Frequency converter

• US 4,608,713 A
• Filed: 08/29/1984
• Issued: 08/26/1986
• Est. Priority Date: 01/20/1983
• 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: Yoshimura, Yoshikazu, Shiomi, Yasufumi
• Primary Examiner(s): NG, JIN FAY
• Application Number:
  US06/642,350
• Time in Patent Office: 727 Days
• Field of Search: 455/325, 455/328, 455/327, 333/104, 333/135, 333/137, 333/208, 333/21 R, 333/26
• US Class Current: 455/325
• CPC Class Codes: H01Q 1/247 with frequency mixer, e.g. for direct satellite reception or Doppler radar
• CPC Class Codes: H03D 9/0641 located in a hollow waveguide

Abstract

A frequency converter is constituted by an unobstructed circular waveguide unit through one end of which received signals are fed thereto and conveying signals in the TE11 mode, a rectangular waveguide unit having a rectangular waveguide microstrip line converter unit in its output end and conveying signals in the TE10 mode, a circular-rectangular waveguide converter unit connecting the output end of the circular waveguide unit and the rectangular waveguide unit to convert the mode of transmission of signals from the TE11 mode in the circular waveguide unit to a principal transmission mode TE10 in the rectangular waveguide unit, and a microwave integrated circuit extending in the direction of and being on the H-wall side of the circular-rectangular waveguide converter unit and the rectangular waveguide unit and connected to the rectangular waveguide-microstrip line converter unit for processing the received signals and delivering the received signals as signals of an intermediate frequency. The diameter of the circular waveguide unit is such as to cause the cutoff frequency of the circular waveguide unit to be lower than the frequency of the received signal and higher than the local oscillation frequency for causing the circular waveguide unit to function as a high pass filter, and the axis of the rectangular waveguide unit is offset relative to that of the circular waveguide unit in the direction parallel to the shorter side of the rectangular waveguide unit and toward the wall along which the microwave integrated circuit is positioned.

Claims

1. A frequency converter comprising:

an unobstructed circular waveguide unit through one end of which received signals are fed thereto and conveying signals in the TE11 mode at an output end;

a rectangular waveguide unit having a rectangular waveguide-microstrip line converter unit in its output end and conveying signals in the TE10 mode;

a circular-rectangular waveguide converter unit connecting the output end of said circular waveguide unit and an input end of said rectangular waveguide unit to convert the mode of transmission of signals from the TE11 mode in the circular waveguide unit to a principal transmission mode TE10 in the rectangular waveguide unit; and

a microwave integrated circuit extending in the direction of and on the H-wall side of said circular-rectangular waveguide converter unit and said rectangular waveguide unit and connected to said rectangular waveguide-microstrip line converter unit for processing the received signals and delivering the received signals as signals of an intermediate frequency;

said circular waveguide unit having a diameter to provide a cutoff frequency of said circular waveguide unit to be lower than the frequency of the received signals and higher than a local oscillation frequency for causing said circular waveguide unit to function as a high pass filter, and the axis of said rectangular waveguide unit being offset relative to that of said circular waveguide unit in the direction parallel to the shorter side of said rectangular waveguide unit and toward the H-wall along which said microwave integrated circuit is positioned.

2. A frequency converter as claimed in claim 1 wherein said circular-rectangular waveguide converter unit comprises a first step converter having a characteristic impedance which is a high impedance and being for converting the TE11 mode of the circular waveguide to the principal transmission mode TE10 of the rectangular waveguide unit, and a second step converter for converting said transmission mode TE10 to another transmission mode TE10 of lower impedance.

3. A frequency converter as claimed in claim 1 wherein said circular-rectangular waveguide converter unit is a tapered waveguide which is at a predetermined angle with respect to the axis of said circular waveguide unit.

4. A frequency converter as claimed in claim 1 wherein said microwave integrated circuit comprises a shield case on which the integrated circuit is mounted, at least one of said circular-rectangular waveguide converter unit and said rectangular waveguide unit being at least partly defined by said shield case.