Abstract: A flush-mounted radiating antenna is disclosed which can be electronically switched to produce a rotating directional field with no moving parts in the antenna element itself or with the appropriate electronics in the entire mechanism. This is accomplished by utilizing pie-shaped sections on the flush surface which are capacitively coupled to a central feed element and shorting some of the pie-shaped capacitively coupled elements to a ground plane whereby the normally omnidirectional pattern is perturbed to a directional pattern.

Abstract: An inflatable antenna for use with a buoy at sea is disclosed. Webs in the inflatable compartment of the antenna have parts metallized to form the feed portions of the radiating elements. Areas of the top inner surface of the inflatable compartment are metallized to form capacitive loading portions of the radiating elements. Conductive inner and outer surfaces of the bottom of the inflatable compartment form a ground plane coupled to the sea water. When the elements of the antenna are fed in phase quadrature, the antenna provides hemispherical coverage including sufficient gain at the horizon.

Abstract: A collinear dual dipole antenna is split into two sections which are connected by a central conductor extending in spaced parallel relation within hollow support mast sections, and forming an effective transmission line providing RF continuity at a high band frequency f, and discontinuity at a low band frequency 1/2 f. The configuration provides a dual band antenna operating in either band from a single source without filtering and without modification of the antenna. In the high frequency band, the antenna operates as a dual dipole array. In the low frequency band, the antenna operates as a single dipole array with each mast section and its respective dipole acting as half of the single dipole array.

Abstract: An antenna system suitable for airborne use is disclosed. The system is of the type having a blade forming a folded monopole antenna with one terminal serving as a radio frequency input and a second terminal connectable to tuning apparatus. Tuning components switchable to various values are connected at the second terminal. A processor receives the value of a new frequency to be used, computes from stored reference values the values of tuning components calculated to render the antenna in tune at the selected frequency, and commands the switching of the tuning components to the calculated values. A phase discriminator at the first terminal provides the processor with an indication of the extent to which the antenna is in tune at the selected frequency. If it is not in tune, the processor iteratively commands the switching of the tuning components until new values are reached for which the antenna is in tune.

Abstract: Crossed dipole antenna apparatus configured so that the ends of adjacent dipoles are connected together to form a version of folded dipole antennas wherein there are slot antennas between adjacent dipole antennas. The combination slot and dipole antennas provide relatively broadband usable frequency range with acceptable radiation patterns.