Patent ID: 7292837

Claim:
A mixer comprising: a balun including two balanced lines each having a first end that is short-circuited and a second end that defines a balanced terminal, and an unbalanced line having a first end that is free and a second end that defines an unbalanced terminal; a pair of mixer diodes connected to respective ones of the balanced terminals; an LO port connected to the unbalanced terminal; a high-pass filter; an RF port connected to a node between said mixer diodes through said high-pass filter; a low-pass filter; and an IF port connected to the node between said mixer diodes through said low-pass filter; wherein said balun, said pair of mixer diodes, said high-pass filter, and said low-pass filter are integrated into a multilayer substrate that includes a plurality of sheet layers stacked on each other; and the multilayer substrate has first external terminals that respectively define said LO port, said RF port, and said IF port at the bottom surfaces thereof, and has second external terminals that define a ground, at least one of the second external terminals being arranged between two of the first external terminals.