Multiband whip antenna

摘要

A multi-band whip antenna having a 30 MHz to 2 GHz bandwidth and an L-band dipole has its coverage extended up to 6 GHz by eliminating nulls and reducing VSWR problems that are cured through the utilization of a sleeve over the feedpoint of the L-band antenna. Chokes in the form of sleeves are provided at either end of the L-band dipole to shorten the L-band antenna for preventing reverse polarity currents at the L-band antenna feedpoint, with the antenna further including the use of double shielded meanderlines to provide improved performance between 410-512 MHz and in which a capacitance sleeve is added at the bottom of the L-band antenna to effectively elongate the antenna below the L-band to permit operation below 700 MHz.

主权项

1. In a multi-band whip antenna including a dipole having a number of in-line tubular sections with a central pair of tubular sections having a gap to provide a feedpoint and further including a pair of tubular sections adjacent the central pair of tubular sections spaced therefrom to form gaps and pair of staggered single meanderlines serving as chokes across non-feedpoint gaps across tubular sections, and a coaxial line feed running through selected tubular sections to an L-band dipole atop said tubular sections, a method for increasing the bandwidth of the multi-band whip antenna up to 6 GHz, comprising the step of:
surrounding the feedpoint of the L-band antenna with a sleeve having a length corresponding to one half wavelength of a 5.0 GHz signal.