An Ultra-Wideband Fully-Planar Inverted-L Monopole (FILM) Array

A new ultra-wideband array is introduced, called the fully-planar inverted-L monopole (FILM) array. The proposed array is the first ever reported tightly coupled monopole array (TCMA). Our FILM array provides a unique solution to realize ultra-wideband tightly coupled apertures in the W and higher millimeter wave (mmWave) bands. The unit-cell architecture of the infinite FILM array is comprised of an inverted-L shaped monopole, and a capacitively coupled via-fence. This novel design eliminates the well-known broadside null from the radiation pattern of the traditional monopole element, and pushes both the common mode and loop mode resonances out of the band. To improve the impedance bandwidth and scanning ability, a dielectric-based superstrate is also used. The proposed array is extremely low profile with a maximum thickness of 0.4 lambda(H). Infinite array simulations of our array demonstrate a bandwidth of 3:1 (33 GHz to 101 GHz) with VSWR<3 for a maximum scan-angle of +/- 45 degrees for all principal E-, H- and D-planes.