摘要:

An expression for the average power-handling capability (a.p.h.c.) of microstrip lines is derived by considering the heat generated in the strip conductor and the dielectric substrate. The analogy between electrostatic fields and heat-flow fields is used for calculation of the rise in temperature of the strip conductor. The computed value of a.p.h.c. for a 50 Ω line on alumina substrate (0.06 cm [25 mil] thick) is 5.26 kW at 10 GHz whereas the corresponding figure for polystyrene substrate is 126 W.

DOI:10.1049/ij-moa.1979.0001

出版商:IEE    

年代:1979

数据来源: IET

摘要:

A new technique for the inherent generation of circular polarisation from compact microstrip antennas is described, based on radiation from curved microstrip transmission lines supporting a single travelling wave. The radiation is analysed in terms of effective magnetic current sources to give an estimate of the decay coefficient of the wave, which is found to be in reasonable agreement with experiment. Good characteristics are obtained from both circular and spiral antennas, with a useable bandwidth of up to 40% being available at 10 GHz for an average efficiency of 50%, owing to power absorbed in the line termination. The advantages obtained over conventional microstrip circular-polarised antennas are the avoidance of band-width limitations owing to resonant matching and the elimination of feed networks to produce circular polarisation.

DOI:10.1049/ij-moa.1979.0002

出版商:IEE    

年代:1979

数据来源: IET

摘要:

A unified, rigorous and efficient hybrid-mode solution to the general planar 3-layer transmission-line problem with shielded, covered and open cross-sectional geometry is achieved by the spectral-domain method. Stress is put on the minimisation of the computational expense required to obtain the frequency-dependent design data of planar line structures with realistic geometrical dimensions. This implies the modal propagation constants, uniformly defined characteristic impedances and any field quantities. On the basis of user-oriented considerations a computer program has been developed which is applicable to fundamental, and higher, even and odd modes on single and coupled coplanar strips and slots. This computational approach includes most of the cases which today are of technical interest, e.g. stripline and microstrip, microstrip with dielectric overlay, suspended substrate strips and slots, slotline, coplanar line and grounded or isolated fin line. It combines analytical simplicity, rigorousness and high efficiency with the possibility of performing studies on numerical accuracy and convergence.

DOI:10.1049/ij-moa.1979.0005

出版商:IEE    

年代:1979

数据来源: IET

摘要:

The paper describes a compact L-band duplexer capable of handling peak powers in the megawatt range. It uses a hybrid waveguide/coaxial construction in which the transmitter power is fed through the waveguide section and the received signal is coupled out by a coaxial probe. A simplified theoretical analysis is included in the paper which predicts the loss and power-handling capacity of the circuit. Measured results are presented for an experimental device operating in the 1.25–1.35 GHz which indicate a transmitter-channel loss of less than 0.2 dB, and a receiver-channel loss of less than 0.5 dB for a 28 dB isolation level.Zusammenfassung: Es wird die Entwicklung eines kompakten L-Band Duplexers beschrieben, bei dem die Sendeleistung durch einen Hohlleiter, die Empfangsleistung aber durch ein Koaxteil geschaltet wird. Eine vereinfachte theoretische Betrachtung zeigt eine gute Übereinstimmung mit den gemessenen Daten.Messungen an einem Labor-Muster zeigen eine Durchlaβdämpfung von ca. 0.5 dB und eine Sperrdämpfung von ca. 28 dB über eine Bandbreite von ca. 10% bei 1.3 GHz. Die Leistungsfestigkeit betrug über 700 kW bei einer Pulslänge von 5 μs und einem Tastverhältnis von 1: 500.

DOI:10.1049/ij-moa.1979.0006

出版商:IEE    

年代:1979

数据来源: IET

摘要:

A mode-matching method is applied to accurate numerical analysis of the elastic waveguide with elliptical cross-section. This method is based on the Rayleigh expansion theorem and on the boundarymatching procedure in the sense of least-squares, and guarantees the uniform convergence of the solutions represented by modal expansions in an arbitrarily shaped cross-section. By this method, the dispersion relations of the waveguide in the case of large ellipticity, the precise analysis of which has been difficult so far, are obtained with extremely high accuracy. Moreover, the field distributions of the particle velocity (deformations of the cross-section) are also made clear for each mode. The degree of accuracy of such results is examined in detail, compared to those of the collocation method. In conclusion, it may be said that the mode-matching method is also a more effective and accurate method for numerical analysis of the elastic field in the waveguide with any other cross-section as well as the elliptical or rectangular ones, compared with the other methods.

DOI:10.1049/ij-moa.1979.0007

出版商:IEE    

年代:1979

数据来源: IET

摘要:

An analysis of Y and Z microwave mixers is presented, incorporating a Schottky-diode model with nonlinear resistance and reactance. The analysis suggests that Y mixers have satisfactory conversion loss and noise figure up to higher frequencies than Z mixers using the same type of diodes. A comparison of four mixer configurations is made.

DOI:10.1049/ij-moa.1979.0008

出版商:IEE    

年代:1979

数据来源: IET