Abstract: A light-emitting system is provided which is removably attachable to headgear for personal illumination to enhance visibility of the user to others. The light-emitting system includes a housing that defines a receiving aperture and is configured to surround a portion of the headgear when the light-emitting system is removably attached to the headgear for use. The light-emitting system further includes at least one lens and a plurality of lighting elements coupled to the annular housing which are configured to selectively generate a halo or at least a partial halo of light that radiates outwardly away from the annular housing through the at least one lens to provide enhanced personal illumination.

Abstract: A low-profile survivable antenna suitable for military use is described. pite its small size, which might be one tenth of a wavelength, the antenna has reasonable transmission range for these applications. Very little operator attention is needed in use, since a special matching circuit within the antenna network enables effective impedance matching, over a 3:1 frequency range, without necessity of switching to different matching circuits over different frequency bands. By including resistive components along with other passive inductive or capacitive elements, the reactance of the single matching circuit is made to effectively compensate the antenna's impedance over the entire frequency range. The impedance of the circuit has a decreasing positive reactance which compensates for the decreasing negative reactance, with frequency, of the antenna.

Abstract: A low-profile survivable antenna suitable for military use is described. pite its small size, which might be one tenth of a wavelength, the antenna has reasonable transmission range for these applications. Very little operator attention is needed in use, since a special matching circuit within the antenna network enables effective impedance matching, over a 3:1 frequency range, without necessity of switching to different matching circuits over different frequency bands. By including resistive components along with other passive inductive or capacitive elements, the reactance of the single matching circuit is made to effectively compensate the antenna's impedance over the entire frequency range. The impedance of the circuit has a decreasing positive reactance which compensates for the decreasing negative reactance, with frequency, of the antenna.

Abstract: A single antenna having hemispherical coverage with circular polarization very low axial ratio is disclosed. Its pancake structure comprises two stacked microstrip antennas, one atop the other, each fed phase shifted in relation to the other.Used as transmitter or receiver antenna, it replaces conventional hemispherical types with an extremely compact and relatively inexpensive device.

Abstract: A VHF monopole antenna unit, particularly adapted for operation in the 30 MHz frequency range, yet capable of embodiment in a compact structure only approximately 11/2 feet in height is described. Coarse tuning is accomplished in a number of switched bands, for each of which is provided a specially designed matching network comprised of inexpensive L-networks of inductors and capacitors. Tuning is accomplished through adjustment of inductor elements. The simple, inexpensive design of the matching circuits eliminates need for intricate mechanisms typically used for automatic impedance matching over a wide band and also for a broadband impedance matching transformer. The compactness made available by the unique top-load structure design is further made possible by provision of a specially designed dielectric filled vertical antenna element, accomplishing the same range and efficiency in an even more compact antenna.