Abstract: A hermetically sealed housing (10) includes a dielectric end portion (118) which provides a transmission-line feedthrough between a printed-circuit such as HDI and exterior connections. A first transmission line (1) on the PC board (30) transitions to a 3-via transmission line (4), which transitions to a third coplanar, microstrip, or stripline transmission line (3). The third transmission line (3) transitions to a second 3-via transmission line (5), which ends at a coplanar transmission line (2) which is outside the housing.

Abstract: A broadband horn-like, linearly polarized antenna element is driven from a microstrip line and a balun. The horn is skeletonized, and has no sides, and consequently operates in TEM mode for broad frequency bandwidth. In another embodiment, two or more baluns feed the horn-like antenna element, thereby allowing a plurality of amplifiers or other sources to be combined at the antenna, for power summation or for multiplexing. An array of such elements, arranged for both vertical and horizontal polarization, makes a structure which presents mostly metallic surfaces, and is therefore rugged, and overpressure resistant.