ATE449434T1 - MICRO STRIP CONDUCT WAVE CONDUCT JUNCTION FOR MILLIMETER BOARD FORMED IN A MULTILAYER CIRCUIT BOARD - Google Patents

Abstract

A microwave to waveguide transition is obtained in a multilayer structure comprising a 100 µm thick dielectric substrate (1) adherent to a rigid copper plate (15) 2 mm thick. The dielectric substrate is one of high-losses type suitable for PCB manufacturing techniques, such as Roger™ 4350. A metallic layout on the dielectric substrate includes a microstrip (2) terminating with a patch (3) acting as a probe inside the cavity of a rectangular waveguide WR15 (1.88 × 3.76 mm) operating in the EHF frequency range of 55-60 GHz (millimetric waves). The introduction of the probe inside the cavity (11) of the waveguide filled with air maintaining the continuity of the microstrip is a problem solved by properly working both the multilayer (1, 15) and the waveguide for a reciprocal penetration. More precisely, the multilayer is removed in correspondence of a window (5, 6) for the insertion of the waveguide (10), with the exception of a narrow central stripe (4) bearing the probe. Two opposite grooves (12, 13) are milled in the edge of the waveguide for the insertion of the stripe with the probe inside the cavity of the waveguide as far as the depth of the grooves allows it. A metallic lid (16) is screwed to the edge of the waveguide for reflecting back to the waveguide (10) the power radiated by the patch (3) in the opposite direction. The multilayer is fixed to the same metallic body which had been worked mechanically to obtain the waveguide. In order to prevent possible detachments of the thin dielectric substrate from the thick copper plate, a crown of metallized through holes is obtained around the edge of the waveguides emerging from the multilayer. The transition is part of a millimetric wave transceiver manufactured on a single multilayer accordingly to PCB, surface mount, and chip-on-board technologies (fig.5).