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

• US 4,679,249 A
• Filed: 02/14/1985
• Issued: 07/07/1987
• Est. Priority Date: 02/15/1984
• Status: Expired due to Fees

• Current Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Original Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Inventors: Shiomi, Yasuhumi, Tanaka, Toshihide, Yoshimura, Yoshikazu, Saka, Hiroshi
• Primary Examiner(s): LaRoche, Eugene R.
• Assistant Examiner(s): LEE, BENNY T
• Application Number:
  US06/701,912
• Time in Patent Office: 873 Days
• Field of Search: 333/26, 333/33-35, 333/21 R, 455/327, 455/328, 455/323, 455/325, 455/333, 455/293, 455/282, 455/281, 455/275
• US Class Current: 455/328
• CPC Class Codes: H01P 5/107 Hollow-waveguide/strip-line transitions
• CPC Class Codes: H03B 2200/0028 based on a monolithic microwave integrated circuit [MMIC]
• CPC Class Codes: H03B 5/1852 the semiconductor device being a field-effect device
• CPC Class Codes: H03B 5/1876 the semiconductor device being a field-effect device
• CPC Class Codes: H03D 7/02 by means of diodes H03D7/14 - H03D7/22 take precedence
• CPC Class Codes: H03D 9/0616 mounted in a hollow waveguide H03D9/0641 takes precedence
• CPC Class Codes: H03D 9/0633 mounted on a stripline circuit
• CPC Class Codes: H03D 9/0641 located in a hollow waveguide

Abstract

In a waveguide-to-microstrip line coupling arrangement, a microstrip line is placed on an outer surface of a wall of a waveguide which is coupled with the microstrip line via a metallic post connected at its one end to a center strip conductor of the microstrip line and is inserted inside the waveguide via through-holes made in a ground plane of the microstrip line and in the wall of the waveguide where the diameter of the through-hole made in the ground plane is made smaller than that of the through-hole made in the wall of the waveguide. The waveguide has a short-circuited end and the metallic post is placed close to the short-circuited end. The coupling arrangement may be used in a microwave frequency converter having an microwave integrated circuit including a local oscillator and a mixer, where the MIC is located on an outer surface of a longitudinal wall extending from a short-circuited end to an open end.

Claims

1. 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.

2. 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.

3. 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.

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

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

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

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

8. 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.

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

10. 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.

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

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

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