Waveguide-to-microstrip line coupling arrangement and a frequency converter having the coupling arrangement

Claim 2

A waveguide-to-microstrip line coupling arrangement comprising: (a) a waveguide having one end which is short-circuited; (b) a microstrip line having a ground plane, a dielectric substrate and a center strip conductor which are stacked in sequence, said center strip conductor having a semicircular end having a radius which corresponds to one half the width of said center strip conductor, said microstrip line being positioned on an outer surface of a wall of said waveguide such that said ground plane is in contact with said waveguide; (c) a metallic post having cylindrical portions, said post having one end adjacent to and connected to said center strip conductor, said metallic post extending from a center of a circle defined by said center conductor, said circle having a half portion which corresponds to said semicircular end of said center conductor, to the inside of said waveguide via circular through-holes made in said dielectric substrate, said ground plane, and said wall of said waveguide, said circular through-holes being coaxial with said metallic post, and the diameter of said circular through-holes made in said ground plane being made smaller than that of said circular through-holes made in said wall of said waveguide said cylindrical portions of, said metallic post including a largediameter portion interposed between first and second smalldiameter portions; and (d) an annular cylindrical dielectric member fitted in said circular through-hole of said wall of said waveguide such that said first small-diameter portion of said metallic post penetrates said annular cylindrical dielectric member and said annular cylindrical dielectric member is supported by one end surface of said large-diameter portion.

Claim 3

A waveguide-to-microstrip line coupling arrangement as claimed in claim 1, wherein the diameter of said through-hole made in said wall of said waveguide is made larger than the width of said center strip conductor of said microstrip line, and wherein the diameter of said through-hole made in said ground plane is made larger than the width of said center strip conductor.

Claim 4

A waveguide-to-microstrip line coupling arrangement as claimed in claim 1, wherein said microstrip line extends along said outer surface of said wall which extends from a short-circuited end to an open end of said waveguide.

Claim 5

A waveguide-to-microstrip line coupling arrangement as claimed in claim 1, wherein said waveguide is a cylindrical waveguide.

Claim 6

A waveguide-to-microstrip line coupling arrangement as recited in claim 1 wherein said dielectric substrate is comprised of Teflon glass fiber.

Claim 7

A waveguide-to-microstrip line coupling arrangement as recited in claim 5 wherein said annular cylindrical dielectric member is comprised of Teflon glass fiber.

Claim 8

A waveguide-to-microstrip line coupling arrangement as recited in claim 1 wherein said annular cylindrical dielectric member is comprised of Teflon glass fiber.

Claim 9

A microwave frequency converter comprising: (a) a waveguide having a pass band covering an RF signal frequency and a cutoff band covering a local oscillator signal frequency which is lower than that of said RF signal frequency, one end of said waveguide being short-circuited; (b) a microwave integrated circuit attached to an outer surface of a wall of said waveguide, said microwave integrated circuit having a microstrip line including a ground plane, a dielectric substrate and a center strip conductor which are stacked in sequence, said center strip conductor having a semicircular end whose radius corresponds to one half the width of said center strip conductor, said microstrip line extending along said outer surface of said wall, extending from the short-circuited end of said waveguide such than said ground plane, is in contact with said waveguide; (c) a metallic post having cylindrical portions, said post having one end adjacent to and connected to said center strip conductor, said metallic post extending from a center of a circle defined by said center conductor, said circle having a half portion which corresponds to said semicircular end of said center conductor, to the inside of said waveguide via circular through-holes made in said dielectric substrate, said ground plane, and said wall of said waveguide, said circular through-holes being coaxial with said metallic post, and the diameter of said circular through-hole made in said ground plane being made smaller than that of said circular through-hole made in said wall of said waveguide, said cylindrical portions of said metallic post including a large-diameter portion interposed between first and second small-diameter portions; (d) an annular cylindrical dielectric member fitted in said circular through-hole of said wall of said waveguide such that said first small-diameter portion of said metallic post penetrates said annular cylindrical dielectric member and said annular cylindrical dielectric member is supported by one end surface of said large-diameter portion; and (e) a local oscillator and a mixer both formed within said microwave integrated circuit for converting said RF signal from said waveguide into an IF signal.

Claim 10

A microwave frequency converter comprising: (a) a waveguide having a pass band covering an RF signal frequency and a cutoff band covering a local oscillator signal frequency which is lower than that of said RF signal frequency, one end of said waveguide being short-circuited; (b) a microwave integrated circuit attached to an outer surface of a wall of said waveguide, said microwave integrated circuit having a microstrip line including a ground plane, a dielectric substrate and a center strip conductor which are stacked in sequence, said center strip conductor having a semicircular end whose radius corresponds to one half the width of said center strip conductor, said microstrip line extending along said outer surface of said wall, extending from the short-circuited end of said waveguide such than said ground plane, is in contact with said waveguide; (c) a metallic post having cylindrical portions, said post having one end adjacent to and connected to said center strip conductor, said metallic post extending from a center of a circle defined by said center conductor, said circle having a half portion which corresponds to said semicircular end of said center conductor, to the inside of said waveguide via circular through-holes made in said dielectric substrate, said ground plane, and said wall of said waveguide, said circular through-holes being coaxial with said metallic post, and the diameter of said circular through-hole made in said ground plane being made smaller than that of said circular through-hole made in said wall of said waveguide, said cylindrical portions of said metallic post including a large-diameter portion interposed between first and second small-diameter portions; (d) an annular cylindrical dielectric member fitted in said circular through-hole of said wall of said waveguide such that said first small-diameter portion of said metallic post penetrates said annular cylindrical dielectric member and said annular cylindrical dielectric member is supported by one end surface of said large-diameter portion; and (e) a local oscillator and a mixer both formed within said microwave integrated circuit for converting said RF signal from said waveguide into an IF signal.

Claim 11

A microwave frequency converter as claimed in claim 8, wherein said waveguide is a cylindrical waveguide.

Claim 12

A microwave frequency converter as claimed in claim 9, further comprising, at a cylindrical waveguide input side, a cylindrical-to-rectangular waveguide adapter having an oblong waveguide and a substantially square waveguide, said oblong waveguide having an opening defined by a pair of parallel sides having equal length and a width greater than the height of an E-plane of said square waveguide, and symmetrical arcuate sides whose diameter is shorter than the length of a diagonal of said square waveguide and longer than the width of an H-plane of said square waveguide, the width of said square waveguide corresponding to said H-plane being substantially equal to the diameter of said cylindrical waveguide and the height of said square waveguide corresponding to said E-plane being substantially longer than the diameter of said cylindrical waveguide.

Claim 13

A microwave frequency converter as recited in claim 8 wherein said dielectric substrate is comprised of Teflon glass fiber.

Claim 14

A microwave frequency converter as recited in claim 11 wherein said annular cylindrical dielectric member is comprised of Teflon glass fiber.

Claim 15

A microwave frequency converter as recited in claim 8 wherein said annular cylindrical dielectric member is comprised of Teflon glass fiber.