Quad-ridge waveguide mixer

A double-balanced waveguide mixer responsive to a receive signal and a local oscillator signal for generating an intermediate frequency signal equal to a product of the receive and local oscillator signals, said mixer comprising:

• a quad-ridge waveguide having four ridges protruding inwardly from the four sides thereof, wherein said quad-ridge waveguide includes two abutting sections one having a length matched to a quarter wavelength of the receive signal and the other having a length matched to a quarter wavelength of the local oscillator signal;
• a first matching section coupled to one end of said quad-ridge waveguide and aligned with two opposed ridges, wherein the receive signal is supplied to one pair of opposed ridges of said quad-ridge waveguide through a first rectangular waveguide and said first matching section, wherein said first matching section includes a rectangular waveguide having a height less than the height of said first rectangular waveguide, having a length that is matched to a quarter wavelength of the receive signal, and having an impedance intermediate to an impedence of said first rectangular waveguide and an impedence of said quad-ridge waveguide;
• a second matching section coupled to the other end of said quad-ridge waveguide and aligned with the other pair of opposed ridges, wherein the local oscillator signal is supplied to the other pair of opposed ridges of said quad-ridge waveguide through a second rectangular waveguide and said second matching section, wherein said second matching section includes a rectangular waveguide having a height less than the height of said second rectangular waveguide, having a length that is matched to a quarter wavelength of the local oscillator signal, and having an impedance intermediate to the impedance of said second rectangular waveguide and the impedance of said quad-ridge waveguide;
• two capacitors each coupled at one terminal thereof to a separate ridge of the pair of opposed ridges that carry the local oscillator signal;
• a diode ring coupled to said quad-ridge waveguide at the interface between the two abutting sections of said quad-ridge waveguide, wherein said diode ring includes four diodes interconnected as a ring with each diode coupled between two of four junctions of said ring and with each junction connecting the anode of one diode to the cathode of an adjacent diode, wherein two opposed junctions of said diode ring are electrically connected to a separate ridge of the pair of opposed ridges that carry the receive signal, and wherein each of the other two opposed junctions of said diode ring is electrically coupled through one of said capacitors to a separate ridge of the pair of opposed ridges that carry the local oscillator signal;
• and
• two transmission lines each coupled at one end thereof to a terminal of a separate capacitor and to a separate one of said opposed junctions of said diode ring, wherein both transmission lines are coupled at the other ends thereof to a center conductor of a coaxial transmission line, and wherein a shield of said coaxial transmission line is coupled to said quad-ridge waveguide.

A mixer responsive to a receive signal and a local oscillator signal for generating an intermediate frequency signal equal to a product of the receive and local oscillator signals, said mixer comprising:

• a quad-ridge waveguide having four ridges protruding inwardly from the walls thereof, wherein the receive signal and the local oscillator signal are conducted by said ridges;
• two capacitors each coupled at one terminal thereof to a separate ridge of a pair of opposed ridges;
• four interconnected diodes coupled between said ridges, wherein said diodes are coupled through said capacitors to said pair of opposed ridges;
• and
• means coupled to said diodes for providing the intermediate frequency signal.

A double-balanced mixer responsive to a receive signal and a local oscillator signal for generating an intermediate frequency signal equal to a lower sideband component of a product of the receive and local oscillator signals, said mixer comprising:

• a square quad-ridge waveguide each having four ridges protruding inwardly from the four sides thereof, wherein said quad-ridge waveguide includes two aligned sections extending in opposite directions from an active plane at the center of said quad-ridge waveguide, wherein a first section has a length matched to a quarter wavelength of the receive signal and a second section has a length matched to a quarter wavelength of the local oscillator signal, and wherein the receive signal is supplied at an end of said second section of said quad-ridge waveguide to a pair of opposed ridges and the local oscillator signal is supplied at an end of said first section of said quad-ridge waveguide to the other pair of opposed ridges;
• two capacitors each coupled at one terminal thereof to a separate ridge of a first pair of opposed ridges;
• a quad ring of Schottky diodes coupled to said quad-ridge waveguide at said active plane, wherein a first pair of opposed junctions of said diode ring is coupled through said capacitors to the first pair of opposed ridges, and wherein a second pair of opposed junctions of said diode ring is coupled to a second pair of opposed ridges;
• and
• filter means coupled to said diodes and said quad-ridge waveguide for separating the lower sideband of the intermediate frequency signal from the receive and local oscillator signals.

A mixer responsive to a transmit signal and a local oscillator signal for up-converting the transmit signal to an intermediate frequency signal equal to the product of the transmit and local oscillator signals, said mixer comprising:

• a quad-ridge waveguide having four ridges protruding inwardly from the walls thereof, wherein the local oscillator signal is supplied to one pair of opposed ridges and the intermediate frequency signal is available at the other pair of opposed ridges;
• two capacitors each coupled at one terminal thereof to a separate ridge of a first pair of opposed ridges;
• a diode ring including four diodes interconnected as a ring with each diode coupled between two of four junctions of said ring and with each junction connecting the anode of one diode to the cathode of an adjacent diode, wherein a first pair of opposed junctions of said diode ring is coupled through said capacitors to said first pair of opposed ridges, and wherein a second pair of opposed junctions of said diode ring is coupled to a second pair of opposed ridges;
• and
• means for supplying the transmit signal to said first pair of opposed junctions of said diode ring,