Abstract: A miniature, multi-branch patch antenna suitable for operating in the 1 GHz to 100 GHz frequency range, a method for making same and a communication system using the same is disclosed. In one embodiment, the antenna comprises a planar dielectric substrate, a plurality of conducting antenna elements each having a feed port, a ground plane and a septum located between each conducting antenna element. In a second embodiment, the antenna comprises a planar dielectric substrate, a plurality of conducting antenna elements each having a feed port, a ground plane and a superstrate that is disposed on the plurality of conducting antenna elements and at least a portion of the dielectric substrate. The septum and the superstrate suppress undesirable coupling mechanisms. In a communication system according to the present invention, the miniature, multi-branch patch antenna is coupled to a transmitter and/or receiver.

Abstract: In an antenna having a conductor of a length L and a dielectric material with a dielectric constant .epsilon..sub.r1 contacting the conductor, a matching dielectric layer .epsilon..sub.r2 less than .epsilon..sub.r1 matches the dielectric constant to free space. Preferably .epsilon..sub.r2 =.sqroot..epsilon..sub.r1 , L=.lambda..sub.o /(2.sqroot..epsilon..sub.r1 ). The depth d of the second dielectric is a quarter wavelength in the matching layer. Multiple matching layers with successively decreasing dielectric constants forms embodiments. In one embodiment the resonant conductive arrangement is a microstrip patch antenna with the dielectric material supporting a patch and matching layer covering the dielectric material.

Abstract: A microstrip patch filter in which a dielectric has a ground plane printed on one of its faces and a conductive arrangement printed on the other of said faces, the conductive arrangement includes a flat patch, input and output leads electromagnetically coupled to the flat patch, the flat patch or the dielectric substrate has a reactance-enhancing metallic constriction located along a portion of the patch. When the constriction is in the patch it forms a current-concentrating inductive constriction. When the constriction is in the dielectric substrate, it enhances the capacitance. In an embodiment, the patch has two mutually-transverse constrictions that divide the patch into four sub-patches cross-connected by current-concentrating inductive constriction.

Abstract: A band-reject filter includes a three port circulator having an input port, a second port connected to a bandpass filter terminated in a matched load, and a third output port. The loss of the band-reject filter is enhanced by controlling the amplitude and phase of a feed-forward signal, passing between the input port and output port, relative to the amplitude and phase of a reflected signal from the matched load.

Abstract: A wireless electronic module includes a folded monopole antenna having an antenna port impedance which is reactive at the RF frequency of operation and which conjugately matches the reactive impedance of the electronic circuit which connects to the antenna port. A grounded shield is interposed between the antenna and the electronic circuit to reduce RF losses at the antenna.

Abstract: A Schottky barrier semiconductor device and process for making same is described wherein edge breakdown is avoided by making the rectifying contact in a curved depression in an epitaxial active layer having a nonuniform doping profile. The depression is formed by anodizing a portion of the epitaxial layer and etching the anodic oxide. Etching and electroplating of the contact are done in the same solution to avoid contamination of the metal-semiconductor interface.

Abstract: A new method of manufacturing semiconductor diodes is described in which the resulting diode chips have ohmic contacts on the four side surfaces of the diode chip. An insulating layer of a material such as silicon-dioxide is first formed on the epitaxial layer of a semiconductor wafer. Notches are then cut in a gridlike pattern into the semiconductor wafer on the side of the chip having the insulating layer. The notches extend approximately halfway into the semiconductor wafer and form a plurality of areas, each one of which has the dimensions of a desired diode chip. An ohmic contact is then established on the walls and bottoms of the notches by depositing a metallic layer and alloying this layer to the semiconductor material. A plurality of diodes are formed in holes in the insulating layer on each one of the areas representing an individual chip.

Abstract: A new method of semiconductor diode processing is described in which the resulting diode chips have an ohmic contact on four side faces of the chip. This is accomplished by cutting notches in the back side of a semiconductor slice before processing and by breaking the slice along the notches after fabricating the diodes on the front side of the slice. The new diode chip has a smaller series resistance than conventional millimeter-wave structures, and it can be readily bonded or soldered to millimeter-wave thin film circuits.

Abstract: In contact type photolithographic masking processes for fabricating planar structures, a photoresist is applied to a wafer and a mask is placed over the photoresist. Illumination through the mask, which has a pattern of opaque areas, produces a photochemical reaction in the photoresist which upon developing creates a duplicate of the mask pattern. However, the photoresist is conventionally applied by a spinning process and the rotation produces a build-up of the photoresist around the edges of the wafer. This build-up prevents the pattern portion of the mask from making good physical contact with the photoresist with a resultant decrease in reproducibility and accuracy of the fabricated pattern. A modified mask is formed with a channel corresponding to the peripheral build-up. The channel accepts the build-up so that good contact may be maintained between the photoresist and the patterned portion of the mask.

Abstract: Photolithographic techniques are employed to fabricate hemispherical or semicylindrical microlenses on the end surfaces of optical fibers. The power coupling efficiency between junction lasers and fibers is thereby significantly increased.