US Government as Represented by the Secretary of the Army

Morris Campi

Frederick G Farrar

Arthur R Sindoris

Daniel Shames

A microstrip array antenna, including spaced radiator elements supplied w microwave power and separated from an underlying ground reference plane by a layer of dielectric material, in which the antenna beam is phase scanned by periodically closing switching devices connected between the reference plane and at least one null point of each radiator element. In one embodiment, the radiator elements are identical rectangular patches disposed along a path, each patch having a length parallel to the path of one-half wavelength and a width transverse to the path not exceeding one wavelength in the underlying dielectric material at the antenna operating frequency. The patches are connected in series to receive microwave power by conductive strip elements whose widths are selected to effect a desired distribution of radiated microwave power from the patches.

Phase scanned microstrip array antenna

A variable microwave stripline power divider, in which the power seen at h of two outputs can be varied over a wide range without appreciably changing the power seen at the other output. In one embodiment, this is accomplished mechanically by shorting posts connecting the patch member to a ground plane member of the device at selected points. In another embodiment of the invention, this is accomplished electronically by a plurality of electronic switching devices connected between a like plurality of patch member shorting points and a ground plane member, which are selectively activated by a microcomputer.

Variable microwave stripline power divider

Two partial circular chips of metal oxide varistor (MOV) material are moud in a TO-5 transistor case. Each chip acts as a capacitive element to ground for a low pass pi-filter network. An inductance, whose value is chosen for the required filter impedance and cut off frequency, is placed across the MOV chips and connected to TO-5 contacts, along with the MOV, completing the filter network. At normal signal levels, the package acts as a normal low-pass pi-filter network. At higher signal levels and transients, the bipolar MOV components clamp the voltage to a given level, determined by the MOV material grain structure and chip thickness.

EMP circuit board filter using MOV devices

Two cylindrical sleeves of metal oxide varistor material (MOV) are used as apacitive elements of a low pass feedthrough pi-filter network. A metallic housing coaxially surrounds the MOV sleeves and provides electrical contact to ground. The inner surface of each sleeve is electrically connected to an inductor whose leads are terminated by feedthrough connectors on either side of the metal housing. The sleeve inner diameter is large enough to envelop the inductance thereby reducing the package length. The combined shunt capacitance and series inductance form the low pass pi-filter network. At normal signal levels, the package acts as a normal feedthrough low pass pi-filter network. At higher signal levels and transients, the bipolar MOV components clamp the voltage to a given level, determined by the MOV material grain structure and sleeve thickness.

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Silver Spring, MD, United States of America

Morris Campi