High gain, frequency tunable variable impedance transmission line loaded antenna having shaped top plates

Abstract

There is disclosed a meanderline loaded antenna comprising a ground plane, a non-driven vertical element affixed thereto, a driven vertical element and a shaped top radiating element conductively connected between the driven and non-driven vertical elements. One or more segments or regions of the top plate are resonant depending on the input signal frequency. Since top plate presents several such segments or portions, several different resonant frequencies (a band of closely spaced resonant frequencies or multiple bands of disparate resonant frequencies) are presented to the antenna driving signal, thus allowing the antenna to resonate at several different frequencies and bands. In another embodiment, the antenna comprises a plurality of top radiating elements in parallel spaced relation or in a single plane, wherein each top radiating element is resonant at a different frequency, when considered with the effective lengths of the other antenna elements. Thus the plurality of top radiating plates accommodate multiple resonant frequencies and wideband operation. A plurality of such antennae can be used as elements to form an antenna array. The antenna functions similarly in a receive mode in accordance with the antenna reciprocity therein.