Wideband planar arrays with variable element sizes

The authors introduce new architectures that permit the operation of antenna arrays over several octaves. The concept is based on adding elements in between and of half the size of other elements in order to extend one octave in frequency. This wideband array with variable element size (WAVES) antennas was demonstrated by calculations and by measurements using Archimedian spirals as elements to maintain a simple clean main beam and principal plane sidelobes below about -10 dB over two octaves. Further measurements were performed on the test array in the lower frequency octave with all eight elements connected. Proper operation here relies on the fact that elements operating below their intended operating frequency have a high input impedance and would effectively not be active.<>