Shielded housing

#The invention relates to a shielded housing for use in various high frequency electromagnetic applications, e.g. a shielded housing for a strip line or microstrip transmission device, a waveguide or some other device with a housing which constitutes the RF ground. The housing is of the kind substantially consisting of an electrically conducting material and having a top wall, a bottom wall and two side walls serving as a ground plane, at least for RF frequencies, said housing comprising an upper part and a lower part being fitted together, and possibly further parts, such as end walls or the like.

#It is commonplace to form a housing of two parts, such as a unitary box-like lower part with bottom and side walls, and a top wall in the form of a lid. Sometimes the lid is fitted into a seat in the form of recesses in the upper portions of the side walls, or the lid is provided with a downwardly extending flange. In any case, it is often a problem to assemble the two parts in such a way that a good direct DC connection or a well-defined capacitive coupling is obtained between the two parts, without causing inter-modulation products or other disturbing effects. Conventional methods of joining the two parts are soldering or mechanically joining the two part by a plurality of fasteners, such as rivets or screws. These methods are generally cumbersome and expensive.

#The main object of the present invention is to provide a shielded housing which can be assembled easily and at low cost while securing a well-defined coupling between the two parts.

#FIG. 1 shows, in a perspective, explosive view, the basic parts of a housing according to the invention;

#FIG. 2 shows, likewise in a perspective view, the housing of FIG. 1 upon assembly,

#FIG. 3 shows a cross-section through the upper and lower housing parts having nominal measures, before assembly;

#In FIG. 1 there are shown upper and lower housing parts 10,20 and two end pieces 30,40, in the illustrated example serving as a housing for a device for adjusting the beam direction of a beam radiated from an antenna with an array of antenna elements coupled to the device, as explained in detail in the separate Swedish patent application entitled “Beam adjusting device” being filed simultaneously with the present application by the same applicant. The disclosure of the separate application is incorporated herein by reference.

#It should be understood that the housing may be of any kind being used in electromagnetic applications where it is important that the housing parts are joined to each other in a well-defined manner, in particular so as to avoid inter-modulation products or similar disturbances. Thus, the housing may serve as a housing for a transmission line (strip line or microstrip), a wave-guide, a resonating cavity or some other electromagnetic device.

#The housing parts 10 and 20 are formed by extrusion of a metal alloy, e.g. of aluminium, and the parts are subsequently coated with an insulating oxide layer in an electrolytic process. Therefore, in the illustrated example, these two parts will be coupled capacitively to each other upon assembly. Both parts 10,20 have side flanges along their longitudinal edges, the side flanges 12,13 and 22,23, respectively, being integrally joined to the respective top and bottom walls 11,21 at longitudinal edge portions 14,15 and 24,25 serving as resilient pivoting axes.