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S.R. Longley

Bio: S.R. Longley is an academic researcher. The author has contributed to research in topics: Circulator & Port (circuit theory). The author has an hindex of 1, co-authored 1 publications receiving 17 citations.

Papers
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Journal ArticleDOI
TL;DR: In this paper, a very compact E-plane waveguide circulator was used to put in the dewar and a compromise may be necessary in choosing between a compact stripline circulator and a comparatively bulky H-plane circulator.
Abstract: When a circulator is used with a parametric amplifier or maser, the noise contribution of the circulator may be reduced by cooling it in liquid nitrogen or liquid helium. Compact devices are required to put in the dewar and, depending on the microwave frequency, a compromise may be necessary in choosing between a compact stripline circulator and a comparatively bulky H-plane waveguide circulator, because waveguide feeds will have lower loss than coaxial line. This problem may be eased by using a very compact E-plane waveguide circulator, as shown in Fig. 1(a).

17 citations


Cited by
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Journal ArticleDOI
TL;DR: In this article, an exact field theory treatment for the N-port E-plane full-height ferrite rod junction circulators is presented, where field expressions are written in each region of the junction in the form of infinite modes, and point matching of the fields at the common boundaries is used to get a set of infinite nonhomogeneous equations in these mode amplitudes.
Abstract: In this paper an exact field theory treatment for the N-port E-plane full-height ferrite rod junction circulators is presented. Field expressions are written in each region of the junction in the form of infinite modes. Matching of the fields at the common boundaries is used to get a set of infinite nonhomogeneous equations in these mode amplitudes. The point matching technique is used to obtain an approximate solution for the field amplitudes by taking a finite number of modes in each region. Three types of junctions have been analyzed by this technique. These junctions are the symmetrical Y junction and two types of T junctions. Experimental measurements have been carried out to verify the obtained numerical results.

26 citations

Journal ArticleDOI
TL;DR: In this paper, a nonradiative dielectric waveguide (NRD) circulator was constructed for use at 50 GHz and a mode suppressor was devised to reduce unwanted modes to a negligible level.
Abstract: A technique is described for constructing a high-performance nonradiative dielectric waveguide (NRD guide) circulator for use at 50 GHz. A mode suppressor, which serves to reduce unwanted modes to a negligible level, was devised and used to improve circulator performance significantly. A half-wavelength step transformer was installed at each port of the circulator to increase the operational bandwidth. The insertion loss of this circulator is less than 0.3 dB, and the 20-dB isolation bandwidth is about 2.6 GHz. Characteristics of the NRD guide circulator are analyzed based on an equivalent circuit representation. This analysis considerably facilitates the design procedure of the circulator. >

25 citations

Proceedings ArticleDOI
20 May 1968
TL;DR: In this paper, the design and performance of an improved E-plane waveguide circulator is described. But, the Eplane circulator has received much less attention than its H-plane counterpart, probably due to the difficulty of achieving broadband performance and the lack of adequate design information.
Abstract: This report describes the design and performance of an improved E-plane waveguide circulator. Although the E-plane circulator has the advantages of higher power operation and more compactness, it has received much less attention than its H-plane counterpart. This has probably been due to the difficulty of achieving broadband performance and the lack of adequate design information. It is proposed in this report that best performance occurs when the dimensions of the ferrite cylinder are adequate to support the fundamental cylindrical dielectric resonator mode. The junction dimensions are reduced to enhance the coupling of the incident energy to this dielectric resonator. At the junction, a novel approach is employed to convert the absorption type cavity to a transmission type. Reduced height transformers match the junction to the standard waveguide ports.

17 citations

Journal ArticleDOI
TL;DR: In this article, the resonator structure employed in an E-plane circulator may be described by a series-resonant circuit as opposed to a parallel circuit in the case of comparable H-plane devices, resulting in a change of the direction of circulation at the edges of the circulator passband.
Abstract: The resonator structure employed in an E-plane circulator may be described by a series-resonant circuit as opposed to a parallel circuit in the case of comparable H-plane devices. This is shown to result in a change of the direction of circulation at the edges of the circulator passband. Employing the equivalent circuit representation methods to increase the bandwidth of the E-plane circulator are discussed.

16 citations

Journal ArticleDOI
TL;DR: In this paper, exact analysis on the waveguide junction circulator and Faraday rotator is presented in detail and the correctness of analysis is demonstrated by its successful prediction about the performance of the devices.
Abstract: In this paper the exact analysis on the waveguide junction circulator and Faraday rotator are presented in detail. The correctness of analysis is demonstrated by its successful prediction about the performance of the devices. Many calculation results are presented by comparing with the experimental results. The approaches of expanding bandwidth of devices at W band are stated.

13 citations