US 2020/0006834 A1Published application

Rf stripline circulator devices and methods

AssigneeValorbec Societe en Commandite

InventorsSHOKRY IBRAHIM ABDELRAZAK SHAMSELDIN, AHMED ABDELWAHED KISHK, MAHMOUD SOBHY ELSAADANY

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Abstract

Microwave circulators are an essentially component in many microwave systems and whilst the waveguide technologies they are implemented in have evolved their design today still employs procedures that are typically approximate and have no regular approach, which in many instances is through dependence on empirical equations or considered a trade secret that gives an edge to commercial suppliers of microwave and RF circulators. The result is expensive isolators where high performance is required as they are merely selected out or require manual tuning. Further, for broadband systems, designer's resort to dividing into sub-bands deploying multiple narrower band circulators. Accordingly, the inventors present a design methodology based on an accurate closed form solution allowing the selection of suitable ferrite specifications for the required operating bandwidth as well as calculating the ferrite disc impedance allowing the necessary matching network to be designed and the circulator design completed.

Claims16

Dependent claims

A microwave circulator comprising:

a pair of electrically non-conductive and ferromagnetic elements with specific magnetic saturation value (Ms) each having a predetermined thickness and a predetermined diameter;
an electrical conductor plane comprising a plurality of microwave tracks and a central circular pad to which each microwave track is coupled at a predetermined location, each microwave track comprising a first portion adjacent the central pad and a second portion extending from the first portion to a distal point;
a lower electrical ground plane;
an upper electrical ground plane;
a first dielectric disposed between the electrical conductor plane and the lower electrical ground plane and having a thickness determined in dependence upon the predetermined thickness of the electrically non-conductive and ferromagnetic elements and an opening determined in dependence upon the predetermined diameter of the electrically non-conductive and ferromagnetic elements;
a second dielectric disposed between the electrical conductor plane and the upper electrical ground plane and having a thickness determined in dependence upon the predetermined thickness of the electrically non-conductive and ferromagnetic elements and an opening determined in dependence upon the predetermined diameter of the electrically non-conductive and ferromagnetic elements;
wherein
the openings within the first dielectric and second dielectric have a diameter establishing a predetermined air gap between the external periphery of an electrically non-conductive and ferromagnetic element and their respective dielectric when the electrically non-conductive and ferromagnetic element is centrally disposed with the opening;
the first portion of each microwave track is air filled microwave track;
and
the second portion of each microwave track is a dielectric filled microwave track.

8 more elements

A microwave circulator comprising:

a set of three parallel electrical planes wherein the middle electrical plane comprises a plurality of microwave tracks and a central region coupled to the plurality of microwave tracks and each outer electrical plane is a ground plane;
wherein
a central portion of the set of three parallel electrical layers comprises an inner region with electrically non-conductive and ferromagnetic elements of predetermined lateral dimensions disposed between each outer electrical plane and the middle electrical plane and an outer region filled with a first dielectric material of low dielectric constant such that those portions of each microwave track in this outer region form microwave feeds coupled to the central region of the middle electrical plane at predetermined locations;
an outer portion of the set of three parallel electrical layers is filled with a second dielectric material such that those portions of each microwave track in this outer portion form microwave matching networks between the portion of each microwave track in the outer region of the central portion and an external microwave circuit to be coupled to the distal ends of each microwave track from the central portion.

1 more element

Dependencies are inferred from the claim text.