Microwave transmission line measuring system

Claim 2

In a microwave measuring device the combination comprising: conductive means including three current paths forming a junction, at least a portion of each of said paths having a substantially resistive characteristic; means for respectively connecting two different impedances and a microwave source to said paths, whereby currents in the path associated with said source branch to flow in the paths associated with said impedances; means connected to one of said paths for deriving signals proportional to the current in said source path; and means connected to the others of said paths for deriving signals proportional to the difference of currents in said impedance paths.

Claim 3

A microwave measuring device as recited in claim 1, wherein said device is associated with a certain characteristic impedance; and the resistance of each of said resistive paths is substantially less than said characteristic impedance.

Claim 4

A microwave measuring device as recited in claim 1, wherein said device is associated with a certain characteristic impedance; and the resistance of each of said resistive paths is less than 0.1 of said characteristic impedance.

Claim 5

A microwave measuring device as recited in claim 1, wherein said device is associated with a certain characteristic impedance; and the resistance of each of said resistive paths is of a value within a range of 0.05 and less of said characteristic impedance.

Claim 6

A microwave measuring device as recited in claim 1, wherein said device includes a planar dielectric sheet and said coplanar current paths are formed on said sheet.

Claim 7

A microwave measuring device as recited in claim 3, wherein the resistive portions of said current paths are films having a thickness which is small relative to the wavelength of the microwave signals at the high operating frequency of the bandwidth of said device.

Claim 8

A microwave measuring device as recited in claim 1, wherein said proportional signal deriving means are connected to the resistive portions of said paths at points that are spaced from said junction a small amount compared to the wavelength at the high operating frequencies of the device.

Claim 9

A microwave measuring device as recited in claim 7, wherein the center of one of said resistive portions is spaced from said junction by less than a quarter-wavelength at said high operating frequencies.

Claim 10

A microwave measuring device as recited in claim 7, wherein the center of one of said resistive portions is spaced from said junction by less than an eighth-wavelength at said high operating frequencies.

Claim 11

A microwave reflectometer comprising: conductive means including three current paths forming a junction, at least a portion of each of said paths having a substantially resistive characteristic; means for respectively connecting two different impedances and a microwave source to said paths, whereby currents in the path associated with said source branch to flow in the paths associated with said impedances; means connected to one of said paths for deriving signals proportional to the current in said source path; and means connected to the others of said paths for deriving signals proportional to the difference of currents in said impedance paths; said source including a sweep frequency microwave generator for supplying microwave signals varying in frequency over a certain band, and having means for varying the level of microwave power; and further comprising: means responsive to the difference between a reference signal and the proportional signals derived from said source path current for controlling said power varying means; and means for indicating the proportional signals derived from said current difference.

Claim 12

A microwave reflectometer comprising: conductive means including three current paths forming a junction, at least a portion of each of said paths having a substantially resistive characteristic; means for respectively connecting two different impedances and a microwave source to said paths, whereby currents in the path associated with said source branch to flow in the paths associated with said impedances; means connected to one of said paths for deriving signals proportional to the current in said source path; and means connected to the others of said paths for deriving signals proportional to the difference of currents in said impedance paths; said source including a sweep frequency microwave generator for supplying microwave signals varying in frequency over a certain band, and having means for varying the level of microwave power; and further comprising: means responsive to the difference between a reference signal and the proportional signals derived from said source path current for controlling said power varying means; and means for indicating the proportional signals derived from said current difference.

Claim 13

In a microwave measuring device the combination comprising a planar dielectric sheet; conductive means mounted on said sheet providing three coplanar current paths connected in a junction; means for respectively connecting different impedances and a microwave source to said current paths at terminals spaced from said junction; and means for deriving signals proportional to the current in one of said paths and the difference in currents in the others of said paths.

Claim 14

In a microwave measuring device the combination comprising a planar dielectric sheet; conductive means mounted on said sheet providing three coplanar current paths connected in a junction; means for respectively connecting different impedances and a microwave source to said current paths at terminals spaced from said junction; and means for deriving signals proportional to the current in one of said paths and the difference in currents in the others of said paths.

Claim 15

A microwave device as recited in claim 11, wherein said three current paths are mounted in a Y-junction configuration.

Claim 16

A microwave device as recited in claim 12, wherein said current paths have rotational and lateral symmetry.

Claim 17

A microwave device as recited in claim 11, and further comprising means for deriving a signal proportional to the ratio of said signals.

Claim 18

A microwave device as recited in claim 11, wherein said current paths include resistive portions.

Claim 19

A microwave device as recited in claim 15, wherein said means for deriving signals proportional to the current in said one path includes two detector means connected across the resistive portion of said one path, said detector means being symmetrically located on opposite sides of said one path.

Claim 20

A microwave device as recited in claim 11, and further comprising a pair of conductive members respectively mounted on and spaced from opposite faces of said sheet to form spaced ground planes for said current paths.

Claim 21

A microwave device as recited in claim 17, wherein said current paths are thin films forming strip-lines between said conductive members.

Claim 22

A microwave device as recited in claim 18, and further comprising means for varying the transmission line characteristics between said oTher paths and the associated diode whereby the symmetry of the connections of the associated diode can be adjusted.

Claim 23

A microwave device as recited in claim 17, wherein said signal deriving means includes separate diodes each connected with a conductive path thereof parallel to said planar sheet and other portions symmetrically located to be projecting above and below said sheet, whereby said diode path is transverse to the electric field to said ground planes and currents tend not to be induced therein by said field.