Patent ID: 6968609

Claim:
A method of manufacturing a nonreciprocal circuit device comprising a permanent magnet, a magnetic material, and a plurality of center conductors arranged on the magnetic material, wherein the permanent magnet, the magnetic material, and the center conductors are housed inside a metal case formed by bonding an upper metal case and a lower metal case at respective bonding surfaces thereof, said method comprising the steps of: forming a protruding portion on a bonding surface of one of the upper metal case and the lower metal case; disposing the upper metal case and the lower metal case so that the respective bonding surfaces including said protruding portion are brought into contact with each other; applying pressure to the upper metal case and the lower metal case by electrode terminals of a resistance welder; and applying welding current to said case via said electrode terminals so as to resistance-weld said respective bonding surfaces via said protruding portion; wherein said pressure is applied to the upper metal case and the lower metal case in a direction parallel to the bonding surfaces.