Abstract: A transformer for connection between a generator and a load may be formed by connecting n transmission lines together, in series at one end and in parallel at the other end. The transmission lines are configured to each have a characteristic impedance of {square root over (RG+L |ZL+L (f0+L |)}, where f0 is the frequency at which each transmission line is one quarter of a wavelength long (quarter-wavelength frequency), |ZL(f0)| is the magnitude of the load impedance at the quarter-wavelength frequency, and RG is the generator resistance. The transformer exhibits a frequency-dependent impedance transformation ratio, allowing a more efficient impedance match of a generator to a load having a frequency-dependent impedance, such as an antenna.

Abstract: A broadband antenna incorporating both electric and magnetic dipole radiators includes a tapered feed, such as a bow-tie feed, having a central feedpoint and first and second outer regions displaced from the central feedpoint. One or more conducting loop elements are connected between the outer regions of the tapered feed. Top loading capacitive elements extending from each of the outer regions may also be provided.

Abstract: An antenna structure may be formed by arranging a current-restricting structure upon a conductive surface. The current-restricting structure may be formed from a ferrite material, and may be in forms including a belt, tiles, or a patterned deposited layer. The conductive surface may be associated with a vehicle or structure. The current-restricting structure alters the paths taken by current on or beneath the conductive surface when a voltage is applied between portions of the surface.