Abstract: A low frequency reject filter element is formed on a printed circuit board that utilizes the fact that power transmission in a waveguide is cut-off below a certain frequency. A quasi waveguide cavity is formed in printed circuit board using the top and bottom ground plane of the stripline circuit and using conductive via holes to form the side walls of the cavity. Waveguide cavity mode is launched from the input and output striplines by shorting them to ground. Transformers and matching via hole elements may be used to improve matching. The resulting filter is compact and is highly effective in suppressing low frequency transmissions.

Abstract: A low frequency reject filter element is formed on a printed circuit board that utilizes the fact that power transmission in a waveguide is cut-off below a certain frequency. A quasi waveguide cavity is formed in printed circuit board using the top and bottom ground plane of the stripline circuit and using conductive via holes to form the side walls of the cavity. Waveguide cavity mode is launched from the input and output striplines by shorting them to ground. Transformers and matching via hole elements may be used to improve matching. The resulting filter is compact and is highly effective in suppressing low frequency transmissions.

Abstract: A multi-layer circuit structure including a plurality of substrate layers. At least one planar transmission line, including microstrip, stripline, or coplanar line, disposed on the plurality of substrate layers. A via transmission line connected to that at least one planar transmission line and extending through the plurality of substrate layers. The via transmission lines having the same topology as the at least one planar transmission line for providing wide frequency band transition between the via transmission lines and the at least one planar transmission line.

Abstract: A multi-layer circuit structure including a plurality of substrate layers. At least one planar transmission line, including microstrip, stripline, or coplanar line, disposed on the plurality of substrate layers. A via transmission line connected to that at least one planar transmission line and extending through the plurality of substrate layers. The via transmission lines having the same topology as the at least one planar transmission line for providing wide frequency band transition between the via transmission lines and the at least one planar transmission line.

Abstract: A high gain antenna that produces a pencil beam along the ground and a lower gain antenna that produces a beam extending above the pencil beam are coupled to a source of r.f. pulses so that the amplitude of the r.f. pulses applied to the high gain antenna is less than the amplitude of the r.f. pulses applied to the lower gain antenna during airplane detection and the full amplitude of the r.f. pulses during a pulse segment is applied to the high gain antenna during wind pattern detection.

Abstract: The variable directional coupler of the subject invention employs 3, 4 or n branches in TEM transmission media, such as coax, stripline and microstrip. Precise control of the coupling is acheived by a variable susceptance connected near the mid-point of the crossover.

Abstract: A multiple-port loop-coupled commutating feed for a circular or cylindrical antenna array which is circumferentially scanned. A rotor assembly having a plurality of elongated coupling loops circumferentially spaced about an arc of its perimeter is fed from a stripline feed configuration excited at the driven central axis of the rotor. The rotor loops are formed by extension of printed circuit traces extant within the stripline feed about an arc of the rotor assembly. A plurality of elongated stator loops with essentially the same radial dimensions as the aforementioned rotor loops is provided, however the stator loops are distributed throughout the full 360.degree. of the circular perimeter of the device to continuously couple a changing fraction of the stator loops to the rotor as the latter is rotated. An output port is provided connected to each stator loop and these output ports may then be discretely connected to corresponding elements of a circular array or columns of elements of a cylindrical array.