Broadband waveguide to coaxial line transition

Claim 1

Apparatus for interconnecting a waveguide to a coaxial transmission line comprising, in combination, a rectangular waveguide section closed off at one end thereof by an end wall and adapted to be connected to said waveguide at the other end thereof, said section being formed by a first unitary member which serves as the bottom wall of said waveguide section and a second unitary member which serves as the other three walls and the end wall of said waveguide section; an impedance transformer integrally formed with said bottom wall, said transformer consisting of a staircase of attached steps with successive steps being progressively higher as said steps occur at nearer distances to said end wall and including a top step which has an overhanging tab with the rear vertical face thereof being parallel to and spaced a preselected distance from said end wall; a coaxial connector mounted on said end wall with the center pin thereof extending into the interior of said waveguide section and terminating at said rear vertical face of said overhanging tab, said center pin, said tab, the rear common face of the other steps and an adjacent surface portion of said bottom wall forming a magnetic field coupling loop and the space between the rear face of said tab and a confronting surface area of said end wall forming a capacitive susceptance for tuning purposes.