presently accepted models. The usefulness of the induced-e.m.f. method is discussed. It is then shown that the slice generator used in the Hallen-King model does not satisfy the requirement for the conservation of power and that the impedance determined from this model depends on a semi-empirical choice of expansion parameter.

DOI:10.1049/pi-c.1962.0004

出版商:IEE    

年代:1962

数据来源: IET

摘要:

By applying a series of detailed approximations to the Rice and Bosse theory of f.m. intermodulation noise, the recent formulae of Medhurst and Roberts for intermodulation noise/signal ratios in f.m. systems with white-noise modulation and networks of polynomial frequency characteristics are extended in three respects: (a) to the calculation of the noise ratio at any modulation frequency, (b) to network real and imaginary characteristics of eighth and seventh degree, respectively, and (c) to the case of pre-emphasis. The theory is illustrated by application to the cases of a signal with C.C.I.R. pre-emphasis passing a stagger-tuned triple without and with groupdelay equalization.

DOI:10.1049/pi-c.1962.0005

出版商:IEE    

年代:1962

数据来源: IET

摘要:

Kirchhoff's topological rules for linear reciprocal networks have been generalized for networks containing non-reciprocal elements as well, in order to be applicable to active networks. A conventional proof of these rules for reciprocal networks is given, and the generalized rules are then shown to be an immediate consequence of this proof, thus requiring no special considerations for their derivation. The exposition is restricted to nodal analysis.

DOI:10.1049/pi-c.1962.0006

出版商:IEE    

年代:1962

数据来源: IET

摘要:

An exact analysis of the gain function of the cavity maser is made and is presented in graphical form suitable for correlation with experiment. Combined with measurements of the reflection coefficient of the passive cavity, and gain and bandwidth of the maser, the results yield accurate values for the unloaded, external and magnetic Q-factors of the cavity maser. The analysis also applies to any other resonant one-port device, e.g. a parametric amplifier.

DOI:10.1049/pi-c.1962.0007

出版商:IEE    

年代:1962

数据来源: IET

摘要:

A loop antenna coupled electromagnetically to a four-wire transmission line is studied theoretically and experimentally in terms of two mutually perpendicular two-wire lines that carry currents that are 90° out of phase. The size of the loop at which resonance occurs is determined. The zero-order and first-order solutions of the current distribution are evaluated, and it is found that at resonance the induced currents in the loop due to each two-wire line oscillate in a dipole mode of the loop. The currents induced by the four-wire line circulate as a travelling wave. The radiation field pattern is also evaluated. The square loop is studied first; it is later shown that the circular loop closely resembles the square loop. An array that consists of many loop antennae coupled electromagnetically to a four-wire transmission line may be expected to have a very high gain with circularly polarized radiation.

DOI:10.1049/pi-c.1962.0008

出版商:IEE    

年代:1962

数据来源: IET

摘要:

Rigorous analysis of the transient behaviour of a solid-cored magnetic circuit of rectangular section, taking into account the resistance of the magnetizing winding, is difficult to obtain and has not been attempted so far in the literature. In this paper an attempt is made to obtain, to a close degree of approximation, the transient behaviour of cores of such sections. It is shown that the complexities of the problem can be reduced by choosing certain contours of constant current density, and on this basis, four alternative solutions are obtained for the transient behaviour. These contours are justified on the basis of (a) flux decay with the magnetizing winding open and (b) eddy-current loss due to alternating flux: rigorous solutions for the two cases are available for comparison. The analysis is illustrated with a specific application to the rise of flux due to an impact excitation on a solid core, and certain conclusions are drawn.An interesting feature of the paper is that, in the majority of cases, the results are presented in a non-dimensional form.

DOI:10.1049/pi-c.1962.0009

出版商:IEE    

年代:1962

数据来源: IET

摘要:

The paper deals with the problem of the realization of a realnth-order square symmetrical matrix as the conductance matrix of resistiven-port based on a network ofn+1 nodes.The technique of synthesis starts with the construction of a tree of the independent voltages along well-known lines, by inspecting the sign pattern in the given matrix. It is shown that, at each stage of this realization process, one can also determine the branch conductances which have to be connected in order to fulfil the requirements of the given matrix, thus entirely realizing the synthesis procedure.The advantage of this method is that it does not require long algebraic computations in the final steps of the synthesis.The branch-conductance synthesis technique is based entirely on some intuitive analysis theorems.

DOI:10.1049/pi-c.1962.0010

出版商:IEE    

年代:1962

数据来源: IET