Abstract: A hand-grip accessory includes a body having a deformably resilient cylindrical shape provided with open end portions and an axial bore formed therebetween. The body further has separable longitudinal edge portions adapting the body between expanded and equilibrium arrangements such that the apparatus can be nested about a dumbbell. The accessory further includes a mechanism for tethering the body to a user's wrist such that the apparatus can be maintained within a restricted spatial distance from the user during operating conditions. The tethering mechanism includes a lanyard having oppositely situated looped end portions securely coupled to the body and removably positional about the user's wrist respectively. One of the looped end portions has a fixed diameter while another of the looped end portions preferably includes a coupling slidably mated to the lanyard.

Abstract: Disclosed is an array antenna (10) that may be reconfigured to point in multiple directions. The array antenna includes a driven element (12) coupled to a transmission line (14) and a pair of passive elements (22) and (24). The passive elements (22) and (24) each include three antenna segments that are coupled together by a pair of optoelectronic switches (26) and (28), respectively. When the optoelectronic switches coupled to a particular passive element are closed the element functions as a reflector; when the switches are open, the element functions as a director. Other reconfigurable antennas are also disclosed, including antennas with reconfigurable gain and field pattern characteristics.

Abstract: Disclosed is a variable angle conical scanning antenna that employs an offset paraboloidal reflector which is rotated about an axis that extends through the focus of the paraboloid of revolution that defines the reflector. Electromagnetic energy is supplied to the reflector by an antenna feed that is mounted at the focus of the paraboloid of revolution and directed along the axis of rotation. In this arrangement the electromagnetic energy that is reflected from the offset paraboloidal reflector forms an angle between the axis of rotation and the beam of reflected electromagnetic energy that is equal to the angle between the axis of rotation and the focal axis of the paraboloid of revolution that defines the reflector. Thus, conical scanning at a cone angle that is equal to twice the angle between the axis of rotation and the reflected beam of electromagnetic energy is achieved as the offset paraboloidal reflector is rotated. Variable angle scanning (i.e.

Abstract: A monopulse spiral antenna system of the type having a minimum of three, interwound spiral arms for multimode, direction of arrival sensing, is disclosed in which the antenna arms are shaped and arranged in an overlapping configuration that allows the interarm impedance of the antenna to be adjusted, substantially independently of other electrical properties of the antenna, for matching of the antenna impedance of a mode forming network while preserving the broadband, directional capabilities of the antenna. Several different embodiments of the impedance adaptive antenna are disclosed including a preferred, eight-arm exponential spiral in which the arms are conductive strips transversely inclined relative to a plane formed by the spiral so that opposed and parallel surfaces of adjacent arm strips create a dominant interarm capacitance that in turn determines the overall input impedance of the antenna.

Abstract: Disclosed is a multiarm spiral antenna for wideband transmission and reception of both right-hand and left-hand circularly polarized electromagnetic energy. Each antenna arm includes a series of cells wherein the impedance of the antenna arm monotonically decreases over a first portion of the cell length and monotonically increases over a second portion of the cell length to thereby provide the signal reflection necessary for mode conversion (operation in both polarization senses) without introducing abrupt impedance transitions. Various cell geometry that can be employed is described.

Abstract: Spiral antennas are disclosed wherein each antenna arm includes one or more choke elements that resonate at predetermined operating frequencies to eliminate or minimize undesired radiation and reception characteristics. Multi-arm arrangements for broadband applications requiring sum and difference mode operation with both right-hand and left-hand circularly polarized radiation characteristics are attained by including a plurality of selectively positioned and dimensioned choke elements in each antenna arm. A variety of transmission line sections, suitable for use as choke elements in several types of spiral antennas, is described.